69:
884:
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
883:
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,
862:
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
824:, 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
1249:
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
1094:) - 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.
217:, 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
660:
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
372:
682:
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.
304:
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.
447:. 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
503:
266:
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.
413:
539:
445:
617:
590:
1078:, 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.
559:
49:
641:
of such code words give us an encoded string. Variable-length codes are especially useful when clear text characters have different probabilities; see also
1235:
796:
that encoded complete phrases into single mouths (commonly five-minute groups) were developed, so that telegraphers became conversant with such "words" as
1246:
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.
1346:
1126:
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.
879:. However, single-byte encodings cannot model character sets with more than 256 characters. Scripts that require large character sets such as
832:
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
313:
458:, the precise mathematical definition of this concept is as follows: let S and T be two finite sets, called the source and target
941:. A sequence of codons results in a corresponding sequence of amino acids that form a protein molecule; a type of codon called a
247:
is the reverse process, converting code symbols back into a form that the recipient understands, such as
English or/and Spanish.
871:(also called variable-length) encodings. The earliest character encodings were single-byte, the best-known example of which is
702:
Codes may also be used to represent data in a way more resistant to errors in transmission or storage. This so-called
1133:
152:
863:
grouped according to the number of bytes required to represent a single character: there are single-byte encodings,
793:
133:
1012:
codes can be used for a financial discount or rebate when purchasing a product from a (usual internet) retailer.
105:
1325:
1019:
are used for different uses: to mark some moments of the day, to command the infantry on the battlefield, etc.
703:
691:
90:
1074:
in military, diplomacy, business, etc.) to trivial (romance, games) can be any kind of imaginative encoding:
739:
112:
813:
634:
1202:
459:
297:
706:
works by including carefully crafted redundancy with the stored (or transmitted) data. Examples include
1456:
119:
1196:
653:
510:
41:
1342:
468:
1292:
1117:
1116:
to tag the structure and other features of a text to facilitate processing by computers. (See also
909:
organisms contain genetic material that is used to control their function and development. This is
562:
1056:
868:
735:
719:
101:
79:
966:
455:
380:
1199:, the study of signals in a digital representation and the processing methods of these signals
792:
messages were the state of the art in rapid long-distance communication, elaborate systems of
1001:
or that of the trashcans devoted to specific types of garbage (paper, glass, organic, etc.).
994:
970:
782:
679:
662:
418:
202:
86:
57:
34:
17:
1379:
715:
628:
595:
568:
240:
652:
is a code with the "prefix property": there is no valid code word in the system that is a
8:
1163:
1137:
1075:
1060:
743:
1383:
619:, which naturally maps each sequence of source symbols to a sequence of target symbols.
519:
307:
Before giving a mathematically precise definition, this is a brief example. The mapping
1451:
1402:
1367:
1302:
1123:
857:
840:
where more-frequently used characters have shorter representations. Techniques such as
633:
In this section, we consider codes that encode each source (clear text) character by a
544:
281:
978:
1430:
1407:
731:
182:
1427:
Codes and
Abbreviations for the Use of the International Telecommunication Services
1397:
1387:
1282:
1190:
1129:
848:
to compress large data files into a more compact form for storage or transmission.
833:
821:
711:
642:
285:
194:
53:
1429:(2nd ed.). Geneva, Switzerland: International Telecommunication Union. 1963.
1193:, methods in communication theory for decoding codewords sent over a noisy channel
126:
1329:
1287:
1157:
1147:
1113:
1070:
Secret codes intended to obscure the real messages, ranging from serious (mainly
829:
170:
892:
character set; UTF-8 is the most common encoding of text media on the
Internet.
1372:
Proceedings of the
National Academy of Sciences of the United States of America
1272:
1229:
1098:
1044:
990:
974:
880:
864:
841:
657:
506:
263:
259:
251:
206:
52:, terms beginning with "Code#" redirect here. For the EPs by Ladies' Code, see
1063:
were once common for ensuring the confidentiality of communications, although
1445:
1023:
918:
825:
638:
275:
222:
166:
1434:
1392:
958:
1411:
1243:
926:
901:
876:
768:
707:
781:) with shorter words, allowing the same information to be sent with fewer
250:
One reason for coding is to enable communication in places where ordinary
29:
System of rules to convert information into another form or representation
1322:
1212:
to decipher print patterns and translate them into the sounds of language
1106:
1033:
954:
934:
178:
1251:
1043:
Specific games have their own code systems to record the matches, e.g.
