58:
873:
variable-width encodings, is a subset of multibyte encodings. These use more complex encoding and decoding logic to efficiently represent large character sets while keeping the representations of more commonly used characters shorter or maintaining backward compatibility properties. This group includes
872:
must be represented with multibyte encodings. Early multibyte encodings were fixed-length, meaning that although each character was represented by more than one byte, all characters used the same number of bytes ("word length"), making them suitable for decoding with a lookup table. The final group,
851:
Character encodings are representations of textual data. A given character encoding may be associated with a specific character set (the collection of characters which it can represent), though some character sets have multiple character encodings and vice versa. Character encodings may be broadly
813:, etc. Meanings were chosen to fit perceived needs: commercial negotiations, military terms for military codes, diplomatic terms for diplomatic codes, any and all of the preceding for espionage codes. Codebooks and codebook publishers proliferated, including one run as a front for the American
1238:
Occasionally, a code word achieves an independent existence (and meaning) while the original equivalent phrase is forgotten or at least no longer has the precise meaning attributed to the code word. For example, '30' was widely used in
1083:) - a basic perceptual process of interpreting incoming stimuli; technically speaking, it is a complex, multi-stage process of converting relatively objective sensory input (e.g., light, sound) into a subjectively meaningful experience.
206:, to communicate what they thought, saw, heard, or felt to others. But speech limits the range of communication to the distance a voice can carry and limits the audience to those present when the speech is uttered. The invention of
649:
is the most known algorithm for deriving prefix codes. Prefix codes are widely referred to as "Huffman codes" even when the code was not produced by a
Huffman algorithm. Other examples of prefix codes are
361:
671:
characterizes the sets of codeword lengths that are possible in a prefix code. Virtually any uniquely decodable one-to-many code, not necessarily a prefix one, must satisfy Kraft's inequality.
293:
strings, which may be in some other target alphabet. An extension of the code for representing sequences of symbols over the source alphabet is obtained by concatenating the encoded strings.
436:. Using the extension of the code, the encoded string 0011001 can be grouped into codewords as 0 011 0 01, and these in turn can be decoded to the sequence of source symbols
492:
255:
encodes parts of the message, typically individual letters, and numbers. Another person standing a great distance away can interpret the flags and reproduce the words sent.
402:
528:
434:
606:
579:
1067:, game cards, clothes, fans, hats, melodies, birds, etc., in which the sole requirement is the pre-agreement on the meaning by both the sender and the receiver.
548:
38:
630:
of such code words give us an encoded string. Variable-length codes are especially useful when clear text characters have different probabilities; see also
1224:
785:
that encoded complete phrases into single mouths (commonly five-minute groups) were developed, so that telegraphers became conversant with such "words" as
1235:
are similarly used on railways but are usually national, so the same code can be used for different stations if they are in different countries.
1335:
1115:
of formal language A informal language B is a method of representing all terms (e.g. programs or descriptions) of language A using language B.
868:. However, single-byte encodings cannot model character sets with more than 256 characters. Scripts that require large character sets such as
821:
between the First and Second World Wars. The purpose of most of these codes was to save on cable costs. The use of data coding for
302:
447:, the precise mathematical definition of this concept is as follows: let S and T be two finite sets, called the source and target
930:. A sequence of codons results in a corresponding sequence of amino acids that form a protein molecule; a type of codon called a
236:
is the reverse process, converting code symbols back into a form that the recipient understands, such as
English or/and Spanish.
860:(also called variable-length) encodings. The earliest character encodings were single-byte, the best-known example of which is
691:
Codes may also be used to represent data in a way more resistant to errors in transmission or storage. This so-called
1122:
141:
852:
grouped according to the number of bytes required to represent a single character: there are single-byte encodings,
782:
122:
1001:
codes can be used for a financial discount or rebate when purchasing a product from a (usual internet) retailer.
94:
1314:
1008:
are used for different uses: to mark some moments of the day, to command the infantry on the battlefield, etc.
692:
680:
79:
1063:
in military, diplomacy, business, etc.) to trivial (romance, games) can be any kind of imaginative encoding:
728:
101:
802:
623:
1191:
448:
286:
695:
works by including carefully crafted redundancy with the stored (or transmitted) data. Examples include
1445:
108:
1185:
642:
499:
30:
1331:
457:
1281:
1106:
1105:
to tag the structure and other features of a text to facilitate processing by computers. (See also
898:
organisms contain genetic material that is used to control their function and development. This is
551:
1045:
857:
724:
708:
90:
68:
955:
444:
369:
1188:, the study of signals in a digital representation and the processing methods of these signals
781:
messages were the state of the art in rapid long-distance communication, elaborate systems of
990:
or that of the trashcans devoted to specific types of garbage (paper, glass, organic, etc.).
