2952:
2639:
50:
1463:) whose frequency can be adjusted with a calibrated timing circuit. The strobe light is pointed at the rotating object and the frequency adjusted up and down. When the frequency of the strobe equals the frequency of the rotating or vibrating object, the object completes one cycle of oscillation and returns to its original position between the flashes of light, so when illuminated by the strobe the object appears stationary. Then the frequency can be read from the calibrated readout on the stroboscope. A downside of this method is that an object rotating at an integer multiple of the strobing frequency will also appear stationary.
541:
1416:
1735:
1427:
2926:
1478:
320:
1571:
1542:
or "beat" signal at the difference between the two frequencies. If the two signals are close together in frequency the heterodyne is low enough to be measured by a frequency counter. This process only measures the difference between the unknown frequency and the reference frequency. To convert
1178:
Calculating the frequency of a repeating event is accomplished by counting the number of times that event occurs within a specific time period, then dividing the count by the period. For example, if 71 events occur within 15 seconds the frequency is:
1517:
and the signal applied to a frequency counter. As of 2018, frequency counters can cover the range up to about 100 GHz. This represents the limit of direct counting methods; frequencies above this must be measured by indirect methods.
793:
1235:
If the number of counts is not very large, it is more accurate to measure the time interval for a predetermined number of occurrences, rather than the number of occurrences within a specified time. The latter method introduces a
1435:
A resonant-reed frequency meter, an obsolete device used from about 1900 to the 1940s for measuring the frequency of alternating current. It consists of a strip of metal with reeds of graduated lengths, vibrated by an
729:
978:
1233:
1354:
916:
1294:
49:
1694:
1140:
1076:
205:
1746:
Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances. In general, frequency components of a sound determine its "color", its
404:
734:
307:
For example, if a heart beats at a frequency of 120 times per minute (2 hertz), the period—the interval between beats—is half a second (60 seconds divided by 120
1381:
1765:
range for humans is typically given as being between about 20 Hz and 20,000 Hz (20 kHz), though the high frequency limit usually reduces with age. Other
1776:
is approximately independent of frequency, so the wavelength of the sound waves (distance between repetitions) is approximately inversely proportional to frequency.
634:
1401:
921:
1182:
1657:
All of these waves, from the lowest-frequency radio waves to the highest-frequency gamma rays, are fundamentally the same, and they are all called
1534:). A reference signal of a known frequency near the unknown frequency is mixed with the unknown frequency in a nonlinear mixing device such as a
1661:. They all travel through vacuum at the same speed (the speed of light), giving them wavelengths inversely proportional to their frequencies.
835:
1543:
higher frequencies, several stages of heterodyning can be used. Current research is extending this method to infrared and light frequencies (
1403:
is the measured frequency. This error decreases with frequency, so it is generally a problem at low frequencies where the number of counts
1830:
and northern South
America, the frequency of the alternating current in household electrical outlets is 60 Hz (between the tones B
429:
1299:
2848:
1665:
369:
is the time taken to complete one cycle of an oscillation or rotation. The frequency and the period are related by the equation
1720:, such as glass, the speed depends somewhat on frequency, so the wavelength is not quite inversely proportional to frequency.
1109:
1045:
2527:
2501:
2480:
2457:
2350:
413:
is used to emphasise that the frequency is characterised by the number of occurrences of a repeating event per unit time.
2575:
373:
1526:
Above the range of frequency counters, frequencies of electromagnetic signals are often measured indirectly utilizing
2400:
1509:
time base. Cyclic processes that are not electrical, such as the rotation rate of a shaft, mechanical vibrations, or
1251:
2217:
1007:(that is, media in which the wave speed is independent of frequency), frequency has an inverse relationship to the
2951:
544:
Diagram of the relationship between the different types of frequency and other wave properties. In this diagram,
2098:
2033:
2073:
2417:
1953:
1750:. When speaking about the frequency (in singular) of a sound, it means the property that most determines its
350:
is defined as the number of cycles or repetitions per unit of time. The conventional symbol for frequency is
2243:
2063:
2048:
1544:
832:(xi), is analogous to temporal frequency, but with a spatial measurement replacing time measurement, e.g.:
1769:
have different hearing ranges. For example, some dog breeds can perceive vibrations up to 60,000 Hz.
1941:
2469:
176:
2942:
2687:
1937:
1490:
169:
34:
472:
and radio, are usually described by their frequency. Some commonly used conversions are listed below:
2808:
1658:
1575:
1565:
2863:
2491:
2447:
1359:
540:
2743:
2600:
2568:
2544:
Keyboard frequencies = naming of notes – The
English and American system versus the German system
1145:
2293:
1610:) is violet light, and between these (in the range 400–800 THz) are all the other colors of the
468:, are more typically described by wave period rather than frequency. Short and fast waves, like
2682:
2592:
2391:
Lombardi, Michael A. (2007). "Fundamentals of Time and
Frequency". In Bishop, Robert H. (ed.).