942:
938:
837:
789:
727:
697:
1297:
1091:
1071:
1005:
845:
289:
255:
68:
1225:
998:
723:
210:
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1239:
1221:
1209:
1185:
1027:
922:
906:
889:
293:
218:
198:
190:
1277:
1238:
are three-letter codes used to designate airports and used for
1224:
and abbreviations can be considered codes, and in a sense, all
1151:
1101:- a specific encoding format for converting a specific type of
1064:
1016:
1009:
817:
673:
225:
214:
254:, spoken or written, is difficult or impossible. For example,
1343:"Western Union "92 Code" & Wood's "Telegraphic Numerals""
1267:
1175:
1141:
1037:
930:
885:
872:
836:
predates the computer era; an early example is the telegraph
367:{\displaystyle C=\{\,a\mapsto 0,b\mapsto 01,c\mapsto 011\,\}}
1255:
1167:
1102:
914:
670:
666:
229:
186:
1030:
for blind people, are based on movement or tactile codes.
762:
1171:
910:
1022:
Communication systems for sensory impairments, such as
228:, extended the range of communication across space and
669:, and the Secondary Synchronization Codes used in the
1236:
International Air
Transport Association airport codes
1160:- the process of converting sensations into memories.
598:
571:
547:
522:
471:
421:
383:
316:
1368:"Case for the genetic code as a triplet of triplets"
1205:, the use of analog circuit for decoding operations
1015:In military environments, specific sounds with the
746:. Error detecting codes can be optimised to detect
93:. Unsourced material may be challenged and removed.
611:
584:
553:
533:
497:
439:
407:
366:
1332:American Journalism Review. Retrieved 2012-07-03.
1150:- the way in which information is represented in
656:(start) of any other valid code word in the set.
1443:
800:("Are you trying to weasel out of our deal?"),
40:"Encoding" redirects here. For other uses, see
1132:transforms a signal into a code optimized for
937:can be translated into one of twenty possible
1254:to mean "end of story", and has been used in
875:. ASCII remains in use today, for example in
812:("Not clearly coded, repeat more clearly.").
434:
422:
402:
384:
377:is a code, whose source alphabet is the set
361:
323:
243:into symbols for communication or storage.
997:employed to mark the nominal value of the
1401:
1391:
685:
478:
360:
326:
153:Learn how and when to remove this message
1365:
804:("Why do you not answer my question?"),
622:
763:Codes in communication used for brevity
221:, which converted spoken language into
14:
1444:
851:
785:, more quickly, and less expensively.
209:. An early example is an invention of
1216:
665:, the country and publisher parts of
415:and whose target alphabet is the set
288:, a code is usually considered as an
1181:Other examples of decoding include:
1086:Other examples of encoding include:
788:Codes can be used for brevity. When
262:held by a signaler or the arms of a
91:adding citations to reliable sources
62:
989:There are codes using colors, like
24:
1419:
1345:. Signal Corps Association. 1996.
1036:are the most common way to encode
921:is derived. This in turn produces
867:(also called wide) encodings, and
773:A cable code replaces words (e.g.
213:, which enabled a person, through
25:
1468:
1081:
945:signals the end of the sequence.
816:were chosen for various reasons:
509:mapping each symbol from S to a
177:is a system of rules to convert
67:
1349:from the original on 2012-05-09
1050:
961:was the basis for the proof of
929:in which a series of triplets (
895:
844:are now used by computer-based
78:needs additional citations for
1335:
1315:
740:low-density parity-check codes
692:Error detection and correction
498:{\displaystyle C:\,S\to T^{*}}
482:
354:
342:
330:
201:, for communication through a
193:—into another form, sometimes
13:
1:
1308:
1232:are codes for human thought.
