681:(PSD), spread-spectrum systems require the same amount of energy per bit before spreading as narrowband systems and therefore the same amount of power if the bitrate before spreading is the same, but since the signal power is spread over a large bandwidth, the signal PSD is much lower — often significantly lower than the noise PSD — so that the adversary may be unable to determine whether the signal exists at all. However, for mission-critical applications, particularly those employing commercially available radios, spread-spectrum radios do not provide adequate security unless, at a minimum, long nonlinear spreading sequences are used and the messages are encrypted.
968:
systems from putting enough energy into any one narrowband to exceed the statutory limits. The usefulness of this method as a means to reduce real-life interference problems is often debated, as it is perceived that spread-spectrum clocking hides rather than resolves higher radiated energy issues by simple exploitation of loopholes in EMC legislation or certification procedures. This situation results in electronic equipment sensitive to narrow bandwidth(s) experiencing much less interference, while those with broadband sensitivity, or even operated at other higher frequencies (such as a radio receiver tuned to a different station), will experience more interference.
670:(interference). Direct sequence (DS) is good at resisting continuous-time narrowband jamming, while frequency hopping (FH) is better at resisting pulse jamming. In DS systems, narrowband jamming affects detection performance about as much as if the amount of jamming power is spread over the whole signal bandwidth, where it will often not be much stronger than background noise. By contrast, in narrowband systems where the signal bandwidth is low, the received signal quality will be severely lowered if the jamming power happens to be concentrated on the signal bandwidth.
36:
870:
918:(EMC) regulations. It has become a popular technique to gain regulatory approval because it requires only simple equipment modification. It is even more popular in portable electronics devices because of faster clock speeds and increasing integration of high-resolution LCD displays into ever smaller devices. As these devices are designed to be lightweight and inexpensive, traditional passive, electronic measures to reduce EMI, such as capacitors or metal shielding, are not viable.
343:
2491:
817:
2501:
2480:
2511:
1319:
628:(radio) band of frequencies. The receiver correlates the received signals to retrieve the original information signal. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called
971:
FCC certification testing is often completed with the spread-spectrum function enabled in order to reduce the measured emissions to within acceptable legal limits. However, the spread-spectrum functionality may be disabled by the user in some cases. As an example, in the area of personal computers,
662:
Techniques known since the 1940s and used in military communication systems since the 1950s "spread" a radio signal over a wide frequency range several magnitudes higher than minimum requirement. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies,
967:
used by EMC testing laboratories divide the electromagnetic spectrum into frequency bands approximately 120 kHz wide. If the system under test were to radiate all its energy in a narrow bandwidth, it would register a large peak. Distributing this same energy into a larger bandwidth prevents
898:
Practical synchronous digital systems radiate electromagnetic energy on a number of narrow bands spread on the clock frequency and its harmonics, resulting in a frequency spectrum that, at certain frequencies, can exceed the regulatory limits for electromagnetic interference (e.g. those of the
677:. The spreading sequence (in DS systems) or the frequency-hopping pattern (in FH systems) is often unknown by anyone for whom the signal is unintended, in which case it obscures the signal and reduces the chance of an adversary making sense of it. Moreover, for a given noise
949:
Even though SSC compatibility is mandatory on SATA receivers, it is not uncommon to find expander chips having problems dealing with such a clock. Consequently, an ability to disable spread-spectrum clocking in computer systems is considered useful.
1163:
a device of my design for secret radio telegraphy which fortunately did not win acceptance, as it was a truly barbaric idea consisting in constant changes of transmitter frequency. The commission did, however, see fit to grant me 5,000
889:
and, because of its periodic nature, has an unavoidably narrow frequency spectrum. In fact, a perfect clock signal would have all its energy concentrated at a single frequency (the desired clock frequency) and its harmonics.
962:
energy, and therefore systems are not necessarily less likely to cause interference. Spreading energy over a larger bandwidth effectively reduces electrical and magnetic readings within narrow bandwidths. Typical
1351:
803:"Secret Communications System" on August 11, 1942. Their approach was unique in that frequency coordination was done with paper player piano rolls, a novel approach which was never put into practice.
1323:
976:
writers include the ability to disable spread-spectrum clock generation as a user setting, thereby defeating the object of the EMI regulations. This might be considered a
1303:
American
National Standard for Electromagnetic Noise and Field Strength Instrumentation, 10 Hz to 40 GHz—Specifications, ANSI C63.2-1996, Section 8.2 Overall Bandwidth
1287:
703:(CDMA) or code-division multiplexing (CDM). Multiple users can transmit simultaneously in the same frequency band as long as they use different spreading sequences.
