Radio receiver - Knowledge

3958: 2262:. Without an input filter the receiver can receive incoming RF signals at two different frequencies,. The receiver can be designed to receive on either of these two frequencies; if the receiver is designed to receive on one, any other radio station or radio noise on the other frequency may pass through and interfere with the desired signal. A single tunable RF filter stage rejects the image frequency; since these are relatively far from the desired frequency, a simple filter provides adequate rejection. Rejection of interfering signals much closer in frequency to the desired signal is handled by the multiple sharply-tuned stages of the intermediate frequency amplifiers, which do not need to change their tuning. This filter does not need great selectivity, but as the receiver is tuned to different frequencies it must "track" in tandem with the local oscillator. The RF filter also serves to limit the bandwidth applied to the RF amplifier, preventing it from being overloaded by strong out-of-band signals. 4999: 4666: 2724: 4433: 2266: 2097: 4871: 2909: 4606: 4417: 3530:. Marconi was able to obtain patents in the UK and France but the US version of his tuned four circuit patent, filed in November 1900, was initially rejected based on it being anticipated by Lodge's tuning system, and refiled versions were rejected because of the prior patents by Braun, and Lodge. A further clarification and re-submission was rejected because it infringed on parts of two prior patents Tesla had obtained for his wireless power transmission system. Marconi's lawyers managed to get a resubmitted patent reconsidered by another examiner who initially rejected it due to a pre-existing 3614: 1588: 3371: 2176: 2962: 4843:, invented in 1914 by Wilhelm Schloemilch and Otto von Bronk, and rediscovered and extended to multiple tubes in 1917 by Marius Latour and William H. Priess, was a design used in some inexpensive radios of the 1920s which enjoyed a resurgence in small portable tube radios of the 1930s and again in a few of the first transistor radios in the 1950s. It is another example of an ingenious circuit invented to get the most out of a limited number of active devices. In the reflex receiver the RF signal from the tuned circuit is passed through one or more amplifying tubes or transistors, 3383: 1619: 4404: 3560: 4396: 2502: 2521: 4908: 3702: 4254: 4231: 2737: 4461: 4789: 4777: 5114:(IC) chips in the 1970s created another revolution, allowing an entire radio receiver to be put on an IC chip. IC chips reversed the economics of radio design used with vacuum-tube receivers. Since the marginal cost of adding additional amplifying devices (transistors) to the chip was essentially zero, the size and cost of the receiver was dependent not on how many active components were used, but on the passive components; inductors and capacitors, which could not be integrated easily on the chip. The development of RF 4832: 4899: 1946: 3679:. It required a long wire antenna, and its sensitivity depended on how large the antenna was. During the wireless era it was used in commercial and military longwave stations with huge antennas to receive long distance radiotelegraphy traffic, even including transatlantic traffic. However, when used to receive broadcast stations a typical home crystal set had a more limited range of about 25 miles. In sophisticated crystal radios the "loose coupler" inductively coupled tuned circuit was used to increase the 3769: 43: 4245: 3572: 5073: 1938: 1356: 31: 2783: 4686: 1457: 4041:. By the 1930s, the broadcast receiver had become a piece of furniture, housed in an attractive wooden case, with standardized controls anyone could use, which occupied a respected place in the home living room. In the early radios the multiple tuned circuits required multiple knobs to be adjusted to tune in a new station. One of the most important ease-of-use innovations was "single knob tuning", achieved by linking the tuning capacitors together mechanically. The 458: 2771: 3950: 3125: 3009: 10655: 3060: 1821: 2398:. In an AM receiver, the amplitude of the audio signal from the detector, and the sound volume, is proportional to the amplitude of the radio signal, so fading causes variations in the volume. In addition as the receiver is tuned between strong and weak stations, the volume of the sound from the speaker would vary drastically. Without an automatic system to handle it, in an AM receiver, constant adjustment of the volume control would be required. 4654: 3584: 1753: 10665: 63: 3247:. Use of tuning in free space "Hertzian waves" (radio) was explained and demonstrated in Oliver Lodge's 1894 lectures on Hertz's work. At the time Lodge was demonstrating the physics and optical qualities of radio waves instead of attempting to build a communication system but he would go on to develop methods (patented in 1897) of tuning radio (what he called "syntony"), including using variable inductance to tune antennas. 4942:, is the design used in almost all modern receivers, except a few specialized applications. It is a more complicated design than the other receivers above, and when it was invented required 6 - 9 vacuum tubes, putting it beyond the budget of most consumers, so it was initially used mainly in commercial and military communication stations. However, by the 1930s the "superhet" had replaced all the other receiver types above. 10644: 893: 1219:- a device that transmits a narrow beam of microwaves which reflect from a target back to a receiver, used to locate objects such as aircraft, spacecraft, missiles, ships or land vehicles. The reflected waves from the target are received by a receiver usually connected to the same antenna, indicating the direction to the target. Widely used in aviation, shipping, navigation, weather forecasting, space flight, vehicle 4178: 3602: 3120:. The radio signal was applied between the cathode and anode. When the anode was positive, a current of electrons flowed from the cathode to the anode, but when the anode was negative the electrons were repelled and no current flowed. The Fleming valve was used to a limited extent but was not popular because it was expensive, had limited filament life, and was not as sensitive as electrolytic or crystal detectors. 1484:(tuned circuits). The resonant circuit is connected between the antenna input and ground. When the incoming radio signal is at the resonant frequency, the resonant circuit has high impedance and the radio signal from the desired station is passed on to the following stages of the receiver. At all other frequencies the resonant circuit has low impedance, so signals at these frequencies are conducted to ground. 1239:- the most widely used electronic navigation device. An automated digital receiver that receives simultaneous data signals from several satellites in low Earth orbit. Using extremely precise time signals it calculates the distance to the satellites, and from this the receiver's location on Earth. GNSS receivers are sold as portable devices, and are also incorporated in cell phones, vehicles and weapons, even 10675: 918: 987: 3358: 3662:, conducting in only one direction. Only particular sites on the crystal surface worked as detector junctions, and the junction could be disrupted by the slightest vibration. So a usable site was found by trial and error before each use; the operator would drag the cat's whisker across the crystal until the radio began functioning. Frederick Seitz, a later semiconductor researcher, wrote: 2292:

provide much of the receiver gain at lower frequencies which may be easier to manage. Tuning is simplified compared to a multi-stage TRF design, and only two stages need to track over the tuning range. The total amplification of the receiver is divided between three amplifiers at different frequencies; the RF, IF, and audio amplifier. This reduces problems with feedback and

2529: 4556:, in which a "tickler" coil in the plate circuit was coupled to the tuning coil in the grid circuit, to provide the feedback. The feedback was controlled by a variable resistor, or alternately by moving the two windings physically closer together to increase loop gain, or apart to reduce it. This was done by an adjustable air core transformer called a 371:, sports commentaries, and image slideshows. Its disadvantage is that it is incompatible with previous radios so that a new DAB receiver must be purchased. As of 2017, 38 countries offer DAB, with 2,100 stations serving listening areas containing 420 million people. The United States and Canada have chosen not to implement DAB. 5031:-sized tube radios like the Emerson 560, that featured molded plastic cases. So-called "pocket portable" radios like the RCA BP10 had existed since the 1940s, but their actual size was compatible with only the largest of coat pockets. But some, like the Privat-ear and Dyna-mite pocket radios, were small enough to fit a pocket. 4722:

they could be adjusted with one knob, but in early receivers the frequencies of the tuned circuits could not be made to "track" well enough to allow this, and each tuned circuit had its own tuning knob. Therefore, the knobs had to be turned simultaneously. For this reason most TRF sets had no more than three tuned RF stages.

4809:, was a TRF receiver with a "neutralizing" circuit added to each radio amplification stage to cancel the feedback to prevent the oscillations which caused the annoying whistles in the TRF. In the neutralizing circuit a capacitor fed a feedback current from the plate circuit to the grid circuit which was 180° 551:. Portable radios typically are small enough to be hand held, or, for larger radios, have a handle or carrying strap. Portable radios may have an arrangement for powering from an outlet, conserving the batteries when an outlet is available. Portable "emergency" radios may be solar and/or hand crank powered. 4591:), howls and whistles. Early regeneratives which oscillated easily were called "bloopers". One preventive measure was to use a stage of RF amplification before the regenerative detector, to isolate it from the antenna. But by the mid-1920s "regens" were no longer sold by the major radio manufacturers. 5219:

A full-featured radio control program allows for scanning and a host of other functions and, in particular, integration of databases in real-time, like a "TV-Guide" type capability. This is particularly helpful in locating all transmissions on all frequencies of a particular broadcaster, at any given

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permits signal processing techniques that would be cumbersome, costly, or otherwise infeasible with analog methods. A digital signal is essentially a stream or sequence of numbers that relay a message through some sort of medium such as a wire. DSP hardware can tailor the bandwidth of the receiver to

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tuning patent, but it was finally approved it in June 1904 based on it having a unique system of variable inductance tuning that was different from Stone who tuned by varying the length of the antenna. When Lodge's Syntonic patent was extended in 1911 for another 7 years the Marconi Company agreed to

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When more than one spark transmitter was radiating in a given area, their frequencies overlapped, so their signals interfered with each other, resulting in garbled reception. Some method was needed to allow the receiver to select which transmitter's signal to receive. Multiple wavelengths produced by

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Receivers usually have several stages of amplification: the radio signal from the bandpass filter is amplified to make it powerful enough to drive the demodulator, then the audio signal from the demodulator is amplified to make it powerful enough to operate the speaker. The degree of amplification of

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which follow the contour of the Earth, so AM radio stations can be reliably received at hundreds of miles distance. Due to their higher frequency, FM band radio signals cannot travel far beyond the visual horizon; limiting reception distance to about 40 miles (64 km), and can be blocked by hills

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Companies first began manufacturing radios advertised as portables shortly after the start of commercial broadcasting in the early 1920s. The vast majority of tube radios of the era used batteries and could be set up and operated anywhere, but most did not have features designed for portability such

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Today the TRF design is used in a few integrated (IC) receiver chips. From the standpoint of modern receivers the disadvantage of the TRF is that the gain and bandwidth of the tuned RF stages are not constant but vary as the receiver is tuned to different frequencies. Since the bandwidth of a filter

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Although it was invented in 1904 in the wireless telegraphy era, the crystal radio receiver could also rectify AM transmissions and served as a bridge to the broadcast era. In addition to being the main type used in commercial stations during the wireless telegraphy era, it was the first receiver to

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of the receiver was equal to the broad bandwidth of the antenna. This was acceptable and even necessary because the first Hertzian spark transmitters also lacked a tuned circuit. Due to the impulsive nature of the spark, the energy of the radio waves was spread over a very wide band of frequencies.

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to select the desired signal out of all the signals picked up by the antenna. Either the capacitor or coil was adjustable to tune the receiver to the frequency of different transmitters. The earliest receivers, before 1897, did not have tuned circuits, they responded to all radio signals picked up

4967:", because it only used five vacuum tubes: usually a converter (mixer/local oscillator), an IF amplifier, a detector/audio amplifier, audio power amplifier, and a rectifier. This design was used for virtually all commercial radio receivers until the transistor replaced the vacuum tube in the 1970s. 4721:

A major problem of early TRF receivers was that they were complicated to tune, because each resonant circuit had to be adjusted to the frequency of the station before the radio would work. In later TRF receivers the tuning capacitors were linked together mechanically ("ganged") on a common shaft so

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of the feedback loop was less than one, so the tube (or other amplifying device) did not oscillate but was close to oscillation, giving large gain. In the superregenerative receiver, the loop gain was made equal to one, so the amplifying device actually began to oscillate, but the oscillations were

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superheterodyne. The incoming RF signal is first mixed with one local oscillator signal in the first mixer to convert it to a high IF frequency, to allow efficient filtering out of the image frequency, then this first IF is mixed with a second local oscillator signal in a second mixer to convert it

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The receiver is easy to tune; to receive a different frequency it is only necessary to change the local oscillator frequency. The stages of the receiver after the mixer operates at the fixed intermediate frequency (IF) so the IF bandpass filter does not have to be adjusted to different frequencies.

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in the late 1950s. Although portable vacuum tube radios were made, tubes were bulky and inefficient, consuming large amounts of power and requiring several large batteries to produce the filament and plate voltage. Transistors did not require a heated filament, reducing power consumption, and were

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Vacuum tubes were bulky, expensive, had a limited lifetime, consumed a large amount of power and produced a lot of waste heat, so the number of tubes a receiver could economically have was a limiting factor. Therefore, a goal of tube receiver design was to get the most performance out of a limited

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requires that radio channels be spaced very close together in frequency. It is extremely difficult to build filters operating at radio frequencies that have a narrow enough bandwidth to separate closely spaced radio stations. TRF receivers typically must have many cascaded tuning stages to achieve

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The power of the radio waves picked up by a receiving antenna decreases with the square of its distance from the transmitting antenna. Even with the powerful transmitters used in radio broadcasting stations, if the receiver is more than a few miles from the transmitter the power intercepted by the

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increased the market for radio receivers greatly, and transformed them into a consumer product. At the beginning of the 1920s the radio receiver was a forbidding high-tech device, with many cryptic knobs and controls requiring technical skill to operate, housed in an unattractive black metal box,

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between the coils. When the operator encountered an interfering signal at a nearby frequency, the secondary could be slid further out of the primary, reducing the coupling, which narrowed the bandwidth, rejecting the interfering signal. A disadvantage was that all three adjustments in the loose

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Although the TRF receiver is used in a few applications, it has practical disadvantages which make it inferior to the superheterodyne receiver below, which is used in most applications. The drawbacks stem from the fact that in the TRF the filtering, amplification, and demodulation are done at the

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The amplifying vacuum tube used energy from a battery or electrical outlet to increase the power of the radio signal, so vacuum tube receivers could be more sensitive and have a greater reception range than the previous unamplified receivers. The increased audio output power also allowed them to

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ruling on the Marconi Company's ability to sue the US government over patent infringement during World War I. The Court rejected the Marconi Company's suit saying they could not sue for patent infringement when their own patents did not seem to have priority over the patents of Lodge, Stone, and

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and used by the Marconi Co. until it adopted the Audion vacuum tube around 1912, this was a mechanical device consisting of an endless band of iron wires which passed between two pulleys turned by a windup mechanism. The iron wires passed through a coil of fine wire attached to the antenna, in a

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At the cost of the extra stages, the superheterodyne receiver provides the advantage of greater selectivity than can be achieved with a TRF design. Where very high frequencies are in use, only the initial stage of the receiver needs to operate at the highest frequencies; the remaining stages can

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front-end to supply an intermediate frequency to the software defined radio. These systems can provide additional capability over "hardware" receivers. For example, they can record large swaths of the radio spectrum to a hard drive for "playback" at a later date. The same SDR that one minute is

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realized that the residual gas was not necessary; the Audion could operate on electron conduction alone. They evacuated tubes to a lower pressure of 10 atm, producing the first "hard vacuum" triodes. These more stable tubes did not require bias adjustments, so radios had fewer controls and were

3207:"Tuning" means adjusting the frequency of the receiver to the frequency of the desired radio transmission. The first receivers had no tuned circuit, the detector was connected directly between the antenna and ground. Due to the lack of any frequency selective components besides the antenna, the 3887:

range, so it was audible as a tone in the earphone whenever the carrier was present. Thus the "dots" and "dashes" of Morse code were audible as musical "beeps". A major attraction of this method during this pre-amplification period was that the heterodyne receiver actually amplified the signal

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though the same amplifier stages for audio amplification. The separate radio and audio signals present simultaneously in the amplifier do not interfere with each other since they are at different frequencies, allowing the amplifying tubes to do "double duty". In addition to single tube reflex

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by stepping through the channels repeatedly, listening briefly to each channel for a transmission. When a transmitter is found the receiver stops at that channel. Scanners are used to monitor emergency police, fire, and ambulance frequencies, as well as other two way radio frequencies such as

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With other types of modulation like FM or FSK the amplitude of the modulation does not vary with the radio signal strength, but in all types the demodulator requires a certain range of signal amplitude to operate properly. Insufficient signal amplitude will cause an increase of noise in the

3526:" at both the transmitters and receivers. His 1900 British #7,777 (four sevens) patent for tuning filed in April 1900 and granted a year later opened the door to patents disputes since it infringed on the Syntonic patents of Oliver Lodge, first filed in May 1897, as well as patents filed by 2486:

to detect them. These primitive devices are more accurately described as radio wave sensors, not "receivers", as they could only detect radio waves within about 100 feet of the transmitter, and were not used for communication but instead as laboratory instruments in scientific experiments.

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To give enough output power to drive a loudspeaker, 2 or 3 additional vacuum tube stages were needed for audio amplification. Many early hobbyists could only afford a single tube receiver, and listened to the radio with earphones, so early tube amplifiers and speakers were sold as add-ons.

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of residual air was key to Audion operation. This made it a more sensitive detector but also caused its electrical characteristics to vary during use. As the tube heated up, gas released from the metal elements would change the pressure in the tube, changing the plate current and other

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were also experimenting with similar radio wave receiving apparatus at the same time in 1894–5, but they are not known to have transmitted Morse code during this period, just strings of random pulses. Therefore, Marconi is usually given credit for building the first radio receivers.

5205:"PC radios", or radios that are designed to be controlled by a standard PC are controlled by specialized PC software using a serial port connected to the radio. A "PC radio" may not have a front-panel at all, and may be designed exclusively for computer control, which reduces cost. 4262:

Example of single tube triode grid-leak receiver from 1920, the first type of amplifying radio receiver. In the grid leak circuit, electrons attracted to the grid during the positive half cycles of the radio signal charge the grid capacitor with a negative voltage of a few volts,

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transmitters which transmitted on a narrow band of frequencies, and broadcasting led to a proliferation of closely spaced radio stations crowding the radio spectrum. Resonant transformers continued to be used as the bandpass filter in vacuum tube radios, and new forms such as the

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which induced a current in the secondary coil which fed the detector. Both primary and secondary were tuned circuits; the primary coil resonated with the capacitance of the antenna, while the secondary coil resonated with the capacitor across it. Both were adjusted to the same

2307:, the band of frequencies it accepts. In order to reject nearby interfering stations or noise, a narrow bandwidth is required. In all known filtering techniques, the bandwidth of the filter increases in proportion with the frequency, so by performing the filtering at the lower 2868:

he could transmit longer distances, beyond the curve of the Earth, demonstrating that radio was not just a laboratory curiosity but a commercially viable communication method. This culminated in his historic transatlantic wireless transmission on December 12, 1901, from

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was important to achieve maximum receiving range in the unamplified receivers of this era. The coils usually had taps which could be selected by a multiposition switch. The second advantage was that due to "loose coupling" it had a much narrower bandwidth than a simple

2672:. Each string of damped waves constituting a Morse "dot" or "dash" caused the needle to swing over, creating a displacement of the line, which could be read off the tape. With such an automated receiver a radio operator did not have to continuously monitor the receiver. 998:- this is a cribside appliance for parents of infants that transmits the baby's sounds to a receiver carried by the parents, so they can monitor the baby while they are in other parts of the house. Many baby monitors now have video cameras to show a picture of the baby. 5232:

to the radio has considerable flexibility, new features can be added by the software designer. Features that can be found in advanced control software programs today include a band table, GUI controls corresponding to traditional radio controls, local time clock and a

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or RF transformer). The antenna and ground were connected to a coil of wire, which was magnetically coupled to a second coil with a capacitor across it, which was connected to the detector. The RF alternating current from the antenna through the primary coil created a

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The signal from the spark gap transmitter consisted of damped waves repeated at an audio frequency rate, from 120 to perhaps 4000 per second, so in the earphone the signal sounded like a musical tone or buzz, and the Morse code "dots" and "dashes" sounded like beeps.

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Therefore, the first radio receivers did not have to extract an audio signal from the radio wave like modern receivers, but just detected the presence of the radio signal, and produced a sound during the "dots" and "dashes". The device which did this was called a

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modem - a very short range (up to 10 m) 2.4-2.83 GHz data transceiver on a portable wireless device used as a substitute for a wire or cable connection, mainly to exchange files between portable devices and connect cellphones and music players with wireless

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of radio waves decreases the farther they travel from the transmitter, so a radio station can only be received within a limited range of its transmitter. The range depends on the power of the transmitter, the sensitivity of the receiver, atmospheric and internal

2025:(size) of the waves. If it was applied directly to the speaker, this signal cannot be converted to sound, because the audio excursions are the same on both sides of the axis, averaging out to zero, which would result in no net motion of the speaker's diaphragm. 374:

DAB radio stations work differently from AM or FM stations: a single DAB station transmits a wide 1,500 kHz bandwidth signal that carries from 9 to 12 channels from which the listener can choose. Broadcasters can transmit a channel at a range of different

3631:) instead of radiotelegraphy, radio listening became a popular hobby, and the crystal was the simplest, cheapest detector. The millions of people who purchased or homemade these inexpensive reliable receivers created the mass listening audience for the first 2817:. When a radio frequency voltage was applied to the electrodes, its resistance dropped and it conducted electricity. In the receiver the coherer was connected directly between the antenna and ground. In addition to the antenna, the coherer was connected in a 4143:

is one of the most important figures in radio receiver history, and during this period invented technology which continues to dominate radio communication. He was the first to give a correct explanation of how De Forest's triode tube worked. He invented the

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in 1913 when he was a 23-year-old college student, was used very widely until the late 1920s particularly by hobbyists who could only afford a single-tube radio. Today transistor versions of the circuit are still used in a few inexpensive applications like

2833:. In order to restore the coherer to its previous nonconducting state to receive the next pulse of radio waves, it had to be tapped mechanically to disturb the metal particles. This was done by a "decoherer", a clapper which struck the tube, operated by an 5007:

as handles and built in speakers. Some of the earliest portable tube radios were the Winn "Portable Wireless Set No. 149" that appeared in 1920 and the Grebe Model KT-1 that followed a year later. Crystal sets such as the Westinghouse Aeriola Jr. and the

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of the iron induced a pulse of current in a sensor coil each time a radio signal passed through the exciting coil. The magnetic detector was used on shipboard receivers due to its insensitivity to vibration. One was part of the wireless station of the

3228:(tuned circuit), and could receive a particular transmission by "tuning" its resonant circuit to the same frequency as the transmitter, analogously to tuning a musical instrument to resonance with another. This is the system used in all modern radio. 3500:

were invented. Another advantage of the double-tuned transformer for AM reception was that when properly adjusted it had a "flat top" frequency response curve as opposed to the "peaked" response of a single tuned circuit. This allowed it to pass the

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with little distortion, unlike a single tuned circuit which attenuated the higher audio frequencies. Until recently the bandpass filters in the superheterodyne circuit used in all modern receivers were made with resonant transformers, called

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receivers, some TRF and superheterodyne receivers had several stages "reflexed". Reflex radios were prone to a defect called "play-through" which meant that the volume of audio did not go to zero when the volume control was turned down.

