73:
445:
1212:
587:
3337:
487:
383:
143:
3347:
395:
32:
3326:
355:
3357:
1669:
460:. These ghosts are particularly bothersome since they move and behave like the normal targets (which they echo), and so the receiver has difficulty in isolating the correct target echo. These problems can be minimized by incorporating a ground map of the radar's surroundings and eliminating all echoes which appear to originate below the ground or above a certain height (altitude).
1505:
398:
In this illustration, an object (in this case an aircraft) pollutes the system by adding a second path. The signal arrives at receiver (RX) by means of two different paths which have different lengths. The main path is the direct path, while the second is due to a reflection from the
440:
and ghosting, seen as a faded duplicate image to the right of the main image. Ghosts occur when transmissions bounce off a mountain or other large object, while also arriving at the antenna by a shorter, direct route, with the receiver picking up two signals separated by a delay.
498:, multipath effects can cause a stationary receiver's output to indicate as if it were randomly jumping about or creeping. When the unit is moving the jumping or creeping may be hidden, but it still degrades the displayed accuracy of location and speed.
1219:
In practical conditions and measurement, the multipath time is computed by considering as last impulse the first one which allows receiving a determined amount of the total transmitted power (scaled by the atmospheric and propagation losses), e.g. 99%.
804:
1290:
1107:
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to
Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle
663:
At the receiver, due to the presence of the multiple electromagnetic paths, more than one pulse will be received, and each one of them will arrive at different times. In fact, since the electromagnetic signals travel at the
370:
whereby a wave from a source travels to a detector via two or more paths and the two (or more) components of the wave interfere constructively or destructively. Multipath interference is a common cause of
1673:
1573:
1521:); it can be shown that, on average, the distance (in Hz) between two consecutive valleys (or two consecutive peaks), is roughly inversely proportional to the multipath time. The so-called
1578:
For example, with a multipath time of 3 μs (corresponding to a 1 km of added on-air travel for the last received impulse), there is a coherence bandwidth of about 330 kHz.
1206:
560:
to avoid ISI. Because multipath propagation behaves differently in each kind of wire, G.hn uses different OFDM parameters (OFDM symbol duration, guard interval duration) for each media.
931:
1100:
1048:
2254:
658:
340:
distribution. All of these descriptions are commonly used and accepted and lead to results. However, they are generic and abstract/hide/approximate the underlying physics.
1510:
where the last right-hand term of the previous equation is easily obtained by remembering that the
Fourier transform of a Dirac pulse is a complex exponential function, an
854:
884:
1144:
1283:
1250:
993:
964:
827:
678:
668:, and since every path has a geometrical length possibly different from that of the other ones, there are different air travelling times (consider that, in
2601:
1500:{\displaystyle H(f)={\mathfrak {F}}(h(t))=\int _{-\infty }^{+\infty }{h(t)e^{-j2\pi ft}dt}=\sum _{n=0}^{N-1}{\rho _{n}e^{j\phi _{n}}e^{-j2\pi f\tau _{n}}}}
998:
More in general, in presence of time variation of the geometrical reflection conditions, this impulse response is time varying, and as such we have
1115:
293:
from water bodies and terrestrial objects such as mountains and buildings. When the same signal is received over more than one path, it can create
410:
The interference will arise owing to the two (or more) components of the wave having, in general, travelled a different length (as measured by
102:
305:; this may cause a radio signal to become too weak in certain areas to be received adequately. For this reason, this effect is also known as
3309:
3281:
3276:
2301:
1717:
2019:
1769:
1618:
1223:
Keeping our aim at linear, time invariant systems, we can also characterize the multipath phenomenon by the channel transfer function
417:
The signal due to indirect paths interferes with the required signal in amplitude as well as phase which is called multipath fading.
207:
476:
179:
3303:
2058:
160:
45:
1678:
414:– geometric length and refraction (differing optical speed)), and thus arriving at the detector out of phase with each other.
3298:
3288:
3268:
3070:
2029:
186:
3386:
2435:
3360:
3293:
3139:
2078:
3065:
495:
337:
325:
193:
1517:
The obtained channel transfer characteristic has a typical appearance of a sequence of peaks and valleys (also called
3159:
1531:
433:
244:
226:
124:
59:
95:
2944:
2492:
2294:
1710:
175:
3055:
1684:
1633:
1152:
829:
is the number of received impulses (equivalent to the number of electromagnetic paths, and possibly very large),
294:
3381:
3050:
2191:
164:
3075:
2039:
889:
472:
1056:
1004:
3350:
3111:
3008:
2551:
2346:
2318:
1966:
3340:
2847:
2287:
2264:
1703:
578:
are usually more intense and complex. Where OFDM training is unsatisfactory, bridge taps may be removed.
