185:
745:
641:
229:). It specifies that for a 0 bit the signal levels will be low–high (assuming an amplitude physical encoding of the data) – with a low level in the first half of the bit period, and a high level in the second half. For a 1 bit the signal levels will be high–low. This is also known as Manchester II or Biphase-L code.
259:
The existence of guaranteed transitions allows the signal to be self-clocking, and also allows the receiver to align correctly; the receiver can identify if it is misaligned by half a bit period, as there will no longer always be a transition during each bit period. The price of these benefits is a
213:
Manchester code always has a transition at the middle of each bit period and may (depending on the information to be transmitted) have a transition at the start of the period also. The direction of the mid-bit transition indicates the data. Transitions at the period boundaries do not carry
645:
988:
247:
If a
Manchester encoded signal is inverted in communication, it is transformed from one convention to the other. This ambiguity can be overcome by using
154:
Manchester coding's data rate is only half that of a non-coded signal, which limits its usefulness to systems where bandwidth is not an issue, such as a
244:(Ethernet) standards. It states that a logic 0 is represented by a high–low signal sequence and a logic 1 is represented by a low–high signal sequence.
458:
119:
whose frequency is the data rate. Manchester code ensures frequent line voltage transitions, directly proportional to the clock rate; this helps
695:
650:
503:
Manchester encoding introduces some difficult frequency-related problems that make it unsuitable for use at higher data rates.
480:
161:
Manchester encoding introduces difficult frequency-related problems that make it unsuitable for use at higher data rates.
414:
359:
by high-to-low transition (according to G. E. Thomas's convention – in the IEEE 802.3 convention, the reverse is true).
130:
of the encoded signal is not dependent on the data and therefore carries no information. Therefore connections may be
889:
575:
537:
787:
772:
393:
388:
248:
656:
138:
coupled, allowing the signal to be conveyed conveniently by galvanically isolated media (e.g., Ethernet) using a
777:
767:
894:
169:
79:
on 1600 bpi computer tapes before the introduction of 6250 bpi tapes which used the more efficient
823:
863:
448:
225:
The first of these was first published by G. E. Thomas in 1949 and is followed by numerous authors (e.g.,
214:
information. They exist only to place the signal in the correct state to allow the mid-bit transition.
945:
688:
108:
155:
96:
65:
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84:
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26:
957:
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50:
8:
983:
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843:
803:
515:
135:
261:
184:
131:
76:
58:
22:
828:
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571:
553:
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233:
143:
69:
858:
724:
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139:
853:
490:
165:
925:
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to achieve the same data rate but may be less tolerant of frequency errors and
120:
116:
977:
729:
563:
525:
486:
112:
626:
422:
274:
127:
54:
613:
Forster, R. (2000). "Manchester encoding: Opposing definitions resolved".
68:, where the coding was used for storing data on the magnetic drums of the
57:. Consequently, electrical connections using a Manchester code are easily
704:
666:
373:
Transitions at the start of a period are overhead and don't signify data.
88:
241:
237:
754:
42:
222:
There are two opposing conventions for the representations of data.
920:
910:
49:
is either low then high, or high then low, for equal time. It is a
232:
The second convention is also followed by numerous authors (e.g.,
453:
873:
703:
173:
64:
Manchester code derives its name from its development at the
915:
818:
813:
808:
195:
189:
92:
260:
doubling of the bandwidth requirement compared to simpler
16:
Line code used in early magnetic data storage and
Ethernet
217:
46:
989:
Department of
Computer Science, University of Manchester
348:
Each bit is transmitted in a fixed time (the period).
176:in the transmitter and receiver reference clocks.