650:(CSS), and combinations of these techniques are forms of spread spectrum. The first two of these techniques employ pseudorandom number sequences—created using
1755:
873:
Spread spectrum of a modern switching power supply (heating up period) incl. waterfall diagram over a few minutes. Recorded with a NF-5030 EMC-Analyzer
1185:
Ari Ben-Menahem, Historical
Encyclopedia of Natural and Mathematical Sciences, Volume 1, Springer Science & Business Media - 2009, pages 4527-4530
688:. The high bandwidth occupied by spread-spectrum signals offer some frequency diversity; i.e., it is unlikely that the signal will encounter severe
914:
Spread-spectrum clocking avoids this problem by reducing the peak radiated energy and, therefore, its electromagnetic emissions and so comply with
318:
1356:
544:
1128:
Tony
Rothman, Random Paths to Frequency Hopping, American Scientist, January–February 2019 Volume 107, Number 1, Page 46 americanscientist.org
2463:
2435:
2430:
1455:
718:
The idea of trying to protect and avoid interference in radio transmissions dates back to the beginning of radio wave signaling. In 1899,
491:
1276:
Intel
Speichersystem SS4000-E: Festplatten, wie beispielsweise die Western Digital WD2500JS SATA, werden nicht erkannt. Woran liegt das?
282:
1263:
1195:
1043:
908:
2457:
1328:
2555:
2452:
2442:
2422:
2224:
440:
1037:
1589:
471:
2514:
2447:
2293:
1217:
311:
227:
2545:
2219:
585:. Spread-spectrum techniques are used for the establishment of secure communications, increasing resistance to natural
537:
430:
654:—to determine and control the spreading pattern of the signal across the allocated bandwidth. Wireless standard
2313:
1391:
1370:
1105:
1011:
900:
856:
713:
635:
476:
206:
2098:
1646:
1448:
1419:
834:
420:
100:
1095:
2550:
2535:
2209:
1334:
989:
639:
570:
481:
416:
375:
287:
201:
173:
140:
115:
67:
2204:
1275:
838:
425:
304:
1127:
2229:
994:
915:
700:
651:
574:
530:
496:
2504:
2265:
2162:
1705:
1500:
1472:
1138:
Jonathan Adolf
Wilhelm Zenneck, Wireless Telegraphy, McGraw-Hill Book Company, Incorporated, 1915, page 331
1048:
1000:
882:
643:
629:
586:
2494:
2001:
1441:
1235:
105:
2353:
2275:
2214:
1921:
779:
722:
experimented with frequency-selective reception in an attempt to minimize interference. The concept of
663:
bandwidths much wider than that required for simple point-to-point communication at the same data rate.
411:
385:
257:
77:
2125:
2086:
1931:
1831:
1760:
1693:
1520:
130:
1380:
Enigma: How the German
Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two
2484:
1726:
1661:
1614:
1574:
1174:
Enigma: How the German
Machine Cipher Was Broken, and How It Was Read by the Allies in World War II
935:
692:
fading over its whole bandwidth. In direct-sequence systems, the signal can be detected by using a
451:
267:
150:
86:
2323:
2308:
2152:
2103:
2026:
1926:
1604:
1490:
1485:
1375:
1169:
938:, can also create challenges for designers. Principal among these is clock/data misalignment, or
827:
350:
164:
43:
946:
on the receiving side needs a high enough bandwidth to correctly track a spread-spectrum clock.
2245:
2031:
1846:
1791:
1786:
1599:
1564:
678:
277:
272:
110:
95:
1411:
2540:
2147:
1951:
1916:
1836:
1816:
1738:
1626:
1547:
689:
647:
598:
518:
513:
262:
196:
1480:
885:(EMI) that these systems generate. A synchronous digital system is one that is driven by a
2061:
2021:
1991:
1748:
1683:
1505:
1383:
1160:
1006:
931:
919:
765:
435:
365:
360:
120:
57:
52:
8:
2071:
2011:
1770:
1732:
1530:
1515:
1091:
878:
590:
562:
145:
2298:
2255:
2186:
2056:
1986:
1961:
1896:
1743:
1464:
1097:
How I Discovered World War II's
Greatest Spy and Other Stories of Intelligence and Code
964:
755:
558:
178:
155:
135:
2338:
2260:
2174:
2157:
2120:
1966:
1796:
1765:
1631:
1525:
1387:
1366:
1101:
943:
881:, especially those containing microprocessors, to reduce the spectral density of the
869:
723:
719:
396:
125:
2006:
930:
In PCIe, USB 3.0, and SATA systems, the most common technique is downspreading, via
2343:
2303:
2283:
2250:
2179:
2137:
2051:
1906:
1891:
1866:
1841:
1801:
1651:
1510:
1495:
1362:
1361:
History on spread spectrum, as given in "Smart Mobs, The Next Social
Revolution",
1338:
735:
578:
466:
380:
370:
252:
247:
72:
62:
1971:
1826:
1594:
1569:
1557:
1423:
1291:
1352:
NTIA Manual of
Regulations and Procedures for Federal Radio Frequency Management
980:, but is generally overlooked as long as spread-spectrum is enabled by default.