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high frequency of the incoming radio signal. The bandwidth of a filter increases with its center frequency, so as the TRF receiver is tuned to different frequencies its bandwidth varies. Most important, the increasing congestion of the

4021:, permitting more than one person to listen. The first loudspeakers were produced around 1915. These changes caused radio listening to evolve explosively from a solitary hobby to a popular social and family pastime. The development of 5167:

current reception conditions and to the type of signal. A typical analog only receiver may have a limited number of fixed bandwidths, or only one, but a DSP receiver may have 40 or more individually selectable filters. DSP is used in

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Such variability, bordering on what seemed the mystical, plagued the early history of crystal detectors and caused many of the vacuum tube experts of a later generation to regard the art of crystal rectification as being close to

5141:(DSP) on the chip. Another benefit of DSP is that the properties of the receiver; channel frequency, bandwidth, gain, etc. can be dynamically changed by software to react to changes in the environment; these systems are known as 5046:, made by the Regency Division of I.D.E.A. (Industrial Development Engineering Associates) of Indianapolis, Indiana, was launched in 1951. The era of true, shirt-pocket sized portable radios followed, with manufacturers such as 4234:

De Forest's first commercial Audion receiver, the RJ6 which came out in 1914. The Audion tube was always mounted upside down, with its delicate filament loop hanging down, so it did not sag and touch the other electrodes in the

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repeating at an audio rate, so the "dots" and "dashes" of Morse code were audible as a tone or buzz in the receivers' earphones. However the new continuous wave radiotelegraph signals simply consisted of pulses of unmodulated

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conditions along the path of the radio waves. The strength of the signal received from a given transmitter varies with time due to changing propagation conditions of the path through which the radio wave passes, such as

1042:- a long-distance high bandwidth point-to-point data transmission link consisting of a dish antenna and transmitter that transmits a beam of microwaves to another dish antenna and receiver. Since the antennas must be in 5224:

to the shortwave databases, so it is possible to "fly" to a given transmitter site location with a click of a mouse. In many cases the user is able to see the transmitting antennas where the signal is originating from.

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line of portable radios were designed to provide entertainment broadcasts as well as being able to tune into weather, marine and international shortwave stations. By the 1950s, a "golden age" of tube portables included

3112:. Fleming, a consultant to Marconi, invented the valve as a more sensitive detector for transatlantic wireless reception. The filament was heated by a separate current through it and emitted electrons into the tube by 4582:

oscillate), and the resulting radio signal was radiated by its wire antenna. In nearby receivers, the regenerative's signal would beat with the signal of the station being received in the detector, creating annoying

2112:, the three functions above are performed consecutively: (1) the mix of radio signals from the antenna is filtered to extract the signal of the desired transmitter; (2) this oscillating voltage is sent through a 4529:

Another advantage of the circuit was that the tube could be made to oscillate, and thus a single tube could serve as both a beat frequency oscillator and a detector, functioning as a heterodyne receiver to make

2896:), such as nearby lights being switched on or off, as well as to the intended signal. Due to the cumbersome mechanical "tapping back" mechanism it was limited to a data rate of about 12-15 words per minute of 2729:

One of Marconi's first coherer receivers, used in his "black box" demonstration at Toynbee Hall, London, 1896. The coherer is at right, with the "tapper" just behind it, The relay is at left, batteries are in

3965:" (1920 to 1950), families gathered to listen to the home radio in the evening, such as this Zenith console model 12-S-568 from 1938, a 12-tube superheterodyne with pushbutton tuning and 12-inch cone speaker. 3034:. The electrolytic action caused current to be conducted in only one direction. The detector was used until about 1910. Electrolytic detectors that Fessenden had installed on US Navy ships received the first 2361:, a narrower bandwidth can be achieved. Modern FM and television broadcasting, cellphones and other communications services, with their narrow channel widths, would be impossible without the superheterodyne. 4617:

in 1922 which used regeneration in a more sophisticated way, to give greater gain. It was used in a few shortwave receivers in the 1930s, and is used today in a few cheap high frequency applications such as

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Radio waves from many transmitters pass through the air simultaneously without interfering with each other and are received by the antenna. These can be separated in the receiver because they have different

1733: 2877:, a distance of 3500 km (2200 miles), which was received by a coherer. However the usual range of coherer receivers even with the powerful transmitters of this era was limited to a few hundred miles. 3728:

The continuous wave radiotelegraphy signals produced by these transmitters required a different method of reception. The radiotelegraphy signals produced by spark gap transmitters consisted of strings of

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to smooth the variations and produce an average level. This is applied as a control signal to an earlier amplifier stage, to control its gain. In a superheterodyne receiver, AGC is usually applied to the

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voice channel, as well as a control channel that handles dialing calls and switching the phone between cell towers. They usually also have several other receivers that connect them with other networks: a

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civilian radio use was prohibited, but by 1920 large-scale production of vacuum tube radios began. The "soft" incompletely evacuated tubes were used as detectors through the 1920s then became obsolete.

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The coherer is an obscure antique device, and even today there is some uncertainty about the exact physical mechanism by which the various types worked. However it can be seen that it was essentially a

3431:, allowing only a narrow band of frequencies through. The form of bandpass filter that was used in the first receivers, which has continued to be used in receivers until recently, was the double-tuned 3635:, which began around 1920. By the late 1920s the crystal receiver was superseded by vacuum tube receivers and became commercially obsolete. However it continued to be used by youth and the poor until 359:

as AM and FM do. Its advantages are that DAB has the potential to provide higher quality sound than FM (although many stations do not choose to transmit at such high quality), has greater immunity to

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stations, historically the first mass-market radio application. A broadcast receiver is commonly called a "radio". However radio receivers are very widely used in other areas of modern technology, in

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settle that patent dispute, purchasing Lodge's radio company with its patent in 1912, giving them the priority patent they needed. Other patent disputes would crop up over the years including a 1943

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to reduce the bandwidth of transmitters and receivers. Different transmitters could then be "tuned" to transmit on different frequencies so they did not interfere. The receiver would also have a

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system combining a radio and audio amplifier in one unit that connects to the speakers and often to other input and output components (e.g. turntable, television, tape deck, and CD and DVD players)

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The coherer's poor performance motivated a great deal of research to find better radio wave detectors, and many were invented. Some strange devices were tried; researchers experimented with using

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devices at this time, the sensitivity of the receiver mostly depended on the detector. Many different detector devices were tried. Radio receivers during the spark era consisted of these parts:

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receiver. To receive radiotelegraphy, the feedback was increased until the tube oscillated, then the oscillation frequency was tuned to one side of the transmitted signal. The incoming radio

3348: 3231:

Tuning was used in Hertz's original experiments and practical application of tuning showed up in the early to mid 1890s in wireless systems not specifically designed for radio communication.

1532:. The bandwidth of the filter must be wide enough to allow the sidebands through without distortion, but narrow enough to block any interfering transmissions on adjacent frequencies (such as 2947:. It was found by trial and error that this could be done by a detector that exhibited "asymmetrical conduction"; a device that conducted current in one direction but not in the other. This 2829:. When the incoming radio wave reduced the resistance of the coherer, the current from the battery flowed through it, turning on the relay to ring a bell or make a mark on a paper tape in a 3522:

Marconi's initial radio system had relatively poor tuning limiting its range and adding to interference. To overcome this drawback he developed a four circuit system with tuned coils in "

8477:

In the early 1920s Armstrong, David Sarnoff head of RCA, and other radio pioneers testified before the US Congress on the need for legislation against radiating regenerative receivers.

4360:

or multiposition switch to control the plate voltage. The filament rheostat was also used as a volume control. The many controls made multitube Audion receivers complicated to operate.

585:- A radio integrated into the dashboard of a vehicle, used for entertainment while driving. Virtually all modern cars and trucks are equipped with radios, which usually also includes a 8872: 3904:, but this was not practical for ordinary receivers. The heterodyne receiver remained a laboratory curiosity until a cheap compact source of continuous waves appeared, the vacuum tube 647:. Besides the broadcast receivers described above, radio receivers are used in a huge variety of electronic systems in modern technology. They can be a separate piece of equipment (a 2626:

by their antennas, so they had little frequency-discriminating ability and received any transmitter in their vicinity. Most receivers used a pair of tuned circuits with their coils

880:- a two-way half-duplex radio operating in the 27 MHz band that can be used without a license. They are often installed in vehicles and used by truckers and delivery services. 5272: 4510:. The early vacuum tubes had very low gain (around 5). Regeneration could not only increase the gain of the tube enormously, by a factor of 15,000 or more, it also increased the 3486:

coupler - primary tuning, secondary tuning, and coupling - were interactive; changing one changed the others. So tuning in a new station was a process of successive adjustments.

4578:) in nearby receivers. In AM reception, to get the most sensitivity the tube was operated very close to instability and could easily break into oscillation (and in CW reception 2104:

to reject stations on adjacent frequencies, multiple cascaded bandpass filter stages had to be used. The dotted line indicates that the bandpass filters must be tuned together.

7235:

Jed Z. Buchwald, Scientific Credibility and Technical Standards in 19th and early 20th century Germany and Britain, Springer Science & Business Media - 1996, pages 158-159

1873:

The modulation signal output by the demodulator is usually amplified to increase its strength, then the information is converted back to a human-usable form by some type of

2359: 2332: 4305:

ability was recognized around 1912. The first tube receivers, invented by De Forest and built by hobbyists until the mid-1920s, used a single Audion which functioned as a

3153:'s 1874 discovery of "asymmetrical conduction" in crystals, these were the most successful and widely used detectors before the vacuum tube era and gave their name to the 2813:

and improved by Lodge and Marconi. The coherer was a glass tube with metal electrodes at each end, with loose metal powder between the electrodes. It initially had a high

7114:

Jed Z. Buchwald, Scientific Credibility and Technical Standards in 19th and early 20th century Germany and Britain, Springer Science & Business Media - 1996, page 158

2214:

or beat frequency at the difference between these two frequencies. The process is similar to the way two musical notes at different frequencies played together produce a

4343:

of about 5 and a short lifetime of about 30 – 100 hours, the primitive Audion had erratic characteristics because it was incompletely evacuated. De Forest believed that

2383:) of the radio signal from a receiver's antenna varies drastically, by orders of magnitude, depending on how far away the radio transmitter is, how powerful it is, and 1578:. When the resonant frequency is equal to the radio transmitter's frequency the tuned circuit oscillates in sympathy, passing the signal on to the rest of the receiver. 5216:

of the radio. The manufacturer can then in effect add new features to the radio over time, such as adding new filters, DSP noise reduction, or simply to correct bugs.

3742:). These were inaudible in the receiver headphones. To receive this new modulation type, the receiver had to produce some kind of tone during the pulses of carrier. 2958:

Below are the detectors that saw wide use before vacuum tubes took over around 1920. All except the magnetic detector could rectify and therefore receive AM signals:

8720: 5248:", where all filtering, modulation and signal manipulation is done in software. This may be a PC soundcard or by a dedicated piece of DSP hardware. There will be a 5137:

which require passive components. In a digital receiver the IF signal is sampled and digitized, and the bandpass filtering and detection functions are performed by

3761:, interrupting the carrier at an audio rate, thus producing a buzz in the earphone when the carrier was present. A similar device was the "tone wheel" invented by 3565:

Prior to 1920 the crystal receiver was the main type used in wireless telegraphy stations, and sophisticated models were made, like this Marconi Type 106 from 1915.

4567:

sharp, attenuating the AM sidebands, thus distorting the audio modulation. This was usually the limiting factor on the amount of feedback that could be employed.

7434:

Marconi Wireless Telegraph Co. of America v. United States. United States v. Marconi Wireless Telegraph Co. of America. 320 U.S. 1 (63 S.Ct. 1393, 87 L.Ed. 1731)

7410:

Marconi Wireless Telegraph Co. of America v. United States. United States v. Marconi Wireless Telegraph Co. of America. 320 U.S. 1 (63 S.Ct. 1393, 87 L.Ed. 1731)

1802:. Since it is easy to amplify a signal to any desired degree, the limit to the sensitivity of many modern receivers is not the degree of amplification but random 3957: 2042:

conducts current in one direction but not in the opposite direction, thus allowing through pulses of current on only one side of the signal. In other words, it

3717:(CW) transmitters began to replace spark transmitters for radiotelegraphy because they had much greater range. The first continuous wave transmitters were the 3239:

for lighting (mainly by what he thought was ground conduction) included elements of tuning. The wireless lighting system consisted of a spark-excited grounded

8218: 2070:

is charged up by the current pulses from the diode, and its voltage follows the peaks of the pulses, the envelope of the audio wave. It performs a smoothing (

3953:

Unlike today, when almost all radios use a variation of the superheterodyne design, during the 1920s vacuum tube radios used a variety of competing circuits.

2688:. Marconi invented little himself, but he was first to believe that radio could be a practical communication medium, and singlehandedly developed the first 4998: 3427:

and interference from other transmitters near in frequency to the desired station, the bandpass filter (tuned circuit) in the receiver has to have a narrow

9919: 5494: 4082:

A vacuum-tube receiver required several power supplies at different voltages, which in early radios were supplied by separate batteries. By 1930 adequate

8990: 1536:

in the diagram). The ability of the receiver to reject unwanted radio stations near in frequency to the desired station is an important parameter called

3243:

with a wire antenna which transmitted power across the room to another resonant transformer tuned to the frequency of the transmitter, which lighted a

2888:

around 1907. In spite of much development work, it was a very crude unsatisfactory device. It was not very sensitive, and also responded to impulsive

4466:

Homemade one-tube Armstrong regenerative receiver from the 1940s. The tickler coil is a variometer winding mounted on a shaft inside the tuning coil

153:

within another device. The most familiar type of radio receiver for most people is a broadcast radio receiver, which reproduces sound transmitted by

4874:

The first superheterodyne receiver built at Armstrong's Signal Corps laboratory in Paris during World War I. It is constructed in two sections, the

8783: 4563:

One problem with the regenerative circuit was that when used with large amounts of regeneration the selectivity (Q) of the tuned circuit could be

4025:(AM) and vacuum-tube transmitters during World War I, and the availability of cheap receiving tubes after the war, set the stage for the start of 433:, than AM. So in countries that still broadcast AM radio, serious music is typically only broadcast by FM stations, and AM stations specialize in 3473:. This gave the coupled tuned circuits much "sharper" tuning, a narrower bandwidth than a single tuned circuit. In the "Navy type" loose coupler 5382: 2402:

demodulator, while excessive signal amplitude will cause amplifier stages to overload (saturate), causing distortion (clipping) of the signal.

1512:, so the filter has to pass a band of frequencies, not just a single frequency. The band of frequencies received by the receiver is called its 7401: 575:

and developed in the 1950s, transistor radios were hugely popular during the 1960s and early 1970s, and changed the public's listening habits.

3671:

The crystal radio was unamplified and ran off the power of the radio waves received from the radio station, so it had to be listened to with

1570:

is adjusting the frequency of the receiver's passband to the frequency of the desired radio transmitter. Turning the tuning knob changes the

1013:- an automated short range digital data transmitter and receiver on a portable wireless device that communicates by microwaves with a nearby 7971: 5436: 3891:

The receiver was ahead of its time, because when it was invented there was no oscillator capable of producing the radio frequency sine wave

3278:, passing the signal of the desired station to the detector, but routing all other signals to ground. The frequency of the station received 10627: 10599: 10594: 9619: 9129: 7405: 330:

Most modern radios are able to receive both AM and FM radio stations, and have a switch to select which band to receive; these are called

6663: 6645: 3030:, this consisted of a thin silver-plated platinum wire enclosed in a glass rod, with the tip making contact with the surface of a cup of 2955:

current whose amplitude varied with the audio modulation signal. When applied to an earphone this would reproduce the transmitted sound.

2231:

that carry the information that was present in the original RF signal. The IF signal passes through filter and amplifier stages, then is

1282:

receiver - this receives data signals to monitor conditions of a process. Telemetry is used to monitor missile and spacecraft in flight,

8697: 8630: 8528: 8419: 8109: 7929: 7699: 7356: 6906: 6829: 6510: 6495: 6460: 5806: 5731: 2273:

To achieve both good image rejection and selectivity, many modern superhet receivers use two intermediate frequencies; this is called a

2198:" (IF), before it is processed. The incoming radio frequency signal from the antenna is mixed with an unmodulated signal generated by a 1199:

and other models include multichannel receivers in model cars, boats, airplanes, and helicopters. A short-range radio system is used in

351:(DAB) is an advanced radio technology which debuted in some countries in 1998 that transmits audio from terrestrial radio stations as a 5014:

Thanks to miniaturized vacuum tubes first developed in 1940, smaller portable radios appeared on the market from manufacturers such as

4782:

Hazeltine's prototype Neutrodyne receiver, presented at a March 2, 1923 meeting of the Radio Society of America at Columbia University.

4665: 2179:

Block diagram of a superheterodyne receiver. The dotted line indicates that the RF filter and local oscillator must be tuned in tandem.

5160:

instead. The benefit is that software is not affected by temperature, physical variables, electronic noise and manufacturing defects.

3305: 3216:

a poorly tuned transmitter caused the signal to "dampen", or die down, greatly reducing the power and range of transmission. In 1892,

2303:

can be achieved by doing the filtering at the lower intermediate frequency. One of the most important parameters of a receiver is its

3589:

After vacuum-tube receivers appeared around 1920, the crystal set became a simple cheap alternative radio used by youth and the poor.

2770: 1666: 1263:

receiver - a receiver with a directional antenna used to track wild animals which have been tagged with a small VHF transmitter, for

4049:

over the previous horn speakers, allowing music to be reproduced with good fidelity. Convenience features like large lighted dials,

3916:

in 1913. After this it became the standard method of receiving CW radiotelegraphy. The heterodyne oscillator is the ancestor of the

1100:

that receives multiple data channels carrying long-distance telephone calls, television signals. or internet traffic on a microwave

6558: 2874: 404:, as well as any geographical obstructions such as hills between transmitter and receiver. AM broadcast band radio waves travel as 7125: 2432:; on entering a dark room the gain of the eye is increased by the iris opening. In its simplest form, an AGC system consists of a 1255:

navigational beacons between 108 and 117.95 MHz to determine the direction to the beacon very accurately, for air navigation.

913:. Scanning capabilities have also become a standard feature in communications receivers, walkie-talkies, and other two-way radios. 5830: 5781: 4957:" (IF), before it is processed. Its operation and advantages over the other radio designs in this section are described above in 4725:

A second problem was that the multiple radio frequency stages, all tuned to the same frequency, were prone to oscillate, and the

4086:

tubes were developed, and the expensive batteries were replaced by a transformer power supply that worked off the house current.

3627:

be used widely by the public. During the first two decades of the 20th century, as radio stations began to transmit in AM voice (

823:. Cellphones have highly automated digital receivers working in the UHF and microwave band that receive the incoming side of the 795:, using a single radio channel in which only one radio can transmit at a time. so different users take turns talking, pressing a 5862: 1137:

ground stations receive data from communications satellites orbiting the Earth. Deep space ground stations such as those of the

10621: 9220: 8822: 8459: 1375:

which is applied to the receiver's input. An antenna typically consists of an arrangement of metal conductors. The oscillating

1092: 323:

receiver, in contrast, only receives a single audio channel that is a combination (sum) of the left and right channels. While

8270: 5409: 4432: 1473:; that is, the radio wave from each transmitter oscillates at a different rate. To separate out the desired radio signal, the 10616: 10606: 10586: 10388: 9084: 8939: 8857: 7586: 7504: 7477: 4920:" because it only required 5 tubes, which was used in almost all broadcast radios until the end of the tube era in the 1970s. 3607:

Simple crystal radio. The capacitance of the wire antenna connected to the coil serves as the capacitor in the tuned circuit.

3577:

Family listening to the first broadcasts around 1920 with a crystal receiver. The mother and father have to share an earphone

2723: 1566:" to the frequency of the desired transmitter. The radio has a dial or digital display showing the frequency it is tuned to. 735: 2296:

that are encountered in receivers where most of the amplifier stages operate at the same frequency, as in the TRF receiver.

8883: 6398: 5253:

demodulating a simple AM broadcast may also be able to decode an HDTV broadcast in the next. An open-source project called

1780:(voltage or current) of the signal. In most modern receivers, the electronic components which do the actual amplifying are 1298:- a calibrated, laboratory grade radio receiver used to measure the characteristics of radio signals. Often incorporates a 9753: 8480: 4317:

explained both its amplifying and demodulating functions in a 1914 paper. The grid-leak detector circuit was also used in

3989:

device and revolutionized radio. Vacuum tube transmitters replaced spark transmitters and made possible four new types of

3250:

By 1897 the advantages of tuned systems had become clear, and Marconi and the other wireless researchers had incorporated

1068:

are used for data transmission between widely separated points on Earth. Other satellites are used for search and rescue,

10678: 10611: 10457: 9235: 2074:) function, removing the radio frequency carrier pulses, leaving the low frequency audio signal to pass through the load 1088:

spacecraft. This and the limited power available to a spacecraft transmitter mean very sensitive receivers must be used.

319:. A stereo receiver contains the additional circuits and parallel signal paths to reproduce the two separate channels. A 8304: 4798:, 1924. For each station the index numbers on the dials had to be written down so that the station could be found again. 4600: 3183:

crystal detectors were also used in some early vacuum tube radios because they were more sensitive than the vacuum tube

840:. The cell tower has sophisticated multichannel receivers that receive the signals from many cell phones simultaneously. 10383: 8906: 8049: 7981: 7899: 7867: 7613: 7552: 7261: 7211: 7175: 7024: 6568: 6363: 6309: 6247: 6215: 6101: 6055: 6028: 5998: 5924: 5872: 5840: 5791: 5761: 5651: 5548: 5504: 5446: 5419: 5392: 5191: 1227: 8066: 3175:) whose surface was touched by a fine springy metal wire mounted on an adjustable arm. This functioned as a primitive 1554:(SAW) filters are often used which have sharper selectivity compared to networks of capacitor-inductor tuned circuits. 10477: 9061: 9026: 7735: 6773: 6336: 6143: 4217: 3765:, a wheel spun by a motor with contacts spaced around its circumference, which made contact with a stationary brush. 1477:

allows the frequency of the desired radio transmission to pass through, and blocks signals at all other frequencies.

8546: 5673: 3926:

today. The heterodyne oscillator had to be retuned each time the receiver was tuned to a new station, but in modern

3038:

on Christmas Eve, 1906, an evening of Christmas music transmitted by Fessenden using his new alternator transmitter.

1259: 955:

bands. Used mostly with a separate shortwave transmitter for two-way voice communication in communication stations,

10262: 9810: 9612: 9240: 9202: 9122: 8663: 8241: 6616: 4916:

During the 1940s the vacuum tube superheterodyne receiver was refined into a cheap-to-manufacture form called the "

4813:

with the feedback which caused the oscillation, canceling it. The Neutrodyne was popular until the advent of cheap

2880:

The coherer remained the dominant detector used in early radio receivers for about 10 years, until replaced by the

2782: 228:

to adjust the loudness of the audio, and some type of "tuning" control to select the radio station to be received.

17: 4963:

By the 1940s the superheterodyne AM broadcast receiver was refined into a cheap-to-manufacture design called the "

3654:, which was lightly touched by a fine springy wire (the "cat whisker") on an adjustable arm. The resulting crude 3481:, the smaller secondary coil was mounted on a rack which could be slid in or out of the primary coil, to vary the 3262:

connected together, into their transmitters and receivers. The tuned circuit acted like an electrical analog of a

2445:, and there may be a second AGC loop to control the gain of the RF amplifier to prevent it from overloading, too. 1046:, distances are limited by the visual horizon to 30–40 miles. Microwave links are used for private business data, 379:, so different channels can have different audio quality. In different countries DAB stations broadcast in either 10373: 8039: 7391:

Howard B. Rockman, Intellectual Property Law for Engineers and Scientists, John Wiley & Sons - 2004, page 198

7276:

Thomas H. Lee, The Design of CMOS Radio-Frequency Integrated Circuits, Cambridge University Press - 2004, page 35

5237:

clock, signal strength meter, a database for shortwave listening with lookup capability, scanning capability, or

3361:

Marconi's inductively coupled coherer receiver from his controversial April 1900 "four circuit" patent no. 7,777.