1113:
Very often, just one parameter is used to denote the severity of multipath conditions: it is called the
3199:
3121:
3060:
2767:
2237:
2206:
1951:
1861:
672:, the light takes 3 μs to cross a 1 km span). Thus, the received signal will be expressed by
51:
20:
2971:
2932:
2777:
2677:
2606:
2539:
2366:
619:
85:
3330:
2572:
2507:
2460:
2420:
549:
534:
507:
468:
316:
Where the magnitudes of the signals arriving by the various paths have a distribution known as the
200:
89:
81:
3169:
3154:
2998:
2949:
2872:
2772:
2450:
2336:
2331:
2216:
2115:
2068:
1976:
153:
1146:, and it is defined as the time delay existing between the first and the last received impulses
3091:
2877:
2692:
2637:
2632:
2445:
2410:
2110:
2024:
1866:
1660:
832:
282:
106:
525:
High-speed power line communication systems usually employ multi-carrier modulations (such as
19:
This article is about the electromagnetic propagation phenomenon. For usage in computing, see
2993:
2797:
2762:
2682:
2662:
2584:
2472:
2393:
2034:
2014:
467:) multipath can cause errors and affect the quality of communications. The errors are due to
372:
317:
274:
2326:
859:
386:
A diagram of the ideal situation for TV signals moving through space: The signal leaves the
2907:
2867:
2837:
2594:
2529:
2351:
1839:
1779:
1764:
1759:
1122:
606:
290:
1259:
1226:
969:
940:
8:
2917:
2857:
2616:
2578:
2376:
2361:
1946:
1817:
1522:
411:
404:
278:
258:
1695:
799:{\displaystyle y(t)=h(t)=\sum _{n=0}^{N-1}{\rho _{n}e^{j\phi _{n}}\delta (t-\tau _{n})}}
3144:
3101:
3032:
2902:
2832:
2807:
2742:
2589:
2310:
2083:
1587:
812:
553:
545:
515:
3184:
3106:
3020:
3003:
2966:
2812:
2642:
2611:
2477:
2371:
2196:
2155:
2073:
1608:
1253:
934:
519:
349:
329:
266:
2852:
2150:
3189:
3149:
3129:
3096:
3025:
2983:
2897:
2752:
2737:
2712:
2687:
2647:
2497:
2356:
2341:
2232:
2176:
2145:
1990:
1801:
1726:
1688:
1593:
610:
595:
457:
444:
390:(TX) and travels through one path to the receiver (the TV set, which is labeled RX)
2135:
2817:
2672:
2440:
2415:
2403:
2201:
2171:
1807:
1638:
594:
The mathematical model of the multipath can be presented using the method of the
321:
3015:
2887:
2862:
2822:
2792:
2667:
2502:
2455:
2430:
2388:
1811:
1598:
665:
1211:
566:
also use orthogonal frequency-division multiplexing to communicate with their
3375:
3164:
2937:
2927:
2842:
2732:
2727:
2717:
2702:
2524:
2383:
2186:
1911:
1791:
1730:
1643:
1623:
1511:
937:(i.e., magnitude and phase) of the generic received pulse. As a consequence,
599:
586:
557:
480:
333:
298:
544:
standard provides a way to create a high-speed (up to 1 gigabit per second)
3042:
2882:
2827:
2757:
2722:
2657:
2556:
2546:
2398:
2258:
1733:
270:
456:
processing, multipath causes ghost targets to appear, deceiving the radar
3242:
2892:
2802:
2787:
2747:
2707:
2566:
2181:
2006:
1797:
1655:
1628:
1613:
387:
359:
3247:
2954:
2652:
2561:
2517:
2487:
2465:
2063:
2049:
1751:
669:
575:
571:
570:
despite multipath. In this case the reflections may be caused by mixed
511:
430:
376:
336:. Where two components dominate, the behavior is best modeled with the
286:
486:
358:
Coherent waves that travel along two different paths will arrive with
3232:
2697:
2512:
2279:
2126:
1985:
563:
475:
are often used to correct the ISI. Alternatively, techniques such as
382:
448:
Radar multipath echoes from an actual target cause ghosts to appear.
142:
3227:
3217:
3134:
2959:
2782:
1876:
1829:
1787:
394:
403:
The condition necessary is that the components of the wave remain
3222:
3207:
2425:
1916:
1871:
1825:
530:
3252:
3212:
2534:
2140:
1956:
1930:
1925:
1884:
1835:
1821:
1603:
437:
302:
1215:
Mathematical model of the multipath channel transfer function.
354:
3237:
3174:
2482:
1961:
1856:
1748:
567:
538:
453:
3179:
541:
526:
367:
1725:
464:
426:
366:
Multipath interference is a phenomenon in the physics of
1590:, a design that can reject extraneous reflection signals
1534:
1293:
1262:
1229:
1155:
1125:
1059:
1007:
972:
943:
892:
862:
835:
815:
681:
622:
590:
Mathematical model of the multipath impulse response.
332:
provides a more accurate model, and this is known as
324:. Where one component (often, but not necessarily, a
375:" in analog television broadcasts and of fading of
167:. Unsourced material may be challenged and removed.
1567:
1499:
1277:
1244:
1200:
1138:
1094:
1042:
987:
958:
925:
878:
848:
821:
798:
652:
277:by two or more paths. Causes of multipath include
3373:
94:but its sources remain unclear because it lacks
1568:{\displaystyle B_{C}\approx {\frac {1}{T_{M}}}}
301:of the signal. Destructive interference causes
966:also represents the impulse response function
2295:
1711:
605:Suppose you want to transmit a single, ideal
407:throughout the whole extent of their travel.
537:that multipath propagation would cause. The
3310:Global telecommunications regulation bodies
1201:{\displaystyle T_{M}=\tau _{N-1}-\tau _{0}}
60:Learn how and when to remove these messages
3346:
2302:
2288:
1718:
1704:
1619:Orthogonal frequency-division multiplexing
1252:, which is defined as the continuous time
463:In digital radio communications (such as
245:Learn how and when to remove this message
227:Learn how and when to remove this message
125:Learn how and when to remove this message
1210:
585:
581:
485:
477:orthogonal frequency division modulation
443:
393:
381:
353:
926:{\displaystyle \rho _{n}e^{j\phi _{n}}}
3374:
2309:
1095:{\displaystyle \rho _{n}=\rho _{n}(t)}
1043:{\displaystyle \tau _{n}=\tau _{n}(t)}
2283:
2096:
1699:
3356:
506:Multipath propagation is similar in
362:, hence interfering with each other.