1998:
1035:
811:
620:
343:
264:
919:
732:
2823:
2721:
2625:
2028:
453:
371:
117:
1663:
446:. A traditional unit of frequency used with rotating mechanical devices, where it is termed
436:(Conférence générale des poids et mesures) in 1960, officially replacing the previous name,
2018:
1758:
1583:
1494:
803:
602:
553:
448:
280:
Frequency is an important parameter used in science and engineering to specify the rate of
8:
2843:
2753:
1988:
1815:
1717:
1004:
563:
27:
2543:
2972:
2929:
2775:
2765:
2726:
2561:
2367:
2083:
2043:
2023:
2003:
1905:
1901:
1883:
1860:
1386:
788:{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} t}}=\omega =2\mathrm {\pi } f.}
465:
20:
2638:
2148:
1455:
An old method of measuring the frequency of rotating or vibrating objects is to use a
2899:
2731:
2523:
2497:
2476:
2453:
2396:
2346:
2038:
1973:
1921:
1872:
1868:
1864:
1819:
1785:
1762:
1531:
1486:
1472:
823:
807:
592:
586:
241:
235:
2909:
2828:
2792:
2760:
2711:
2620:
2424:
2169:
1993:
1978:
1963:
1611:
998:
438:
2318:
1594:
traveling through space. The frequency of the wave determines its color: 400 THz (
2904:
2858:
2699:
2657:
2340:
2078:
2068:
2013:
1948:
1845:
1729:
1498:
1440:. When the unknown frequency is applied to the electromagnet, the reed which is
1165:
1149:
1505:
to count the number of cycles during a time interval established by a precision
1415:
2956:
2853:
2838:
2785:
2008:
1983:
1773:
1591:
1587:
1444:
at that frequency will vibrate with large amplitude, visible next to the scale.
1103:
1028:
983:
596:
425:
619:
waveform (notably in oscillations and waves), or as the rate of change of the
2966:
2818:
2780:
2748:
2703:
2665:
2615:
2610:
2428:
1925:
1827:
1803:
1751:
1502:
1437:
624:
612:
2423:(Report). Gaithersburg, MD: National Institute of Standards and Technology.
724:{\displaystyle y(t)=\sin \theta (t)=\sin(\omega t)=\sin(2\mathrm {\pi } ft)}
2813:
1968:
1823:
1734:
1527:
1506:
1460:
1237:
1081:
442:(cps). The SI unit for the period, as for all measurements of time, is the
289:
226:
221:
129:
59:
2833:
2645:
2221:
2088:
2058:
1837:
1643:
1456:
1426:
1153:
973:{\displaystyle {\frac {\mathrm {d} \theta }{\mathrm {d} x}}=k=2\pi \xi .}
557:
359:
335:
308:
281:
1228:{\displaystyle f={\frac {71}{15\,{\text{s}}}}\approx 4.73\,{\text{Hz}}.}
2894:
2884:
2670:
2124:
2093:
2053:
1739:
1631:
1539:
1514:
1510:
1152:
to another, their frequency remains the same—only their wavelength and
1008:
297:
2393:
Mechatronic
Systems, Sensors, and Actuators: Fundamentals and Modeling
2675:
2605:
2584:
2220:. BIPM (International Bureau of Weights and Measures). Archived from
1876:
1841:
1799:
1651:
1627:
1441:
1024:
616:
285:
1477:
456:, abbreviated r/min or rpm. 60 rpm is equivalent to one hertz.
225:(symbol: Hz), is the number of occurrences of a repeating event per
2770:
2738:
1848:
can show in which of these general regions the recording was made.
1623:
324:
319:
55:
2716:
2548:
1766:
1634:. Likewise, an electromagnetic wave with a frequency higher than
1493:
which measures the frequency of an applied repetitive electronic
1241:
93:
1811:
1795:
1791:
1747:
1642:
will also be invisible to the human eye; such waves are called
1085:
1016:
799:
443:
263:) is the interval of time between events, so the period is the
136:
1626:(IR) radiation. At even lower frequency, the wave is called a
1570:
1349:{\textstyle {\frac {\Delta f}{f}}={\frac {1}{2fT_{\text{m}}}}}
2889:
2496:. Elsevere Ocean Engineering. Vol. 2. Oxford: Elsevier.