606:
593:Manchester Data Encoding for Radio Communications
975:
188:An example of Manchester encoding showing both
689:
449:"Old, but Still Useful: The Manchester Code"
355:is expressed by a low-to-high transition, a
615:Engineering Science & Education Journal
696:
682:
552:
514:
546:
508:
240:(token bus) and lower speed versions of
183:
179:
612:
107:Manchester coding is a special case of
976:
788:Differential Manchester/biphase (Bi-φ)
412:
218:Conventions for representation of data
190:conventions for representation of data
164:There are more complex codes, such as
768:Non-return-to-zero, level (NRZ/NRZ-L)
677:
344:Encoding conventions are as follows:
773:Non-return-to-zero, inverted (NRZ-I)
442:
440:
146:which cannot convey a DC component.
111:(BPSK), where the data controls the
83:. Manchester code was used in early
75:Manchester code was widely used for
461:from the original on 22 August 2022
446:
45:in which the encoding of each data
13:
370:occur at the midpoint of a period.
14:
1000:
890:Carrier-suppressed return-to-zero
778:Non-return-to-zero, space (NRZ-S)
437:
415:"Digital Magnetic Tape Recording"
743:
644: This article incorporates
639:
559:Data and Computer Communications
394:Binary offset carrier modulation
389:Differential Manchester encoding
249:differential Manchester encoding
707:(digital baseband transmission)
657:General Services Administration
87:standards and is still used in
895:Alternate-phase return-to-zero
584:
473:
447:Oed, Richard (22 April 2022).
406:
362:The transitions which signify
149:
1:
399:
864:Eight-to-fourteen modulation
413:Savard, John J. G. (2018) .
7:
377:
267:
254:
102:
10:
1005:
946:Pulse-amplitude modulation
903:
882:
796:
752:
741:
712:
323:
307:
299:
296:
277:logic (802.3 convention)
109:binary phase-shift keying
941:Pulse modulation methods
824:Alternate mark inversion
156:local area network (LAN)
97:near-field communication
66:University of Manchester
936:Ethernet physical layer
85:Ethernet physical layer
652:Federal Standard 1037C
646:public domain material
210:
952:Pulse-code modulation
869:Delay/Miller encoding
665: (in support of
627:10.1049/esej:20000609
482:Ethernet Technologies
187:
180:Encoding and decoding
142:—a simple one-to-one
81:group-coded recording
59:galvanically isolated
958:Serial communication
931:Digital transmission
834:Coded mark inversion
516:Tanenbaum, Andrew S.
384:Coded mark inversion
273:Encoding data using
51:self-clocking signal
963:Category:Line codes
844:Hybrid ternary code
804:Conditioned diphase
797:Extended line codes
763:Return to zero (RZ)
663:on 22 January 2022.
493:on 28 December 2018
278:
883:Optical line codes
554:Stallings, William
272:
211:
77:magnetic recording
23:telecommunications
971:
970:
829:Modified AMI code
720:Unipolar encoding
521:Computer Networks
342:
341:
292:Manchester value
234:William Stallings
144:pulse transformer
115:of a square wave
70:Manchester Mark 1
996:
859:64b/66b encoding
747:
725:Bipolar encoding
698:
691:
684:
675:
674:
670:
664:
659:. Archived from
643:
642:
631:
630:
610:
604:
603:
602:
600:
588:
582:
581:
562:(7th ed.).
550:
544:
543:
524:(4th ed.).
512:
506:
505:
500:
498:
489:, archived from
477:
471:
470:
468:
466:
444:
435:
434:
432:
430:
421:. Archived from
410:
369:
365:
358:
354:
279:
271:
264:coding schemes.