130:

to increase the power of the signal for further processing, and finally recovers the desired information through

3460:

of the antenna could be matched to the impedance of the receiver, to transfer maximum RF power to the receiver.

10368: 9100: 4703: 4643: 4322: 2258:

The RF filter on the front end of the receiver is needed to prevent interference from any radio signals at the

2109: 2091: 495:. Table radios typically plug into a wall outlet, although some "cordless" battery powered table radios exist. 8994: 3274:, but a low impedance at all other frequencies. Connected between the antenna and the detector it served as a 2692:

systems, transmitters and receivers, beginning in 1894–5, mainly by improving technology invented by others.

803:, a bidirectional link using two radio channels so both people can talk at the same time, as in a cell phone. 10393: 6585: 5941: 5322: 5260:

All-digital radio transmitters and receivers present the possibility of advancing the capabilities of radio.

4659:

Early 6 tube TRF receiver from around 1920. The 3 large knobs adjust the 3 tuned circuits to tune in stations

4515: 3428: 3208: 2580:, creating different length pulses of damped radio waves ("dots" and "dashes") to spell out text messages in 2304: 1526: 679: 659:

and receiver combined in one unit. Below is a list of a few of the most common types, organized by function.

7226:

Peter Rowlands, Oliver Lodge and the Liverpool Physical Society, Liverpool University Press - 1990, page 117

3650:

in 1904, to extract the audio from the radio frequency signal. It consisted of a mineral crystal, usually

571:- an older term for a portable pocket-sized broadcast radio receiver. Made possible by the invention of the 10668: 10429: 10326: 9869: 9664: 9636: 8924:"CMOS power amplifier design for cellular applications: an EDGE/GSM dual-mode quad-band PA in 0.18 μm CMOS" 5290: 4575: 4090:

number of tubes. The major radio receiver designs, listed below, were invented during the vacuum tube era.

2893: 2285: 2265: 1790: 414: 8767: 8594: 8561: 8439: 8181: 7914: 7831: 7811: 7725: 7339: 7288: 7099: 7042: 6975: 6945: 6876: 6763: 6480: 6299: 5713: 4757:

is proportional to the frequency, as the receiver is tuned to higher frequencies its bandwidth increases.

2120:

to increase its strength to a level sufficient to drive the demodulator; (3) the demodulator recovers the

10658: 10165: 9605: 9571: 9115: 7767: 7568: 6326: 6133: 5035: 4272: 2798: 2697: 1022: 869: 857: 824: 5208:

Some PC radios have the great advantage of being field upgradable by the owner. New versions of the DSP

4313:

and amplified the radio signal. There was uncertainty about the operating principle of the Audion until

3810:, along with the radio signal from the antenna. In the detector the two signals mixed, creating two new 1310:- specialized antenna and radio receiver used as a scientific instrument to study weak radio waves from 1183:

receivers receive digital commands that control a device, which may be as complex as a space vehicle or

511:. The alarm clock can be set to turn on the radio in the morning instead of an alarm, to wake the owner. 118:

which are applied to the receiver, and the receiver extracts the desired information. The receiver uses

10517: 10439: 10378: 10085: 9056:

Communications Receivers, Third Edition, Ulrich L. Rohde, Jerry Whitaker, McGraw Hill, New York, 2001,

5366: 5301: 5179: 4741:

notes), whistles and moans, in the speaker. This was solved by the invention of the Neutrodyne circuit

4199: 4188: 4153: 4093:

A defect in many early vacuum-tube receivers was that the amplifying stages could oscillate, act as an

4006: 3647: 3146: 2275: 2096: 1220: 1142: 1113: 1085: 791:

in the same device, used for bidirectional person-to-person voice communication. The radio link may be

764: 598: 348: 343: 282:

bands, between about 2.3 and 26 MHz, which are used for long distance international broadcasting.

4560:(variocoupler). Regenerative detectors were sometimes also used in TRF and superheterodyne receivers. 2536:

at RCA's New York receiving center in 1920. The translation of the Morse code is given below the tape.

1632:

received by the antenna. From top, the graphs show the voltage from the antenna applied to the filter

10699: 10289: 10250: 10095: 9995: 9924: 9857: 9684: 5312: 5163: 5138: 3918: 3643: 3191:

During the vacuum tube era, the term "detector" changed from meaning a radio wave detector to mean a

2572:

transmission. So spark transmitters could not transmit sound, and instead transmitted information by

1311: 1252: 1247: 1236: 1043: 446: 7891:

Dawn of the Electronic Age: Electrical Technologies in the Shaping of the Modern World, 1914 to 1945

4870: 3179:

which conducted electric current in only one direction. In addition to their use in crystal radios,

3167:, a crystal detector consisted of a pea-sized pebble of a crystalline semiconductor mineral such as 2908: 1828:

After the radio signal is filtered and amplified, the receiver must extract the information-bearing

1597:

of a typical radio signal from an AM or FM radio transmitter. It consists of a component (C) at the

449:

so reception distances are limited by the visual horizon to about 30–40 miles (48–64 km).

10648: 9890: 9825: 9778: 9738: 9018:

Cosine-/Sine-Modulated Filter Banks: General Properties, Fast Algorithms and Integer Approximations

5342: 5229: 5187: 4865: 4326: 4157: 3212:

To receive enough energy from this wideband signal the receiver had to have a wide bandwidth also.

2337: 2310: 2170: 1128: 1105: 1097: 368: 7683: 7636: 7083: 6799: 6447: 4979:

in 1947 revolutionized radio technology, making truly portable receivers possible, beginning with

4195: 3639:. Today these simple radio receivers are constructed by students as educational science projects. 563:

stereo sound system in the form of a box with a handle, which became popular during the mid-1970s.

10487: 10472: 10316: 10267: 10190: 10090: 9768: 9654: 9649: 9478: 7453:

Susan J. Douglas, Listening in: Radio and the American Imagination, U of Minnesota Press, page 50

5337: 5295: 4605: 4067: 3923: 3722: 3440: 2951:

the alternating current radio signal, removing one side of the carrier cycles, leaving a pulsing

2900:, while a spark-gap transmitter could transmit Morse at up to 100 WPM with a paper tape machine. 1184: 1138: 1134: 1065: 1060: 925: 47: 8754: 5569: 4679:. The loudspeaker consists of an earphone coupled to an acoustic horn which amplifies the sound. 2194:

In the superheterodyne, the radio frequency signal from the antenna is shifted down to a lower "

409:

between the transmitter and receiver. However FM radio is less susceptible to interference from

34:

A portable battery-powered AM/FM broadcast receiver, used to listen to audio broadcast by local

10409: 10195: 10010: 9955: 9950: 9763: 9728: 9448: 9417: 9397: 9357: 9162: 8615:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers, 1952, p. 177-179

8577:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers, 1952, p. 170-175

8516:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers, 1952, p. 190-193

8402:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers, 1952, p. 187-190

8129: 5698:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers, 1952, p. 195-197

5470: 5245: 5142: 5038:

in the early 1950s resulted in it being licensed to a number of electronics companies, such as

4954: 4506:); some of the energy from the tube's output circuit is fed back into the input circuit with a 4058: 3931: 3659: 3655: 3267: 2560:. Each spark produced a transient pulse of radio waves which decreased rapidly to zero. These 2471: 2442: 2421: 2389: 2370: 2220: 2195: 1863: 1196: 768: 543:

that can be carried with a person. Radios are now often integrated with other audio sources in

9016: 8896: 8614: 8576: 8515: 8401: 8361: 7889: 7857: 7603: 7520: 7251: 7165: 7057: 6990: 6960: 6891: 6814: 6687: 6527: 6417: 6387: 6237: 5697: 4416: 10311: 10115: 10080: 10000: 9980: 9902: 9790: 9711: 9382: 9255: 9250: 8923: 8847: 8196: 8015: 7796: 7576: 7542: 7494: 7467: 7201: 7014: 6846: 6269: 6045: 6018: 5990: 5984: 5641: 5609: 5538: 5347: 5317: 4726: 4478: 4390: 4349: 4149: 4145: 4098: 4094: 3905: 3807: 3706: 3018: 2885: 2822: 2814: 2742:

A typical commercial radiotelegraphy receiver from the first decade of the 20th century. The

2549: 2293: 2248: 1799: 1551: 1350: 1014: 548: 540: 217: 9644: 7379:

Hong, Sungook (2001). Wireless: From Marconi's Black-box to the Audion. MIT Press. pp. 91-99

6930: 6353: 6205: 6091: 5914: 5751: 3725:

developed 1906–1910, which were replaced by vacuum tube transmitters beginning around 1920.

3613: 3370: 1587: 10225: 10185: 10155: 9912: 9847: 9669: 9557: 9513: 9483: 9245: 9152: 8141: 4806: 4553: 4318: 4161: 4050: 4022: 4002: 3998: 3511: 3457: 3436: 3382: 3240: 3164: 3150: 3097: 2928: 2631: 2569: 2565: 2528: 2175: 1997: 1856: 1849: 1287: 1121: 703: 286: 255: 127: 107: 7657: 7433: 7409: 4403: 3559: 2935:) were being made. So a second goal of detector research was to find detectors that could 8: 10235: 10175: 9934: 9896: 9694: 9679: 9576: 9552: 9377: 9280: 9265: 9187: 9157: 8649: 7752: 5195: 4711: 4519: 4454:

powered the tube filaments, while the 2 rectangular "B" batteries provided plate voltage.

3962: 3768: 3762: 3684: 3113: 3105: 2961: 2854: 2689: 2501: 2496: 2300: 2191:

is the design used in almost all modern receivers except a few specialized applications.

2101: 1898: 1618: 1538: 1264: 1149:

around 85 ft (25 m) in diameter, and extremely sensitive radio receivers similar to

979: 974: 960: 952: 876: 865: 719: 715: 686: 610: 401: 302: 173:

and other components of communications, remote control, and wireless networking systems.

115: 71: 8145: 7677: 7630: 7444:

Hong, Sungook (2001). Wireless: From Marconi's Black-box to the Audion. MIT Press. p. 48

7077: 6441: 4395: 3701: 2544:, used during the initial three decades of radio from 1887 to 1917, a period called the 1430:

Practical radio receivers perform three basic functions on the signal from the antenna:

670:

representing a moving image, composed of a sequence of still images, and a synchronized

10462: 10419: 10350: 10220: 10150: 10125: 10060: 9907: 9628: 9530: 9503: 9422: 9094: 8327: 8157: 8153: 7314: 7137: 6707: 5153: 5111: 5015: 4950: 4907: 4707: 4623: 4609:

Armstrong presenting his superregenerative receiver, June 28, 1922, Columbia University

4523: 4491: 4352:

adjustments to keep it at the correct operating point. Each Audion stage usually had a

4340: 4306: 4297:

for radio receivers, by adding a third electrode to the thermionic diode detector, the

4113:); annoying whistles, moans, and howls in the speaker. The oscillations were caused by 4046: 4033: 3913: 3777: 3632: 3461: 3450: 3432: 3388:

Crystal receiver from 1914 with "loose coupler" tuning transformer. The secondary coil

3271: 3184: 3027: 2627: 2524:

Generic block diagram of an unamplified radio receiver from the wireless telegraphy era

2520: 1594: 1571: 1415: 1403: 1294: 1195:

channel to transmit data on the state of the controlled device back to the controller.

1188: 1018: 931: 849: 707: 675: 605: 426: 312: 154: 150: 9041: 6732: 4691:

Tuning all 3 stages of a TRF set in unison. This 1925 Grebe Synchrophase receiver has

4557: 4253: 4230: 3937:

Armstrong later used Fessenden's heterodyne principle in his superheterodyne receiver

2652:, which converted the pulses of current into sound waves. The first receivers used an 1211:- This is the use of radio waves to determine the location or direction of an object. 771:

and transported to the box through a coaxial cable. The subscriber pays a monthly fee.

767:

22,000 miles (35,000 km) above the Earth, and the signal is converted to a lower

327:

transmitters and receivers exist, they have not achieved the popularity of FM stereo.

192:

The most familiar form of radio receiver is a broadcast receiver, often just called a

10502: 10424: 10338: 10321: 10284: 10130: 9960: 9929: 9795: 9689: 9197: 9182: 9080: 9057: 9022: 8972: 8935: 8902: 8853: 8045: 7977: 7895: 7863: 7731: 7609: 7582: 7548: 7500: 7473: 7257: 7207: 7171: 7020: 6769: 6564: 6359: 6332: 6305: 6243: 6211: 6139: 6097: 6051: 6024: 5994: 5920: 5868: 5836: 5787: 5757: 5647: 5544: 5500: 5442: 5415: 5388: 5332: 5285: 5130: 5054:

offering various models. The Sony TR-63 released in 1957 was the first mass-produced

5051: 5039: 4964: 4917: 4571: 4522:

greatly. The receiver had a control to adjust the feedback. The tube also acted as a

4503: 3482: 3470: 2980: 2976: 2971: 2685: 2541: 2505: 2384: 2244: 1971: 1932: 1640: 1547: 1395: 1319: 1299: 1146: 1051: 1047: 816: 298: 263: 119: 10170: 8219:"The Pure Electron Discharge and its Applications in Radio Telegraphy and Telephony" 8161: 8098:, Nos. 1665 and 1666, November 30, 1907 and December 7, 1907, p.348-350 and 354-356. 6711: 3456:

This circuit had two advantages. One was that by using the correct turns ratio, the

2736: 2420:

of the amplifiers to give the optimum signal level for demodulation. This is called

10507: 10467: 10447: 10414: 10343: 10301: 10215: 10070: 10055: 10030: 10005: 9965: 9815: 9674: 9659: 9566: 9463: 9303: 9172: 8964: 8331: 8319: 8233: 8149: 8078: 7572: 6699: 5753:

The Technician's Radio Receiver Handbook: Wireless and Telecommunication Technology

5055: 5019: 4993: 4980: 4879: 4848: 4588: 4372: 4364: 4294: 4106: 4054: 4038: 3817: 3803: 3750: 3536: 3531: 3225: 3137: 3082: 2881: 2861: 2802: 2639: 2617: 2609: 2590: 2461: 2448:

In certain receiver designs such as modern digital receivers, a related problem is

2215: 2200: 2161:

section below describes how the superheterodyne receiver overcomes these problems.

1841: 1803: 1481: 940: 609:- This is a broadcast radio that also receives the shortwave bands. It is used for 567: 492: 430: 271: 7578:

Crystal fire: the invention of the transistor and the birth of the information age

6395: 5461:

Marianne Fedunkiw, Inventing the Radio, Crabtree Publishing Company, 2007, page 17

4788: 4776: 4695:

instead of knobs which can be turned with a finger, so a third hand is not needed.

4634:

interrupted periodically. This allowed a single tube to produce gains of over 10.

4460: 1414:, or mounted separately and connected to the receiver by a cable, as with rooftop 799:

button on their radio which switches on the transmitter. Or the radio link may be

251:

Two types of modulation are used in analog radio broadcasting systems; AM and FM.

102:

and converts the information carried by them to a usable form. It is used with an

74:, 1925–1955, families gathered to listen to the home radio receiver in the evening 10135: 9990: 9758: 9733: 9721: 9523: 9518: 9498: 9488: 9443: 9427: 9402: 9352: 9308: 9260: 9177: 9167: 6047:

The Science of Radio: With Matlab and Electronics Workbench Demonstration, 2nd Ed

5249: 5146: 4935: 4927: 4875: 4840: 4826: 4614: 4534: 4531: 4482: 4368: 4314: 4140: 4076: 4026: 3994: 3927: 3909: 3884: 3714: 3527: 3490: 3275: 3217: 3109: 3035: 2830: 2754: 2657: 2622: 2604: 2573: 2533: 2425: 2376: 2259: 2206: 2188: 2184: 2137: 2129: 2113: 2071: 2007: 1945: 1497:) in a radio transmission is contained in two narrow bands of frequencies called 1474: 1451: 1431: 1391: 1368: 1364: 1331: 1315: 1306: 1240: 1162: 1150: 1117: 1038: 900: 593: 396: 294: 259: 221: 123: 111: 103: 55: 8082: 7651: 5780:

Rembovsky, Anatoly; Ashikhmin, Alexander; Kozmin, Vladimir; et al. (2009).

5481: 4898: 4831: 3949: 2474:. Hertz used spark-excited dipole antennas to generate the waves and micrometer 1794:, which is the minimum signal strength of a station at the antenna, measured in 1251:

receiver - navigational instrument on an aircraft that uses the VHF signal from

601:. The subscriber must pay a monthly fee. They are mostly designed as car radios. 491:" - A self-contained radio with speaker designed to sit on a table, cabinet, or 10333: 10205: 10180: 10140: 10110: 9985: 9820: 9773: 9748: 9706: 9508: 9493: 9458: 9367: 9342: 9327: 9230: 9076: 8968: 8931: 8323: 8237: 7190:

Cecil Lewis Fortescue, Wireless Telegraphy, Read Books Ltd - 2013, chapter XIII

6703: 5306: 5238: 5134: 5119: 5092: 5088: 4730: 4542: 4268: 3735: 3628: 3445: 3236: 2985: 2952: 2932: 2865: 2818: 2810: 2557: 2479: 2467: 2437: 2417: 2409: 2240: 2153: 1918: 1910: 1902: 1543: 1419: 1380: 1376: 1180: 1175: 1081: 1069: 1009: 982:

used onstage by musical artists, public speakers, and television personalities.

948: 844: 829: 743: 535: 364: 352: 275: 213: 166: 146: 141:. The information produced by the receiver may be in the form of sound, video ( 42: 8664:"Tuned Radio Frequency Amplification With Neutralization of Capacity Coupling" 4244: 3571: 597:

receiver - subscription radio receiver that receives audio programming from a

305:(VHF) range. The exact frequency ranges vary somewhat in different countries. 10693: 10482: 10255: 10245: 10160: 10050: 10045: 10035: 10020: 9842: 9701: 9362: 9313: 9192: 8976: 8335: 7522:

Army Technical Manual TM 11-665: C-W and A-M Radio Transmitters and Receivers

7421: 7308: 5183: 5175: 5084: 5067: 5023: 4715: 4619: 4507: 4487: 4357: 4298: 4290: 4072: 3982: 3549: 3478: 3466: 3251: 3244: 3155: 3129: 3117: 3088: 2860:

In a long series of experiments Marconi found that by using an elevated wire

2834: 2661: 2653: 2577: 2060:

no longer averages zero; its peak value is proportional to the audio signal.

1575: 1461: 1207: 1200: 1080:

can involve very long path lengths, from 35,786 km (22,236 mi) for

956: 936: 910: 905: 884: 780: 761: 627: 560: 520: 515: 356: 201: 51: 35: 8650:"Method and electric circuit arrangement for neutralizing capacity coupling" 3900:

with the required stability. Fessenden first used his large radio frequency

2845:

device, a radio-wave-operated switch, and so it did not have the ability to

2532:

Example of transatlantic radiotelegraph message recorded on paper tape by a

2204:(LO) in the receiver. The mixing is done in a nonlinear circuit called the " 1937: 1776:

circuit uses electric power from batteries or the wall plug to increase the

30: 10360: 10200: 10145: 10075: 10040: 9975: 9874: 9864: 9716: 9392: 9372: 9275: 5277: 5221: 5213: 5126:

during the 1980s and 1990s, allowed low power wireless devices to be made.

5103: 5043: 5042:, who produced a limited run of transistorized radios as a sales tool. The 4939: 4844: 4810: 4738: 4102: 3636: 3506: 3232: 3172: 2944: 2940: 2794: 2693: 2665: 2483: 2284:

to a low IF frequency for good bandpass filtering. Some receivers even use

2133: 2125: 2014: 2010: 1959: 1954:

The easiest type of demodulation to understand is AM demodulation, used in

1906: 1894: 1878: 1866:(used to transmit digital data in wireless devices) uses an FSK demodulator 1833: 1815: 1598: 1505: 1439: 1407: 1367:

which converts some of the energy from the incoming radio wave into a tiny

1355: 1323: 1283: 1232: 1154: 994: 861: 837: 796: 726: 671: 667: 528: 442: 240: 197: 186: 131: 7859:

Electric Sounds: Technological Change and the Rise of Corporate Mass Media

5072: 4714:

by using several stages of amplification before the detector, each with a

4685: 2621:, consisting of a capacitor connected to a coil of wire, which acted as a 2576:. The transmitter was switched on and off rapidly by the operator using a 1322:

up to 500 meters in diameter, and extremely sensitive radio circuits. The

1021:

or gateway, connecting the portable device with a local computer network (

860:

radio link, instead of being attached by a cord. Both the handset and the

149:. A radio receiver may be a separate piece of electronic equipment, or an 62: 10560: 10210: 10120: 10105: 10065: 10025: 9884: 9347: 9285: 9225: 9138: 5212:

can be downloaded from the manufacturer's web site and uploaded into the

4931: 4495: 4438:

Commercial regenerative receiver from the early 1920s, the Paragon RA-10

4377: 4118: 4042: 4014: 3978: 3730: 3718: 3676: 3489:

Selectivity became more important as spark transmitters were replaced by

3424: 3285: 3263: 3192: 3180: 3093: 3031: 2998: 2921: 2889: 2842: 2561: 2553: 2141: 1967: 1890: 1837: 1456: 1335: 1166: 856:

is portable and communicates with the rest of the phone by a short range

800: 792: 788: 784: 731: 656: 652: 631: 618: 508: 504: 499: 483: 466: 462: 457: 410: 405: 360: 205: 170: 67: 5087:

transmitters and receivers to connect to different devices, including a

3008: 2608:, to intercept the radio waves and convert them to tiny radio frequency 2508:, who built the first radio receivers, with his early spark transmitter 10565: 10272: 9970: 9879: 9835: 9805: 9783: 9547: 9412: 9332: 5327: 5168: 5077: 4976: 4946: 4766: 4734: 4692: 4584: 4546: 4545:

and local oscillation signal mixed in the tube and produced an audible

4344: 4126: 4110: 3990: 3901: 3812: 3696: 3294: 3196: 2993: 2936: 2897: 2850: 2750: 2669: 2581: 2232: 2225: 2211: 2121: 2018: 1963: 1882: 1874: 1870:

Many other types of modulation are also used for specialized purposes.

1829: 1781: 1662:

is the amount of signal that gets through the filter at each frequency:

1494: 1318:. They are the most sensitive radio receivers that exist, having large 1077: 1054:

to transmit distance phone calls and television signals between cities.

820: 739: 711: 572: 524: 438: 434: 316: 236: 162: 158: 142: 99: 5942:"Pioneers of Electrical Communication part 5 - Heinrich Rudolph Hertz" 3059: 3004:

which was used to summon help during its famous 15 April 1912 sinking.