2200:
2198:
1958:
1647:
1561:
1535:
606:
469:
464:
As a matter of convenience, longer and slower waves, such as
421:
328:
301:
293:
98:
67:
2553:
2449:
Handbook of
Condition Monitoring: Techniques and Methodology
1170:
Measurement of frequency can be done in the following ways:
562:(nu), is defined as the instantaneous rate of change of the
2879:
2297:
1913:
1807:
1248:
and causes an average error in the calculated frequency of
433:
339:
2549:
A frequency generator with sound, useful for hearing tests
2244:"Special Publication 811: NIST Guide to the SI, Chapter 8"
2195:
2183:
1622:
will be invisible to the human eye; such waves are called
828:
327:
with a period of 2.8 s and a frequency of 0.36
1513:, can be converted to a repetitive electronic signal by
911:{\displaystyle y(t)=\sin \theta (t,x)=\sin(\omega t+kx)}
1646:(UV) radiation. Even higher-frequency waves are called
986:
or wavelength is the spatial analog to temporal period.
417:
250:
1302:
1254:
548:
is the input to the function represented by the arrow.
2940:
1840:
above the
European frequency). The frequency of the '
1669:
1668:
1614:. An electromagnetic wave with a frequency less than
1389:
1362:
1185:
1112:
1048:
924:
838:
737:
637:
376:
179:
2261:
1875:(s) or, in the case of radioactivity, with the unit
1240:
into the count of between zero and one count, so on
2128:, analogously corresponds to the (temporal) period.
2468:
1688:
1459:. This is an intense repetitively flashing light (
1395:
1375:
1348:
1288:
1227:
1134:
1070:
972:
910:
787:
723:
398:
249:, with SI unit radian per second) by a factor of 2
199:
2273:
1757:The frequencies an ear can hear are limited to a
2964:
2359:
1630:, and at still lower frequencies it is called a
1289:{\textstyle \Delta f={\frac {1}{2T_{\text{m}}}}}
814:. Angular frequency is frequency multiplied by 2
19:"Frequencies" redirects here. For the film, see
1742:spectrum, with rough guide of some applications
1485:Higher frequencies are usually measured with a
2415:
1867:phenomena, including random processes such as
2569:
2467:Serway, Raymond A.; Faughn, Jerry S. (1989).
601:(omega), is defined as the rate of change of
16:Number of occurrences or cycles per unit time
2466:
2204:
2189:
1019:). Even in dispersive media, the frequency
2576:
2562:
1689:{\displaystyle \displaystyle c=f\lambda ,}
459:
288:phenomena, such as mechanical vibrations,
48:
1216:
1201:
430:International Electrotechnical Commission
229:. It is also occasionally referred to as
2416:Newell, David B; Tiesinga, Eite (2019).
2390:
2366:Condon, Tim (2003). Elert, Glenn (ed.).
2338:
1733:
1569:
1476:
1135:{\displaystyle f={\frac {c}{\lambda }}.}
1071:{\displaystyle f={\frac {v}{\lambda }}.}
539:
318:
314:
2218:"Resolution 12 of the 11th CGPM (1960)"
1106:in vacuum, and this expression becomes
806:, can also be expressed as radians per
424:(Hz), named after the German physicist
233:for clarity and to distinguish it from
2965:
2445:
2418:The international system of units (SI)
2365:
2267:
1851:
1497:and displays the result in hertz on a
992:
611:(theta), or the rate of change of the
595:, usually denoted by the Greek letter
556:, usually denoted by the Greek letter
183:
2557:
2489:
2279:
1521:
798:The unit of angular frequency is the
585:it is a type of frequency applied to
535:
2520:Physics for Scientists and Engineers
1578:with the visible portion highlighted
1466:
239:. Ordinary frequency is related to
2291:
1705:in vacuum or less in other media),
13:
2511:
1863:of incidence or occurrence of non-
1306:
1255:
939:
929:
918:
752:
742:
731:
200:{\displaystyle {\mathsf {T}}^{-1}}
14:
2984:
2537:
399:{\displaystyle f={\frac {1}{T}}.}
370:
62:in 60 s, a frequency of 0.41
2950:
2925:
2924:
2637:
2368:"Frequency range of dog hearing"
1871:. It is expressed with the unit
1772:In many media, such as air, the
1662:
1425:
1414:
2522:(2nd ed.). Prentice Hall.
2475:. London: Thomson/Brooks-Cole.