793:
developed an intended jamming-resistant radio guidance system for use in Allied
573:(e.g., an electrical, electromagnetic, or acoustic) generated with a particular
2169:
2041:
2016:
1976:
1946:
1821:
1656:
1609:
1584:
1542:
1053:
1016:
790:
582:
1264:
Western Digital Raid Edition III HDDs werden vom RAID Controller nicht erkannt
799:
760:
2529:
2318:
2091:
2081:
1996:
1886:
1881:
1871:
1856:
1678:
1537:
1032:
934:
with a lower-frequency source. Spread-spectrum clocking, like other kinds of
751:
693:
674:
667:
594:
35:
2196:
2036:
1981:
1911:
1876:
1811:
1710:
1700:
1552:
1165:
886:
768:
731:
334:
292:
232:
211:
2396:
2046:
1956:
1941:
1901:
1861:
1720:
1344:
1027:
783:
747:
655:
1416:
2401:
2108:
1806:
1715:
1671:
1641:
1619:
1021:
939:
922:
techniques such as spread-spectrum clocking are needed in these cases.
841: in this section. Unsourced material may be challenged and removed.
743:
727:
621:
342:
27:
1168:
for executing a model and as encouragement to further work." Cited in
746:
was using it previously. It saw limited use by the German military in
2386:
1851:
1666:
1433:
959:
602:
237:
1236:"CATC SATracer / Trainer Application Note: Spread Spectrum Clocking"
816:
2381:
2371:
2288:
2113:
1936:
977:
787:
625:
605:
24:
2376:
2361:
1579:
794:
772:
758:
in 1929, showed up in a patent in the 1930s by Willem Broertjes (
1428:
2406:
2366:
1688:
1024:
military frequency-hopping UHF radio voice communication system
685:
2391:
2328:
1636:
904:
617:
486:
242:
2333:
1386:, Frederick, MD, University Publications of America, 1984,
1075:
Principles of Spread-Spectrum Communication Systems, 4th ed
973:
1159:
Danilewicz later recalled: "In 1929, we proposed to the
877:
Spread-spectrum clock generation (SSCG) is used in some
1218:"Spread Spectrum Clock Generation – Theory and Debate"
616:
Spread spectrum generally makes use of a sequential
1294: (archived 2010-04-29) (Seagate Knowledge Base)
730:and also described in part of a 1903 US patent by
707:
658:uses either FHSS or DSSS in its radio interface.
608:), and to enable multiple-access communications.
2527:
1357:National Information Systems Security Glossary
620:-like signal structure to spread the normally
1449:
538:
312:
1397:Andrew S. Tanenbaum and David J. Wetherall,
958:Note that this method does not reduce total
764:issued Aug. 2, 1932), and in the top-secret
2464:Global telecommunications regulation bodies
2500:
1456:
1442:
1215:
806:
545:
531:
319:
305:
16:Spreading the frequency domain of a signal
1044:Spread-spectrum time-domain reflectometry
857:Learn how and when to remove this message
1211:
1209:
1072:
868:
726:was adopted by the German radio company
2528:
1463:
1086:
1084:
1437:
1288:SSC Toggle Utility – Barracuda 7200.9
1206:
1141:
742:describes the process and notes that
699:Multiple access capability, known as
624:information signal over a relatively
611:
2510:
1090:
1066:
1038:Orthogonal variable spreading factor
839:adding citations to reliable sources
810:
1081:
13:
1412:A short history of spread spectrum
14:
2567:
1405:
1012:Frequency-hopping spread spectrum
714:Frequency-hopping spread spectrum
636:Frequency-hopping spread spectrum
597:, to prevent detection, to limit
2509:
2499:
2490:
2489:
2478:
2099:Free-space optical communication
1429:Spread Spectrum Scene newsletter
1322: This article incorporates
1317:
815:
341:
34:
1335:General Services Administration
1297:
1281:
1269:
1257:
1228:
1149:Haig's Command - A Reassessment
990:Direct-sequence spread spectrum
826:needs additional citations for
640:direct-sequence spread spectrum
1188:
1179:
1153:
1132:
1121:
708:Invention of frequency hopping
652:pseudorandom number generators
577:is deliberately spread in the
1:
995:Electromagnetic compatibility
916:electromagnetic compatibility
893:
797:, patenting the device under
701:code-division multiple access
2556:Spectrum (physical sciences)
2485:Telecommunication portal
2266:Telecommunications equipment
1216:Item Media (19 March 2013).