236:) as well as by
209:
168:, that use less
140:network isolator
1004:
1003:
999:
998:
997:
995:
994:
993:
974:
973:
972:
967:
899:
878:
854:8b/10b encoding
792:
748:
739:
708:
702:
672:
649:
640:
638:
635:
634:
611:
607:
598:
596:
590:
589:
585:
578:
551:
547:
540:
513:
509:
496:
494:
479:
478:
474:
464:
462:
445:
438:
428:
426:
411:
407:
402:
380:
367:
363:
356:
352:
301:
270:
257:
220:
208:
201:
193:
192:, where :
182:
166:8B/10B encoding
152:
105:
33:(also known as
31:Manchester code
17:
12:
11:
5:
1002:
992:
991:
986:
969:
968:
966:
965:
960:
955:
949:
943:
938:
933:
928:
926:Digital signal
923:
918:
913:
904:
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898:
897:
892:
886:
884:
880:
879:
877:
876:
871:
866:
861:
856:
851:
849:6b/8b encoding
846:
841:
839:MLT-3 encoding
836:
831:
826:
821:
816:
811:
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800:
798:
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785:
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735:Mark and space
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678:
636:
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632:
621:(6): 278–280.
605:
583:
576:
545:
538:
507:
472:
436:
425:on 2 July 2018
404:
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288:
285:
283:
282:Original data
269:
266:
256:
253:
227:Andy Tanenbaum
219:
216:
206:
199:
181:
178:
151:
148:
121:clock recovery
104:
101:
35:phase encoding
15:
9:
6:
4:
3:
2:
1001:
990:
987:
985:
982:
981:
979:
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827:
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802:
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771:
769:
766:
764:
761:
760:
758:
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751:
746:
736:
733:
731:
730:On-off keying
728:
726:
723:
721:
718:
717:
715:
713:Main articles
711:
706:
699:
694:
692:
687:
685:
680:
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671:
668:
662:
658:
654:
653:
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628:
624:
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616:
609:
595:
594:
587:
579:
577:0-13-100681-9
573:
569:
565:
564:Prentice Hall
561:
560:
555:
549:
541:
539:0-13-066102-3
535:
531:
527:
526:Prentice Hall
523:
522:
517:
511:
504:
492:
488:
487:Cisco Systems
484:
483:
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62:
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56:
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44:
40:
36:
32:
28:
24:
19:
907:
782:
661:the original
651:
637:
618:
614:
608:
597:, retrieved
592:
586:
558:
548:
520:
510:
502:
497:12 September
495:, retrieved
491:the original
481:
475:
463:. Retrieved
452:
427:. Retrieved
423:the original
418:
408:
343:
275:exclusive or
258:
246:
231:
224:
221:
212:
203:
194:
163:
160:
153:
136:capacitively
128:DC component
125:
106:
74:
63:
55:DC component
38:
34:
30:
27:data storage
20:
18:
705:Line coding
667:MIL-STD-188
566:. pp.
528:. pp.
204:10100111001
150:Limitations
132:inductively
91:protocols,
89:consumer IR
984:Line codes
978:Categories
783:Manchester
755:line codes
465:2 February
400:References
242:IEEE 802.3
238:IEEE 802.4
72:computer.
908:See also:
419:quadibloc
170:bandwidth
43:line code
921:Bit rate
911:Baseband
556:(2004).
518:(2002).
459:Archived
378:See also
268:Encoding
255:Decoding
103:Features
53:with no
568:137–138
530:274–275
454:DigiKey
429:16 July
117:carrier
41:) is a
874:TC-PAM
753:Basic
599:28 May
574:
536:
287:Clock
174:jitter
954:(PCM)
948:(PAM)
648:from
113:phase
37:, or
916:Baud
819:2B1Q
814:4B5B
809:4B3T
601:2018
572:ISBN
534:ISBN
499:2017
467:2023
431:2018
300:XOR
196:1337
126:The
95:and
93:RFID
25:and
623:doi
366:or
262:NRZ
134:or
47:bit
21:In
980::
669:).
655:.
617:.
570:.
532:.
501:,
485:,
457:.
451:.
439:^
417:.
351:A
338:0
330:1
324:1
319:1
311:0
308:=
305:0
302:⊕
297:0
251:.
202:=
200:10
158:.
123:.
99:.
61:.
39:PE
29:,
697:e
690:t
683:v
629:.
625::
619:9
580:.
542:.
469:.
433:.
368:1
364:0
357:1
353:0
335:1
327:0
316:1
207:2
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