2409:
2384:
2332:
2311:
2112:
2099:Orders of magnitude (frequency)
2034:Least-squares spectral analysis
1779:
432:in 1930. It was adopted by the
334:For cyclical phenomena such as
2285:
2236:
2210:
2162:
2141:
2074:Signaling (telecommunications)
1450:
1159:
905:
887:
875:
863:
848:
842:
718:
701:
689:
680:
668:
662:
647:
641:
1:
2583:
2135:
2122:, sometimes used in place of
1954:Bandwidth (signal processing)
1759:specific range of frequencies
1244:half a count. This is called
2064:Radar signal characteristics
2049:Periodicity (disambiguation)
1822:is 50 Hz (close to the
1820:household electrical outlets
1586:, consisting of oscillating
1545:optical heterodyne detection
1376:{\displaystyle T_{\text{m}}}
1084:of electromagnetic waves in
802:per second (rad/s) but, for
7:
2345:. For Dummies. p. 97.
1942:Category:Units of frequency
1931:
1602:Hz) is red light, 800 THz (
1550:
1383:is the timing interval and
1296:, or a fractional error of
1173:
10:
2989:
2493:Wind Generated Ocean Waves
2439:
2339:Pilhofer, Michael (2007).
1938:Frequency (disambiguation)
1935:
1783:
1727:
1559:
1470:
1163:
996:
219:), most often measured in
35:Frequency (disambiguation)
18:
2920:
2872:
2801:
2698:
2656:
2632:
2591:
2149:"Definition of FREQUENCY"
1904:counted or the number of
1659:electromagnetic radiation
1576:electromagnetic radiation
1566:Electromagnetic radiation
420:unit of frequency is the
168:
142:
127:
105:
92:
74:
47:
42:
2429:10.6028/nist.sp.330-2019
2342:Music Theory for Dummies
2205:Serway & Faughn 1989
2190:Serway & Faughn 1989
2105:
1723:
1555:
1481:Modern frequency counter
570:, with respect to time:
526:1 THz (10 Hz)
518:1 GHz (10 Hz)
510:1 MHz (10 Hz)
502:1 kHz (10 Hz)
486:1 mHz (10 Hz)
2601:Architectural acoustics
2518:Giancoli, D.C. (1988).
1814:, the frequency of the
1701:is the speed of light (
1650:, and higher still are
494:1 Hz (10 Hz)
460:Period versus frequency
2688:Fletcher–Munson curves
2683:Equal-loudness contour
2593:Acoustical engineering
2490:Young, Ian R. (1999).
2452:. New York: Springer.
2170:"Definition of PERIOD"
1999:Frequency distribution
1743:
1690:
1579:
1482:
1397:
1377:
1350:
1290:
1229:
1136:
1072:
1003:For periodic waves in
974:
912:
812:dimensionless quantity
789:
725:
549:
529:1 ps (10 s)
521:1 ns (10 s)
513:1 μs (10 s)
505:1 ms (10 s)
489:1 ks (10 s)
400:
344:simple harmonic motion
331:
315:Definitions and units
201:
114:cycle per second (cps)
33:. For other uses, see
2824:Hermann von Helmholtz
2722:Fundamental frequency
2626:Sympathetic resonance
2395:. Austin: CRC Press.
2319:"Definition of SOUND"
2029:Interaction frequency
1737:
1709:is the frequency and
1691:
1574:Complete spectrum of
1573:
1491:electronic instrument
1480:
1398:
1378:
1351:
1291:
1230:
1137:
1073:
997:Further information:
975:
913:
804:discrete-time signals
790:
726:
543:
497:1 s (10 s)
454:revolution per minute
401:
342:, or for examples of
322:
202:
118:revolution per minute
26:. For the album, see
2372:The Physics Factbook
2019:Frequency modulation
1666:
1584:electromagnetic wave
1582:Visible light is an
1532:frequency conversion
1387:
1360:
1300:
1252:
1183:
1110:
1046:
993:In wave propagation
922:
836:
735:
635:
603:angular displacement
554:Rotational frequency
449:rotational frequency
374:
362:) is also used. The
177:
2844:Werner Meyer-Eppler
2754:Missing fundamental
2446:Davies, A. (1997).
2433:sub§2.3.4, Table 4.
2294:"Spatial Frequency"
1989:Frequency converter
1882:It is defined as a
1857:Aperiodic frequency
1852:Aperiodic frequency
1816:alternating current
1713:is the wavelength.
1146:monochromatic waves
1005:nondispersive media
605:(during rotation),
564:number of rotations
466:ocean surface waves
58:making 25 complete
2727:Frequency spectrum
2292:Boreman, Glenn D.