2081:. The audio signal is amplified and applied to earphones or a speaker. 1072:, weather reporting and scientific research. Radio communication with 531:

which is fed into the system and played through the system's speakers.

315:(stereo), transmitting two sound channels representing left and right 10550: 10015: 9830: 9597: 9535: 9407: 9270: 8898:

The 100 Most Significant Events in American Business: An Encyclopedia

6020:

Radio Receiver Technology: Principles, Architectures and Applications

5540:

Radio Receiver Technology: Principles, Architectures and Applications

5254: 5096: 4630: 4310: 4302: 4083: 3986: 3758: 3754: 3739: 3255: 3221: 2948: 2846: 2656:

instead. Later receivers in commercial wireless systems used a Morse

2643:, which produced a pulse of DC current for each damped wave received. 2595: 2475: 2449: 2433: 2429: 2380: 2117: 2100:

Block diagram of a tuned radio frequency receiver. To achieve enough

2043: 2022: 1985: 1820: 1795: 1777: 1773: 1769: 1757: 1747: 1522: 1470: 1435: 1327: 1278: 1192: 1158: 1073: 1029: 944: 833: 812: 807: 754: 586: 581: 544: 479:- A self-contained radio with speaker designed to stand on the floor. 324: 308: 290: 279: 258:(AM) the strength of the radio signal is varied by the audio signal. 182: 4953:

is used to shift the frequency of the radio signal down to a lower "

4653: 3583: 3124: 3100:, consisted of an evacuated glass bulb containing two electrodes: a 1844:). Each type of modulation requires a different type of demodulator 10545: 10535: 10452: 10277: 10100: 9585: 9541: 9453: 9318: 9067:

Buga, N.; Falko A.; Chistyakov N.I. (1990). Chistyakov N.I. (ed.).

7387: 7385: 5209: 5157: 5028: 4754: 4538: 4511: 4422:

Homemade Armstrong regenerative receiver, 1922. The "tickler" coil

4353: 4114: 4018: 3680: 3672: 3502: 3496: 3259: 2917: 2648: 2406: 2252: 2228: 2145: 1955: 1914: 1886: 1765: 1752: 1609: 1514: 1498: 1411: 1399: 1384: 1109: 757: 699: 555: 422: 380: 376: 320: 267: 225: 209: 2749:

detects the pulses of radio waves, and the "dots" and "dashes" of

1108:

and retransmits the data to another ground station on a different

10540: 10525: 9743: 9473: 9337: 8955:

O'Neill, A. (2008). "Asad Abidi Recognized for Work in RF-CMOS".

5081: 4814: 4746: 4426:

is visible on the front panel, coupled to the input tuning coils.

4264: 4134: 4130: 4097:, producing unwanted radio frequency alternating currents. These 4061:(AGC) were added. The receiver market was divided into the above 3108:

similar to that in an incandescent light bulb, and a metal plate

3101: 2806: 2743: 2710: 2516:

from the 1890s. The receiver records the Morse code on paper tape

2239:

The fixed frequency allows modern receivers to use sophisticated

1806:

present in the circuit, which can drown out a weak radio signal.

1608:, with the modulation contained in narrow frequency bands called 1406:

of cell phones; attached to the outside of the receiver, as with

1372: 892: 853: 747: 643:

Radio receivers are essential components of all systems that use

418: 137:

Radio receivers are essential components of all systems that use

7382: 6419:

The Principles of Electric Wave Telegraphy and Telephony, 2nd Ed

4570:

A more serious drawback was that it could act as an inadvertent

3047: 2660:, which consisted of an ink pen mounted on a needle swung by an 1387:

in the antenna back and forth, creating an oscillating voltage.

904:- a receiver that continuously monitors multiple frequencies or 651:), or a subsystem incorporated into other electronic devices. A 10570: 10530: 9852: 9322: 9072: 8199:

The Design of CMOS Radio Frequency Integrated Circuits, 2nd Ed.

8018:

The Design of CMOS Radio Frequency Integrated Circuits, 2nd Ed.

7375: 7373: 7371: 6933:

The Design of CMOS Radio Frequency Integrated Circuits, 2nd Ed.

5612:

The Design of CMOS Radio Frequency Integrated Circuits, 2nd Ed.

5058:, leading to the mass-market penetration of transistor radios. 4286: 4282: 4122: 3974: 3970: 3746: 3651: 3601: 3168: 3065:

Marconi valve receiver for use on ships had two Fleming valves

2989: 2870: 2452:

of the signal. This is corrected by a similar feedback system.

2394: 1881:, representing sound, as in a broadcast radio, is converted to 1728:{\displaystyle V_{\text{out}}(f)={\text{T}}(f)V_{\text{in}}(f)} 1141:

receive the weak signals from distant scientific spacecraft on

1101: 917: 384: 126:

signal from all the other signals picked up by the antenna, an

9107: 8983: 5916:

The Design of CMOS Radio-Frequency Integrated Circuits, 2nd Ed

4446:

and three tube DA-2 detector and 2-stage audio amplifier unit

2046:

the AC current to a pulsing DC current. The resulting voltage

1962:

modulation signal, which represents sound and is converted to

986: 10555: 10492: 9800: 9562: 9468: 6560:

The Continuous Wave: Technology and American Radio, 1900-1932

5199: 5099: 4271:, so the tube conducts only during the positive half-cycles, 3934:, so the beat frequency oscillator can be a fixed frequency. 3357: 3176: 2927:

By the first years of the 20th century, experiments in using

2826: 2470:'s 1887 series of experiments to prove James Clerk Maxwell's 1978: 1215: 644: 138: 79: 7368: 5171:

systems to reduce the data rate required to transmit voice.

4105:

of the radio signal in the detector tube, producing audible

4005:(FM) around 1938 which had much improved audio quality, and 2912:

Experiment to use human brain as a radio wave detector, 1902

2132:

rate representing the sound waves) from the modulated radio

472:

Radios are manufactured in a range of styles and functions:

293:

of the radio signal is varied slightly by the audio signal.

200:

programs intended for public reception transmitted by local

10497: 9581: 9066: 5220:

time. Some control software designers have even integrated

5123: 5115: 5047: 2776:

Circuit of Marconi's first coherer radio receiver from 1896

2416:

level of the radio signal at the detector, and adjusts the

2269:

Block diagram of a dual-conversion superheterodyne receiver

4671:

Atwater-Kent TRF receiver from the 1920s with 2 RF stages

3780:

had invented a better means of accomplishing this. In his

3145:) - invented around 1904–1906 by Henry H. C. Dunwoody and 1798:, necessary to receive the signal clearly, with a certain 1290:, and unmanned scientific instruments in remote locations. 8784:"Reflexing Today: Operating economy with the newer tubes" 6050:. Springer Science & Business Media. pp. 45–48. 5234: 5008: 2334:, rather than the frequency of the original radio signal 1116:

the transponder broadcasts a stronger signal directly to

819:

by radio signals exchanged with a local antenna called a

212:

which plugs into a jack on the radio. The radio requires

9089:

First published in Russian as «Радиоприёмные устройства»

7656:. New York: Scientific American Publishing Co. pp. 6993:

The Principles of Electric Wave Telegraphy and Telephony

6963:

The Principles of Electric Wave Telegraphy and Telephony

6894:

The Principles of Electric Wave Telegraphy and Telephony

6867:

copied on Stephenson's marconigraph.com personal website

6817:

The Principles of Electric Wave Telegraphy and Telephony

5779: 4749:

later around 1930, and better shielding between stages.

1394:

may be enclosed inside the receiver's case, as with the

54:

communication stations to talk with remote locations by

7567: 5133:

on the chip to do functions that were formerly done by

4885:

and three IF amplification stages and a detector stage

4794:

Tuning a Neutrodyne TRF receiver with 3 tuned circuits

4601:

Regenerative receiver § Superregenerative receiver

4549:(beat) tone at the difference between the frequencies. 3199:

signal from a radio signal. That is its meaning today.

2136:; (4) the modulation signal is amplified further in an 2085: 1788:

a radio receiver is measured by a parameter called its

682:

than an audio signal, from 600 kHz to 6 MHz.

367:

bandwidth, and provides advanced user features such as

7167:

Intellectual Property Law for Engineers and Scientists

5864:

Radio-Frequency Electronics: Circuits and Applications

4407:

Circuit of single tube Armstrong regenerative receiver

2466:

Radio waves were first identified in German physicist

2436:

which converts the RF signal to a varying DC level, a

1624:

How the bandpass filter selects a single radio signal

9071:. Translated from the Russian by Boris V. Kuznetsov. 6847:"The Marconi Wireless Installation in R.M.S. Titanic" 4198:. Please help to ensure that disputed statements are 3784:

an unmodulated sine wave radio signal at a frequency

3705:

Radio receiver with Poulsen "tikker" consisting of a

3308: 2340: 2313: 1669: 978:

receiver - these receive the short range signal from

220:

inside the radio or a power cord which plugs into an

8067:"The Audion; A New Receiver for Wireless Telegraphy" 7608:. Institution of Electrical Engineers. p. 191. 7424:, filed: February 8, 1900, granted: December 2, 1902 5832:

Modern Communications Receiver Design and Technology

5267: 3220:

gave a lecture on radio in which he suggested using

2564:

could not be modulated to carry sound, as in modern

1772:. To increase the power of the recovered signal, an 1764:

receiver's antenna is very small, perhaps as low as

8845: 8816: 8814: 8812: 8758:, filed December 28, 1917; granted February 7, 1922 8453: 8451: 7581:. USA: W. W. Norton & Company. pp. 19–21. 6422:. London: Longmans, Green and Co. pp. 420–428. 5786:. Springer Science and Business Media. p. 26. 5414:. Springer Science and Business Media. p. 63. 5011:Radiola 1 were also advertised as portable radios. 4835:

Block diagram of simple single tube reflex receiver

4384: 4117:in the amplifiers; one major feedback path was the 2235:in a detector, recovering the original modulation. 888:- a handheld short range half-duplex two-way radio. 337: 8705:. New York: McGraw-Hill Book Co. pp. 468–469. 8638:. New York: McGraw-Hill Book Co. pp. 438–439. 8536:. New York: McGraw-Hill Book Co. pp. 662–663. 8117:. New York: McGraw-Hill Book Co. pp. 564–565. 5989:. London: Inst. of Electrical Engineers. pp. 5384:A Broadcast Engineering Tutorial for Non-Engineers 4514:of the tuned circuit, decreasing (sharpening) the 4470:which can be rotated by a knob on the front panel. 4167: 4001:(AM) around 1915 which could carry audio (sound), 3922:(BFO) which is used to receive radiotelegraphy in 3757:at the tuner output which served as a rudimentary 3342: 2353: 2326: 1727: 1191:. Remote control systems often also incorporate a 698:(TV) - Televisions contains an integral receiver ( 8305:"Some recent developments in the Audion receiver" 7730:. New York: Murray Hill Books. pp. 133–136. 7496:The Third Element: A Brief History of Electronics 6617:"The effect of electric waves on the human brain" 5783:Radio Monitoring: Problems, Methods and Equipment 5257:is dedicated to evolving a high-performance SDR. 5002:A Zenith transistor based portable radio receiver 4984:smaller and much less fragile than vacuum tubes. 2405:Therefore, almost all modern receivers include a 2108:In the simplest type of radio receiver, called a 2017:(the sound) is contained in the slow variations ( 10691: 8841: 8839: 8837: 8809: 8448: 7306: 7203:Wireless: From Marconi's Black-box to the Audion 7016:Wireless: From Marconi's Black-box to the Audion 6355:Wireless: From Marconi's Black-box to the Audion 6012: 6010: 5919:. UK: Cambridge University Press. pp. 1–8. 5745: 5743: 3709:disk turned by a motor to interrupt the carrier. 3343:{\displaystyle f={\frac {1}{2\pi {\sqrt {LC}}}}} 2000:radio signal from the tuned circuit is shown at 935:- a general purpose audio receiver covering the 868:band that receive the short range bidirectional 270:range, and between 526 and 1706 kHz in the 239:is the process of adding information to a radio 181:"AM/FM" redirects here. Not to be confused with 8776: 8610: 8608: 8606: 8511: 8509: 8397: 8395: 8393: 8391: 8389: 8387: 7756:, filed July 27, 1905; granted January 14, 1913 7525:. US Dept. of the Army. 1952. pp. 167–169. 6615:Collins, Archie Frederick (February 22, 1902). 6586:"Frog's leg method of detecting wireless waves" 5574:Proceedings of the Institute of Radio Engineers 5570:"A new system of radio frequency amplification" 5532: 5530: 5528: 5526: 5524: 5522: 5520: 5518: 5516: 4958: 4537:transmissions audible. This mode was called an 3802:was applied to a rectifying detector such as a 3069:in case one burned out. It was used on the RMS 2793:The first radio receivers invented by Marconi, 2364: 1562:: To select a particular station the radio is " 1425: 452: 8820: 8652:; filed August 7, 1919; granted March 27, 1923 8642: 8457: 7750:US patent no. 1050441, Reginald A. Fessenden, 7472:. UK: Cambridge University Press. p. 44. 5693: 5691: 5689: 5687: 5685: 4518:of the receiver by the same factor, improving 3930:receivers the BFO signal beats with the fixed 3690: 2210:". The result at the output of the mixer is a 1647:, and the voltage at the output of the filter 1542:determined by the filter. In modern receivers 266:which are between 148 and 283 kHz in the 9613: 9123: 8852:. University of Arizona Press. pp. 66–. 8834: 8830:. Wireless Press for RCA. pp. 1140–1141. 8648:US Patent No. 1450080, Louis Alan Hazeltine, 8590: 8588: 8586: 8584: 8467:. Wireless Press for RCA. pp. 1223–1224. 8094:The link is to a reprint of the paper in the 7965: 7963: 7961: 7827: 7825: 7823: 7744: 7364:. New York: McGraw-Hill Book Co. p. 170. 7307:Marx, Harry J.; Van Muffling, Adrian (1922). 6231: 6229: 6227: 6007: 5740: 5563: 5561: 4805:The Neutrodyne receiver, invented in 1922 by 4718:, all tuned to the frequency of the station. 4594: 4029:, which sprang up spontaneously around 1920. 3772:Fessenden's heterodyne radio receiver circuit 3745:The first crude device that did this was the 3619:Typical "loose coupler" crystal radio circuit 3128:A galena cat's whisker detector from a 1920s 2857:(AM) radio transmissions that carried sound. 2634:(oscillation transformer) or "loose coupler". 2552:which generated radio waves by discharging a 2164: 1314:in space like stars, nebulas and galaxies in 363:and interference, makes better use of scarce 8957:IEEE Solid-State Circuits Society Newsletter 8948: 8755:Audion or lamp relay or amplifying apparatus 8603: 8570: 8506: 8435: 8433: 8431: 8384: 8212: 8210: 8208: 7959: 7957: 7955: 7953: 7951: 7949: 7947: 7945: 7943: 7941: 7851: 7849: 7847: 7845: 7843: 7536: 7534: 7532: 7414: 6659: 6657: 6127: 6125: 6123: 6121: 6119: 6117: 6115: 6113: 6016: 5978: 5976: 5974: 5972: 5970: 5775: 5773: 5709: 5707: 5705: 5669: 5667: 5665: 5663: 5536: 5513: 4851:, then the resulting audio signal is passed 4450:. The 4 cylindrical dry cell "A" batteries 4356:to adjust the filament current, and often a 3793:offset from the incoming radio wave carrier 2299:The most important advantage is that better 1970:. It is accomplished by a circuit called an 1480:The bandpass filter consists of one or more 1161:cooled to −195.79 °C (−320 °F) by 921:Modern communications receiver, ICOM RC-9500 176: 10628:Global telecommunications regulation bodies 9014: 8954: 8624: 8622: 8415: 8413: 8411: 8409: 8353: 8296: 8175: 8121: 8033: 8031: 8029: 8027: 7883: 7881: 7879: 7719: 7717: 7715: 7713: 7711: 7649: 7643: 7513: 7335: 7333: 7331: 7329: 7327: 7284: 7282: 7082:. New York: Moffatt, Yard and Co. pp. 7079:Wireless Telegraphy: An Elementary Treatise 7071: 7069: 6681: 6679: 6677: 6675: 6583: 6476: 6474: 6472: 6411: 6409: 6407: 6293: 6291: 6289: 6287: 6285: 6283: 6281: 6210:. McGraw-Hill Professional. pp. 5–13. 5856: 5854: 5852: 5682: 5499:. PHI Learning Pvt. Ltd. pp. 286–289. 4859: 4442:with separate 10R single tube RF amplifier 3753:. This was a vibrating interrupter with a 2124:signal (which in broadcast receivers is an 10664: 9620: 9606: 9130: 9116: 8928:RF and mm-Wave Power Generation in Silicon 8926:. In Wang, Hua; Sengupta, Kaushik (eds.). 8761: 8714: 8712: 8655: 8581: 8555: 8540: 8058: 7908: 7862:. Columbia Univ. Press. pp. 147–148. 7820: 7805: 7675: 7461: 7459: 7245: 7243: 7241: 7159: 7157: 7155: 7051: 7038: 7036: 6844: 6838: 6686:Marriott, Robert H. (September 17, 1915). 6383: 6381: 6379: 6377: 6375: 6224: 5824: 5822: 5820: 5818: 5727: 5725: 5558: 5471:Radio Attic Gallery of Table/Mantle Radios 5380: 4129:circuit, and later the development of the 3646:, invented by Harrison H. C. Dunwoody and 3396:to adjust the coupling. Other components: 2788:Coherer from 1904 as developed by Marconi. 1832:signal from the modulated radio frequency 746:receives many channels all modulated on a 8721:"The Story of Reflex and Radio Frequency" 8661: 8481:"The Case Against the Radiating Receiver" 8428: 8359: 8302: 8264: 8262: 8205: 8127: 8064: 7938: 7894:. John Wiley and Sons. pp. 159–160. 7840: 7693: 7601: 7595: 7529: 7170:. John Wiley and Sons. pp. 196–199. 6900: 6823: 6795: 6793: 6791: 6789: 6787: 6785: 6654: 6639: 6590:Electrical Review and Western Electrician 6504: 6489: 6454: 6435: 6433: 6431: 6429: 6265: 6263: 6261: 6259: 6235: 6110: 5967: 5939: 5933: 5770: 5702: 5660: 5567: 5309: – List of specific models of radios 5129:The current trend in receivers is to use 4889:. The intermediate frequency was 75 kHz. 4675:, detector and two audio amplifier tubes 4348:characteristics, so it required periodic 4218:Learn how and when to remove this message 3888:somewhat, the detector had "mixer gain". 3543: 3116:, an effect which had been discovered by 1084:satellites to billions of kilometers for 990:Baby monitor. The receiver is on the left 301:between about 65 and 108 MHz in the 8888: 8689: 8619: 8549:The New Radio Receiver Building Handbook 8520: 8406: 8216: 8101: 8024: 8011: 8009: 8007: 8005: 8003: 8001: 7999: 7997: 7995: 7993: 7973:The New Radio Receiver Building Handbook 7969: 7923: 7876: 7855: 7708: 7671: 7669: 7667: 7544:The New Radio Receiver Building Handbook 7540: 7420:US Patent no. 714,756, John Stone Stone 7324: 7279: 7075: 7066: 7008: 7006: 7004: 7002: 6984: 6969: 6954: 6939: 6885: 6870: 6808: 6755: 6685: 6672: 6584:Worthington, George (January 18, 1913). 6577: 6469: 6404: 6401:2016-05-17 at the Portuguese Web Archive 6297: 6278: 6199: 6197: 6195: 6193: 6191: 6189: 6187: 6185: 6183: 6181: 6179: 6177: 6175: 5982: 5849: 5676:The New Radio Receiver Building Handbook 5635: 5633: 5631: 5629: 5627: 5625: 5623: 5621: 5071: 4997: 4869: 4830: 4604: 4402: 4394: 4229: 4194:Relevant discussion may be found on the 4045:invented in 1924 greatly improved audio 3956: 3948: 3767: 3700: 3356: 3235:'s March 1893 lecture demonstrating the 3195:, a device that could extract the audio 3123: 3007: 2960: 2907: 2903: 2753:were recorded in ink on paper tape by a 2680:The first person to use radio waves for 2527: 2519: 2500: 2264: 2174: 2095: 1944: 1936: 1819: 1751: 1455: 1354: 985: 916: 891: 456: 98:, is an electronic device that receives 61: 41: 29: 9015:Britanak, Vladimir; Rao, K. R. (2017). 8993:. Radio-Electronics.Com. Archived from 8894: 8746: 8709: 8037: 7887: 7790: 7723: 7561: 7465: 7456: 7348: 7313:. New York: G. Putnam's Sons. pp. 7302: 7300: 7253:Syntony and Spark: The Origins of Radio 7238: 7163: 7152: 7123: 7117: 7102:Syntony and Spark: The origins of radio 7093: 7045:Syntony and Spark: The origins of radio 7033: 6926: 6924: 6922: 6920: 6918: 6768:. Murray Hill Books. pp. 121–123. 6761: 6614: 6550: 6415: 6372: 6324: 6318: 6207:Old Time Radios! Restoration and Repair 6173: 6171: 6169: 6167: 6165: 6163: 6161: 6159: 6157: 6155: 6131: 6085: 6083: 6081: 6079: 6077: 6075: 6073: 6071: 6069: 6067: 5908: 5906: 5904: 5828: 5815: 5800: 5722: 5605: 5603: 5601: 5599: 5597: 5595: 5492: 3856:between these frequencies. By choosing 3505:of AM modulation on either side of the 1145:exploration missions. These have large 674:representing the associated sound. The 465:that combines a radio receiver with an 278:. AM broadcasting is also permitted in 70:console radio in the 1940s. During the 14: 10692: 9627: 8718: 8695: 8628: 8526: 8303:Armstrong, Edwin H. (September 1915). 8259: 8128:Armstrong, Edwin (December 12, 1914). 8107: 7759: 7676:Lauer, Henri; Brown, Harry L. (1920). 7628: 7622: 7492: 7486: 7354: 7319:loose coupler variometer variocoupler. 7256:. Princeton Univ. Press. p. 255. 7249: 6782: 6563:. Princeton Univ. Press. p. 190. 6556: 6426: 6256: 5902: 5900: 5898: 5896: 5894: 5892: 5890: 5888: 5886: 5884: 5486: 5411:Signal And Image Processing Sourcebook 5407: 4760: 4399:Block diagram of regenerative receiver 4281:The first amplifying vacuum tube, the 2801:in 1894-5 used a primitive radio wave 1897:, representing moving images, as in a 1612:(SB) just above and below the carrier. 1025:) to exchange data with other devices. 969:One-way (simplex) voice communications 864:have radio receivers operating in the 204:. The sound is reproduced either by a 106:. The antenna intercepts radio waves ( 9601: 9111: 8824:Radiotron Designer's Handbook, 4th Ed 8752:US Patent no. 1405523, Marius Latour 8471: 8461:Radiotron Designer's Handbook, 4th Ed 8271:"The Saga of the Vacuum Tube, Part 9" 8190: 7990: 7765: 7664: 7635:. New York: Wireless Press. pp. 7193: 7124:Crookes, William (February 1, 1892). 6999: 6730: 6724: 6692:Proc. of the Inst. Of Radio Engineers 6608: 6525: 6519: 6439: 6345: 6331:. Murray Hill Books. pp. 37–45. 6138:. Murray Hill Books. pp. 57–68. 6043: 6037: 6023:. John Wiley and Sons. pp. 1–2. 5867:. Cambridge Univ. Press. p. 60. 5860: 5639: 5618: 5568:Armstrong, Edwin H. (February 1921). 5434: 5401: 5061: 5022:. First introduced in 1942, Zenith's 3392:can be slid in or out of the primary 3376:Braun receiving transformer from 1904 3352: 2251:(SAW) IF filters that have very high 2218:. This lower frequency is called the 2031:When this signal is applied as input 1852:) radio signal uses an AM demodulator 1836:. This is done by a circuit called a 1460:Symbol for a bandpass filter used in 1445: 1344: 736:direct-broadcast satellite television 638: 27:Device for receiving radio broadcasts 10674: 8915: 8478: 8269:Tyne, Gerald F. J. (December 1943). 8268: 7297: 7199: 7012: 6915: 6351: 6203: 6152: 6064: 5749: 5592: 5428: 5374: 4970: 4704:tuned radio frequency (TRF) receiver 4498:or transistor is increased by using 4171: 4121:between the plate and grid in early 2110:tuned radio frequency (TRF) receiver 2086:Tuned radio frequency (TRF) receiver 1921:, which interacts with human users. 1363:A radio receiver is connected to an 527:. It has no speakers but outputs an 523:AM/FM radio receiver in a component 8921: 8873:The Portable Radio in American Life 8849:The Portable Radio in American Life 8217:Langmuir, Irving (September 1915). 7126:"Some Possibilities of Electricity" 6845:Stephenson, Parks (November 2001). 6731:Secor, H. Winfield (January 1917). 6089: 5912: 5881: 5381:Pizzi, Skip; Jones, Graham (2014). 5152:Many of the functions performed by 4733:in the detector, producing audible 4490:. In the regenerative receiver the 4301:. It was not widely used until its 2704: 1521:, and the width of the passband in 231: 24: 9050: 8671:Proc. of the Radio Club of America 8662:Hazeltine, Louis A. (March 1923). 8360:Armstrong, Edwin H. (April 1921). 8154:10.1111/j.1749-6632.1916.tb55188.x 8130:"Operating features of the Audion" 7408:, 3/20/1900 (filed Sept. 2, 1897) 6532:American Monthly Review of Reviews 6526:Maver, William Jr. (August 1904). 5835:. Artech House. pp. 325–330. 5244:The next level in integration is " 5192:modified discrete cosine transform 5182:(DAB), the analog audio signal is 4987: 4820: 3944: 3517: 2979:in 1902 from a method invented by 2424:(AGC). AGC can be compared to the 1228:Global navigation satellite system 1096:- A receiver and transmitter in a 678:received by a TV occupies a wider 25: 10711: 6688:"United States Radio Development" 5940:Appleyard, Rollo (October 1927). 4629:In the regenerative receiver the 2931:(AM) to transmit sound by radio ( 2224:(IF). The IF signal also has the 2006:. The rapid oscillations are the 1848:an AM receiver that receives an ( 738:, and displays it on an ordinary 445:. Like FM, DAB signals travel by 10673: 10663: 10654: 10653: 10642: 10263:Free-space optical communication 9241:Failure of electronic components 9035: 9008: 8895:Skrabec, Quentin R. Jr. (2012). 8877: 8866: 8479:Wing, Willis K. (October 1924). 7766:Hogan, John V. L. (April 1921). 5270: 4906: 4897: 4787: 4775: 4710:, improved both sensitivity and 4684: 4664: 4652: 4613:This was a receiver invented by 4459: 4431: 4415: 4385:Regenerative (autodyne) receiver 4252: 4243: 4176: 3985:in 1906 was the first practical 3612: 3600: 3582: 3570: 3558: 3381: 3369: 3165:semiconductor electronic devices 3058: 3046: 2781: 2769: 2735: 2722: 2668:) which drew a line on a moving 2646:An indicating device such as an 1741: 1617: 1586: 622:(in context often just called a 338:Digital audio broadcasting (DAB) 9137: 8991:"History of the Radio Receiver" 8065:De Forest, Lee (January 1906). 7970:Williams, Lyle Russell (2006). 7650:Lescarboura, Austin C. (1922). 7541:Williams, Lyle Russell (2006). 7499:. AuthorHouse. pp. 44–45. 7447: 7438: 7427: 7394: 7270: 7229: 7220: 7184: 7108: 6446:. D. Van Nostrand Co. pp. 4729:mixed with the radio station's 4637: 4168:The first vacuum-tube receivers 3865:correctly the lower heterodyne 2158: 1862:an FSK receiver which receives 1855:an FM receiver that receives a 1809: 1493:: See graphs. The information ( 687:Terrestrial television receiver 8547:Williams, Lyle Russell (2006) 8096:Scientific American Supplement 7753:Electrical signaling apparatus 7629:Bucher, Elmer Eustice (1917). 7019:. MIT Press. pp. 89–100. 6416:Fleming, John Ambrose (1910). 6304:. ABC-CLIO. pp. 159–161. 5674:Williams, Lyle Russell (2006) 5493:Ganguly, Partha Kumar (2015). 5482:Solar/Hand Crank Powered Radio 5475: 5464: 5455: 5360: 4644:Tuned radio frequency receiver 3687:compared to modern receivers. 3237:wireless transmission of power 2943:(sound) signal from the radio 2187:receiver, invented in 1918 by 2148:to convert it to sound waves. 2128:, a voltage oscillating at an 2092:Tuned radio frequency receiver 1949:How an envelope detector works 1722: 1716: 1703: 1697: 1686: 1680: 1124:receivers in consumer's homes. 664:Broadcast television reception 13: 1: 8696:Terman, Frederick E. (1943). 8629:Terman, Frederick E. (1943). 8527:Terman, Frederick E. (1943). 8108:Terman, Frederick E. (1943). 8044:. IOS Press. pp. 17–22. 7632:Practical Wireless Telegraphy 7355:Terman, Frederick E. (1943). 6991:Fleming, John Ambrose (1910) 6961:Fleming, John Ambrose (1910) 6892:Fleming, John Ambrose (1910) 6815:Fleming, John Ambrose (1910) 6621:Electrical World and Engineer 5646:. CRC Press. pp. 57–61. 5353: 5323:Receiver (information theory) 5178:broadcasting systems such as 4945:In the superheterodyne, the " 4552:A widely used design was the 2939:an AM signal, extracting the 2924:from a cadaver as detectors. 2354:{\displaystyle f_{\text{RF}}} 2327:{\displaystyle f_{\text{IF}}} 1901:, is converted to light by a 1859:signal uses an FM demodulator 559:- a portable battery-powered 10649:Telecommunication portal 10430:Telecommunications equipment 9236:List of emerging electronics 8901:. ABC-CLIO. pp. 195–7. 8846:Michael B. Schiffer (1991). 8420:Terman, Frederick E. (1943) 7930:Terman, Frederick E. (1943) 7679:Radio Engineering Principles 7422:Method of electric signaling 7076:Kennelly, Arthur E. (1906). 6733:"Radio Detector Development" 6528:"Wireless Telegraphy To-Day" 5983:Phillips, Vivian J. (1980). 5807:Terman, Frederick E. (1943) 5732:Terman, Frederick E. (1943) 5291:Dielectric wireless receiver 3683:. However it still had poor 3404:secondary tuning capacitor, 2490: 2365:Automatic gain control (AGC) 1426:Main functions of a receiver 777:Two-way voice communications 734:which receives subscription 453:Types of broadcast receivers 390: 311:radio stations broadcast in 246: 114:) and converts them to tiny 7: 10166:Alexander Stepanovich Popov 8821:Langford-Smith, F. (1953). 8458:Langford-Smith, F. (1953). 8083:10.1109/t-aiee.1906.4764762 7856:Wurtzler, Steve J. (2007). 7469:The Evolution of Technology 7164:Rockman, Howard B. (2004). 6802:Elements of Radiotelegraphy 6443:Elements of Radiotelegraphy 6358:. MIT Press. pp. 1–2. 6096:. McFarland. pp. 3–8. 6017:Rudersdorfer, Ralf (2013). 5537:Rudersdorfer, Ralf (2013). 5263: 5050:, Zenith, RCA, DeWald, and 5036:bipolar junction transistor 4745:and the development of the 3691:Heterodyne receiver and BFO 2038:to the detector, the diode 1913:, is applied as input to a 1654:as a function of frequency 1628:from all the radio signals 1383:of the radio wave push the 1231:(GNSS) receiver, such as a 1221:collision avoidance systems 1048:wide area computer networks 10: 10716: 9870:Telecommunications history 9099:: CS1 maint: postscript ( 8969:10.1109/N-SSC.2008.4785694 8884:Popular Mechanics aug 1953 8719:Grimes, David (May 1924). 8362:"The Regenerative Circuit" 8324:10.1109/JRPROC.1915.216677 8238:10.1109/jrproc.1915.216680 7888:Nebeker, Frederik (2009). 7702:Early Radio Wave Detectors 7250:Aitken, Hugh G.J. (2014). 7206:. MIT Press. p. 199. 6909:Early Radio Wave Detectors 6832:Early Radio Wave Detectors 6704:10.1109/jrproc.1917.217311 6666:Early Radio Wave Detectors 6648:Early Radio Wave Detectors 6557:Aitken, Hugh G.J. (2014). 6513:Early Radio Wave Detectors 6498:Early Radio Wave Detectors 6463:Early Radio Wave Detectors 6298:Klooster, John W. (2007). 5986:Early Radio Wave Detectors 5387:. CRC Press. p. 208. 5302:Direct conversion receiver 5180:Digital Audio Broadcasting 5065: 4991: 4959:The superheterodyne design 4930:, invented in 1918 during 4863: 4824: 4764: 4641: 4598: 4595:Superregenerative receiver 4574:, producing interference ( 4526:to rectify the AM signal. 