165:adding citations to reliable sources
136:
66:
25:
1311:
995:of the equivalent multipath model.
13:
2097:
1353:
1345:
496:Global Positioning System receiver
338:two-wave with diffuse power (TWDP)
14:
3398:
856:is the time delay of the generic
501:
41:This article has multiple issues.
3355:
3345:
3336:
3335:
3324:
2945:Free-space optical communication
2252:
1672: This article incorporates
1667:
141:
71:
30:
1685:General Services Administration
1634:Two-ray ground-reflection model
653:{\displaystyle x(t)=\delta (t)}
343:
152:needs additional citations for
49:or discuss these issues on the
2192:Error detection and correction
1368:
1362:
1331:
1328:
1322:
1316:
1303:
1297:
1272:
1266:
1239:
1233:
1089:
1083:
1037:
1031:
982:
976:
953:
947:
792:
773:
706:
700:
691:
685:
647:
641:
632:
626:
16:Concept in radio communication
1:
1649:
3331:Telecommunication portal
3112:Telecommunications equipment
548:using existing home wiring (
7:
3387:Radio frequency propagation
2848:Alexander Stepanovich Popov
2265:Comparison of radio systems
1581:
420:
269:phenomenon that results in
10:
3405:
2552:Telecommunications history
2238:International broadcasting
2207:FM extended band in Brazil
490:GPS error due to multipath
347:
21:Multipath (disambiguation)
18:
3319:
3261:
3198:
3160:Public Switched Telephone
3120:
3084:
3041:
2982:
2972:telecommunication circuit
2933:Fiber-optic communication
2916:
2678:Francis Blake (telephone)
2625:
2473:Optical telecommunication
2317:
2246:
2225:
2164:
2124:
2103:
2092:
2048:
2005:
1975:
1939:
1904:
1897:
1849:
1778:
1747:
1740:
849:{\displaystyle \tau _{n}}
556:). G.hn uses OFDM with a
3071:Orbital angular-momentum
2508:Satellite communications
2347:Communications satellite
1514:of every linear system.
1256:of the impulse response
535:intersymbol interference
508:power line communication
469:intersymbol interference
328:component) dominates, a
80:This article includes a
2950:Molecular communication
2773:Gardiner Greene Hubbard
2602:Undersea telegraph line
2337:Cable protection system
2217:Shortwave relay station
2116:Audio signal processing
273:reaching the receiving
176:"Multipath propagation"
109:more precise citations.
3092:Communication protocol
2878:Charles Sumner Tainter
2693:Walter Houser Brattain
2638:Edwin Howard Armstrong
2446:Information revolution
2111:Audio data compression
1680:Federal Standard 1037C
1674:public domain material
1661:Federal Standard 1037C
1569:
1501:
1432:
1279:
1246:
1216:
1202:
1140:
1096:
1044:
989:
960:
927:
880:
879:{\displaystyle n^{th}}
850:
823:
800:
738:
654:
613:power at time 0, i.e.
591:
491:
449:
400:
391:
363:
307:multipath interference
283:ionospheric reflection
3382:Broadcast engineering
3066:Polarization-division
2798:Narinder Singh Kapany
2763:Erna Schneider Hoover
2683:Jagadish Chandra Bose
2663:Alexander Graham Bell
2394:online video platform
2212:Multipath propagation
2035:MPEG-1 Audio Layer II
1905:Frequency allocations
1780:Frequency allocations
1570:
1502:
1406:
1280:
1247:
1214:
1203:
1141:
1139:{\displaystyle T_{M}}
1097:
1045:
990:
961:
928:
881:
851:
824:
801:
712:
655:
589:
582:Mathematical modeling
489:
447:
397:
385:
357:
318:Rayleigh distribution
2908:Vladimir K. Zworykin
2868:Almon Brown Strowger
2838:Charles Grafton Page
2493:Prepaid mobile phone
2421:Electrical telegraph
2165:Technical (emission)
1532:
1291:
1278:{\displaystyle h(t)}
1260:
1245:{\displaystyle H(f)}
1227:
1153:
1123:
1057:
1005:
988:{\displaystyle h(t)}
970:
959:{\displaystyle y(t)}
941:
890:
860:
833:
813:
679:
620:
311:multipath distortion
161:improve this article
2858:Johann Philipp Reis
2617:Wireless revolution
2579:The Telephone Cases
2436:Hydraulic telegraph
1525:is thus defined as
1523:coherence bandwidth
1357:
552:, phone lines, and
533:OFDM) to avoid the
436:, multipath causes
412:optical path length
330:Rician distribution
320:, this is known as
279:atmospheric ducting
259:radio communication
3056:Frequency-division
3033:Telephone exchange
2903:Charles Wheatstone
2833:Jun-ichi Nishizawa
2808:Innocenzo Manzetti
2743:Reginald Fessenden
2478:Optical telegraphy
2311:Telecommunications
1588:Choke ring antenna
1565:
1497:
1337:
1275:
1242:
1217:
1198:
1136:
1109:
1092:
1040:
985:
956:
923:
876:
846:
819:
796:
650:
598:used for studying
592:
546:local area network
516:impedance mismatch
514:. In either case,
492:
450:
401:
392:
364:
82:list of references
3369:
3368:
3107:Store and forward
3102:Data transmission
3016:Network switching
2967:Transmission line
2813:Guglielmo Marconi
2778:Internet pioneers
2643:Mohamed M. Atalla
2612:Whistled language
2277:
2276:
2273:
2272:
2197:FM broadcast band
2104:Technical (audio)
2001:
2000:
1893:
1892:
1594:Diversity schemes
1563:
1254:Fourier transform
1108:\phi_n=\phi_n(t)}
1106:
935:complex amplitude
822:{\displaystyle N}
574:, but those from
520:signal reflection
510:and in telephone
350:Wave interference
255:
254:
247:
237:
236:
229:
211:
135:
134:
127:
64:
3394:
3359:
3358:
3349:
3348:
3339:
3338:
3329:
3328:
3327:
3200:Notable networks
3190:Wireless network
3130:Cellular network
3122:Types of network
3097:Computer network
2984:Network topology
2898:Thomas A. Watson
2753:Oliver Heaviside
2738:Philo Farnsworth
2713:Daniel Davis Jr.