2084:Spectral component
2044:Negative frequency
2024:Frequency spectrum
2004:Frequency extender
1902:number of entities
1836:and B; that is, a
1744:
1686:
1685:
1580:
1522:Heterodyne methods
1483:
1393:
1373:
1346:
1286:
1225:
1132:
1068:
1038:by the wavelength
970:
908:
826:, denoted here by
785:
721:
550:
536:Related quantities
411:temporal frequency
396:
358:(the Greek letter
332:
267:of the frequency:
231:temporal frequency
197:
131:SI base units
2938:
2937:
2900:Musical acoustics
2732:harmonic spectrum
2529:978-0-13-669201-0
2503:978-0-08-043317-2
2482:978-05344-0-814-5
2459:978-0-412-61320-3
2352:978-0-470-16794-6
2250:. 28 January 2016
2039:Natural frequency
1974:Electronic filter
1922:physical quantity
1912:) during a given
1873:reciprocal second
1869:radioactive decay
1786:Utility frequency
1763:audible frequency
1538:. This creates a
1487:frequency counter
1473:Frequency counter
1467:Frequency counter
1396:{\displaystyle f}
1370:
1344:
1340:
1316:
1284:
1280:
1220:
1208:
1205:
1127:
1063:
947:
824:Spatial frequency
808:sampling interval
760:
593:Angular frequency
587:rotational motion
533:
532:
391:
242:angular frequency
236:spatial frequency
210:
209:
2980:
2955:
2954:
2946:
2928:
2927:
2829:Carleen Hutchins
2761:Combination tone
2648:
2641:
2621:String vibration
2578:
2571:
2564:
2555:
2554:
2533:
2507:
2486:
2474:
2463:
2434:
2432:
2422:
2413:
2407:
2406:
2388:
2382:
2381:
2379:
2378:
2363:
2357:
2356:
2336:
2330:
2329:
2327:
2325:
2315:
2309:
2308:
2306:
2304:
2289:
2283:
2277:
2271:
2265:
2259:
2258:
2256:
2255:
2240:
2234:
2233:
2231:
2229:
2214:
2208:
2202:
2193:
2187:
2181:
2180:
2178:
2176:
2166:
2160:
2159:
2157:
2155:
2145:
2129:
2116:
1994:Frequency domain
1979:Fourier analysis
1964:Cutoff frequency
1900:, involving the
1899:
1835:
1834:
1718:dispersive media
1696:
1693:
1692:
1687:
1641:
1639:
1621:
1619:
1612:visible spectrum
1609:
1607:
1601:
1599:
1429:
1418:
1402:
1400:
1399:
1394:
1382:
1380:
1379:
1374:
1372:
1371:
1368:
1355:
1353:
1352:
1347:
1345:
1343:
1342:
1341:
1338:
1322:
1317:
1312:
1304:
1295:
1293:
1292:
1287:
1285:
1283:
1282:
1281:
1278:
1265:
1234:
1232:
1231:
1226:
1221:
1218:
1209:
1207:
1206:
1203:
1193:
1148:travel from one
1141:
1139:
1138:
1133:
1128:
1120:
1097:
1077:
1075:
1074:
1069:
1064:
1056:
1027:is equal to the
999:Wave propagation
980:
977:
976:
971:
948:
946:
942:
936:
932:
926:
917:
915:
914:
909:
817:
795:
792:
791:
786:
778:
761:
759:
755:
749:
745:
739:
730:
728:
727:
722:
711:
584:
475:
474:
439:cycle per second
406:
403:
402:
397:
392:
384:
276:
253:
206:
204:
203:
198:
196:
195:
187:
186:
161:
146:other quantities
144:Derivations from
132:
88:
65:
52:
40:
39:
2988:
2987:
2983:
2982:
2981:
2979:
2978:
2977:
2963:
2962:
2961:
2949:
2941:
2939:
2934:
2916:
2868:
2859:D. Van Holliday
2797:
2766:Mersenne's laws
2700:Audio frequency
2694:
2658:Psychoacoustics
2652:
2651:
2644:
2630:
2587:
2582:
2540:
2530:
2517:
2514:
2512:Further reading
2504:
2483:
2471:College Physics
2460:
2442:
2437:
2420:
2414:
2410:
2403:
2389:
2385:
2376:
2374:
2364:
2360:
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2237:
2227:
2225:
2224:on 8 April 2020
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2163:
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2151:
2147:
2146:
2142:
2138:
2133:
2132:
2117:
2113:
2108:
2103:
2079:Spread spectrum
2069:Radio frequency
2014:Frequency level
1949:Audio frequency
1944:
1934:
1887:
1854:
1846:audio recording
1832:
1831:
1826:G), whereas in
1788:
1782:
1732:
1730:Audio frequency
1726:
1667:
1664:
1637:
1635:
1617:
1615:
1605:
1603:
1597:
1595:
1592:magnetic fields
1568:
1560:Main articles:
1558:
1553:
1524:
1499:digital display
1475:
1469:
1453:
1448:
1447:
1446:
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1432:
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1421:
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1419:
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1253:
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1184:
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1176:
1168:
1166:Frequency meter
1162:
1119:
1111:
1108:
1107:
1089:
1055:
1047:
1044:
1043:
1025:sinusoidal wave
1001:
995:
938:
937:
928:
927:
925:
923:
920:
837:
834:
833:
815:
774:
751:
750:
741:
740:
738:
736:
733:
707:
636:
633:
632:
571:
538:
462:
383:
375:
372:
317:
268:
251:
188:
182:
181:
180:
178:
175:
174:
164:
153:
147:
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130:
123:
108:
80:
77:
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63:
38:
17:
12:
11:
5:
2986:
2976:
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2933:
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2921:
2918:
2917:
2915:
2914:
2913:
2912:
2907:
2897:
2892:
2887:
2882:
2876:
2874:
2873:Related topics
2870:
2869:
2867:
2866:
2861:
2856:
2854:Joseph Sauveur
2851:
2846:
2841:
2839:Marin Mersenne
2836:
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2826:
2821:
2816:
2811:
2805:
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2595:
2589:
2588:
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2580:
2573:
2566:
2558:
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2551:
2546:
2539:
2538:External links
2536:
2535:
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2510:
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2487:
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2464:
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2408:
2401:
2383:
2358:
2351:
2331:
2310:
2284:
2272:
2270:, p. 275.