1049:Time-hopping spread spectrum
1001:Electromagnetic interference
883:electromagnetic interference
771:communications system named
644:time-hopping spread spectrum
630:low probability of intercept
7:
2002:Alexander Stepanovich Popov
1382:, edited and translated by
983:
879:synchronous digital systems
10:
2572:
1706:Telecommunications history
1310:
1196:"Spread Spectrum Clocking"
711:
569:are techniques by which a
228:Capacity-approaching codes
2546:Radio resource management
2473:
2415:
2352:
2314:Public Switched Telephone
2274:
2238:
2195:
2136:
2126:telecommunication circuit
2087:Fiber-optic communication
2070:
1832:Francis Blake (telephone)
1779:
1627:Optical telecommunication
1471:
1117:– via Google Books.
953:
925:
2225:Orbital angular-momentum
1662:Satellite communications
1501:Communications satellite
1417:CDMA and spread spectrum
1059:
936:dynamic frequency change
452:Statistical multiplexing
2104:Molecular communication
1927:Gardiner Greene Hubbard
1756:Undersea telegraph line
1491:Cable protection system
1278:(Intel Reseller-Center)
1222:Interference Technology
807:Clock signal generation
780:Golden Age of Hollywood
165:Hierarchical modulation
2551:Radio modulation modes
2536:Channel access methods
2246:Communication protocol
2032:Charles Sumner Tainter
1847:Walter Houser Brattain
1792:Edwin Howard Armstrong
1600:Information revolution
1330:Federal Standard 1037C
1324:public domain material
1073:Torrieri, Don (2018).
903:in the United States,
874:
679:power spectral density
514:Channel access methods
2220:Polarization-division
1952:Narinder Singh Kapany
1917:Erna Schneider Hoover
1837:Jagadish Chandra Bose
1817:Alexander Graham Bell
1548:online video platform
1343: (in support of
872:
800:U.S. patent 2,292,387
778:During World War II,
761:U.S. patent 1,869,659
750:, was put forward by
712:Further information:
648:chirp spread spectrum
519:Medium access control
2062:Vladimir K. Zworykin
2022:Almon Brown Strowger
1992:Charles Grafton Page
1647:Prepaid mobile phone
1575:Electrical telegraph
1384:Christopher Kasparek
1094:(January 17, 2014).
1007:Frequency allocation
932:frequency modulation
920:Active EMI reduction
835:improve this article
766:US Army Signal Corps
738:'s 1908 German book
455:(variable bandwidth)
400:(constant bandwidth)
2012:Johann Philipp Reis
1771:Wireless revolution
1733:The Telephone Cases
1590:Hydraulic telegraph
1266:(Thomas Krenn Wiki)
965:measuring receivers
740:Wireless Telegraphy
563:radio communication
2210:Frequency-division
2187:Telephone exchange
2057:Charles Wheatstone
1987:Jun-ichi Nishizawa
1962:Innocenzo Manzetti
1897:Reginald Fessenden
1632:Optical telegraphy
1465:Telecommunications
1422:2009-04-16 at the
1376:Władysław Kozaczuk
1170:Władysław Kozaczuk
875:
756:Leonard Danilewicz
612:Telecommunications
599:power flux density
559:telecommunications
87:Digital modulation
2523:
2522:
2261:Store and forward
2256:Data transmission
2170:Network switching
2121:Transmission line
1967:Guglielmo Marconi
1932:Internet pioneers
1797:Mohamed M. Atalla
1766:Whistled language
1399:Computer Networks
944:phase-locked loop
907:in Japan and the
867:
866:
859:
724:Frequency-hopping
720:Guglielmo Marconi
555:
554:
351:Analog modulation
329:
328:
44:Analog modulation
2563:
2513:
2512:
2503:
2502:
2493:
2492:
2483:
2482:
2481:
2354:Notable networks
2344:Wireless network
2284:Cellular network
2276:Types of network
2251:Computer network
2138:Network topology
2052:Thomas A. Watson
1907:Oliver Heaviside
1892:Philo Farnsworth
1867:Daniel Davis Jr.
1842:Charles Bourseul
1802:John Logie Baird
1511:Data compression
1506:Computer network
1458:
1451:
1444:
1435:
1434:
1401:, Fifth Edition.