2688:Charles Bourseul
2648:John Logie Baird
2357:Data compression
2352:Computer network
2304:
2297:
2290:
2281:
2280:
2259:Radio portal
2257:
2256:
2255:
2233:History of radio
2177:AM expanded band
2094:
2093:
1977:Commercial radio
1902:
1901:
1745:
1744:
1720:
1713:
1706:
1697:
1696:
1693:
1692:
1687:. Archived from
1671:
1670:
1574:
1572:
1571:
1566:
1564:
1562:
1561:
1549:
1544:
1543:
1506:
1504:
1503:
1498:
1496:
1495:
1494:
1493:
1492:
1463:
1462:
1461:
1460:
1443:
1442:
1431:
1420:
1402:
1395:
1394:
1356:
1348:
1315:
1314:
1284:
1282:
1281:
1276:
1251:
1249:
1248:
1243:
1207:
1205:
1204:
1199:
1197:
1196:
1184:
1183:
1165:
1164:
1145:
1143:
1142:
1137:
1135:
1134:
1101:
1099:
1098:
1093:
1082:
1081:
1069:
1068:
1049:
1047:
1046:
1041:
1030:
1029:
1017:
1016:
994:
992:
991:
986:
965:
963:
962:
957:
932:
930:
929:
924:
922:
921:
920:
919:
902:
901:
885:
883:
882:
877:
875:
874:
855:
853:
852:
847:
845:
844:
828:
826:
825:
820:
805:
803:
802:
797:
795:
791:
790:
769:
768:
767:
766:
749:
748:
737:
726:
659:
657:
656:
651:
596:impulse response
250:
243:
232:
225:
221:
218:
212:
210:
169:
145:
137:
130:
123:
119:
116:
110:
105:this article by
96:inline citations
75:
74:
67:
56:
34:
33:
26:
3404:
3403:
3397:
3396:
3395:
3393:
3392:
3391:
3372:
3371:
3370:
3365:
3325:
3323:
3315:
3257:
3194:
3116:
3080:
3037:
2986:
2978:
2919:
2912:
2818:Robert Metcalfe
2673:Tim Berners-Lee
2621:
2441:Information Age
2313:
2308:
2278:
2269:
2253:
2251:
2242:
2221:
2202:FM broadcasting
2172:AM broadcasting
2160:
2120:
2099:
2088:
2044:
1997:
1971:
1940:Digital systems
1935:
1920:
1889:
1850:Digital systems
1845:
1774:
1736:
1724:
1677:
1668:
1666:
1652:
1639:Ultra wide-band
1584:
1557:
1553:
1548:
1539:
1535:
1533:
1530:
1529:
1488:
1484:
1468:
1464:
1456:
1452:
1448:
1444:
1438:
1434:
1433:
1421:
1410:
1375:
1371:
1358:
1349:
1341:
1310:
1309:
1292:
1289:
1288:
1261:
1258:
1257:
1228:
1225:
1224:
1192:
1188:
1173:
1169:
1160:
1156:
1154:
1151:
1150:
1130:
1126:
1124:
1121:
1120:
1077:
1073:
1064:
1060:
1058:
1055:
1054:
1025:
1021:
1012:
1008:
1006:
1003:
1002:
971:
968:
967:
942:
939:
938:
915:
911:
907:
903:
897:
893:
891:
888:
887:
867:
863:
861:
858:
857:
840:
836:
834:
831:
830:
814:
811:
810:
786:
782:
762:
758:
754:
750:
744:
740:
739:
727:
716:
680:
677:
676:
621:
618:
617:
611:electromagnetic
584:
504:
423:
352:
346:
322:Rayleigh fading
251:
240:
239:
238:
233:
222:
216:
213:
170:
168:
158:
146:
131:
120:
114:
111:
100:
86:related reading
76:
72:
35:
31:
24:
17:
12:
11:
5:
3402:
3401:
3390:
3389:
3384:
3367:
3366:
3364:
3363:
3353:
3343:
3333:
3320:
3317:
3316:
3314:
3313:
3306:
3301:
3296:
3291:
3286:
3285:
3284:
3279:
3271:
3265:
3263:
3259:
3258:
3256:
3255:
3250:
3245:
3240:
3235:
3230:
3225:
3220:
3215:
3210:
3204:
3202:
3196:
3195:
3193:
3192:
3187:
3182:
3177:
3172:
3167:
3162:
3157:
3152:
3147:
3142:
3137:
3132:
3126:
3124:
3118:
3117:
3115:
3114:
3109:
3104:
3099:
3094:
3088:
3086:
3082:
3081:
3079:
3078:
3073:
3068:
3063:
3058:
3053:
3051:Space-division
3047:
3045:
3039:
3038:
3036:
3035:
3030:
3029:
3028:
3023:
3013:
3012:
3011:
3001:
2996:
2990:
2988:
2980:
2979:
2977:
2976:
2975:
2974:
2964:
2963:
2962:
2952:
2947:
2942:
2941:
2940:
2930:
2924:
2922:
2914:
2913:
2911:
2910:
2905:
2900:
2895:
2890:
2888:Camille Tissot
2885:
2880:
2875:
2870:
2865:
2863:Claude Shannon
2860:
2855:
2853:Tivadar Puskás
2850:
2845:
2840:
2835:
2830:
2825:
2823:Antonio Meucci
2820:
2815:
2810:
2805:
2800:
2795:
2793:Charles K. Kao
2790:
2785:
2780:
2775:
2770:
2768:Harold Hopkins
2765:
2760:
2755:
2750:
2745:
2740:
2735:
2730:
2725:
2720:
2715:
2710:
2705:
2700:
2695:
2690:
2685:
2680:
2675:
2670:
2668:Emile Berliner
2665:
2660:
2655:
2650:
2645:
2640:
2635:
2629:
2627:
2623:
2622:
2620:
2619:
2614:
2609:
2607:Videotelephony
2604:
2599:
2598:
2597:
2592:
2582:
2575:
2570:
2564:
2559:
2554:
2549:
2544:
2543:
2542:
2537:
2532:
2522:
2521:
2520:
2510:
2505:
2503:Radiotelephone
2500:
2495:
2490:
2485:
2480:
2475:
2470:
2469:
2468:
2458:
2453:
2448:
2443:
2438:
2433:
2428:
2423:
2418:
2413:
2408:
2407:
2406:
2401:
2396:
2391:
2389:Internet video
2381:
2380:
2379:
2374:
2369:
2364:
2354:
2349:
2344:
2339:
2334:
2329:
2323:
2321:
2315:
2314:
2307:
2306:
2299:
2292:
2284:
2275:
2274:
2271:
2270:
2268:
2267:
2262:
2247:
2244:
2243:
2241:
2240:
2235:
2229:
2227:
2223:
2222:
2220:
2219:
2214:
2209:
2204:
2199:
2194:
2189:
2184:
2179:
2174:
2168:
2166:
2162:
2161:
2159:
2158:
2153:
2151:Kahn-Hazeltine
2148:
2143:
2138:
2132:
2130:
2122:
2121:
2119:
2118:
2113:
2107:
2105:
2101:
2100:
2098:Related topics
2090:
2089:
2087:
2086:
2081:
2076:
2071:
2066:
2061:
2055:
2053:
2046:
2045:
2043:
2042:
2037:
2032:
2027:
2022:
2017:
2011:
2009:
2003:
2002:
1999:
1998:
1996:
1995:
1994:
1993:
1982:
1980:
1973:
1972:
1970:
1969:
1964:
1959:
1954:
1949:
1943:
1941:
1937:
1936:
1934:
1933:
1928:
1923:
1918:
1914:
1908:
1906:
1899:
1895:
1894:
1891:
1890:
1888:
1887:
1882:
1879:
1874:
1869:
1864:
1859:
1853:
1851:
1847:
1846:
1844:
1843:
1833:
1815:
1805:
1795:
1784:
1782:
1776:
1775:
1773:
1772:
1767:
1762:
1756:
1754:
1742:
1738:
1737:
1723:
1722:
1715:
1708:
1700:
1691:on 2022-01-22.
1664:
1663:
1658:
1651:
1648:
1647:
1646:
1641:
1636:
1631:
1626:
1621:
1616:
1611:
1609:Lloyd's mirror
1606:
1601:
1599:Doppler spread
1596:
1591:
1583:
1580:
1576:
1575:
1560:
1556:
1552:
1547:
1542:
1538:
1508:
1507:
1491:
1487:
1483:
1480:
1477:
1474:
1471:
1467:
1459:
1455:
1451:
1447:
1441:
1437:
1430:
1427:
1424:
1419:
1416:
1413:
1409:
1405:
1401:
1398:
1393:
1390:
1387:
1384:
1381:
1378:
1374:
1370:
1367:
1364:
1361:
1355:
1352:
1347:
1344:
1340:
1336:
1333:
1330:
1327:
1324:
1321:
1318:
1313:
1308:
1305:
1302:
1299:
1296:
1274:
1271:
1268:
1265:
1241:
1238:
1235:
1232:
1209:
1208:
1195:
1191:
1187:
1182:
1179:
1176:
1172:
1168:
1163:
1159:
1133:
1129:
1116:multipath time
1111:
1110:
1103:
1102:
1091:
1088:
1085:
1080:
1076:
1072:
1067:
1063:
1051:
1050:
1039:
1036:
1033:
1028:
1024:
1020:
1015:
1011:
984:
981:
978:
975:
955:
952:
949:
946:
933:represent the
918:
914:
910:
906:
900:
896:
873:
870:
866:
843:
839:
818:
807:
806:
794:
789:
785:
781:
778:
775:
772:
765:
761:
757:
753:
747:
743:
736:
733:
730:
725:
722:
719:
715:
711:
708:
705:
702:
699:
696:
693:
690:
687:
684:
666:speed of light
661:
660:
649:
646:
643:
640:
637:
634:
631:
628:
625:
600:linear systems
583:
580:
554:coaxial cables
503:
502:In wired media
500:
481:rake receivers
422:
419:
348:Main article:
345:
342:
299:phase shifting
253:
252:
235:
234:
149:
147:
140:
133:
132:
90:external links
79:
77:
70:
65:
39:
38:
36:
29:
15:
9:
6:
4:
3:
2:
3400:
3399:
3388:
3385:
3383:
3380:
3379:
3377:
3362:
3354:
3352:
3344:
3342:
3334:
3332:
3322:
3321:
3318:
3311:
3307:
3305:
3302:
3300:
3297:
3295:
3292:
3290:
3287:
3283:
3280:
3278:
3275:
3274:
3272:
3270:
3267:
3266:
3264:
3260:
3254:
3251:
3249:
3246:
3244:
3241:
3239:
3236:
3234:
3231:
3229:
3226:
3224:
3221:
3219:
3216:
3214:
3211:
3209:
3206:
3205:
3203:
3201:
3197:
3191:
3188:
3186:
3183:
3181:
3178:
3176:
3173:
3171:
3168:
3166:
3163:
3161:
3158:
3156:
3153:
3151:
3148:
3146:
3143:
3141:
3138:
3136:
3133:
3131:
3128:
3127:
3125:
3123:
3119:
3113:
3110:
3108:
3105:
3103:
3100:
3098:
3095:
3093:
3090:
3089:
3087:
3083:
3077:
3076:Code-division
3074:
3072:
3069:
3067:
3064:
3062:
3061:Time-division
3059:
3057:
3054:
3052:
3049:
3048:
3046:
3044:
3040:
3034:
3031:
3027:
3024:
3022:
3019:
3018:
3017:
3014:
3010:
3007:
3006:
3005:
3002:
3000:
2997:
2995:
2992:
2991:
2989:
2987:and switching
2985:
2981:
2973:
2970:
2969:
2968:
2965:
2961:
2958:
2957:
2956:
2953:
2951:
2948:
2946:
2943:
2939:
2938:optical fiber
2936:
2935:
2934:
2931:
2929:
2928:Coaxial cable
2926:
2925:
2923:
2921:
2915:
2909:
2906:
2904:
2901:
2899:
2896:
2894:
2891:
2889:
2886:
2884:
2881:
2879:
2876:
2874:
2871:
2869:
2866:
2864:
2861:
2859:
2856:
2854:
2851:
2849:
2846:
2844:
2843:Radia Perlman
2841:
2839:
2836:
2834:
2831:
2829:
2826:
2824:
2821:
2819:
2816:
2814:
2811:
2809:
2806:
2804:
2801:
2799:
2796:
2794:
2791:
2789:
2786:
2784:
2781:
2779:
2776:
2774:
2771:
2769:
2766:
2764:
2761:
2759:
2756:
2754:
2751:
2749:
2746:
2744:
2741:
2739:
2736:
2734:
2733:Lee de Forest
2731:
2729:
2728:Thomas Edison
2726:
2724:
2721:
2719:
2718:Donald Davies
2716:
2714:
2711:
2709:
2706:
2704:
2703:Claude Chappe
2701:
2699:
2696:
2694:
2691:
2689:
2686:
2684:
2681:
2679:
2676:
2674:
2671:
2669:
2666:
2664:
2661:
2659:
2656:
2654:
2651:
2649:
2646:
2644:
2641:
2639:
2636:
2634:
2631:
2630:
2628:
2624:
2618:
2615:
2613:
2610:
2608:
2605:
2603:
2600:
2596:
2593:
2591:
2588:
2587:
2586:
2583:
2581:
2580:
2576:
2574:
2571:
2568:
2565:
2563:
2560:
2558:
2555:
2553:
2550:
2548:
2547:Smoke signals
2545:
2541:
2538:
2536:
2533:
2531:
2528:
2527:
2526:
2525:Semiconductor
2523:
2519:
2516:
2515:
2514:
2511:
2509:
2506:
2504:
2501:
2499:
2496:
2494:
2491:
2489:
2486:
2484:
2481:
2479:
2476:
2474:
2471:
2467:
2464:
2463:
2462:
2459:
2457:
2454:
2452:
2449:
2447:
2444:
2442:
2439:
2437:
2434:
2432:
2429:
2427:
2424:
2422:
2419:
2417:
2414:
2412:
2409:
2405:
2402:
2400:
2397:
2395:
2392:
2390:
2387:
2386:
2385:
2384:Digital media
2382:
2378:
2375:
2373:
2370:
2368:
2365:
2363:
2360:
2359:
2358:
2355:
2353:
2350:
2348:
2345:
2343:
2340:
2338:
2335:
2333:
2330:
2328:
2325:
2324:
2322:
2320:
2316:
2312:
2305:
2300:
2298:
2293:
2291:
2286:
2285:
2282:
2266:
2263:
2261:
2260:
2249:
2248:
2245:
2239:
2236:
2234:
2231:
2230:
2228:
2224:
2218:
2215:
2213:
2210:
2208:
2205:
2203:
2200:
2198:
2195:
2193:
2190:
2188:
2187:Digital radio
2185:
2183:
2180:
2178:
2175:
2173:
2170:
2169:
2167:
2163:
2157:
2154:
2152:
2149:
2147:
2144:
2142:
2139:
2137:
2134:
2133:
2131:
2128:
2123:
2117:
2114:
2112:
2109:
2108:
2106:
2102:
2095:
2091:
2085:
2082:
2080:
2077:
2075:
2072:
2070:
2067:
2065:
2062:
2060:
2057:
2056:
2054:
2051:
2047:
2041:
2038:
2036:
2033:
2031:
2028:
2026:
2023:
2021:
2018:
2016:
2013:
2012:
2010:
2008:
2004:
1992:
1989:
1988:
1987:
1984:
1983:
1981:
1978:
1974:
1968:
1965:
1963:
1960:
1958:
1955:
1953:
1950:
1948:
1945:
1944:
1942:
1938:
1932:
1929:
1927:
1924:
1922:
1915:
1913:
1910:
1909:
1907:
1903:
1900:
1896:
1886:
1883:
1880:
1878:
1875:
1873:
1870:
1868:
1865:
1863:
1860:
1858:
1855:
1854:
1852:
1848:
1841:
1837:
1834:
1831:
1827:
1823:
1819:
1816:
1813:
1809:
1806:
1803:
1799:
1796:
1793:
1789:
1786:
1785:
1783:
1781:
1777:
1771:
1768:
1766:
1763:
1761:
1758:
1757:
1755:
1753:
1750:
1746:
1743:
1739:
1735:
1732:
1731:digital audio
1728:
1721:
1716:
1714:
1709:
1707:
1702:
1701:
1698:
1694:
1690:
1686:
1682:
1681:
1675:
1662:
1659:
1657:
1654:
1653:
1645:
1644:Rake receiver
1642:
1640:
1637:
1635:
1632:
1630:
1627:
1625:
1624:Rician fading
1622:
1620:
1617:
1615:
1612:
1610:
1607:
1605:
1602:
1600:
1597:
1595:
1592:
1589:
1586:
1585:
1579:
1558:
1554:
1550:
1545:
1540:
1536:
1528:
1527:
1526:
1524:
1520:
1515:
1513:
1512:eigenfunction
1489:
1485:
1481:
1478:
1475:
1472:
1469:
1465:
1457:
1453:
1449:
1445:
1439:
1435:
1428:
1425:
1422:
1417:
1414:
1411:
1407:
1403:
1399:
1396:
1391:
1388:
1385:
1382:
1379:
1376:
1372:
1365:
1359:
1350:
1342:
1338:
1334:
1325:
1319:
1306:
1300:
1294:
1287:
1286:
1285:
1269:
1263:
1255:
1236:
1230:
1221:
1213:
1193:
1189:
1185:
1180:
1177:
1174:
1170:
1166:
1161:
1157:
1149:
1148:
1147:
1131:
1127:
1118:
1117:
1105:
1104:
1086:
1078:
1074:
1070:
1065:
1061:
1053:
1052:
1034:
1026:
1022:
1018:
1013:
1009:
1001:
1000:
999:
996:
979:
973:
950:
944:
936:
916:
912:
908:
904:
898:
894:
886:impulse, and
871:
868:
864:
841:
837:
816:
787:
783:
779:
776:
770:
763:
759:
755:
751:
745:
741:
734:
731:
728:
723:
720:
717:
713:
709:
703:
697:
694:
688:
682:
675:
674:
673:
671:
667:
644:
638:
635:
629:
623:
616:
615:
614:
612:
608:
603:
601:
597:
588:
579:
577:
573:
569:
565:
561:
559:
558:cyclic prefix
555:
551:
547:
543:
540:
536:
532:
528:
523:
521:
517:
513:
509:
499:
497:
488:
484:
483:may be used.
482:
478:
474:
470:
466:
461:
459:
455:
446:
442:
439:
435:
432:
428:
418:
415:
413:
408:
406:
396:
389:
384:
380:
378:
374:
369:
361:
356:
351:
341:
339:
335:
334:Rician fading
331:
327:
326:line of sight
323:
319:
314:
312:
308:
304:
300:
296:
292:
288:
284:
280:
276:
272:
271:radio signals
268:
264:
260:
249:
246:
231:
228:
220:
209:
206:
202:
199:
195:
192:
188:
185:
181:
178: –
177:
173:
172:Find sources:
166:
162:
156:
155:
150:This article
148:
144:
139:
138:
129:
126:
118:
115:November 2009
108:
104:
98:
97:
91:
87:
83:
78:
69:
68:
63:
61:
54:
53:
48:
47:
42:
37:
28:
27:
22:
3043:Multiplexing
2918:Transmission
2883:Nikola Tesla
2873:Henry Sutton
2828:Samuel Morse
2758:Robert Hooke
2723:Amos Dolbear
2658:John Bardeen
2577:
2557:Telautograph
2461:Mobile phone
2416:Edholm's law
2399:social media
2332:Broadcasting
2250:
2211:
1734:broadcasting
1689:the original
1679:
1665:
1577:
1518:
1516:
1509:
1222:
1218:
1114:
1112:
997:
808:
662:
604:
593:
562:
524:
505:
493:
462:
451:
434:transmission
424:
416:
409:
402:
365:
344:Interference
315:
310:
306:
295:interference
262:
256:
241:
223:
217:October 2021
214:
204:
197:
190:
183:
171:
159:Please help
154:verification
151:
121:
112:
101:Please help
93:
57:
50:
44:
43:Please help
40:
3243:NPL network
2955:Radio waves
2893:Alfred Vail
2803:Hedy Lamarr
2788:Dawon Kahng
2748:Elisha Gray
2708:Yogen Dalal
2633:Nasir Ahmed
2567:Teleprinter
2431:Heliographs
2182:Cable radio
2125:Technical (
1885:DVB-T2 Lite
1741:Terrestrial
1656:MIL-STD-188
1629:Signal flow
1614:Olivia MFSK
607:Dirac pulse
576:bridge taps
572:wire gauges
550:power lines
512:local loops
388:transmitter
377:radio waves
360:phase shift
267:propagation
107:introducing
3376:Categories
3289:Antarctica
3248:Toasternet
3170:Television
2653:Paul Baran
2585:Television
2569:(teletype)
2562:Telegraphy
2540:transistor
2518:Phryctoria
2488:Photophone
2466:Smartphone
2456:Mass media