4388: 4376:easier to operate. During 4363:By 1914, Harold Arnold at 4289:, was invented in 1906 by 4154:superregenerative receiver 3694: 3648:Greenleaf Whittier Pickard 3547: 3400:primary tuning capacitor, 3147:Greenleaf Whittier Pickard 2708: 2494: 2459: 2455: 2368: 2255:, to improve selectivity. 2168: 2165:The superheterodyne design 2157:adequate selectivity. The 2089: 1930: 1813: 1745: 1449: 1348: 1312:astronomical radio sources 1114:direct broadcast satellite 765:direct broadcast satellite 599:direct broadcast satellite 349:Digital audio broadcasting 344:Digital audio broadcasting 341: 180: 10637: 10579: 10516: 10478:Public Switched Telephone 10438: 10402: 10359: 10300: 10290:telecommunication circuit 10251:Fiber-optic communication 10234: 9996:Francis Blake (telephone) 9943: 9791:Optical telecommunication 9635: 9436: 9294: 9211: 9145: 9021:. Springer. p. 478. 8770:Radio's Conquest of Space 8699:Radio Engineers' Handbook 8632:Radio Engineers' Handbook 8597:Radio's Conquest of Space 8564:Radio's Conquest of Space 8530:Radio Engineers' Handbook 8442:Radio's Conquest of Space 8422:Radio Engineers' Handbook 8184:Radio's Conquest of Space 8111:Radio Engineers' Handbook 8041:History of Electron Tubes 7932:Radio Engineers' Handbook 7917:Radio's Conquest of Space 7834:Radio's Conquest of Space 7814:Radio's Conquest of Space 7768:"The Heterodyne Receiver" 7727:Radio's Conquest of Space 7404:, 3/15/1900, and part of 7358:Radio Engineers' Handbook 7342:Radio's Conquest of Space 7291:Radio's Conquest of Space 7136:: 174–176. Archived from 6978:Radio's Conquest of Space 6948:Radio's Conquest of Space 6879:Radio's Conquest of Space 6765:Radio's Conquest of Space 6483:Radio's Conquest of Space 6440:Stone, Ellery W. (1919). 6328:Radio's Conquest of Space 6242:. IET. pp. 184–186. 6135:Radio's Conquest of Space 6093:Wireless Radio: A History 5829:Drentea, Cornell (2010). 5809:Radio Engineers' Handbook 5756:. Newnes. pp. 8–11. 5734:Radio Engineers' Handbook 5716:Radio's Conquest of Space 5496:Principles of Electronics 5441:. Elsevier. p. 258. 5435:Olsen, George H. (2013). 5369:Radio Receiver Technology 5313:Minimum detectable signal 5164:Digital signal processing 5139:digital signal processing 4327:superheterodyne receivers 4125:. This was solved by the 3919:beat frequency oscillator 3820:) frequencies at the sum 3721:invented in 1904 and the 3642:The crystal radio used a 3202: 3104:consisting of a hot wire 3026:") - Invented in 1903 by 1941:Envelope detector circuit 1490:Bandwidth and selectivity 1326:of the receiver is often 1320:parabolic (dish) antennas 1237:Global Positioning System 1157:of the receiver is often 815:that is connected to the 421:, static) and has higher 177:Broadcast radio receivers 10389:Orbital angular-momentum 9826:Satellite communications 9665:Communications satellite 7976:. Lulu. pp. 24–27. 7724:McNicol, Donald (1946). 7682:. McGraw-Hill. pp. 7547:. Lulu. pp. 20–24. 7466:Basalla, George (1988). 6762:McNicol, Donald (1946). 6325:McNicol, Donald (1946). 6132:McNicol, Donald (1946). 5949:Electrical Communication 5750:Carr, Joseph J. (2001). 5343:Radio transmitter design 5230:Graphical User Interface 4949:" technique invented by 4866:Superheterodyne receiver 4860:Superheterodyne receiver 4339:In addition to very low 4158:superheterodyne receiver 4068:communications receivers 4043:dynamic cone loudspeaker 3924:communications receivers 2875:St. John's, Newfoundland 2171:Superheterodyne receiver 1824:Symbol for a demodulator 1658:. The transfer function 1129:Satellite ground station 1106:satellite ground station 1098:communications satellite 1066:Communication satellites 1061:Satellite communications 666:- Televisions receive a 387:(1.452–1.492 GHz). 369:electronic program guide 122:to separate the desired 10268:Molecular communication 10091:Gardiner Greene Hubbard 9920:Undersea telegraph line 9655:Cable protection system 9479:Electromagnetic warfare 8768:McNicol, Donald (1946) 8595:McNicol, Donald (1946) 8562:McNicol, Donald (1946) 8440:McNicol, Donald (1946) 8182:McNicol, Donald (1946) 7915:McNicol, Donald (1946) 7832:McNicol, Donald (1946) 7812:McNicol, Donald (1946) 7602:Beauchamp, Ken (2001). 7493:Corbin, Alfred (2006). 7340:McNicol, Donald (1946) 7289:McNicol, Donald (1946) 6976:McNicol, Donald (1946) 6946:McNicol, Donald (1946) 6877:McNicol, Donald (1946) 6737:Electrical Experimenter 6481:McNicol, Donald (1946) 6236:Beauchamp, Ken (2001). 6044:Nahin, Paul J. (2001). 5913:Lee, Thomas H. (2004). 5714:McNicol, Donald (1946) 5543:. John Wiley and Sons. 5438:Electronics Made Simple 5408:Libbey, Robert (1994). 5338:Television receive-only 5296:Digital Audio Broadcast 5143:software-defined radios 5034:The development of the 4075:communications such as 3723:Alexanderson alternator 3675:; it could not drive a 3441:oscillation transformer 2594:". Since there were no 2140:, then is applied to a 1185:unmanned aerial vehicle 1139:NASA Deep Space Network 1135:communication satellite 926:Communications receiver 48:communications receiver 10410:Communication protocol 10196:Charles Sumner Tainter 10011:Walter Houser Brattain 9956:Edwin Howard Armstrong 9764:Information revolution 9449:Automotive electronics 9398:Robotic vacuum cleaner 9358:Information technology 9163:Electronic engineering 9042:Pizzicato Comes of Age 8366:The Electrical Journal 8226:Proceedings of the IRE 8197:Lee, Thomas H. (2004) 8038:Okamura, Sōgo (1994). 8016:Lee, Thomas H. (2004) 7797:Nahin, Paul J. (2001) 7700:Phillips, Vivian 1980 7200:Hong, Sungook (2001). 7130:The Fortnightly Review 7058:Beauchamp, Ken (2001) 7013:Hong, Sungook (2001). 6931:Lee, Thomas H. (2004) 6907:Phillips, Vivian 1980 6830:Phillips, Vivian 1980 6664:Phillips, Vivian 1980 6646:Phillips, Vivian 1980 6511:Phillips, Vivian 1980 6496:Phillips, Vivian 1980 6461:Phillips, Vivian 1980 6352:Hong, Sungook (2001). 6270:Nahin, Paul J. (2001) 5861:Hagen, Jon B. (1996). 5640:Dixon, Robert (1998). 5610:Lee, Thomas H. (2004) 5246:software-defined radio 5107: 5003: 4955:intermediate frequency 4890: 4836: 4727:parasitic oscillations 4706:, invented in 1916 by 4610: 4408: 4400: 4236: 4099:parasitic oscillations 4071:, which were used for 4059:automatic gain control 4037:with a tinny-sounding 3997:(CW) radiotelegraphy, 3966: 3954: 3932:intermediate frequency 3773: 3749:, invented in 1908 by 3713:Beginning around 1905 3710: 3669: 3660:Schottky barrier diode 3656:semiconductor junction 3644:cat's whisker detector 3544:Crystal radio receiver 3362: 3344: 3302:in the tuned circuit: 3284:was determined by the 3143:cat's whisker detector 3132: 3096:, invented in 1904 by 3013: 2966: 2913: 2837:powered by the relay. 2809:, invented in 1890 by 2760:and transcribed later. 2550:spark gap transmitters 2537: 2525: 2517: 2472:electromagnetic theory 2422:automatic gain control 2390:multipath interference 2371:Automatic gain control 2355: 2328: 2294:parasitic oscillations 2270: 2221:intermediate frequency 2196:intermediate frequency 2180: 2105: 1950: 1942: 1864:frequency-shift keying 1825: 1760: 1729: 1504:on either side of the 1465: 1360: 1197:Radio controlled model 991: 922: 897: 769:intermediate frequency 702:) which receives free 626:) is a component in a 549:portable media players 507:that also includes an 469: 383:(174–240 MHz) or 75: 59: 39: 10384:Polarization-division 10116:Narinder Singh Kapany 10081:Erna Schneider Hoover 10001:Jagadish Chandra Bose 9981:Alexander Graham Bell 9712:online video platform 9383:Portable media player 9256:Molecular electronics 9251:Low-power electronics 9069:Radio Receiver Theory 8922:Kim, Woonyun (2015). 8797:(17): 3. July 8, 1933 8247:on September 24, 2015 7605:History of Telegraphy 7140:on September 29, 2018 7060:History of Telegraphy 6800:Stone, Ellery (1919) 6388:Sarkar et al. (2006) 6239:History of Telegraphy 6204:Carr, Joseph (1990). 5643:Radio Receiver Design 5348:Radio receiver design 5318:Radiogram (furniture) 5075: 5001: 4975:The invention of the 4873: 4834: 4608: 4494:(amplification) of a 4479:regenerative receiver 4406: 4398: 4391:Regenerative receiver 4233: 4150:regenerative receiver 4053:, pushbutton tuning, 3960: 3952: 3906:electronic oscillator 3808:electrolytic detector 3771: 3704: 3664: 3360: 3345: 3127: 3019:Electrolytic detector 3012:Electrolytic detector 3011: 2964: 2911: 2904:Other early detectors 2886:electrolytic detector 2531: 2523: 2512:and coherer receiver 2504: 2356: 2329: 2268: 2249:surface acoustic wave 2178: 2099: 2066:The bypass capacitor 1948: 1940: 1823: 1800:signal-to-noise ratio 1755: 1730: 1552:surface acoustic wave 1459: 1396:ferrite loop antennas 1359:Symbol for an antenna 1358: 1351:Radio receiver design 1093:Satellite transponder 1010:Wireless (WiFi) modem 989: 920: 895: 619:AV or Stereo receiver 539:- a radio powered by 460: 216:, provided either by 108:electromagnetic waves 65: 45: 33: 10226:Vladimir K. Zworykin 10186:Almon Brown Strowger 10156:Charles Grafton Page 9811:Prepaid mobile phone 9739:Electrical telegraph 9577:Terahertz technology 9558:Open-source hardware 9514:Consumer electronics 9484:Electronics industry 9246:Flexible electronics 9153:Analogue electronics 7799:The Science of Radio 7772:The Electric Journal 7088:selective signaling. 6851:Old Timer's Bulletin 6272:The Science of Radio 5190:, typically using a 5156:can be performed by 5118:chips, pioneered by 4293:as a more sensitive 4187:factual accuracy is 4162:frequency modulation 4023:amplitude modulation 4003:frequency modulation 3999:amplitude modulation 3437:resonant transformer 3306: 3241:resonant transformer 3151:Karl Ferdinand Braun 3098:John Ambrose Fleming 3053:Early Fleming valve. 2929:amplitude modulation 2632:resonant transformer 2628:magnetically coupled 2338: 2311: 2053:applied to the load 1667: 1288:oil and gas drilling 1260:Wild animal tracking 1187:, or as simple as a 1122:satellite television 980:wireless microphones 704:broadcast television 692:broadcast television 297:is permitted in the 287:frequency modulation 256:amplitude modulation 224:. All radios have a 128:electronic amplifier 116:alternating currents 80:radio communications 10176:Johann Philipp Reis 9935:Wireless revolution 9897:The Telephone Cases 9754:Hydraulic telegraph 9553:Nuclear electronics 9378:Networking hardware 9281:Quantum electronics 9266:Organic electronics 9188:Printed electronics 9158:Digital electronics 8146:1916NYASA..27..215A 7653:Radio for Everybody 6390:History of Wireless 6090:Coe, Lewis (2006). 5367:Radio-Electronics, 5196:audio coding format 5110:The development of 4938:when he was in the 4817:tubes around 1930. 4761:Neutrodyne receiver 4624:garage door openers 4146:feedback oscillator 4063:broadcast receivers 3963:Golden Age of Radio 3838:and the difference 3782:heterodyne receiver 3763:Rudolph Goldschmidt 3477:, widely used with 3433:inductively-coupled 3423:In order to reject 3163:. One of the first 3114:thermionic emission 2864:instead of Hertz's 2855:amplitude modulated 2690:wireless telegraphy 2497:Wireless telegraphy 2412:which monitors the 1998:amplitude modulated 1899:television receiver 1857:frequency modulated 1850:amplitude modulated 1416:television antennas 1265:wildlife management 1223:, and the military. 1052:telephone companies 1004:Data communications 975:Wireless microphone 961:shortwave listening 877:Citizens band radio 708:television stations 611:shortwave listening 303:very high frequency 208:in the radio or an 72:golden age of radio 10374:Frequency-division 10351:Telephone exchange 10221:Charles Wheatstone 10151:Jun-ichi Nishizawa 10126:Innocenzo Manzetti 10061:Reginald Fessenden 9796:Optical telegraphy 9629:Telecommunications 9531:Marine electronics 9504:Integrated circuit 9423:Video game console 9221:2020s in computing 9203:Thermal management 8934:. pp. 89–90. 8284:(6): 30–31, 56, 58 7688:tikker heterodyne. 7402:Patent No. 649,621 7100:Aitken, Hugh 2014 7043:Aitken, Hugh 2014 6301:Icons of Invention 5154:analog electronics 5112:integrated circuit 5108: 5062:Digital technology 5004: 4951:Reginald Fessenden 4891: 4837: 4708:Ernst Alexanderson 4611: 4524:grid-leak detector 4409: 4401: 4307:grid-leak detector 4275:the radio carrier. 4267:the grid near its 4237: 4047:frequency response 4034:radio broadcasting 3967: 3955: 3914:Alexander Meissner 3778:Reginald Fessenden 3774: 3711: 3462:Impedance matching 3451:resonant frequency 3412:crystal detector, 3363: 3353:Inductive coupling 3340: 3272:resonant frequency 3185:grid-leak detector 3133: 3036:AM radio broadcast 3028:Reginald Fessenden 3014: 2967: 2914: 2849:the radio wave to 2542:radio transmitters 2538: 2526: 2518: 2351: 2324: 2271: 2181: 2106: 2072:low pass filtering 1991:across its output. 1977:, consisting of a 1951: 1943: 1826: 1761: 1725: 1595:frequency spectrum 1572:resonant frequency 1466: 1464:of radio receivers 1446:Bandpass filtering 1404:inverted F antenna 1361: 1345:How receivers work 1295:Measuring receiver 1189:garage door opener 992: 959:stations, and for 932:shortwave receiver 923: 898: 850:landline telephone 676:television channel 639:Other applications 606:Shortwave receiver 470: 427:frequency response 313:stereophonic sound 299:FM broadcast bands 274:(MF) range of the 264:AM broadcast bands 262:is allowed in the 155:radio broadcasting 151:electronic circuit 120:electronic filters 86:, also known as a 76: 66:Girl listening to 60: 40: 10687: 10686: 10425:Store and forward 10420:Data transmission 10334:Network switching 10285:Transmission line 10131:Guglielmo Marconi 10096:Internet pioneers 9961:Mohamed M. Atalla 9930:Whistled language 9595: 9594: 9572:Radio electronics 9198:Schematic capture 9183:Power electronics 9086:978-5-03-001321-3 8941:978-0-12-409522-9 8859:978-0-8165-1284-3 8728:Radio in the Home 8140:(24): 1149–1152. 7588:978-0-393-31851-7 7506:978-1-4208-9084-6 7479:978-0-521-29681-6 5333:Telecommunication 5286:Batteryless radio 5131:digital circuitry 5089:cellular receiver 5040:Texas Instruments 4981:transistor radios 4971:Semiconductor era 4965:All American Five 4918:All American Five 4572:radio transmitter 4554:Armstrong circuit 4504:positive feedback 4332:until the 1930s. 4228: 4227: 4220: 4055:tuning indicators 3483:mutual inductance 3479:crystal receivers 3471:mutual inductance 3338: 3335: 2981:Ernest Rutherford 2977:Guglielmo Marconi 2972:Magnetic detector 2965:Magnetic detector 2686:Guglielmo Marconi 2610:electric currents 2506:Guglielmo Marconi 2428:mechanism in the 2392:; this is called 2348: 2321: 2286:triple-conversion 2281:double-conversion 2245:ceramic resonator 1972:envelope detector 1933:Envelope detector 1713: 1695: 1677: 1641:transfer function 1548:ceramic resonator 1482:resonant circuits 1300:spectrum analyzer 1235:used with the US 817:telephone network 787:, a receiver and 525:home audio system 196:, which receives 16:(Redirected from 10707: 10700:Receiver (radio) 10677: 10676: 10667: 10666: 10657: 10656: 10647: 10646: 10645: 10518:Notable networks 10508:Wireless network 10448:Cellular network 10440:Types of network 10415:Computer network 10302:Network topology 10216:Thomas A. Watson 10071:Oliver Heaviside 10056:Philo Farnsworth 10031:Daniel Davis Jr. 10006:Charles Bourseul 9966:John Logie Baird 9675:Data compression 9670:Computer network 9622: 9615: 9608: 9599: 9598: 9567:Radio navigation 9464:Data acquisition 9173:Microelectronics 9132: 9125: 9118: 9109: 9108: 9104: 9098: 9090: 9044: 9039: 9033: 9032: 9012: 9006: 9005: 9003: 9002: 8987: 8981: 8980: 8952: 8946: 8945: 8919: 8913: 8912: 8892: 8886: 8881: 8875: 8870: 8864: 8863: 8843: 8832: 8831: 8829: 8818: 8807: 8806: 8804: 8802: 8788: 8780: 8774: 8765: 8759: 8750: 8744: 8743: 8741: 8739: 8725: 8716: 8707: 8706: 8704: 8693: 8687: 8686: 8684: 8682: 8668: 8659: 8653: 8646: 8640: 8639: 8637: 8626: 8617: 8612: 8601: 8592: 8579: 8574: 8568: 8559: 8553: 8544: 8538: 8537: 8535: 8524: 8518: 8513: 8504: 8503: 8501: 8499: 8485: 8475: 8469: 8468: 8466: 8455: 8446: 8437: 8426: 8417: 8404: 8399: 8382: 8381: 8379: 8377: 8357: 8351: 8350: 8348: 8346: 8341:on July 28, 2013 8340: 8334:. Archived from 8309: 8300: 8294: 8293: 8291: 8289: 8275: 8266: 8257: 8256: 8254: 8252: 8246: 8240:. Archived from 8223: 8214: 8203: 8194: 8188: 8179: 8173: 8172: 8170: 8168: 8134:Electrical World 8125: 8119: 8118: 8116: 8105: 8099: 8093: 8091: 8089: 8062: 8056: 8055: 8035: 8022: 8013: 7988: 7987: 7967: 7936: 7927: 7921: 7912: 7906: 7905: 7885: 7874: 7873: 7853: 7838: 7829: 7818: 7809: 7803: 7794: 7788: 7787: 7785: 7783: 7763: 7757: 7748: 7742: 7741: 7721: 7706: 7697: 7691: 7690: 7673: 7662: 7661: 7647: 7641: 7640: 7626: 7620: 7619: 7599: 7593: 7592: 7573:Lillian Hoddeson 7569:Riordan, Michael 7565: 7559: 7558: 7538: 7527: 7526: 7517: 7511: 7510: 7490: 7484: 7483: 7463: 7454: 7451: 7445: 7442: 7436: 7431: 7425: 7418: 7412: 7398: 7392: 7389: 7380: 7377: 7366: 7365: 7363: 7352: 7346: 7337: 7322: 7321: 7304: 7295: 7286: 7277: 7274: 7268: 7267: 7247: 7236: 7233: 7227: 7224: 7218: 7217: 7197: 7191: 7188: 7182: 7181: 7161: 7150: 7149: 7147: 7145: 7121: 7115: 7112: 7106: 7097: 7091: 7090: 7073: 7064: 7055: 7049: 7040: 7031: 7030: 7010: 6997: 6988: 6982: 6973: 6967: 6958: 6952: 6943: 6937: 6928: 6913: 6904: 6898: 6889: 6883: 6874: 6868: 6866: 6864: 6862: 6842: 6836: 6827: 6821: 6812: 6806: 6797: 6780: 6779: 6759: 6753: 6752: 6750: 6748: 6728: 6722: 6721: 6719: 6718: 6683: 6670: 6661: 6652: 6643: 6637: 6636: 6634: 6632: 6612: 6606: 6605: 6603: 6601: 6581: 6575: 6574: 6554: 6548: 6547: 6545: 6543: 6523: 6517: 6508: 6502: 6493: 6487: 6478: 6467: 6458: 6452: 6451: 6437: 6424: 6423: 6413: 6402: 6385: 6370: 6369: 6349: 6343: 6342: 6322: 6316: 6315: 6295: 6276: 6267: 6254: 6253: 6233: 6222: 6221: 6201: 6150: 6149: 6129: 6108: 6107: 6087: 6062: 6061: 6041: 6035: 6034: 6014: 6005: 6004: 5980: 5965: 5964: 5962: 5960: 5946: 5937: 5931: 5930: 5910: 5879: 5878: 5858: 5847: 5846: 5826: 5813: 5804: 5798: 5797: 5777: 5768: 5767: 5747: 5738: 5729: 5720: 5711: 5700: 5695: 5680: 5671: 5658: 5657: 5637: 5616: 5607: 5590: 5589: 5587: 5585: 5565: 5556: 5554: 5534: 5511: 5510: 5490: 5484: 5479: 5473: 5468: 5462: 5459: 5453: 5452: 5432: 5426: 5425: 5405: 5399: 5398: 5378: 5372: 5364: 5280: 5275: 5274: 5273: 5056:transistor radio 5020:General Electric 4994:Transistor radio 4910: 4901: 4880:local oscillator 4791: 4779: 4688: 4668: 4656: 4463: 4435: 4419: 4365:Western Electric 4256: 4247: 4223: 4216: 4212: 4209: 4203: 4200:reliably sourced 4180: 4179: 4172: 4039:horn loudspeaker 3804:crystal detector 3751:Valdemar Poulsen 3658:functioned as a 3633:radio broadcasts 3616: 3604: 3586: 3574: 3562: 3537:US Supreme Court 3532:John Stone Stone 3385: 3373: 3349: 3347: 3346: 3341: 3339: 3337: 3336: 3328: 3316: 3266:. It had a high 3254:, consisting of 3226:resonant circuit 3138:Crystal detector 3083:Thermionic diode 3062: 3050: 3024:liquid barretter 2882:crystal detector 2871:Poldhu, Cornwall 2862:monopole antenna 2785: 2773: 2739: 2726: 2705:Coherer receiver 2462:History of radio 2360: 2358: 2357: 2352: 2350: 2349: 2346: 2333: 2331: 2330: 2325: 2323: 2322: 2319: 2201:local oscillator 2064: 2029: 2004: 1996:See graphs. The 1804:electronic noise 1734: 1732: 1731: 1726: 1715: 1714: 1711: 1696: 1693: 1679: 1678: 1675: 1621: 1590: 1420:satellite dishes 1241:artillery shells 1151:radio telescopes 1112:frequency. In a 896:Handheld scanner 568:Transistor radio 493:fireplace mantel 431:audio distortion 272:medium frequency 232:Modulation types 21: 18:Receiver (radio) 10715: 10714: 10710: 10709: 10708: 10706: 10705: 10704: 10690: 10689: 10688: 10683: 10643: 10641: 10633: 10575: 10512: 10434: 10398: 10355: 10304: 10296: 10237: 10230: 10136:Robert Metcalfe 9991:Tim Berners-Lee 9939: 9759:Information Age 9631: 9626: 9596: 9591: 9524:Small appliance 9519:Major appliance 9499:Home automation 9489:Embedded system 9444:Audio equipment 9432: 9428:Washing machine 9353:Home theater PC 9309:Central heating 9304:Air conditioner 9296: 9290: 9261:Nanoelectronics 9213: 9207: 9178:Optoelectronics 9168:Instrumentation 9141: 9136: 9092: 9091: 9087: 9053: 9051:Further reading 