1363:Howard Rheingold
1348:
1342:
1337:. Archived from
1321:
1320:
1304:
1301:
1295:
1285:
1279:
1273:
1267:
1261:
1255:
1254:
1252:
1250:
1240:
1232:
1226:
1225:
1213:
1204:
1203:
1192:
1186:
1183:
1177:
1157:
1151:
1145:
1139:
1136:
1130:
1125:
1119:
1118:
1116:
1114:
1088:
1079:
1078:
1070:
862:
855:
851:
848:
842:
819:
811:
802:
786:and avant-garde
763:
736:Jonathan Zenneck
734:. Radio pioneer
579:frequency domain
547:
540:
533:
467:Packet switching
456:
401:
345:
331:
330:
321:
314:
307:
38:
21:
20:
2571:
2570:
2566:
2565:
2564:
2562:
2561:
2560:
2526:
2525:
2524:
2519:
2479:
2477:
2469:
2411:
2348:
2270:
2234:
2191:
2140:
2132:
2073:
2066:
1972:Robert Metcalfe
1827:Tim Berners-Lee
1775:
1595:Information Age
1467:
1462:
1424:Wayback Machine
1408:
1327:
1318:
1316:
1313:
1308:
1307:
1302:
1298:
1292:Wayback Machine
1286:
1282:
1274:
1270:
1262:
1258:
1248:
1246:
1238:
1234:
1233:
1229:
1214:
1207:
1194:
1193:
1189:
1184:
1180:
1158:
1154:
1146:
1142:
1137:
1133:
1126:
1122:
1112:
1110:
1108:
1089:
1082:
1071:
1067:
1062:
986:
956:
928:
896:
863:
852:
846:
843:
832:
820:
809:
798:
759:
716:
710:
614:
567:spread spectrum
551:
501:
458:
454:
453:
445:
403:
399:
398:
390:
325:
188:Spread spectrum
17:
12:
11:
5:
2569:
2559:
2558:
2553:
2548:
2543:
2538:
2521:
2520:
2518:
2517:
2507:
2497:
2487:
2474:
2471:
2470:
2468:
2467:
2460:
2455:
2450:
2445:
2440:
2439:
2438:
2433:
2425:
2419:
2417:
2413:
2412:
2410:
2409:
2404:
2399:
2394:
2389:
2384:
2379:
2374:
2369:
2364:
2358:
2356:
2350:
2349:
2347:
2346:
2341:
2336:
2331:
2326:
2321:
2316:
2311:
2306:
2301:
2296:
2291:
2286:
2280:
2278:
2272:
2271:
2269:
2268:
2263:
2258:
2253:
2248:
2242:
2240:
2236:
2235:
2233:
2232:
2227:
2222:
2217:
2212:
2207:
2205:Space-division
2201:
2199:
2193:
2192:
2190:
2189:
2184:
2183:
2182:
2177:
2167:
2166:
2165:
2155:
2150:
2144:
2142:
2134:
2133:
2131:
2130:
2129:
2128:
2118:
2117:
2116:
2106:
2101:
2096:
2095:
2094:
2084:
2078:
2076:
2068:
2067:
2065:
2064:
2059:
2054:
2049:
2044:
2042:Camille Tissot
2039:
2034:
2029:
2024:
2019:
2017:Claude Shannon
2014:
2009:
2007:Tivadar Puskás
2004:
1999:
1994:
1989:
1984:
1979:
1977:Antonio Meucci
1974:
1969:
1964:
1959:
1954:
1949:
1947:Charles K. Kao
1944:
1939:
1934:
1929:
1924:
1922:Harold Hopkins
1919:
1914:
1909:
1904:
1899:
1894:
1889:
1884:
1879:
1874:
1869:
1864:
1859:
1854:
1849:
1844:
1839:
1834:
1829:
1824:
1822:Emile Berliner
1819:
1814:
1809:
1804:
1799:
1794:
1789:
1783:
1781:
1777:
1776:
1774:
1773:
1768:
1763:
1761:Videotelephony
1758:
1753:
1752:
1751:
1746:
1736:
1729:
1724:
1718:
1713:
1708:
1703:
1698:
1697:
1696:
1691:
1686:
1676:
1675:
1674:
1664:
1659:
1657:Radiotelephone
1654:
1649:
1644:
1639:
1634:
1629:
1624:
1623:
1622:
1612:
1607:
1602:
1597:
1592:
1587:
1582:
1577:
1572:
1567:
1562:
1561:
1560:
1555:
1550:
1545:
1543:Internet video
1535:
1534:
1533:
1528:
1523:
1518:
1508:
1503:
1498:
1493:
1488:
1483:
1477:
1475:
1469:
1468:
1461:
1460:
1453:
1446:
1438:
1432:
1431:
1426:
1414:
1407:
1406:External links
1404:
1403:
1402:
1395:
1373:
1359:
1354:
1349:
1341:on 2022-01-22.
1312:
1309:
1306:
1305:
1296:
1280:
1268:
1256:
1245:. July 2, 2003
1227:
1205:
1187:
1178:
1176:, 1984, p. 27.