2260:
2235:
2209:
2207:, p. 354.
2194:
2192:, p. 346.
2182:
2161:
2139:
2137:
2134:
2131:
2130:
2120:spatial period
2110:
2109:
2107:
2104:
2102:
2101:
2096:
2091:
2086:
2081:
2076:
2071:
2066:
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2046:
2041:
2036:
2031:
2026:
2021:
2016:
2011:
2009:Frequency grid
2006:
2001:
1996:
1991:
1986:
1984:Frequency band
1981:
1976:
1971:
1966:
1961:
1956:
1951:
1945:
1933:
1930:
1853:
1850:
1784:Main article:
1781:
1778:
1774:speed of sound
1728:Main article:
1725:
1722:
1684:
1681:
1678:
1675:
1672:
1557:
1554:
1552:
1549:
1523:
1520:
1471:Main article:
1468:
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1188:
1175:
1172:
1161:
1158:
1131:
1126:
1123:
1118:
1115:
1104:speed of light
1067:
1062:
1059:
1054:
1051:
1029:phase velocity
994:
991:
990:
989:
988:
987:
984:Spatial period
969:
966:
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951:
945:
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426:Heinrich Hertz
395:
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316:
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208:
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185:
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122:
121:
120:(rpm or r/min)
115:
111:
109:
106:
103:
102:
96:
90:
89:
78:
76:Common symbols
75:
72:
71:
53:
45:
44:
15:
9:
6:
4:
3:
2:
2985:
2974:
2971:
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2923:
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2898:
2896:
2893:
2891:
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2881:
2878:
2877:
2875:
2871:
2865:
2862:
2860:
2857:
2855:
2852:
2850:
2849:Lord Rayleigh
2847:
2845:
2842:
2840:
2837:
2835:
2832:
2830:
2827:
2825:
2822:
2820:
2819:Ernst Chladni
2817:
2815:
2812:
2810:
2807:
2806:
2804:
2800:
2794:
2791:
2787:
2784:
2783:
2782:
2781:Standing wave
2779:
2777:
2774:
2772:
2769:
2767:
2764:
2762:
2759:
2755:
2752:
2750:
2749:Inharmonicity
2747:
2745:
2742:
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2740:
2737:
2733:
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2728:
2725:
2723:
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2659:
2655:
2647:
2643:
2640:
2636:
2635:
2627:
2624:
2622:
2619:
2617:
2616:Soundproofing
2614:
2612:
2611:Reverberation
2609:
2607:
2604:
2602:
2599:
2598:
2596:
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2590:
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2579:
2574:
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2499:
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2473:
2472:
2465:
2461:
2455:
2451:
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2443:
2430:
2426:
2419:
2412:
2404:
2402:9781420009002
2398:
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2199:
2191:
2186:
2171:
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2127:
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2020:
2017:
2015:
2012:
2010:
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2002:
2000:
1997:
1995:
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1985:
1982:
1980:
1977:
1975:
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1967:
1965:
1962:
1960:
1957:
1955:
1952:
1950:
1947:
1946:
1943:
1939:
1929:
1927:
1926:temporal rate
1923:
1919:
1915:
1914:time duration
1911:
1907:
1903:
1898:
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1890:
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1878:
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1862:
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1829:
1828:North America
1825:
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1804:South America
1801:
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1533:
1529:
1519:
1516:
1512:
1508:
1504:
1503:digital logic
1500:
1496:
1492:
1489:. This is an
1488:
1479:
1474:
1464:
1462:
1458:
1443:
1439:
1438:electromagnet
1428:
1417:
1408:
1406:
1390:
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1129:
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1105:
1101:
1096:
1092:
1087:
1083:
1078:
1065:
1060:
1057:
1052:
1049:
1042:of the wave:
1041:
1037:
1033:
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1022:
1018:
1014:
1010:
1006:
1000:
985:
982:
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979:
967:
964:
961:
958:
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949:
943:
933:
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872:
869:
866:
860:
857:
854:
851:
845:
839:
831:
830:
825:
822:
821:
813:
810:, which is a
809:
805:
801:
797:
794:
782:
779:
775:
771:
768:
765:
762:
756:
746:
715:
712:
708:
704:
698:
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686:
683:
677:
674:
671:
665:
659:
656:
653:
650:
644:
638:
631:
630:
626:
625:sine function
622:
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614:
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609:
604:
600:
599:
594:
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588:
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569:
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516:
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467:
457:
455:
451:
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435:
431:
427:
423:
419:
414:
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407:
405:
393:
388:
385:
380:
377:
368:
365:
361:
357:
353:
349:
345:
341:
337:
330:
326:
321:
312:
310:
305:
303:
299:
295:
291:
290:audio signals
287:
283:
278:
275:
271:
266:
262:
258:
254:
248:
244:
243:
238:
237:
232:
228:
224:
223:
218:
214:
192:
189:
173:
171:
167:
160:
156:
152:
151:
149:
141:
138:
135:
133:
126:
119:
116:
113:
112:
110:
104:
100:
97:
95:
91:
87:
83:
79:
73:
69:
61:
57:
51:
46:
41:
36:
32:
30:
25:
23:
2864:Thomas Young
2814:Jens Blauert
2802:Acousticians
2519:
2492:
2470:
2448:
2411:
2392:
2386:
2375:. Retrieved
2371:
2361:
2341:
2334:
2322:. Retrieved
2313:
2301:. Retrieved
2287:
2282:, p. 7.
2275:
2263:
2252:. Retrieved
2247:
2238:
2226:. Retrieved
2222:the original
2212:
2185:
2173:. Retrieved
2164:
2152:. Retrieved
2143:
2123:
2119:
2114:
1969:Downsampling
1917:
1909:
1896:
1892:
1888:
1881:
1856:
1855:
1789:
1780:Line current
1771:
1756:
1745:
1715:
1710:
1706:
1702:
1698:
1656:
1581:
1528:heterodyning
1525:
1484:
1461:strobe light
1454:
1404:
1246:gating error
1245:
1238:random error
1177:
1169:
1143:
1099:
1094:
1090:
1082:special case
1079:
1039:
1034:of the wave
1031:
1020:
1012:
1002:
827:
607:
597:
580:
576:
572:
567:
558:
545:
463:
447:
437:
415:
410:
408:
366:
363:
355:
351:
347:
336:oscillations
333:
306:
279:
273:
269:
260:
256:
246:
240:
234:
230:
227:unit of time
220:
216:
212:
211:
158:
154:
94:SI unit
85:
81:
60:oscillations
28:
21:
2834:Franz Melde
2809:John Backus
2793:Subharmonic
2646:Spectrogram
2268:Davies 1997
2089:Transverter
2059:Preselector
1920:); it is a
1838:minor third
1802:, southern
1644:ultraviolet
1515:transducers
1511:sound waves
1457:stroboscope
1451:Stroboscope
1160:Measurement
346:, the term
298:radio waves
282:oscillatory
107:Other units
29:Frequencies
22:Frequencies
2895:Ultrasound
2885:Infrasound
2671:Bark scale
2377:2008-10-22
2303:22 January
2280:Young 1999
2254:2022-11-08
2228:21 January
2136:References
2125:wavelength
2094:Upsampling
2054:Pink noise
1936:See also:
1908:happened (
1806:, most of
1740:sound wave
1652:gamma rays
1640:10 Hz
1632:radio wave
1620:10 Hz
1608:10 Hz
1540:heterodyne
1501:. It uses
1407:is small.
1164:See also:
1009:wavelength
617:sinusoidal
478:Frequency
265:reciprocal
2973:Frequency
2776:Resonance
2676:Mel scale
2606:Monochord
2585:Acoustics
2324:3 October
2175:3 October
2154:3 October
2118:The term
1877:becquerel
1800:Australia
1680:λ
1628:microwave
1307:Δ
1256:Δ
1211:≈
1125:λ
1061:λ
965:ξ
962:π
934:θ
891:ω
885:
861:θ
858:
776:π
766:ω
747:θ
709:π
699:
684:ω
678:
660:θ
657:
409:The term
348:frequency
286:vibratory
213:Frequency
190:−
170:Dimension
43:Frequency
2967:Category
2930:Category
2771:Overtone
2739:Harmonic
1932:See also
1924:of type
1844:' in an
1833:♭
1624:infrared
1588:electric
1551:Examples
1442:resonant
1174:Counting
1156:change.