983:
959:
771:
668:
651:
407:
191:
75:
46:
23:
1368:
704:
617:
584:
557:
229:
641:
is a code with the "prefix property": there is no valid code word in the system that is a
8:
1152:
1126:
1064:
1049:
732:
1372:
608:, which naturally maps each sequence of source symbols to a sequence of target symbols.
508:
296:
Before giving a mathematically precise definition, this is a brief example. The mapping
1440:
1391:
1356:
1291:
1112:
846:
829:
where more-frequently used characters have shorter representations. Techniques such as
622:
In this section, we consider codes that encode each source (clear text) character by a
533:
270:
967:
1419:
1396:
720:
171:
1416:
Codes and
Abbreviations for the Use of the International Telecommunication Services
1386:
1376:
1271:
1179:
1118:
837:
to compress large data files into a more compact form for storage or transmission.
822:
810:
700:
631:
274:
183:
42:
1418:(2nd ed.). Geneva, Switzerland: International Telecommunication Union. 1963.
1182:, methods in communication theory for decoding codewords sent over a noisy channel
115:
1318:
1276:
1146:
1136:
1102:
1059:
Secret codes intended to obscure the real messages, ranging from serious (mainly
818:
159:
881:
character set; UTF-8 is the most common encoding of text media on the
Internet.
1361:
Proceedings of the
National Academy of Sciences of the United States of America
1261:
1218:
1087:
1033:
979:
963:
869:
853:
830:
646:
495:
252:
248:
240:
195:
41:, terms beginning with "Code#" redirect here. For the EPs by Ladies' Code, see
1052:
were once common for ensuring the confidentiality of communications, although
1434:
1012:
907:
814:
627:
264:
211:
155:
1423:
1381:
947:
1400:
1232:
915:
890:
865:
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696:
770:) with shorter words, allowing the same information to be sent with fewer
239:
One reason for coding is to enable communication in places where ordinary
18:
System of rules to convert information into another form or representation
1311:
1201:
to decipher print patterns and translate them into the sounds of language
1095:
1022:
943:
923:
167:
1240:
1032:
Specific games have their own code systems to record the matches, e.g.
931:
927:
826:
778:
716:
686:
1286:
1080:
1060:
994:
834:
278:
244:
57:
1214:
987:
712:
199:
951:
1228:
1210:
1198:
1174:
1016:
911:
895:
878:
282:
207:
187:
179:
1266:
1227:
are three-letter codes used to designate airports and used for
1213:
and abbreviations can be considered codes, and in a sense, all
1140:
1090:- a specific encoding format for converting a specific type of
1053:
1005:
998:
806:
662:
214:
203:
243:, spoken or written, is difficult or impossible. For example,
1332:"Western Union "92 Code" & Wood's "Telegraphic Numerals""
1256:
1164:
1130:
1026:
919:
874:
861:
825:
predates the computer era; an early example is the telegraph
356:{\displaystyle C=\{\,a\mapsto 0,b\mapsto 01,c\mapsto 011\,\}}
1244:
1156:
1091:
903:
659:
655:
218:
175:
1019:
for blind people, are based on movement or tactile codes.
751:
1160:
899:
1011:
Communication systems for sensory impairments, such as
217:, extended the range of communication across space and
658:, and the Secondary Synchronization Codes used in the
1225:
International Air
Transport Association airport codes
1149:- the process of converting sensations into memories.
587:
560:
536:
511:
460:
410:
372:
305:
1357:"Case for the genetic code as a triplet of triplets"
1194:, the use of analog circuit for decoding operations
1004:In military environments, specific sounds with the
735:. Error detecting codes can be optimised to detect
82:. Unsourced material may be challenged and removed.
600:
573:
542:
522:
486:
428:
396:
355:
1321:American Journalism Review. Retrieved 2012-07-03.
1139:- the way in which information is represented in
645:(start) of any other valid code word in the set.
1432:
789:("Are you trying to weasel out of our deal?"),
29:"Encoding" redirects here. For other uses, see
1121:transforms a signal into a code optimized for
926:can be translated into one of twenty possible
1243:to mean "end of story", and has been used in
864:. ASCII remains in use today, for example in
801:("Not clearly coded, repeat more clearly.").
423:
411:
391:
373:
366:is a code, whose source alphabet is the set
350:
312:
232:into symbols for communication or storage.
986:employed to mark the nominal value of the
1390:
1380:
674:
467:
349:
315:
142:Learn how and when to remove this message
1354:
793:("Why do you not answer my question?"),
611:
752:Codes in communication used for brevity
210:, which converted spoken language into
1433:
840:
774:, more quickly, and less expensively.