1152:
1147:Denis Winter,
1140:
1131:
1120:
1106:
1080:
1064:
1063:
1061:
1058:
1057:
1056:
1054:Ultra-wideband
1051:
1046:
1041:
1035:
1030:
1025:
1019:
1017:George Antheil
1014:
1009:
1004:
998:
992:
985:
982:
955:
952:
927:
924:
895:
892:
865:
864:
823:
821:
814:
808:
805:
791:George Antheil
709:
706:
705:
704:
697:
684:Resistance to
682:
673:Resistance to
671:
666:Resistance to
664:
613:
610:
583:frequency band
553:
552:
550:
549:
542:
535:
527:
524:
523:
522:
521:
516:
508:
507:
506:Related topics
503:
502:
500:
499:
494:
489:
484:
479:
474:
469:
463:
460:
459:
450:
447:
446:
444:
443:
438:
433:
428:
423:
414:
408:
405:
404:
395:
392:
391:
389:
388:
383:
378:
373:
368:
363:
357:
354:
353:
347:
346:
338:
337:
327:
326:
324:
323:
316:
309:
301:
298:
297:
296:
295:
290:
285:
280:
275:
270:
265:
260:
255:
250:
245:
240:
235:
230:
222:
221:
217:
216:
215:
214:
209:
204:
199:
191:
190:
184:
183:
182:
181:
176:
168:
167:
161:
160:
159:
158:
153:
148:
143:
138:
133:
128:
123:
118:
113:
108:
103:
98:
90:
89:
83:
82:
81:
80:
75:
70:
65:
60:
55:
47:
46:
40:
39:
31:
30:
15:
9:
6:
4:
3:
2:
2568:
2557:
2554:
2552:
2549:
2547:
2544:
2542:
2539:
2537:
2534:
2533:
2531:
2516:
2508:
2506:
2498:
2496:
2488:
2486:
2476:
2475:
2472:
2465:
2461:
2459:
2456:
2454:
2451:
2449:
2446:
2444:
2441:
2437:
2434:
2432:
2429:
2428:
2426:
2424:
2421:
2420:
2418:
2414:
2408:
2405:
2403:
2400:
2398:
2395:
2393:
2390:
2388:
2385:
2383:
2380:
2378:
2375:
2373:
2370:
2368:
2365:
2363:
2360:
2359:
2357:
2355:
2351:
2345:
2342:
2340:
2337:
2335:
2332:
2330:
2327:
2325:
2322:
2320:
2317:
2315:
2312:
2310:
2307:
2305:
2302:
2300:
2297:
2295:
2292:
2290:
2287:
2285:
2282:
2281:
2279:
2277:
2273:
2267:
2264:
2262:
2259:
2257:
2254:
2252:
2249:
2247:
2244:
2243:
2241:
2237:
2231:
2230:Code-division
2228:
2226:
2223:
2221:
2218:
2216:
2215:Time-division
2213:
2211:
2208:
2206:
2203:
2202:
2200:
2198:
2194:
2188:
2185:
2181:
2178:
2176:
2173:
2172:
2171:
2168:
2164:
2161:
2160:
2159:
2156:
2154:
2151:
2149:
2146:
2145:
2143:
2141:and switching
2139:
2135:
2127:
2124:
2123:
2122:
2119:
2115:
2112:
2111:
2110:
2107:
2105:
2102:
2100:
2097:
2093:
2092:optical fiber
2090:
2089:
2088:
2085:
2083:
2082:Coaxial cable
2080:
2079:
2077:
2075:
2069:
2063:
2060:
2058:
2055:
2053:
2050:
2048:
2045:
2043:
2040:
2038:
2035:
2033:
2030:
2028:
2025:
2023:
2020:
2018:
2015:
2013:
2010:
2008:
2005:
2003:
2000:
1998:
1997:Radia Perlman
1995:
1993:
1990:
1988:
1985:
1983:
1980:
1978:
1975:
1973:
1970:
1968:
1965:
1963:
1960:
1958:
1955:
1953:
1950:
1948:
1945:
1943:
1940:
1938:
1935:
1933:
1930:
1928:
1925:
1923:
1920:
1918:
1915:
1913:
1910:
1908:
1905:
1903:
1900:
1898:
1895:
1893:
1890:
1888:
1887:Lee de Forest
1885:
1883:
1882:Thomas Edison
1880:
1878:
1875:
1873:
1872:Donald Davies
1870:
1868:
1865:
1863:
1860:
1858:
1857:Claude Chappe
1855:
1853:
1850:
1848:
1845:
1843:
1840:
1838:
1835:
1833:
1830:
1828:
1825:
1823:
1820:
1818:
1815:
1813:
1810:
1808:
1805:
1803:
1800:
1798:
1795:
1793:
1790:
1788:
1785:
1784:
1782:
1778:
1772:
1769:
1767:
1764:
1762:
1759:
1757:
1754:
1750:
1747:
1745:
1742:
1741:
1740:
1737:
1735:
1734:
1730:
1728:
1725:
1722:
1719:
1717:
1714:
1712:
1709:
1707:
1704:
1702:
1701:Smoke signals
1699:
1695:
1692:
1690:
1687:
1685:
1682:
1681:
1680:
1679:Semiconductor
1677:
1673:
1670:
1669:
1668:
1665:
1663:
1660:
1658:
1655:
1653:
1650:
1648:
1645:
1643:
1640:
1638:
1635:
1633:
1630:
1628:
1625:
1621:
1618:
1617:
1616:
1613:
1611:
1608:
1606:
1603:
1601:
1598:
1596:
1593:
1591:
1588:
1586:
1583:
1581:
1578:
1576:
1573:
1571:
1568:
1566:
1563:
1559:
1556:
1554:
1551:
1549:
1546:
1544:
1541:
1540:
1539:
1538:Digital media
1536:
1532:
1529:
1527:
1524:
1522:
1519:
1517:
1514:
1513:
1512:
1509:
1507:
1504:
1502:
1499:
1497:
1494:
1492:
1489:
1487:
1484:
1482:
1479:
1478:
1476:
1474:
1470:
1466:
1459:
1454:
1452:
1447:
1445:
1440:
1439:
1436:
1430:
1427:
1425:
1421:
1418:
1415:
1413:
1410:
1409:
1400:
1396:
1393:
1392:0-89093-547-5
1389:
1385:
1381:
1377:
1374:
1372:
1371:0-7382-0608-3
1368:
1364:
1360:
1358:
1355:
1353:
1350:
1346:
1340:
1336:
1332:
1331:
1325:
1315:
1314:
1300:
1293:
1289:
1284:
1277:
1272:
1265:
1260:
1244:
1237:
1231:
1223:
1219:
1212:
1210:
1201:
1197:
1191:
1182:
1175:
1171:
1167:
1162:
1161:General Staff
1156:
1150:
1144:
1135:
1129:
1124:
1109:
1107:9781466561991
1103:
1100:. CRC Press.
1099:
1098:
1093:
1087:
1085:
1076:
1069:
1065:
1055:
1052:
1050:
1047:
1045:
1042:
1039:
1036:
1034:
1033:Open spectrum
1031:
1029:
1026:
1023:
1020:
1018:
1015:
1013:
1010:
1008:
1005:
1002:
999:
996:
993:
991:
988:
987:
981:
979:
975:
969:
966:
961:
951:
947:
945:
941:
937:
933:
923:
921:
917:
912:
910:
906:
902:
891:
888:
884:
880:
871:
861:
858:
850:
840:
836:
830:
829:
824:This section
822:
818:
813:
812:
804:
801:
796:
792:
789:
785:
781:
776:
774:
770:
767:
762:
757:
753:
749:
745:
741:
737:
733:
729:
725:
721:
715:
702:
698:
695:
694:rake receiver
691:
687:
683:
680:
676:
675:eavesdropping
672:
669:
665:
661:
660:
659:
657:
653:
649:
645:
641:
637:
633:
631:
627:
623:
619:
609:
607:
604:
600:
596:
592:
588:
584:
581:over a wider
580:
576:
572:
568:
564:
561:, especially
560:
548:
543:
541:
536:
534:
529:
528:
526:
525:
520:
517:
515:
512:
511:
510:
509:
505:
504:
498:
495:
493:
490:
488:
485:
483:
480:
478:
475:
473:
470:
468:
465:
464:
462:
461:
457:
449:
448:
442:
439:
437:
434:
432:
429:
427:
424:
422:
418:
415:
413:
410:
409:
407:
406:
402:
394:
393:
387:
384:
382:
379:
377:
374:
372:
369:
367:
364:
362:
359:
358:
356:
355:
352:
349:
348:
344:
340:
339:
336:
333:
332:
322:
317:
315:
310:
308:
303:
302:
300:
299:
294:
291:
289:
286:
284:
281:
279:
276:
274:
271:
269:
266:
264:
261:
259:
256:
254:
251:
249:
246:
244:
241:
239:
236:
234:
231:
229:
226:
225:
224:
223:
219:
218:
213:
210:
208:
205:
203:
200:
198:
195:
194:
193:
192:
189:
186:
185:
180:
177:
175:
172:
171:
170:
169:
166:
163:
162:
157:
154:
152:
149:
147:
144:
142:
139:
137:
134:
132:
129:
127:
124:
122:
119:
117:
114:
112:
109:
107:
104:
102:
99:
97:
94:
93:
92:
91:
88:
85:
84:
79:
76:
74:
71:
69:
66:
64:
61:
59:
56:
54:
51:
50:
49:
48:
45:
42:
41:
37:
33:
32:
29:
26:
23:
22:
19:
2541:Multiplexing
2197:Multiplexing
2072:Transmission
2037:Nikola Tesla
2027:Henry Sutton
1982:Samuel Morse
1912:Robert Hooke
1877:Amos Dolbear
1812:John Bardeen
1731:
1711:Telautograph
1615:Mobile phone
1570:Edholm's law
1553:social media
1486:Broadcasting
1398:
1379:
1339:the original
1329:
1299:
1283:
1271:
1259:
1247:. Retrieved
1242:
1230:
1221:
1199:
1190:
1181:
1173:
1155:
1148:
1143:
1134:
1123:
1111:. Retrieved
1096:
1074:
1068:
970:
957:
948:
929:
913:
911:in Europe).