1098:, where
621:argument
325:pendulum
259:(symbol
245:(symbol
215:(symbol
56:pendulum
2957:Physics
2717:Formant
2440:Sources
1859:is the
1767:species
1761:. The
1242:average
1102:is the
1088:, then
1080:In the
1036:divided
623:to the
481:Period
428:by the
255:. The
31:(album)
2943:Portal
2910:Violin
2744:Series
2526:
2500:
2479:
2456:
2399:
2349:
1906:events
1865:cyclic
1812:Russia
1810:, and
1796:Africa
1792:Europe
1748:timbre
1697:where
1648:X-rays
1507:quartz
1495:signal
1356:where
1150:medium
1086:vacuum
1017:lambda
800:radian
444:second
364:period
300:, and
257:period
157:= 1 /
86:ν
66:
24:(film)
2905:Piano
2890:Sound
2704:pitch
2666:Pitch
2421:(PDF)
2106:Notes
1959:Chirp
1752:pitch
1724:Sound
1562:Light
1556:Light
1536:diode
1154:speed
1144:When
1023:of a
615:of a
613:phase
470:audio
452:, is
422:hertz
340:waves
309:beats
302:light
294:sound
222:hertz
99:hertz
2880:Echo
2786:Node
2712:Beat
2702:and
2524:ISBN
2498:ISBN
2477:ISBN
2454:ISBN
2397:ISBN
2347:ISBN
2326:2016
2305:2021
2298:SPIE
2248:NIST
2230:2021
2177:2016
2156:2016
1940:and
1884:rate
1861:rate
1824:tone
1808:Asia
1738:The
1590:and
1564:and
1214:4.73
434:CGPM
416:The
284:and
272:= 1/
101:(Hz)
2425:doi
1842:hum
1818:in
1790:In
1716:In
1547:).
882:sin
855:sin
696:sin
675:sin
654:sin
575:= d
354:or
311:).
296:),
128:In
2969::
2370:.
2296:.
2246:.
2197:^
1928:.
1916:(Δ
1895:/Δ
1891:=
1886:,
1879:.
1798:,
1794:,
1754:.
1654:.
1600:10
1219:Hz
1199:15
1195:71
1093:=
1011:,
579:/d
566:,
418:SI
360:nu
338:,
329:Hz
323:A
304:.
277:.
84:,
68:Hz
54:A
2945::
2577:e
2570:t
2563:v
2532:.
2506:.
2485:.
2462:.
2431:.
2427::
2405:.
2380:.
2355:.
2328:.
2307:.
2257:.
2232:.
2179:.
2158:.
1918:t
1910:N
1897:t
1893:N
1889:f
1711:λ
1707:f
1703:c
1699:c
1683:,
1677:f
1674:=
1671:c
1638:×
1636:8
1618:×
1616:4
1606:×
1604:8
1598:×
1596:4
1530:(
1405:N
1391:f
1369:m
1365:T
1339:m
1335:T
1331:f
1328:2
1324:1
1319:=
1314:f
1310:f
1279:m
1275:T
1271:2
1267:1
1262:=
1259:f
1223:.
1204:s
1190:=
1187:f
1130:.
1122:c
1117:=
1114:f
1100:c
1095:c
1091:v
1066:.
1058:v
1053:=
1050:f
1040:λ
1032:v
1021:f
1015:(
1013:λ
968:.
959:2
956:=
953:k
950:=
944:x
940:d
930:d
906:)
903:x
900:k
897:+
894:t
888:(
879:=
876:)
873:x
870:,
867:t
864:(
852:=
849:)
846:t
843:(
840:y
829:ξ
818:.
816:π
783:.
780:f
772:2
769:=
763:=
757:t
753:d
743:d
719:)
716:t
713:f
705:2
702:(
693:=
690:)
687:t
681:(
672:=
669:)
666:t
663:(
651:=
648:)
645:t
642:(
639:y
627::
608:θ
598:ω
589:.
583:;
581:t
577:N
573:ν
568:N
559:ν
546:x
394:.
389:T
386:1
381:=
378:f
367:T
356:ν
352:f
292:(
274:f
270:T
261:T
252:π
247:ω
217:f
193:1
184:T
159:T
155:f
137:s
82:f
64:6
37:.
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