9048: 9047: 9040: 9036: 9029: 9013: 9009: 9000: 8998: 8989: 8988: 8984: 8953: 8949: 8942: 8920: 8916: 8909: 8893: 8889: 8882: 8878: 8871: 8867: 8860: 8844: 8835: 8827: 8819: 8810: 8800: 8798: 8786: 8782: 8781: 8777: 8766: 8762: 8751: 8747: 8737: 8735: 8723: 8717: 8710: 8702: 8694: 8690: 8680: 8678: 8666: 8660: 8656: 8647: 8643: 8635: 8627: 8620: 8613: 8604: 8593: 8582: 8575: 8571: 8560: 8556: 8545: 8541: 8533: 8525: 8521: 8514: 8507: 8497: 8495: 8488:Broadcast Radio 8483: 8476: 8472: 8464: 8456: 8449: 8438: 8429: 8418: 8407: 8400: 8385: 8375: 8373: 8358: 8354: 8344: 8342: 8338: 8307: 8301: 8297: 8287: 8285: 8273: 8267: 8260: 8250: 8248: 8244: 8221: 8215: 8206: 8195: 8191: 8180: 8176: 8166: 8164: 8126: 8122: 8114: 8106: 8102: 8087: 8085: 8063: 8059: 8052: 8036: 8025: 8014: 7991: 7984: 7968: 7939: 7928: 7924: 7913: 7909: 7902: 7886: 7877: 7870: 7854: 7841: 7830: 7821: 7810: 7806: 7795: 7791: 7781: 7779: 7764: 7760: 7749: 7745: 7738: 7722: 7709: 7698: 7694: 7674: 7665: 7648: 7644: 7627: 7623: 7616: 7600: 7596: 7589: 7566: 7562: 7555: 7539: 7530: 7519: 7518: 7514: 7507: 7491: 7487: 7480: 7464: 7457: 7452: 7448: 7443: 7439: 7432: 7428: 7419: 7415: 7399: 7395: 7390: 7383: 7378: 7369: 7361: 7353: 7349: 7338: 7325: 7310:Radio Reception 7305: 7298: 7287: 7280: 7275: 7271: 7264: 7248: 7239: 7234: 7230: 7225: 7221: 7214: 7198: 7194: 7189: 7185: 7178: 7162: 7153: 7143: 7141: 7122: 7118: 7113: 7109: 7098: 7094: 7074: 7067: 7056: 7052: 7041: 7034: 7027: 7011: 7000: 6989: 6985: 6974: 6970: 6959: 6955: 6944: 6940: 6929: 6916: 6905: 6901: 6890: 6886: 6875: 6871: 6860: 6858: 6843: 6839: 6828: 6824: 6813: 6809: 6798: 6783: 6776: 6760: 6756: 6746: 6744: 6729: 6725: 6716: 6714: 6684: 6673: 6662: 6655: 6644: 6640: 6630: 6628: 6613: 6609: 6599: 6597: 6582: 6578: 6571: 6555: 6551: 6541: 6539: 6524: 6520: 6509: 6505: 6494: 6490: 6479: 6470: 6459: 6455: 6438: 6427: 6414: 6405: 6386: 6373: 6366: 6350: 6346: 6339: 6323: 6319: 6312: 6296: 6279: 6268: 6257: 6250: 6234: 6225: 6218: 6202: 6153: 6146: 6130: 6111: 6104: 6088: 6065: 6058: 6042: 6038: 6031: 6015: 6008: 6001: 5981: 5968: 5958: 5956: 5944: 5938: 5934: 5927: 5911: 5882: 5875: 5859: 5850: 5843: 5827: 5816: 5805: 5801: 5794: 5778: 5771: 5764: 5748: 5741: 5730: 5723: 5712: 5703: 5696: 5683: 5672: 5661: 5654: 5638: 5619: 5608: 5593: 5583: 5581: 5566: 5559: 5551: 5535: 5514: 5507: 5491: 5487: 5480: 5476: 5469: 5465: 5460: 5456: 5449: 5433: 5429: 5422: 5406: 5402: 5395: 5379: 5375: 5365: 5361: 5356: 5276: 5271: 5269: 5266: 5147:cognitive radio 5135:analog circuits 5070: 5064: 4996: 4990: 4988:Portable radios 4973: 4936:Edwin Armstrong 4928:superheterodyne 4924: 4923: 4922: 4921: 4913: 4912: 4911: 4903: 4902: 4868: 4862: 4841:reflex receiver 4829: 4827:Reflex receiver 4823: 4821:Reflex receiver 4807:Louis Hazeltine 4803: 4802: 4801: 4800: 4799: 4792: 4784: 4783: 4780: 4769: 4763: 4700: 4699: 4698: 4697: 4696: 4689: 4681: 4680: 4669: 4661: 4660: 4657: 4646: 4640: 4615:Edwin Armstrong 4603: 4597: 4535:radiotelegraphy 4483:Edwin Armstrong 4475: 4474: 4473: 4472: 4471: 4464: 4456: 4455: 4436: 4428: 4427: 4420: 4393: 4387: 4369:Irving Langmuir 4315:Edwin Armstrong 4279: 4278: 4277: 4276: 4259: 4258: 4257: 4249: 4248: 4224: 4213: 4207: 4204: 4193: 4185:This section's 4181: 4177: 4170: 4141:Edwin Armstrong 4101:mixed with the 4077:shortwave radio 4027:AM broadcasting 4007:single sideband 3995:continuous wave 3947: 3945:Vacuum tube era 3928:superheterodyne 3910:Edwin Armstrong 3898: 3885:audio frequency 3881: 3872: 3863: 3854: 3845: 3836: 3827: 3800: 3791: 3715:continuous wave 3699: 3693: 3624: 3623: 3622: 3621: 3620: 3617: 3609: 3608: 3605: 3594: 3593: 3592: 3591: 3590: 3587: 3579: 3578: 3575: 3567: 3566: 3563: 3552: 3546: 3528:Ferdinand Braun 3520: 3518:Patent disputes 3512:IF transformers 3491:continuous wave 3421: 3420: 3419: 3418: 3417: 3386: 3378: 3377: 3374: 3355: 3327: 3320: 3315: 3307: 3304: 3303: 3276:bandpass filter 3218:William Crookes 3205: 3078: 3077: 3076: 3075: 3074: 3063: 3055: 3054: 3051: 2988:created by two 2975:- Developed by 2906: 2866:dipole antennas 2831:siphon recorder 2821:circuit with a 2799:Alexander Popov 2789: 2786: 2777: 2774: 2765: 2764: 2763: 2762: 2761: 2755:siphon recorder 2740: 2732: 2731: 2727: 2715: 2713: 2707: 2698:Alexander Popov 2658:siphon recorder 2623:bandpass filter 2574:radiotelegraphy 2534:siphon recorder 2499: 2493: 2464: 2458: 2426:dark adaptation 2377:signal strength 2373: 2367: 2345: 2341: 2339: 2336: 2335: 2318: 2314: 2312: 2309: 2308: 2276:dual-conversion 2260:image frequency 2189:Edwin Armstrong 2185:superheterodyne 2173: 2167: 2138:audio amplifier 2130:audio frequency 2114:radio frequency 2094: 2088: 2080: 2062: 2059: 2052: 2037: 2027: 2008:radio frequency 2002: 1966:by the radio's 1958:to recover the 1935: 1926:AM demodulation 1818: 1812: 1750: 1744: 1739: 1738: 1737: 1736: 1735: 1710: 1706: 1692: 1674: 1670: 1668: 1665: 1664: 1663: 1653: 1638: 1622: 1614: 1613: 1607: 1591: 1475:bandpass filter 1454: 1452:Bandpass filter 1448: 1428: 1381:magnetic fields 1369:radio frequency 1353: 1347: 1332:liquid nitrogen 1316:radio astronomy 1307:Radio telescope 1169:in the circuit. 1163:liquid nitrogen 1118:satellite radio 1050:(WANs), and by 1039:Microwave relay 751: 641: 594:Satellite radio 487:also called a " 455: 397:signal strength 393: 355:rather than an 346: 340: 295:FM broadcasting 260:AM broadcasting 249: 234: 222:electric outlet 190: 179: 167:wireless modems 124:radio frequency 112:radio frequency 56:shortwave radio 28: 23: 22: 15: 12: 11: 5: 10713: 10703: 10702: 10685: 10684: 10682: 10681: 10671: 10661: 10651: 10638: 10635: 10634: 10632: 10631: 10624: 10619: 10614: 10609: 10604: 10603: 10602: 10597: 10589: 10583: 10581: 10577: 10576: 10574: 10573: 10568: 10563: 10558: 10553: 10548: 10543: 10538: 10533: 10528: 10522: 10520: 10514: 10513: 10511: 10510: 10505: 10500: 10495: 10490: 10485: 10480: 10475: 10470: 10465: 10460: 10455: 10450: 10444: 10442: 10436: 10435: 10433: 10432: 10427: 10422: 10417: 10412: 10406: 10404: 10400: 10399: 10397: 10396: 10391: 10386: 10381: 10376: 10371: 10369:Space-division 10365: 10363: 10357: 10356: 10354: 10353: 10348: 10347: 10346: 10341: 10331: 10330: 10329: 10319: 10314: 10308: 10306: 10298: 10297: 10295: 10294: 10293: 10292: 10282: 10281: 10280: 10270: 10265: 10260: 10259: 10258: 10248: 10242: 10240: 10232: 10231: 10229: 10228: 10223: 10218: 10213: 10208: 10206:Camille Tissot 10203: 10198: 10193: 10188: 10183: 10181:Claude Shannon 10178: 10173: 10171:Tivadar Puskás 10168: 10163: 10158: 10153: 10148: 10143: 10141:Antonio Meucci 10138: 10133: 10128: 10123: 10118: 10113: 10111:Charles K. Kao 10108: 10103: 10098: 10093: 10088: 10086:Harold Hopkins 10083: 10078: 10073: 10068: 10063: 10058: 10053: 10048: 10043: 10038: 10033: 10028: 10023: 10018: 10013: 10008: 10003: 9998: 9993: 9988: 9986:Emile Berliner 9983: 9978: 9973: 9968: 9963: 9958: 9953: 9947: 9945: 9941: 9940: 9938: 9937: 9932: 9927: 9925:Videotelephony 9922: 9917: 9916: 9915: 9910: 9900: 9893: 9888: 9882: 9877: 9872: 9867: 9862: 9861: 9860: 9855: 9850: 9840: 9839: 9838: 9828: 9823: 9821:Radiotelephone 9818: 9813: 9808: 9803: 9798: 9793: 9788: 9787: 9786: 9776: 9771: 9766: 9761: 9756: 9751: 9746: 9741: 9736: 9731: 9726: 9725: 9724: 9719: 9714: 9709: 9707:Internet video 9699: 9698: 9697: 9692: 9687: 9682: 9672: 9667: 9662: 9657: 9652: 9647: 9641: 9639: 9633: 9632: 9625: 9624: 9617: 9610: 9602: 9593: 9592: 9590: 9589: 9588:Communications 9579: 9574: 9569: 9560: 9555: 9550: 9545: 9539: 9533: 9528: 9527: 9526: 9521: 9516: 9509:Home appliance 9506: 9501: 9496: 9494:Home appliance 9491: 9486: 9481: 9476: 9471: 9466: 9461: 9459:Control system 9456: 9451: 9446: 9440: 9438: 9434: 9433: 9431: 9430: 9425: 9420: 9415: 9410: 9405: 9400: 9395: 9390: 9385: 9380: 9375: 9370: 9368:Microwave oven 9365: 9360: 9355: 9350: 9345: 9340: 9335: 9330: 9325: 9316: 9311: 9306: 9300: 9298: 9292: 9291: 9289: 9288: 9283: 9278: 9273: 9268: 9263: 9258: 9253: 9248: 9243: 9238: 9233: 9231:Bioelectronics 9228: 9223: 9217: 9215: 9209: 9208: 9206: 9205: 9200: 9195: 9190: 9185: 9180: 9175: 9170: 9165: 9160: 9155: 9149: 9147: 9143: 9142: 9135: 9134: 9127: 9120: 9112: 9106: 9105: 9085: 9077:Mir Publishers 9064: 9052: 9049: 9046: 9045: 9034: 9027: 9007: 8982: 8947: 8940: 8932:Academic Press 8914: 8908:978-0313398636 8907: 8887: 8876: 8865: 8858: 8833: 8808: 8775: 8760: 8745: 8708: 8688: 8654: 8641: 8618: 8602: 8580: 8569: 8554: 8539: 8519: 8505: 8470: 8447: 8427: 8405: 8383: 8352: 8318:(9): 215–247. 8295: 8258: 8232:(3): 261–293. 8204: 8189: 8174: 8120: 8100: 8057: 8051:978-9051991451 8050: 8023: 7989: 7983:978-1847285263 7982: 7937: 7922: 7907: 7901:978-0470409749 7900: 7875: 7869:978-0231510080 7868: 7839: 7819: 7804: 7789: 7758: 7743: 7736: 7707: 7692: 7663: 7642: 7621: 7615:978-0852967928 7614: 7594: 7587: 7560: 7554:978-1847285263 7553: 7528: 7512: 7505: 7485: 7478: 7455: 7446: 7437: 7426: 7413: 7393: 7381: 7367: 7347: 7323: 7296: 7278: 7269: 7263:978-1400857883 7262: 7237: 7228: 7219: 7213:978-0262082983 7212: 7192: 7183: 7177:978-0471697398 7176: 7151: 7116: 7107: 7092: 7065: 7050: 7032: 7026:978-0262082983 7025: 6998: 6983: 6968: 6953: 6938: 6914: 6899: 6884: 6869: 6837: 6822: 6807: 6781: 6774: 6754: 6723: 6671: 6653: 6638: 6607: 6576: 6570:978-1400854608 6569: 6549: 6518: 6503: 6488: 6468: 6453: 6425: 6403: 6371: 6365:978-0262082983 6364: 6344: 6337: 6317: 6311:978-0313347436 6310: 6277: 6255: 6249:978-0852967928 6248: 6223: 6217:978-0071507660 6216: 6151: 6144: 6109: 6103:978-0786426621 6102: 6063: 6057:978-0387951508 6056: 6036: 6030:978-1118647844 6029: 6006: 6000:978-0906048245 5999: 5966: 5932: 5926:978-0521835398 5925: 5880: 5874:978-0521553568 5873: 5848: 5842:978-1596933101 5841: 5814: 5799: 5793:978-0387981000 5792: 5769: 5763:978-0750673198 5762: 5739: 5721: 5701: 5681: 5659: 5653:978-0824701611 5652: 5617: 5591: 5557: 5550:978-1118647844 5549: 5512: 5506:978-8120351240 5505: 5485: 5474: 5463: 5454: 5448:978-1483140780 5447: 5427: 5421:978-0442308612 5420: 5400: 5394:978-1317906834 5393: 5373: 5358: 5357: 5355: 5352: 5351: 5350: 5345: 5340: 5335: 5330: 5325: 5320: 5315: 5310: 5307:List of radios 5304: 5299: 5293: 5288: 5282: 5281: 5265: 5262: 5239:text-to-speech 5120:Asad Ali Abidi 5093:wireless modem 5063: 5060: 4989: 4986: 4972: 4969: 4915: 4914: 4905: 4904: 4896: 4895: 4894: 4893: 4892: 4864:Main article: 4861: 4858: 4825:Main article: 4822: 4819: 4793: 4786: 4785: 4781: 4774: 4773: 4772: 4771: 4770: 4765:Main article: 4762: 4759: 4690: 4683: 4682: 4670: 4663: 4662: 4658: 4651: 4650: 4649: 4648: 4647: 4642:Main article: 4639: 4636: 4620:walkie-talkies 4599:Main article: 4596: 4593: 4543:carrier signal 4488:walkie-talkies 4481:, invented by 4465: 4458: 4457: 4437: 4430: 4429: 4421: 4414: 4413: 4412: 4411: 4410: 4389:Main article: 4386: 4383: 4269:cutoff voltage 4261: 4260: 4251: 4250: 4242: 4241: 4240: 4239: 4238: 4226: 4225: 4184: 4182: 4175: 4169: 4166: 4032:The advent of 3946: 3943: 3896: 3879: 3870: 3861: 3852: 3843: 3834: 3825: 3798: 3789: 3695:Main article: 3692: 3689: 3629:radiotelephony 3618: 3611: 3610: 3606: 3599: 3598: 3597: 3596: 3595: 3588: 3581: 3580: 3576: 3569: 3568: 3564: 3557: 3556: 3555: 3554: 3553: 3548:Main article: 3545: 3542: 3519: 3516: 3446:magnetic field 3408:loading coil, 3387: 3380: 3379: 3375: 3368: 3367: 3366: 3365: 3364: 3354: 3351: 3334: 3331: 3326: 3323: 3319: 3314: 3311: 3252:tuned circuits 3204: 3201: 3189: 3188: 3122: 3121: 3092:) - The first 3064: 3057: 3056: 3052: 3045: 3044: 3043: 3042: 3041: 3040: 3039: 3006: 3005: 2986:magnetic field 2933:radiotelephony 2905: 2902: 2811:Edouard Branly 2791: 2790: 2787: 2780: 2778: 2775: 2768: 2741: 2734: 2733: 2728: 2721: 2720: 2719: 2718: 2717: 2709:Main article: 2706: 2703: 2674: 2673: 2644: 2635: 2613: 2558:electric spark 2495:Main article: 2492: 2489: 2468:Heinrich Hertz 2460:Main article: 2457: 2454: 2438:lowpass filter 2410:control system 2369:Main article: 2366: 2363: 2344: 2317: 2241:quartz crystal 2169:Main article: 2166: 2163: 2154:radio spectrum 2090:Main article: 2087: 2084: 2083: 2082: 2078: 2057: 2050: 2035: 1993: 1992: 1984:with a bypass 1931:Main article: 1929: 1928: 1919:microprocessor 1911:wireless modem 1868: 1867: 1860: 1853: 1814:Main article: 1811: 1808: 1756:Symbol for an 1746:Main article: 1743: 1740: 1724: 1721: 1718: 1709: 1705: 1702: 1699: 1691: 1688: 1685: 1682: 1673: 1651: 1643:of the filter 1636: 1623: 1616: 1615: 1605: 1592: 1585: 1584: 1583: 1582: 1581: 1580: 1579: 1555: 1544:quartz crystal 1525:is called the 1462:block diagrams 1450:Main article: 1447: 1444: 1427: 1424: 1346: 1343: 1342: 1341: 1340: 1339: 1303: 1291: 1270: 1269: 1268: 1256: 1244: 1224: 1204: 1181:Remote control 1176:Remote control 1172: 1171: 1170: 1143:interplanetary 1125: 1104:signal from a 1086:interplanetary 1082:geosynchronous 1070:remote sensing 1057: 1056: 1055: 1035: 1026: 1001: 1000: 999: 983: 966: 965: 964: 914: 906:radio channels 889: 881: 873: 845:Cordless phone 841: 774: 773: 772: 760:signal from a 749: 744:satellite dish 723: 640: 637: 636: 635: 614: 602: 590: 578: 577: 576: 564: 536:Portable radio 532: 512: 496: 480: 454: 451: 392: 389: 365:radio spectrum 353:digital signal 342:Main article: 339: 336: 276:radio spectrum 248: 245: 233: 230: 226:volume control 214:electric power 202:radio stations 178: 175: 94:, or simply a 84:radio receiver 36:radio stations 26: 9: 6: 4: 3: 2: 10712: 10701: 10698: 10697: 10695: 10680: 10672: 10670: 10662: 10660: 10652: 10650: 10640: 10639: 10636: 10629: 10625: 10623: 10620: 10618: 10615: 10613: 10610: 10608: 10605: 10601: 10598: 10596: 10593: 10592: 10590: 10588: 10585: 10584: 10582: 10578: 10572: 10569: 10567: 10564: 10562: 10559: 10557: 10554: 10552: 10549: 10547: 10544: 10542: 10539: 10537: 10534: 10532: 10529: 10527: 10524: 10523: 10521: 10519: 10515: 10509: 10506: 10504: 10501: 10499: 10496: 10494: 10491: 10489: 10486: 10484: 10481: 10479: 10476: 10474: 10471: 10469: 10466: 10464: 10461: 10459: 10456: 10454: 10451: 10449: 10446: 10445: 10443: 10441: 10437: 10431: 10428: 10426: 10423: 10421: 10418: 10416: 10413: 10411: 10408: 10407: 10405: 10401: 10395: 10394:Code-division 10392: 10390: 10387: 10385: 10382: 10380: 10379:Time-division 10377: 10375: 10372: 10370: 10367: 10366: 10364: 10362: 10358: 10352: 10349: 10345: 10342: 10340: 10337: 10336: 10335: 10332: 10328: 10325: 10324: 10323: 10320: 10318: 10315: 10313: 10310: 10309: 10307: 10305:and switching 10303: 10299: 10291: 10288: 10287: 10286: 10283: 10279: 10276: 10275: 10274: 10271: 10269: 10266: 10264: 10261: 10257: 10256:optical fiber 10254: 10253: 10252: 10249: 10247: 10246:Coaxial cable 10244: 10243: 10241: 10239: 10233: 10227: 10224: 10222: 10219: 10217: 10214: 10212: 10209: 10207: 10204: 10202: 10199: 10197: 10194: 10192: 10189: 10187: 10184: 10182: 10179: 10177: 10174: 10172: 10169: 10167: 10164: 10162: 10161:Radia Perlman 10159: 10157: 10154: 10152: 10149: 10147: 10144: 10142: 10139: 10137: 10134: 10132: 10129: 10127: 10124: 10122: 10119: 10117: 10114: 10112: 10109: 10107: 10104: 10102: 10099: 10097: 10094: 10092: 10089: 10087: 10084: 10082: 10079: 10077: 10074: 10072: 10069: 10067: 10064: 10062: 10059: 10057: 10054: 10052: 10051:Lee de Forest 10049: 10047: 10046:Thomas Edison 10044: 10042: 10039: 10037: 10036:Donald Davies 10034: 10032: 10029: 10027: 10024: 10022: 10021:Claude Chappe 10019: 10017: 10014: 10012: 10009: 10007: 10004: 10002: 9999: 9997: 9994: 9992: 9989: 9987: 9984: 9982: 9979: 9977: 9974: 9972: 9969: 9967: 9964: 9962: 9959: 9957: 9954: 9952: 9949: 9948: 9946: 9942: 9936: 9933: 9931: 9928: 9926: 9923: 9921: 9918: 9914: 9911: 9909: 9906: 9905: 9904: 9901: 9899: 9898: 9894: 9892: 9889: 9886: 9883: 9881: 9878: 9876: 9873: 9871: 9868: 9866: 9865:Smoke signals 9863: 9859: 9856: 9854: 9851: 9849: 9846: 9845: 9844: 9843:Semiconductor 9841: 9837: 9834: 9833: 9832: 9829: 9827: 9824: 9822: 9819: 9817: 9814: 9812: 9809: 9807: 9804: 9802: 9799: 9797: 9794: 9792: 9789: 9785: 9782: 9781: 9780: 9777: 9775: 9772: 9770: 9767: 9765: 9762: 9760: 9757: 9755: 9752: 9750: 9747: 9745: 9742: 9740: 9737: 9735: 9732: 9730: 9727: 9723: 9720: 9718: 9715: 9713: 9710: 9708: 9705: 9704: 9703: 9702:Digital media 9700: 9696: 9693: 9691: 9688: 9686: 9683: 9681: 9678: 9677: 9676: 9673: 9671: 9668: 9666: 9663: 9661: 9658: 9656: 9653: 9651: 9648: 9646: 9643: 9642: 9640: 9638: 9634: 9630: 9623: 9618: 9616: 9611: 9609: 9604: 9603: 9600: 9587: 9583: 9580: 9578: 9575: 9573: 9570: 9568: 9564: 9561: 9559: 9556: 9554: 9551: 9549: 9546: 9543: 9540: 9537: 9534: 9532: 9529: 9525: 9522: 9520: 9517: 9515: 9512: 9511: 9510: 9507: 9505: 9502: 9500: 9497: 9495: 9492: 9490: 9487: 9485: 9482: 9480: 9477: 9475: 9472: 9470: 9467: 9465: 9462: 9460: 9457: 9455: 9452: 9450: 9447: 9445: 9442: 9441: 9439: 9435: 9429: 9426: 9424: 9421: 9419: 9416: 9414: 9411: 9409: 9406: 9404: 9401: 9399: 9396: 9394: 9391: 9389: 9386: 9384: 9381: 9379: 9376: 9374: 9371: 9369: 9366: 9364: 9361: 9359: 9356: 9354: 9351: 9349: 9346: 9344: 9341: 9339: 9336: 9334: 9331: 9329: 9326: 9324: 9320: 9317: 9315: 9314:Clothes dryer 9312: 9310: 9307: 9305: 9302: 9301: 9299: 9293: 9287: 9284: 9282: 9279: 9277: 9274: 9272: 9269: 9267: 9264: 9262: 9259: 9257: 9254: 9252: 9249: 9247: 9244: 9242: 9239: 9237: 9234: 9232: 9229: 9227: 9224: 9222: 9219: 9218: 9216: 9210: 9204: 9201: 9199: 9196: 9194: 9193:Semiconductor 9191: 9189: 9186: 9184: 9181: 9179: 9176: 9174: 9171: 9169: 9166: 9164: 9161: 9159: 9156: 9154: 9151: 9150: 9148: 9144: 9140: 9133: 9128: 9126: 9121: 9119: 9114: 9113: 9110: 9102: 9096: 9088: 9082: 9078: 9074: 9070: 9065: 9063: 9062:0-07-136121-9 9059: 9055: 9054: 9043: 9038: 9030: 9028:9783319610801 9024: 9020: 9019: 9011: 8997:on 2007-09-16 8996: 8992: 8986: 8978: 8974: 8970: 8966: 8962: 8958: 8951: 8943: 8937: 8933: 8929: 8925: 8918: 8910: 8904: 8900: 8899: 8891: 8885: 8880: 8874: 8869: 8861: 8855: 8851: 8850: 8842: 8840: 8838: 8826: 8825: 8817: 8815: 8813: 8796: 8792: 8785: 8779: 8773: 8771: 8764: 8757: 8756: 8749: 8733: 8729: 8722: 8715: 8713: 8701: 8700: 8692: 8676: 8672: 8665: 8658: 8651: 8645: 8634: 8633: 8625: 8623: 8616: 8611: 8609: 8607: 8600: 8598: 8591: 8589: 8587: 8585: 8578: 8573: 8567: 8565: 8558: 8552: 8550: 8543: 8532: 8531: 8523: 8517: 8512: 8510: 8493: 8489: 8482: 8474: 8463: 8462: 8454: 8452: 8445: 8443: 8436: 8434: 8432: 8425: 8423: 8416: 8414: 8412: 8410: 8403: 8398: 8396: 8394: 8392: 8390: 8388: 8371: 8367: 8363: 8356: 8337: 8333: 8329: 8325: 8321: 8317: 8313: 8306: 8299: 8283: 8279: 8272: 8265: 8263: 8243: 8239: 8235: 8231: 8227: 8220: 8213: 8211: 8209: 8202: 8200: 8193: 8187: 8185: 8178: 8163: 8159: 8155: 8151: 8147: 8143: 8139: 8135: 8131: 8124: 8113: 8112: 8104: 8097: 8084: 8080: 8076: 8072: 8068: 8061: 8053: 8047: 8043: 8042: 8034: 8032: 8030: 8028: 8021: 8019: 8012: 8010: 8008: 8006: 8004: 8002: 8000: 7998: 7996: 7994: 7985: 7979: 7975: 7974: 7966: 7964: 7962: 7960: 7958: 7956: 7954: 7952: 7950: 7948: 7946: 7944: 7942: 7935: 7933: 7926: 7920: 7918: 7911: 7903: 7897: 7893: 7892: 7884: 7882: 7880: 7871: 7865: 7861: 7860: 7852: 7850: 7848: 7846: 7844: 7837: 7835: 7828: 7826: 7824: 7817: 7815: 7808: 7802: 7800: 7793: 7777: 7773: 7769: 7762: 7755: 7754: 7747: 7739: 7737:9780405060526 7733: 7729: 7728: 7720: 7718: 7716: 7714: 7712: 7705: 7703: 7696: 7689: 7685: 7681: 7680: 7672: 7670: 7668: 7659: 7655: 7654: 7646: 7638: 7634: 7633: 7625: 7617: 7611: 7607: 7606: 7598: 7590: 7584: 7580: 7579: 7574: 7570: 7564: 7556: 7550: 7546: 7545: 7537: 7535: 7533: 7524: 7523: 7516: 7508: 7502: 7498: 7497: 7489: 7481: 7475: 7471: 7470: 7462: 7460: 7450: 7441: 7435: 7430: 7423: 7417: 7411: 7407: 7403: 7397: 7388: 7386: 7376: 7374: 7372: 7360: 7359: 7351: 7345: 7343: 7336: 7334: 7332: 7330: 7328: 7320: 7316: 7312: 7311: 7303: 7301: 7294: 7292: 7285: 7283: 7273: 7265: 7259: 7255: 7254: 7246: 7244: 7242: 7232: 7223: 7215: 7209: 7205: 7204: 7196: 7187: 7179: 7173: 7169: 7168: 7160: 7158: 7156: 7139: 7135: 7131: 7127: 7120: 7111: 7105: 7103: 7096: 7089: 7085: 7081: 7080: 7072: 7070: 7063: 7061: 7054: 7048: 7046: 7039: 7037: 7028: 7022: 7018: 7017: 7009: 7007: 