897:
887:clock signal
876:
853:
847:January 2020
844:
833:Please help
828:verification
825:
777:
769:World War II
739:
732:Nikola Tesla
717:
634:
615:
587:interference
566:
556:
472:Dynamic TDMA
431:Polarization
419: /
397:Circuit mode
335:Multiplexing
293:Multiplexing
233:Demodulation
187:
18:
2397:NPL network
2109:Radio waves
2047:Alfred Vail
1957:Hedy Lamarr
1942:Dawon Kahng
1902:Elisha Gray
1862:Yogen Dalal
1787:Nasir Ahmed
1721:Teleprinter
1585:Heliographs
1345:MIL-STD-188
1113:November 9,
1092:Kahn, David
1028:Hedy Lamarr
784:Hedy Lamarr
748:World War I
656:IEEE 802.11
238:Line coding
2530:Categories
2443:Antarctica
2402:Toasternet
2324:Television
1807:Paul Baran
1739:Television
1723:(teletype)
1716:Telegraphy
1694:transistor
1672:Phryctoria
1642:Photophone
1620:Smartphone
1610:Mass media
1022:HAVE QUICK
940:clock skew
894:Background
744:Telefunken
728:Telefunken
622:narrowband
601:(e.g., in
28:modulation
2427:Americas
2416:Locations
2387:Internet2
2148:Bandwidth
1852:Vint Cerf
1749:streaming
1727:Telephone
1667:Semaphore
1558:streaming
1200:Microsemi
795:torpedoes
754:engineer
690:multipath
606:downlinks
603:satellite
575:bandwidth
2495:Category
2382:Internet
2372:CYCLADES
2289:Ethernet
2239:Concepts
2163:terminal
2114:wireless
1937:Bob Kahn
1780:Pioneers
1605:Internet
1496:Cable TV
1420:Archived
984:See also
978:loophole
960:radiated
788:composer
782:actress
646:(THSS),
642:(DSSS),
638:(FHSS),
626:wideband
220:See also
25:Passband
2515:Commons
2505:Outline
2458:Oceania
2377:FidoNet
2362:ARPANET
2175:circuit
1744:digital
1473:History
1311:Sources
1290:at the
773:SIGSALY
668:jamming
632:(LPI).
595:jamming
436:Spatial
2453:Europe
2423:Africa
2407:Usenet
2367:BITNET
2304:Mobile
2180:packet
1689:MOSFET
1684:device
1481:Beacon
1390:
1369:
1249:20 May
1166:zlotys
1104:
1040:(OVSF)
954:Effect
926:Method
752:Polish
686:fading
593:, and
571:signal
492:SC-FDM
146:SC-FDE
2436:South
2431:North
2392:JANET
2329:Telex
2319:Radio
2158:Nodes
2153:Links
2074:media
1652:Radio
1637:Pager
1565:Drums
1531:video
1526:image
1516:audio
1326:from
1239:(PDF)
1060:Notes
1003:(EMI)
997:(EMC)
972:some
905:JEITA
618:noise
591:noise
497:MC-SS
487:OFDMA
243:Modem
2448:Asia
2334:UUCP
2294:ISDN
1388:ISBN
1367:ISBN
1251:2023
1243:CATC
1115:2022
1102:ISBN
974:BIOS
942:. A
482:DSSS
477:FHSS
426:SDMA
283:OFDM
212:THSS
207:FHSS
202:DSSS
116:MFSK
101:APSK
2339:WAN
2309:NGN
2299:LAN
1580:Fax
1521:DCT
909:IEC
901:FCC
837:by
557:In
441:OAM
421:WDM
417:FDM
412:TDM
386:SSB
376:QAM
288:FDM
278:ΔΣM
273:PWM
268:PDM
263:PCM
258:PAM
253:PoM
248:AnM
197:CSS
179:WDM
174:QAM
156:WDM
151:TCM
141:QAM
136:PSK
131:PPM
126:OOK
121:MSK
111:FSK
106:CPM
96:ASK
78:SSB
68:QAM
2532::
1378:,
1365:,
1347:).
1333:.
1241:.
1220:.
1208:^
1198:.
1172:,
1083:^
775:.
589:,
565:,
381:SM
371:PM
366:FM
361:AM
73:SM
63:PM
58:FM
53:AM
2466:)
2462:(
1457:e
1450:t
1443:v
1394:.
1253:.
1224:.
1202:.
1077:.
860:)
854:(
849:)
845:(
831:.
696:.
546:e
539:t
532:v
320:e
313:t
306:v
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