948:
913:, which contains units named
258:, where the configuration of
969:. Here, the idea was to map
881:Chinese, Japanese and Korean
239:converts information from a
7:
1366:Chevance, Fabienne (2017).
1261:
1203:Digital-to-analog converter
1186:Decoding (computer science)
757:
724:Bose–Chaudhuri–Hochquenghem
10:
1473:
1208:Word decoding, the use of
899:
855:
766:
695:
689:
637:from some dictionary, and
626:
273:
47:
31:
1197:Digital signal processing
408:{\displaystyle \{a,b,c\}}
292:that uniquely represents
269:
42:Encoding (disambiguation)
1293:Quantum error correction
1140:, generally done with a
1118:Text Encoding Initiative
984:
808:("You're a skunk!"), or
736:algebraic geometry codes
1393:10.1073/pnas.1614896114
1057:history of cryptography
440:{\displaystyle \{0,1\}}
1258:to signify "the end".
1067:are now used instead.
967:incompleteness theorem
686:Error-correcting codes
676:3G Wireless Standard.
613:
586:
555:
535:
499:
456:formal language theory
441:
409:
368:
171:information processing
1112:Text encoding uses a
971:mathematical notation
888:, an encoding of the
704:error-correcting code
663:country calling codes
623:Variable-length codes
614:
612:{\displaystyle T^{*}}
587:
585:{\displaystyle S^{*}}
556:
536:
500:
442:
410:
369:
203:communication channel
58:Code 02 Pretty Pretty
35:Code (disambiguation)
1026:for deaf people and
999:electrical resistors
629:Variable-length code
596:
569:
545:
520:
469:
419:
381:
314:
87:improve this article
33:For other uses, see
1384:2017PNAS..114.4745C
1164:Television encoding
933:) of four possible
852:Character encodings
511:sequence of symbols
189:, sound, image, or
1328:2010-12-12 at the
1303:Universal language
1217:Codes and acronyms
1124:Semantics encoding
858:Character encoding
680:Kraft's inequality
609:
582:
551:
534:{\displaystyle C'}
531:
495:
462:, respectively. A
437:
405:
364:
282:information theory
1457:Signal processing
1378:(18): 4745–4750.
554:{\displaystyle C}
454:Using terms from
296:from some source
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50:technical reasons
16:(Redirected from
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1283:Code (semiotics)
1191:Decoding methods
1130:Data compression
834:data compression
822:pronounceability
794:commercial codes
744:space–time codes
643:entropy encoding
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54:Code 01 Bad Girl
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1420:Further reading
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1330:Wayback Machine
1323:"So Why Not 29"
1320:
1316:
1311:
1288:Equipment codes
1264:
1230:writing systems
1219:
1158:Memory encoding
1148:Neural encoding
1114:markup language
1084:
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979:Gödel numbering
951:
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830:Herbert Yardley
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264:semaphore tower
235:The process of
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1321:Kogan, Hadass
1313:
1312:
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1306:
1305:
1300:
1295:
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1273:Asemic writing
1270:
1263:
1260:
1256:other contexts
1218:
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1161:
1155:
1145:
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1110:
1099:content format
1095:
1083:
1082:Other examples
1080:
1052:
1049:
1045:chess notation
1034:Musical scores
991:traffic lights
986:
983:
975:natural number
950:
947:
900:Main article:
897:
894:
869:variable-width
856:Main article:
853:
850:
842:Huffman coding
767:Main article:
764:
761:
759:
756:
720:Walsh–Hadamard
690:Main article:
687:
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658:Huffman coding
627:Main article:
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507:total function
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252:plain language
207:storage medium
167:communications
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1245:
1244:Station codes
1241:
1237:
1233:
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1227:
1223:
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1201:
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1192:
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1131:
1128:
1125:
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1111:
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1100:
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1090:Encoding (in
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1046:
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1024:sign language
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919:messenger RNA
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827:
826:Black Chamber
823:
819:
815:
811:
807:
803:
799:
795:
791:
786:
784:
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770:
755:
753:
752:random errors
749:
745:
741:
737:
733:
729:
725:
721:
717:
713:
709:
708:Hamming codes
705:
699:
693:
683:
681:
677:
675:
672:
668:
664:
659:
655:
651:
646:
644:
640:
639:concatenation
636:
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104: –
103:
99:
98:Find sources:
92:
88:
82:
81:
76:This article
74:
70:
65:
64:
59:
55:
51:
43:
36:
27:
19:
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1371:
1351:. Retrieved
1337:
1317:
1248:
1234:
1220:
1180:
1134:transmission
1085:
1069:
1054:
1051:Cryptography
1042:
1032:
1021:
1014:
1003:
988:
952:
927:genetic code
905:
902:Genetic code
896:Genetic code
877:HTTP headers
861:
809:
805:
801:
797:
787:
778:
774:
772:
769:Brevity code
751:
748:burst errors
747:
712:Reed–Solomon
701:
678:
649:
647:
632:
563:homomorphism
514:
513:over T. The
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279:
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236:
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85:Please help
80:verification
77:
26:
1107:information
955:mathematics
939:amino acids
935:nucleotides
917:from which
716:Reed–Muller
650:prefix code
181:—such as a
179:information
1446:Categories
1353:2012-07-03
1309:References
1252:journalism
995:color code
959:Gödel code
949:Gödel code
943:stop codon
925:through a
907:Biological
846:algorithms
838:Morse code
814:Code words
783:characters
698:Block code
696:See also:
143:March 2010
113:newspapers
1452:Encodings
1298:Semiotics
1226:languages
1092:cognition
1072:espionage
1006:marketing
977:(using a
865:multibyte
790:telegraph
635:code word
605:∗
578:∗
515:extension
491:∗
483:→
460:alphabets
355:↦
343:↦
331:↦
290:algorithm
256:semaphore
195:shortened
1435:13677884
1412:28416671
1347:Archived
1326:Archived
1262:See also
1240:bag tags
1222:Acronyms
923:proteins
758:Examples
528:′
298:alphabet
245:Decoding
237:encoding
211:language
1403:5422812
1380:Bibcode
1210:phonics
1152:neurons
1138:storage
1076:flowers
1065:ciphers
1055:In the
1028:braille
890:Unicode
828:run by
779:invoice
561:, is a
302:encoded
294:symbols
226:symbols
219:writing
191:gesture
127:scholar
1433:
1410:
1400:
1278:Cipher
1017:cornet
1010:coupon
993:, the
931:codons
818:length
742:, and
654:prefix
270:Theory
241:source
223:visual
215:speech
199:secret
183:letter
129:
122:
115:
108:
102:"Code"
100:
1268:ADDML
1176:SECAM
1142:codec
1061:codes
1038:music
985:Other
973:to a
963:Gödel
915:genes
886:UTF-8
873:ASCII
810:AYYLU
806:BMULD
802:LIOUY
798:BYOXO
750:, or
732:Golay
728:Turbo
674:WCDMA
667:ISBNs
592:into
505:is a
300:, by
260:flags
134:JSTOR
120:books
18:Codes
1431:OCLC
1408:PMID
1228:and
1174:and
1168:NTSC
1103:data
957:, a
775:ship
671:UMTS
464:code
449:acab
284:and
230:time
187:word
175:code
169:and
106:news
56:and
48:For
1398:PMC
1388:doi
1376:114
1172:PAL
1136:or
1105:to
1004:In
981:).
965:'s
953:In
911:DNA
777:or
565:of
541:of
358:011
280:In
197:or
165:In
89:by
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1170:,
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1120:.)
1097:A
1059:,
1047:.
1040:.
1008:,
820:,
754:.
738:,
734:,
730:,
726:,
722:,
718:,
714:,
710:,
648:A
645:.
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232:.
185:,
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1437:.
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1390::
1382::
1356:.
1154:.
1144:.
1109:.
601:T
574:S
549:C
525:C
487:T
480:S
476::
473:C
435:}
432:1
429:,
426:0
423:{
403:}
400:c
397:,
394:b
391:,
388:a
385:{
362:}
352:c
349:,
340:b
337:,
334:0
328:a
324:{
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318:C
156:)
150:(
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141:(
131:·
124:·
117:·
110:·
83:.
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