7005: 7003: 6996: 6994: 6987: 6981: 6979: 6972: 6966: 6964: 6957: 6951: 6949: 6942: 6936: 6934: 6927: 6925: 6923: 6921: 6919: 6912: 6910: 6903: 6897: 6895: 6888: 6882: 6880: 6873: 6856: 6852: 6848: 6841: 6835: 6833: 6826: 6820: 6818: 6811: 6805: 6803: 6796: 6794: 6792: 6790: 6788: 6786: 6777: 6775:9780405060526 6771: 6767: 6766: 6758: 6742: 6738: 6734: 6727: 6713: 6709: 6705: 6701: 6697: 6693: 6689: 6682: 6680: 6678: 6676: 6669: 6667: 6660: 6658: 6651: 6649: 6642: 6626: 6622: 6618: 6611: 6595: 6591: 6587: 6580: 6572: 6566: 6562: 6561: 6553: 6537: 6533: 6529: 6522: 6516: 6514: 6507: 6501: 6499: 6492: 6486: 6484: 6477: 6475: 6473: 6466: 6464: 6457: 6449: 6445: 6444: 6436: 6434: 6432: 6430: 6421: 6420: 6412: 6410: 6408: 6400: 6397: 6393: 6391: 6384: 6382: 6380: 6378: 6376: 6367: 6361: 6357: 6356: 6348: 6340: 6338:9780405060526 6334: 6330: 6329: 6321: 6313: 6307: 6303: 6302: 6294: 6292: 6290: 6288: 6286: 6284: 6282: 6275: 6273: 6266: 6264: 6262: 6260: 6251: 6245: 6241: 6240: 6232: 6230: 6228: 6219: 6213: 6209: 6208: 6200: 6198: 6196: 6194: 6192: 6190: 6188: 6186: 6184: 6182: 6180: 6178: 6176: 6174: 6172: 6170: 6168: 6166: 6164: 6162: 6160: 6158: 6156: 6147: 6145:9780405060526 6141: 6137: 6136: 6128: 6126: 6124: 6122: 6120: 6118: 6116: 6114: 6105: 6099: 6095: 6094: 6086: 6084: 6082: 6080: 6078: 6076: 6074: 6072: 6070: 6068: 6059: 6053: 6049: 6048: 6040: 6032: 6026: 6022: 6021: 6013: 6011: 6002: 5996: 5992: 5988: 5987: 5979: 5977: 5975: 5973: 5971: 5954: 5950: 5943: 5936: 5928: 5922: 5918: 5917: 5909: 5907: 5905: 5903: 5901: 5899: 5897: 5895: 5893: 5891: 5889: 5887: 5885: 5876: 5870: 5866: 5865: 5857: 5855: 5853: 5844: 5838: 5834: 5833: 5825: 5823: 5821: 5819: 5812: 5810: 5803: 5795: 5789: 5785: 5784: 5776: 5774: 5765: 5759: 5755: 5754: 5746: 5744: 5737: 5735: 5728: 5726: 5719: 5717: 5710: 5708: 5706: 5699: 5694: 5692: 5690: 5688: 5686: 5679: 5677: 5670: 5668: 5666: 5664: 5655: 5649: 5645: 5644: 5636: 5634: 5632: 5630: 5628: 5626: 5624: 5622: 5615: 5613: 5606: 5604: 5602: 5600: 5598: 5596: 5579: 5575: 5571: 5564: 5562: 5552: 5546: 5542: 5541: 5533: 5531: 5529: 5527: 5525: 5523: 5521: 5519: 5517: 5508: 5502: 5498: 5497: 5489: 5483: 5478: 5472: 5467: 5458: 5450: 5444: 5440: 5439: 5431: 5423: 5417: 5413: 5412: 5404: 5396: 5390: 5386: 5385: 5377: 5371: 5370: 5363: 5359: 5349: 5346: 5344: 5341: 5339: 5336: 5334: 5331: 5329: 5326: 5324: 5321: 5319: 5316: 5314: 5311: 5308: 5305: 5303: 5300: 5297: 5294: 5292: 5289: 5287: 5284: 5283: 5279: 5268: 5261: 5258: 5256: 5251: 5247: 5242: 5240: 5236: 5231: 5226: 5223: 5217: 5215: 5211: 5206: 5203: 5201: 5197: 5193: 5189: 5185: 5181: 5177: 5176:digital radio 5172: 5170: 5165: 5161: 5159: 5155: 5150: 5148: 5144: 5140: 5136: 5132: 5127: 5125: 5121: 5117: 5113: 5105: 5101: 5098: 5094: 5090: 5086: 5085:digital radio 5083: 5079: 5074: 5069: 5068:Digital radio 5059: 5057: 5053: 5049: 5045: 5041: 5037: 5032: 5030: 5025: 5024:Trans-Oceanic 5021: 5017: 5012: 5010: 5000: 4995: 4985: 4982: 4978: 4968: 4966: 4961: 4960: 4956: 4952: 4948: 4943: 4941: 4937: 4933: 4929: 4919: 4909: 4900: 4888: 4884: 4881: 4877: 4872: 4867: 4857: 4854: 4850: 4846: 4842: 4833: 4828: 4818: 4816: 4812: 4808: 4797: 4796:(large knobs) 4790: 4778: 4768: 4758: 4756: 4753:with a given 4750: 4748: 4744: 4740: 4736: 4732: 4728: 4723: 4719: 4717: 4716:tuned circuit 4713: 4709: 4705: 4694: 4687: 4678: 4674: 4667: 4655: 4645: 4635: 4632: 4627: 4625: 4621: 4616: 4607: 4602: 4592: 4590: 4586: 4581: 4577: 4573: 4568: 4566: 4561: 4559: 4555: 4550: 4548: 4544: 4540: 4536: 4533: 4527: 4525: 4521: 4517: 4513: 4509: 4508:feedback loop 4505: 4501: 4497: 4493: 4489: 4484: 4480: 4469: 4468:(upper right) 4462: 4453: 4449: 4445: 4441: 4434: 4425: 4418: 4405: 4397: 4392: 4382: 4379: 4374: 4370: 4366: 4361: 4359: 4358:potentiometer 4355: 4351: 4346: 4342: 4337: 4333: 4331: 4328: 4324: 4320: 4316: 4312: 4308: 4304: 4300: 4299:Fleming valve 4296: 4292: 4291:Lee De Forest 4288: 4284: 4274: 4270: 4266: 4255: 4246: 4232: 4222: 4219: 4211: 4201: 4197: 4191: 4190: 4183: 4174: 4173: 4165: 4163: 4160:, and modern 4159: 4155: 4151: 4147: 4142: 4138: 4137:around 1930. 4136: 4132: 4128: 4124: 4120: 4116: 4112: 4108: 4104: 4100: 4096: 4091: 4087: 4085: 4080: 4078: 4074: 4073:two-way radio 4070: 4069: 4064: 4060: 4056: 4052: 4051:tone controls 4048: 4044: 4040: 4035: 4030: 4028: 4024: 4020: 4016: 4010: 4008: 4004: 4000: 3996: 3992: 3988: 3984: 3983:Lee De Forest 3980: 3976: 3972: 3964: 3959: 3951: 3942: 3940: 3935: 3933: 3929: 3925: 3921: 3920: 3915: 3911: 3907: 3903: 3899: 3895: 3889: 3886: 3882: 3878: 3874: − 3873: 3869: 3864: 3860: 3855: 3851: 3847: − 3846: 3842: 3837: 3833: 3829: + 3828: 3824: 3819: 3815: 3814: 3809: 3805: 3801: 3797: 3792: 3788: 3783: 3779: 3770: 3766: 3764: 3760: 3756: 3752: 3748: 3743: 3741: 3737: 3732: 3726: 3724: 3720: 3716: 3708: 3703: 3698: 3688: 3686: 3682: 3678: 3674: 3668: 3667:disreputable. 3663: 3661: 3657: 3653: 3649: 3645: 3640: 3638: 3634: 3630: 3615: 3603: 3585: 3573: 3561: 3551: 3550:Crystal radio 3541: 3538: 3533: 3529: 3525: 3515: 3513: 3508: 3504: 3499: 3498: 3492: 3487: 3484: 3480: 3476: 3475:(see picture) 3472: 3468: 3467:tuned circuit 3463: 3459: 3454: 3452: 3447: 3442: 3438: 3434: 3430: 3426: 3415: 3411: 3407: 3403: 3399: 3395: 3391: 3384: 3372: 3359: 3350: 3332: 3329: 3324: 3321: 3317: 3312: 3309: 3301: 3300: 3296: 3292: 3291: 3287: 3283: 3282: 3277: 3273: 3269: 3265: 3261: 3257: 3253: 3248: 3246: 3245:Geissler tube 3242: 3238: 3234: 3229: 3227: 3223: 3219: 3213: 3210: 3200: 3198: 3194: 3186: 3182: 3178: 3174: 3170: 3166: 3162: 3158: 3157: 3156:crystal radio 3152: 3148: 3144: 3140: 3139: 3135: 3134: 3131: 3130:crystal radio 3126: 3119: 3118:Thomas Edison 3115: 3111: 3107: 3103: 3099: 3095: 3091: 3090: 3089:Fleming valve 3085: 3084: 3080: 3079: 3072: 3068: 3061: 3049: 3037: 3033: 3029: 3025: 3021: 3020: 3016: 3015: 3010: 3003: 3002: 2995: 2991: 2987: 2982: 2978: 2974: 2973: 2969: 2968: 2963: 2959: 2956: 2954: 2950: 2946: 2942: 2938: 2934: 2930: 2925: 2923: 2919: 2910: 2901: 2899: 2895: 2891: 2887: 2883: 2878: 2876: 2872: 2867: 2863: 2858: 2856: 2852: 2848: 2844: 2838: 2836: 2835:electromagnet 2832: 2828: 2824: 2820: 2816: 2812: 2808: 2804: 2800: 2796: 2784: 2779: 2772: 2767: 2766: 2759: 2756: 2752: 2748: 2745: 2738: 2725: 2716: 2712: 2702: 2699: 2695: 2691: 2687: 2683: 2682:communication 2678: 2671: 2667: 2663: 2662:electromagnet 2659: 2655: 2654:electric bell 2651: 2650: 2645: 2642: 2641: 2636: 2633: 2629: 2624: 2620: 2619: 2618:tuned circuit 2614: 2611: 2607: 2606: 2601: 2600: 2599: 2597: 2593: 2592: 2585: 2583: 2579: 2578:telegraph key 2575: 2571: 2567: 2563: 2559: 2555: 2551: 2547: 2543: 2535: 2530: 2522: 2515: 2511: 2507: 2503: 2498: 2488: 2485: 2484:loop antennas 2481: 2477: 2473: 2469: 2463: 2453: 2451: 2446: 2444: 2439: 2435: 2431: 2427: 2423: 2419: 2415: 2411: 2408: 2403: 2399: 2397: 2396: 2391: 2386: 2382: 2378: 2372: 2362: 2342: 2315: 2306: 2302: 2297: 2295: 2289: 2287: 2282: 2278: 2277: 2267: 2263: 2261: 2256: 2254: 2250: 2246: 2242: 2236: 2234: 2230: 2227: 2223: 2222: 2217: 2213: 2209: 2208: 2203: 2202: 2197: 2192: 2190: 2186: 2177: 2172: 2162: 2160: 2155: 2149: 2147: 2143: 2139: 2135: 2131: 2127: 2123: 2119: 2115: 2111: 2103: 2098: 2093: 2077: 2073: 2069: 2065: 2056: 2049: 2045: 2041: 2034: 2030: 2024: 2020: 2016: 2012: 2009: 2005: 1999: 1995: 1994: 1990: 1987: 1983: 1980: 1976: 1975:(see circuit) 1973: 1969: 1965: 1961: 1957: 1953: 1952: 1947: 1939: 1934: 1927: 1924: 1923: 1922: 1920: 1916: 1912: 1908: 1904: 1900: 1896: 1892: 1888: 1884: 1880: 1876: 1871: 1865: 1861: 1858: 1854: 1851: 1847: 1846: 1845: 1843: 1839: 1835: 1831: 1822: 1817: 1807: 1805: 1801: 1797: 1793: 1792: 1785: 1783: 1779: 1775: 1771: 1767: 1759: 1754: 1749: 1742:Amplification 1719: 1707: 1700: 1689: 1683: 1671: 1661: 1657: 1650: 1646: 1642: 1635: 1631: 1627: 1620: 1611: 1604: 1600: 1596: 1589: 1577: 1576:tuned circuit 1573: 1569: 1565: 1561: 1560: 1556: 1553: 1549: 1545: 1541: 1540: 1535: 1531: 1528: 1524: 1520: 1517: 1516: 1511: 1507: 1503: 1500: 1496: 1492: 1491: 1487: 1486: 1485: 1483: 1478: 1476: 1472: 1463: 1458: 1453: 1443: 1441: 1437: 1436:amplification 1433: 1423: 1421: 1417: 1413: 1409: 1408:whip antennas 1405: 1402:and the flat 1401: 1397: 1393: 1388: 1386: 1382: 1378: 1374: 1370: 1366: 1357: 1352: 1337: 1333: 1329: 1328:cryogenically 1325: 1321: 1317: 1313: 1309: 1308: 1304: 1301: 1297: 1296: 1292: 1289: 1285: 1281: 1280: 1276: 1275: 1274: 1271: 1266: 1262: 1261: 1257: 1254: 1250: 1249: 1245: 1242: 1238: 1234: 1230: 1229: 1225: 1222: 1218: 1217: 1213: 1212: 1210: 1209: 1208:Radiolocation 1205: 1202: 1201:keyless entry 1198: 1194: 1190: 1186: 1182: 1178: 1177: 1173: 1168: 1164: 1160: 1159:cryogenically 1156: 1152: 1148: 1147:dish antennas 1144: 1140: 1136: 1132: 1130: 1126: 1123: 1119: 1115: 1111: 1107: 1103: 1099: 1095: 1094: 1090: 1089: 1087: 1083: 1079: 1075: 1071: 1067: 1063: 1062: 1058: 1053: 1049: 1045: 1044:line-of-sight 1041: 1040: 1036: 1032: 1031: 1027: 1024: 1020: 1016: 1012: 1011: 1007: 1006: 1005: 1002: 997: 996: 988: 984: 981: 977: 976: 972: 971: 970: 967: 962: 958: 957:amateur radio 954: 950: 946: 942: 938: 934: 933: 928: 927: 919: 915: 912: 911:citizens band 907: 903: 902: 894: 890: 887: 886: 885:Walkie-talkie 882: 879: 878: 874: 871: 867: 863: 859: 855: 852:in which the 851: 847: 846: 842: 839: 836:modem, and a 835: 831: 826: 822: 818: 814: 811:- a portable 810: 809: 805: 804: 802: 798: 794: 790: 786: 782: 781:two-way radio 778: 775: 770: 766: 763: 762:geostationary 759: 756: 753: 745: 741: 737: 733: 730:receiver - a 729: 728: 724: 721: 717: 713: 709: 705: 701: 697: 693: 689: 688: 684: 683: 681: 677: 673: 669: 665: 662: 661: 660: 658: 654: 650: 646: 633: 629: 625: 621: 620: 615: 612: 608: 607: 603: 600: 596: 595: 591: 588: 584: 583: 579: 574: 570: 569: 565: 562: 561:high fidelity 558: 557: 553: 552: 550: 546: 542: 538: 537: 533: 530: 526: 522: 521:high fidelity 518: 517: 513: 510: 506: 502: 501: 497: 494: 490: 486: 485: 481: 478: 477:Console radio 475: 474: 473: 468: 464: 459: 450: 448: 447:line of sight 444: 440: 436: 432: 428: 424: 420: 416: 412: 407: 403: 398: 388: 386: 382: 378: 372: 370: 366: 362: 358: 357:analog signal 354: 350: 345: 335: 333: 328: 326: 322: 318: 314: 310: 306: 304: 300: 296: 292: 288: 283: 281: 277: 273: 269: 265: 261: 257: 252: 244: 242: 238: 229: 227: 223: 219: 215: 211: 207: 203: 199: 195: 188: 184: 174: 172: 168: 164: 160: 156: 152: 148: 144: 140: 135: 133: 129: 125: 121: 117: 113: 109: 105: 101: 97: 93: 89: 85: 81: 73: 69: 64: 57: 53: 52:two-way radio 49: 44: 37: 32: 19: 10361:Multiplexing 10236:Transmission 10201:Nikola Tesla 10191:Henry Sutton 10146:Samuel Morse 10076:Robert Hooke 10041:Amos Dolbear 9976:John Bardeen 9895: 9875:Telautograph 9779:Mobile phone 9734:Edholm's law 9717:social media 9650:Broadcasting 9437:Applications 9418:Water heater 9393:Refrigerator 9387: 9373:Mobile phone 9276:Piezotronics 9068: 9037: 9017: 9010: 8999:. Retrieved 8995:the original 8985: 8963:(1): 57–58. 8960: 8956: 8950: 8927: 8917: 8897: 8890: 8879: 8868: 8848: 8823: 8799:. Retrieved 8794: 8790: 8778: 8772:, p. 283-284 8769: 8763: 8753: 8748: 8736:. Retrieved 8731: 8727: 8698: 8691: 8679:. Retrieved 8674: 8670: 8657: 8644: 8631: 8599:, p. 263-267 8596: 8572: 8566:, p. 279-282 8563: 8557: 8548: 8542: 8529: 8522: 8496:. Retrieved 8494:(6): 478–482 8491: 8487: 8473: 8460: 8444:, p. 260-262 8441: 8424:, p. 574-575 8421: 8374:. Retrieved 8372:(4): 153–154 8369: 8365: 8355: 8343:. Retrieved 8336:the original 8315: 8311: 8298: 8286:. Retrieved 8281: 8277: 8249:. Retrieved 8242:the original 8229: 8225: 8198: 8192: 8183: 8177: 8165:. Retrieved 8137: 8133: 8123: 8110: 8103: 8095: 8086:. Retrieved 8074: 8070: 8060: 8040: 8017: 7972: 7931: 7925: 7919:, p. 336-340 7916: 7910: 7890: 7858: 7836:, p. 341-344 7833: 7816:, p. 267-270 7813: 7807: 7798: 7792: 7780:. Retrieved 7778:(4): 116–119 7775: 7771: 7761: 7751: 7746: 7726: 7704:, p. 172-185 7701: 7695: 7687: 7678: 7652: 7645: 7631: 7624: 7604: 7597: 7577: 7563: 7543: 7521: 7515: 7495: 7488: 7468: 7449: 7440: 7429: 7416: 7396: 7357: 7350: 7344:, p. 254-259 7341: 7318: 7309: 7293:, p. 242-253 7290: 7272: 7252: 7231: 7222: 7202: 7195: 7186: 7166: 7142:. Retrieved 7138:the original 7133: 7129: 7119: 7110: 7101: 7095: 7087: 7078: 7062:, p. 189-190 7059: 7053: 7044: 7015: 6995:, p. 471-475 6992: 6986: 6980:, p. 123-131 6977: 6971: 6965:, p. 476-483 6962: 6956: 6950:, p. 157-162 6947: 6941: 6932: 6908: 6902: 6896:, p. 460-464 6893: 6887: 6881:, p. 115-119 6878: 6872: 6859:. Retrieved 6854: 6850: 6840: 6831: 6825: 6819:, p. 446-455 6816: 6810: 6804:, p. 209-221 6801: 6764: 6757: 6745:. Retrieved 6743:(9): 652–656 6740: 6736: 6726: 6715:. Retrieved 6695: 6691: 6668:, p. 205-209 6665: 6650:, p. 198-203 6647: 6641: 6629:. Retrieved 6627:(8): 335–338 6624: 6620: 6610: 6598:. Retrieved 6593: 6589: 6579: 6559: 6552: 6540:. Retrieved 6535: 6531: 6521: 6512: 6506: 6497: 6491: 6485:, p. 107-113 6482: 6462: 6456: 6442: 6418: 6392:, p. 349-358 6389: 6354: 6347: 6327: 6320: 6300: 6271: 6238: 6206: 6134: 6092: 6046: 6039: 6019: 5985: 5959:December 19, 5957:. Retrieved 5952: 5948: 5935: 5915: 5863: 5831: 5808: 5802: 5782: 5752: 5736:, p. 636-638 5733: 5718:, p. 272-278 5715: 5675: 5642: 5611: 5584:December 23, 5582:. Retrieved 5577: 5573: 5539: 5495: 5488: 5477: 5466: 5457: 5437: 5430: 5410: 5403: 5383: 5376: 5368: 5362: 5278:Radio portal 5259: 5243: 5227: 5222:Google Earth 5218: 5214:flash memory 5207: 5204: 5173: 5162: 5151: 5128: 5109: 5104:GPS receiver 5080:has several 5044:Regency TR-1 5033: 5013: 5005: 4974: 4962: 4944: 4940:Signal Corps 4925: 4886: 4882: 4852: 4838: 4811:out of phase 4804: 4795: 4751: 4742: 4724: 4720: 4701: 4676: 4672: 4638:TRF receiver 4628: 4612: 4579: 4569: 4564: 4562: 4551: 4528: 4500:regeneration 4499: 4476: 4467: 4452:(right rear) 4451: 4447: 4443: 4439: 4423: 4362: 4338: 4334: 4329: 4325:, and early 4319:regenerative 4280: 4214: 4208:October 2020 4205: 4186: 4139: 4092: 4088: 4081: 4066: 4062: 4031: 4015:loudspeakers 4011: 3981:invented by 3968: 3961:During the " 3938: 3936: 3917: 3908:invented by 3893: 3892: 3890: 3876: 3875: 3867: 3866: 3858: 3857: 3849: 3848: 3840: 3839: 3831: 3830: 3822: 3821: 3811: 3795: 3794: 3786: 3785: 3781: 3775: 3744: 3731:damped waves 3727: 3712: 3670: 3665: 3641: 3637:World War II 3625: 3523: 3521: 3495: 3488: 3474: 3455: 3435:circuit, or 3422: 3413: 3409: 3405: 3401: 3397: 3393: 3389: 3298: 3297: 3289: 3288: 3280: 3279: 3249: 3233:Nikola Tesla 3230: 3214: 3206: 3190: 3173:lead sulfide 3160: 3154: 3142: 3136: 3087: 3081: 3070: 3066: 3023: 3017: 3000: 2970: 2957: 2945:carrier wave 2926: 2915: 2879: 2859: 2839: 2795:Oliver Lodge 2792: 2757: 2746: 2714: 2694:Oliver Lodge 2681: 2679: 2675: 2666:galvanometer 2647: 2638: 2616: 2603: 2589: 2586: 2562:damped waves 2545: 2539: 2513: 2509: 2478:attached to 2465: 2447: 2443:IF amplifier 2413: 2404: 2400: 2393: 2374: 2298: 2290: 2280: 2274: 2272: 2257: 2237: 2219: 2205: 2199: 2193: 2182: 2150: 2134:carrier wave 2126:audio signal 2107: 2075: 2067: 2061: 2054: 2047: 2039: 2032: 2026: 2015:audio signal 2011:carrier wave 2001: 1988: 1981: 1974: 1925: 1907:Digital data 1895:video signal 1879:audio signal 1872: 1869: 1834:carrier wave 1827: 1816:Demodulation 1810:Demodulation 1789: 1786: 1762: 1659: 1655: 1648: 1644: 1633: 1629: 1625: 1602: 1599:carrier wave 1567: 1563: 1558: 1557: 1537: 1533: 1529: 1518: 1513: 1509: 1501: 1489: 1488: 1479: 1467: 1440:demodulation 1429: 1389: 1362: 1324:RF front end 1305: 1293: 1284:well logging 1277: 1272: 1258: 1246: 1233:GPS receiver 1226: 1214: 1206: 1174: 1155:RF front end 1127: 1091: 1059: 1037: 1028: 1015:access point 1008: 1003: 995:Baby monitor 993: 973: 968: 930: 924: 899: 883: 875: 862:base station 843: 838:GPS receiver 806: 797:push to talk 783:is an audio 776: 742:. A rooftop 727:Satellite TV 725: 695: 691: 685: 672:audio signal 668:video signal 663: 648: 642: 632:home theatre 623: 617: 604: 592: 580: 566: 554: 534: 529:audio signal 514: 503:- A bedside 498: 489:Mantel radio 488: 482: 476: 471: 443:sports radio 406:ground waves 394: 373: 347: 332:AM/FM radios 331: 329: 307: 284: 253: 250: 241:carrier wave 235: 193: 191: 187:AM/FM (song) 171:radio clocks 147:digital data 136: 132:demodulation 95: 91: 87: 83: 77: 10561:NPL network 10273:Radio waves 10211:Alfred Vail 10121:Hedy Lamarr 10106:Dawon Kahng 10066:Elisha Gray 10026:Yogen Dalal 9951:Nasir Ahmed 9885:Teleprinter 9749:Heliographs 9544:electronics 9348:Home cinema 9286:Spintronics 9226:Atomtronics 9139:Electronics 8801:January 16, 8791:Radio World 8738:January 24, 8498:January 16, 8376:January 11, 8251:January 12, 8077:: 735–763. 8071:Trans. AIEE 7782:January 28, 6834:, p. 85-108 6631:January 26, 6600:January 30, 5241:interface. 4932:World War I 4845:demodulated 4735:heterodynes 4712:selectivity 4693:thumbwheels 4585:heterodynes 4520:selectivity 4496:vacuum tube 4378:World War I 4309:which both 4119:capacitance 4111:heterodynes 4017:instead of 3979:vacuum tube 3883:was in the 3719:Poulsen arc 3685:selectivity 3677:loudspeaker 3425:radio noise 3286:capacitance 3264:tuning fork 3193:demodulator 3181:carborundum 3149:, based on 3094:vacuum tube 3032:nitric acid 2922:human brain 2920:and even a 2890:radio noise 2630:, called a 2556:through an 2554:capacitance 2385:propagation 2301:selectivity 2233:demodulated 2142:loudspeaker 2102:selectivity 1964:sound waves 1891:loudspeaker 1883:sound waves 1838:demodulator 1791:sensitivity 1782:transistors 1539:selectivity 1471:frequencies 1336:radio noise 1167:radio noise 872:radio link. 801:full duplex 793:half-duplex 789:transmitter 785:transceiver 732:set-top box 712:TV channels 706:from local 657:transmitter 653:transceiver 509:alarm clock 505:table radio 500:Clock radio 484:Table radio 467:alarm clock 463:clock radio 411:radio noise 361:radio noise 317:microphones 206:loudspeaker 163:cell phones 159:televisions 100:radio waves 68:vacuum tube 10607:Antarctica 10566:Toasternet 10488:Television 9971:Paul Baran 9903:Television 9887:(teletype) 9880:Telegraphy 9858:transistor 9836:Phryctoria 9806:Photophone 9784:Smartphone 9774:Mass media 9548:Multimedia 9538:technology 9413:Television 9343:Home robot 9333:Dishwasher 9295:Electronic 9001:2007-11-23 8734:(12): 9–10 8551:, p. 31-32 8345:August 29, 8278:Radio News 8020:, p. 15-18 7144:August 19, 7104:, p. 31-48 7047:, p. 70-73 6911:, p. 65-81 6747:January 3, 6717:2010-01-19 6698:(3): 184. 6542:January 2, 6515:, p. 57-60 6500:, p. 38-42 6465:, p. 18-21 6274:, p. 53-56 5678:, p. 28-30 5614:, p. 14-15 5354:References 5328:Distortion 5228:Since the 5188:compressed 5169:cell phone 5078:smartphone 5066:See also: 4992:See also: 4977:transistor 4947:heterodyne 4767:Neutrodyne 4558:variometer 4547:heterodyne 4345:ionization 4303:amplifying 4285:, a crude 4273:rectifying 4127:Neutrodyne 4095:oscillator 3991:modulation 3987:amplifying 3902:alternator 3813:heterodyne 3740:sine waves 3707:commutator 3697:Heterodyne 3497:variometer 3416:headphones 3295:inductance 3256:capacitors 3197:modulation 2994:hysteresis 2937:demodulate 2898:Morse code 2853:the later 2851:demodulate 2815:resistance 2751:Morse code 2730:background 2670:paper tape 2596:amplifying 2582:Morse code 2540:The first 2476:spark gaps 2226:modulation 2212:heterodyne 2159:Advantages 2122:modulation 2019:modulation 1909:, as in a 1875:transducer 1830:modulation 1796:microvolts 1770:femtowatts 1630:S2, S3 ... 1601:frequency 1508:frequency 1495:modulation 1349:See also: 1334:to reduce 1330:cooled by 1165:to reduce 1078:spacecraft 1074:satellites 1034:earphones. 830:WiFi modem 821:cell tower 740:television 696:television 573:transistor 545:CD players 461:A bedside 439:talk radio 435:radio news 289:(FM), the 237:Modulation 143:television 50:, used in 10591:Americas 10580:Locations 10551:Internet2 10312:Bandwidth 10016:Vint Cerf 9913:streaming 9891:Telephone 9831:Semaphore 9722:streaming 9536:Microwave 9408:Telephone 9297:equipment 9271:Photonics 9095:cite book 8977:1098-4232 8677:(8): 7–12 8312:Proc. 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