198:. An early example is an invention of
1205:
654:, the country and publisher parts of
404:and whose target alphabet is the set
277:, a code is usually considered as an
1170:Other examples of decoding include:
1075:Other examples of encoding include:
777:Codes can be used for brevity. When
251:held by a signaler or the arms of a
80:adding citations to reliable sources
51:
978:There are codes using colors, like
13:
1408:
1334:. Signal Corps Association. 1996.
1025:are the most common way to encode
910:is derived. This in turn produces
856:(also called wide) encodings, and
762:A cable code replaces words (e.g.
202:, which enabled a person, through
14:
1457:
1070:
934:signals the end of the sequence.
805:were chosen for various reasons:
498:mapping each symbol from S to a
166:is a system of rules to convert
56:
1338:from the original on 2012-05-09
1039:
950:was the basis for the proof of
918:in which a series of triplets (
884:
833:are now used by computer-based
67:needs additional citations for
1324:
1304:
729:low-density parity-check codes
681:Error detection and correction
487:{\displaystyle C:\,S\to T^{*}}
471:
343:
331:
319:
190:, for communication through a
182:—into another form, sometimes
1:
1297:
1221:are codes for human thought.
937:
902:, which contains units named
247:, where the configuration of
958:. Here, the idea was to map
870:Chinese, Japanese and Korean
228:converts information from a
7:
1355:Chevance, Fabienne (2017).
1250:
1192:Digital-to-analog converter
1175:Decoding (computer science)
746:
713:Bose–Chaudhuri–Hochquenghem
10:
1464:
1197:Word decoding, the use of
888:
844:
755:
684:
678:
626:from some dictionary, and
615:
262:
36:
20:
1186:Digital signal processing
397:{\displaystyle \{a,b,c\}}
281:that uniquely represents
258:
31:Encoding (disambiguation)
1282:Quantum error correction
1129:, generally done with a
1107:Text Encoding Initiative
973:
797:("You're a skunk!"), or
725:algebraic geometry codes
1382:10.1073/pnas.1614896114
1046:history of cryptography
429:{\displaystyle \{0,1\}}
1247:to signify "the end".
1056:are now used instead.
956:incompleteness theorem
675:Error-correcting codes
665:3G Wireless Standard.
602:
575:
544:
524:
488:
445:formal language theory
430:
398:
357:
160:information processing
1101:Text encoding uses a
960:mathematical notation
877:, an encoding of the
693:error-correcting code
652:country calling codes
612:Variable-length codes
603:
601:{\displaystyle T^{*}}
576:
574:{\displaystyle S^{*}}
545:
525:
489:
431:
399:
358:
192:communication channel
47:Code 02 Pretty Pretty
24:Code (disambiguation)
1015:for deaf people and
988:electrical resistors
618:Variable-length code
585:
558:
534:
509:
458:
408:
370:
303:
76:improve this article
22:For other uses, see
1373:2017PNAS..114.4745C
1153:Television encoding
922:) of four possible
841:Character encodings
500:sequence of symbols
178:, sound, image, or
1317:2010-12-12 at the
1292:Universal language
1206:Codes and acronyms
1113:Semantics encoding
847:Character encoding
669:Kraft's inequality
598:
571:
540:
523:{\displaystyle C'}
520:
484:
451:, respectively. A
426:
394:
353:
271:information theory
1446:Signal processing
1367:(18): 4745–4750.
543:{\displaystyle C}
443:Using terms from
285:from some source
152:
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126:
39:technical reasons
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1404:
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1384:
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1346:
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1322:
1308:
1272:Code (semiotics)
1180:Decoding methods
1119:Data compression
823:data compression
811:pronounceability
783:commercial codes
733:space–time codes
632:entropy encoding
607:
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194:or storage in a
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43:Code 01 Bad Girl
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1409:Further reading
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1350:
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1339:
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1329:
1325:
1319:Wayback Machine
1312:"So Why Not 29"
1309:
1305:
1300:
1277:Equipment codes
1253:
1219:writing systems
1208:
1147:Memory encoding
1137:Neural encoding
1103:markup language
1073:
1042:
976:
968:Gödel numbering
940:
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887:
849:
843:
819:Herbert Yardley
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253:semaphore tower
224:The process of
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35:
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1323:
1310:Kogan, Hadass
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1294:
1289:
1284:
1279:
1274:
1269:
1264:
1262:Asemic writing
1259:
1252:
1249:
1245:other contexts
1207:
1204:
1203:
1202:
1195:
1189:
1183:
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1168:
1167:
1150:
1144:
1134:
1116:
1110:
1099:
1088:content format
1084:
1072:
1071:Other examples
1069:
1041:
1038:
1034:chess notation
1023:Musical scores
980:traffic lights
975:
972:
964:natural number
939:
936:
889:Main article:
886:
883:
858:variable-width
845:Main article:
842:
839:
831:Huffman coding