2064:DirectBand
2050:Subcarrier
1752:modulation
1650:References
670:free space
564:DSL modems
473:Equalizers
431:television
425:In analog
291:reflection
287:refraction
187:newspapers
46:improve it
3273:Americas
3262:Locations
3233:Internet2
2994:Bandwidth
2698:Vint Cerf
2595:streaming
2573:Telephone
2513:Semaphore
2404:streaming
2127:AM stereo
1986:Sirius XM
1979:providers
1898:Satellite
1546:≈
1486:τ
1479:π
1470:−
1454:ϕ
1436:ρ
1426:−
1408:∑
1386:π
1377:−
1354:∞
1346:∞
1343:−
1339:∫
1190:τ
1186:−
1178:−
1171:τ
1075:ρ
1062:ρ
1023:τ
1010:τ
913:ϕ
895:ρ
838:τ
784:τ
780:−
771:δ
760:ϕ
742:ρ
732:−
714:∑
639:δ
427:facsimile
263:multipath
52:talk page
3341:Category
3228:Internet
3218:CYCLADES
3135:Ethernet
3085:Concepts
3009:terminal
2960:wireless
2783:Bob Kahn
2626:Pioneers
2451:Internet
2342:Cable TV
2226:Cultural
2156:Magnavox
2129:formats)
2079:SCA/SCMO
2074:RDS/RBDS
1877:HD Radio
1867:DRM/DRM+
1862:DAB/DAB+
1582:See also
458:receiver
421:Examples
405:coherent
373:ghosting
3361:Commons
3351:Outline
3304:Oceania
3223:FidoNet
3208:ARPANET
3021:circuit
2590:digital
2319:History
2052:signals
2020:AMR-WB+
1872:FMeXtra
1519:notches
531:wavelet
518:causes
471:(ISI).
275:antenna
265:is the
201:scholar
103:improve
3299:Europe
3269:Africa
3253:Usenet
3213:BITNET
3150:Mobile
3026:packet
2535:MOSFET
2530:device
2327:Beacon
2146:Harris
2141:C-QUAM
2030:HE-AAC
2007:Codecs
1991:Canada
1957:DVB-SH
1931:S band
1926:L band
1912:C band
1836:L band
1727:Analog
1604:Fading
809:where
438:jitter
399:plane.
303:fading
289:, and
203:
196:
189:
182:
174:
3282:South
3277:North
3238:JANET
3175:Telex
3165:Radio
3004:Nodes
2999:Links
2920:media
2498:Radio
2483:Pager
2411:Drums
2377:video
2372:image
2362:audio
2136:Belar
1962:S-DMB
1952:DAB-S
1857:CAM-D
1770:COFDM
1749:Radio
1676:from
568:DSLAM
539:ITU-T
494:In a
454:radar
368:waves
208:JSTOR
194:books
88:, or
3294:Asia
3180:UUCP
3140:ISDN
2084:DARC
2059:AMSS
2040:DRA+
1921:band
1830:high
1729:and
542:G.hn
527:OFDM
479:and
429:and
297:and
285:and
180:news
3185:WAN
3155:NGN
3145:LAN
2426:Fax
2367:DCT
2069:PAD
2025:HDC
2015:AAC
1967:SDR
1947:ADR
1881:CDR
1840:UHF
1826:mid
1822:low
1818:VHF
609:of
529:or
522:.
465:GSM
452:In
309:or
257:In
163:by
3378::
1828:/
1824:/
1812:HF
1808:SW
1802:MF
1798:MW
1792:LF
1788:LW
1765:FM
1760:AM
1683:.
1119:,
602:.
379:.
313:.
281:,
261:,
92:,
84:,
55:.
3312:)
3308:(
2303:e
2296:t
2289:v
1919:u
1917:K
1842:)
1838:(
1832:)
1820:(
1814:)
1810:(
1804:)
1800:(
1794:)
1790:(
1719:e
1712:t
1705:v
1559:M
1555:T
1551:1
1541:C
1537:B
1490:n
1482:f
1476:2
1473:j
1466:e
1458:n
1450:j
1446:e
1440:n
1429:1
1423:N
1418:0
1415:=
1412:n
1404:=
1400:t
1397:d
1392:t
1389:f
1383:2
1380:j
1373:e
1369:)
1366:t
1363:(
1360:h
1351:+
1335:=
1332:)
1329:)
1326:t
1323:(
1320:h
1317:(
1312:F
1307:=
1304:)
1301:f
1298:(
1295:H
1273:)
1270:t
1267:(
1264:h
1240:)
1237:f
1234:(
1231:H
1194:0
1181:1
1175:N
1167:=
1162:M
1158:T
1132:M
1128:T
1090:)
1087:t
1084:(
1079:n
1071:=
1066:n
1038:)
1035:t
1032:(
1027:n
1019:=
1014:n
983:)
980:t
977:(
974:h
954:)
951:t
948:(
945:y
917:n
909:j
905:e
899:n
872:h
869:t
865:n
842:n
817:N
793:)
788:n
777:t
774:(
764:n
756:j
752:e
746:n
735:1
729:N
724:0
721:=
718:n
710:=
707:)
704:t
701:(
698:h
695:=
692:)
689:t
686:(
683:y
648:)
645:t
642:(
636:=
633:)
630:t
627:(
624:x
371:"
248:)
242:(
230:)
224:(
219:)
215:(
205:·
198:·
191:·
184:·
157:.
128:)
122:(
117:)
113:(
99:.
62:)
58:(
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