756:Main article:
753:
750:
748:
745:
709:Walsh–Hadamard
679:Main article:
676:
673:
647:Huffman coding
616:Main article:
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496:total function
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241:plain language
196:storage medium
156:communications
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1242:
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1234:
1233:Station codes
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1226:
1222:
1220:
1216:
1212:
1200:
1196:
1193:
1190:
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1120:
1117:
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1111:
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1085:
1082:
1079:Encoding (in
1078:
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1062:
1057:
1055:
1051:
1047:
1037:
1035:
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1018:
1014:
1013:sign language
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957:
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908:messenger RNA
905:
901:
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871:
867:
863:
859:
855:
848:
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836:
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828:
824:
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816:
815:Black Chamber
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800:
796:
792:
788:
784:
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773:
769:
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742:
741:random errors
738:
734:
730:
726:
722:
718:
714:
710:
706:
702:
698:
697:Hamming codes
694:
688:
682:
672:
670:
666:
664:
661:
657:
653:
648:
644:
640:
635:
633:
629:
628:concatenation
625:
619:
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265:Coding theory
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96:
93: –
92:
88:
87:Find sources:
81:
77:
71:
70:
65:This article
63:
59:
54:
53:
48:
44:
40:
32:
25:
16:
1415:
1364:
1360:
1340:. Retrieved
1326:
1306:
1237:
1223:
1209:
1169:
1123:transmission
1074:
1058:
1043:
1040:Cryptography
1031:
1021:
1010:
1003:
992:
977:
941:
916:genetic code
894:
891:Genetic code
885:Genetic code
866:HTTP headers
850:
798:
794:
790:
786:
776:
767:
763:
761:
758:Brevity code
740:
737:burst errors
736:
701:Reed–Solomon
690:
667:
638:
636:
621:
552:homomorphism
503:
502:over T. The
452:
442:
437:
365:
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238:
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225:
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129:
119:
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98:
86:
74:Please help
69:verification
66:
15:
1096:information
944:mathematics
928:amino acids
924:nucleotides
906:from which
705:Reed–Muller
639:prefix code
170:—such as a
168:information
1435:Categories
1342:2012-07-03
1298:References
1241:journalism
984:color code
948:Gödel code
938:Gödel code
932:stop codon
914:through a
896:Biological
835:algorithms
827:Morse code
803:Code words
772:characters
687:Block code
685:See also:
132:March 2010
102:newspapers
1441:Encodings
1287:Semiotics
1215:languages
1081:cognition
1061:espionage
995:marketing
966:(using a
854:multibyte
779:telegraph
624:code word
594:∗
567:∗
504:extension
480:∗
472:→
449:alphabets
344:↦
332:↦
320:↦
279:algorithm
245:semaphore
184:shortened
1424:13677884
1401:28416671
1336:Archived
1315:Archived
1251:See also
1229:bag tags
1211:Acronyms
912:proteins
747:Examples
517:′
287:alphabet
234:Decoding
226:encoding
200:language
1392:5422812
1369:Bibcode
1199:phonics
1141:neurons
1127:storage
1065:flowers
1054:ciphers
1044:In the
1017:braille
879:Unicode
817:run by
768:invoice
550:, is a
291:encoded
283:symbols
215:symbols
208:writing
180:gesture
116:scholar
1422:
1399:
1389:
1267:Cipher
1006:cornet
999:coupon
982:, the
920:codons
807:length
731:, and
643:prefix
259:Theory
230:source
212:visual
204:speech
188:secret
172:letter
118:
111:
104:
97:
91:"Code"
89:
1257:ADDML
1165:SECAM
1131:codec
1050:codes
1027:music
974:Other
962:to a
952:Gödel
904:genes
875:UTF-8
862:ASCII
799:AYYLU
795:BMULD
791:LIOUY
787:BYOXO
739:, or
721:Golay
717:Turbo
663:WCDMA
656:ISBNs
581:into
494:is a
289:, by
249:flags
123:JSTOR
109:books
1420:OCLC
1397:PMID
1217:and
1163:and
1157:NTSC
1092:data
946:, a
764:ship
660:UMTS
453:code
438:acab
273:and
219:time
176:word
164:code
158:and
95:news
45:and
37:For
1387:PMC
1377:doi
1365:114
1161:PAL
1125:or
1094:to
993:In
970:).
954:'s
942:In
900:DNA
766:or
554:of
530:of
347:011
269:In
186:or
154:In
78:by
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809:,
743:.
727:,
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715:,
711:,
707:,
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174:,
162:,
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1133:.
1098:.
590:T
563:S
538:C
514:C
476:T
469:S
465::
462:C
424:}
421:1
418:,
415:0
412:{
392:}
389:c
386:,
383:b
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377:a
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341:c
338:,
329:b
326:,
323:0
317:a
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139:(
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120:·
113:·
106:·
99:·
72:.
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