1、ITU-T RECMNtG-701 73 = 4862591 0583324 641 i4TERNATIOh L TE ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU .ECOMMU N KATION GENERAL ASPECTS OF DIGITAL TRANSMISSION SYSTEMS JNION G.701 (03/93) VOCABULARY OF DIGITAL TRANSMISSION AND MULTIPLEXING, AND PULSE CODE MODULATION (PCM) TERMS ITU-T Reco
2、mmendation G.701 (Previously “CCIlT Recommendation”) FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on t
3、hem with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T Recomm
4、endation G.701 was revised by the ITU-T Study Group XV (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to exist as of 28 February 1993. In its place, the ITU T
5、elecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references co
6、ntaining the acronyms “CCIT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation wiil contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a recognized operating agency. In th
7、is Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in w
8、riting from the ITU. ITU-T RECMN*G.70L 93 = 48b25L 0583326 YLY CONTENTS Page 1 Introduction 2 Vocabulary of digital transmission and multiplexing and pulse code modulation terms (PCM) . 2.1 General 2.2 Digital signals . 2.3 Digital transmission 2.4 Digital multiplexing 2.5 Frame alignment . 2.6 . Ti
9、ming 2.7 Synchronization 2.8 Pulse code modulation 2.9 Codes Annex A - Alphabetical list of terms defined in this Recommendation . Reference . Appendix I - List of abbreviations used in G-, H- and J-Series Recommendations . Recommendation 6.701 (03/93) 1 1 1 3 7 11 17 18 21 23 30 32 35 35 i ITU-T RE
10、CMN*G.703 93 = 4862573 0583327 350 = Recommendation G.701 VOCABULARY OF DIGITAL TRANSMISSION AND MULTIPLEXING, AND PULSE CODE MODULATION (PCM) TERMS (Melbourne, 1988; revised at Helsinki, 1993) 1 Introduction This Recommendation provides a vocabulary of terms and definitions that are appropriate to
11、digital and pulse code modulation multiplexing and transmission systems. A srnail number of the terms in the Recommendation are duplicated in Recommendation 1.112. References to these definitions are given in parenthesis as an aid to ensuring consistency between the two Recommendations in the event
12、of future amendments. According to the conventions applied in this Recommendation any term in common usage, but whose use is deprecated in the sense defined, is shown after the recommended term as in the following example: “2026 controlled slip slip”. Where a truncated term is widely used in an unde
13、rstood context the complete term is quoted following the colloquial form, for example: “1007 circuit, telecommunication circuit”. Furthermore, any term which is in general use in addition to the principal term is shown after the principal term as in the following example: “6002 timing recovery (timi
14、ng extraction)”. In the interest of standardization in the drafting of documents the following abbreviations are recommended: kbids; Mbids; Gbids. To avoid misinterpretation of the use of the point (.) and the comma (,) in different languages to separate the whole and decimal parts, it is recommende
15、d that the use of decimals should be avoided wherever possible. For example, “2048 kbitls” is preferred to “2.048 Mbids” or “2,048 Mbit/s”. Annex A to this Recommendation contains an alphabetical list of all of the terms defined in this Recommendation. Appendix I to this Recommendation contains a li
16、st of abbreviations used in G-, H- and J-Series Recommendations. 2 Vocabulary of digital transmission and multiplexing and pulse code modulation terms (PCM) 2.1 General For the purposes of this Recommendation, the following definitions apply. 1001 signai lo21 F: signal S: seal A physical phenomenon
17、one or more of whose characteristics may vary to represent information. 1002 analogue signai lo31 F: signal analogique S: seal anaigica A signal one of whose characteristic quantities follows continuously the variations of another physical quantity representing information. Recommendation G.701 (03/
18、93) 1 ITU-T RECMN*G-703 73 = 4862573 0583328 277 = 1003 discretely-timed signal 1041 F: signal (temporel) discret S: seul discretamente temporid A signai composed of successive elements in time, each element having one or more characteristics which can convey information, for example, its duration,
19、its waveform and its amplitude. 1004 transmission lo61 F: transmission S: transmisin The action of conveying signals from one point to one or more other points. NOTES 1 2 Transmission can be effected directly or indirectly, with or without intermediate storage. The use of the English word “transmiss
20、ion” in the sense of “emission” is deprecated. 1005 channel, transmhion channel 1081 F: voie, voie de transmission S: canal, canal de transmisin A means of unidirectional transmission of signals between two points. NOTES 1 or a particular time slot. 2 arbitrary designation. 3 Several channels may sh
21、are a common path; for example each channel may be allocated a particular frequency band The term may be qualified by the nature of the transmitted signals, by the bandwidth, by the digit rate, or by an See also Recommendation I. 112, Term 414, access channel. 1006 telecommunication 1101 F: tlcommun
22、ication S: telecomunicacin Any transmission andor emission and reception of signals representing signs, writing, images and sounds or intelligence 1007 of any nature by wire, radio, optical or other electromagnetic systems. circuit, telecommunication circuit 1 1 i F: circuit, circuit de tlcommunicat
23、ions S: circuito, circuito de telecomunicacin A comLiation of two transmission channels permitting bidirectional transmission of signals between tw support a single communication. NOTES points, to 1 2 3 4 If the telecommunication is by nature unidirectional (for example: long distance television tra
24、nsmission), the term “circuit” is sometimes used to designate the single channel providing the facility. In a telecommunication network, the use of the term “circuit” is generally limited to a telecommunication circuit directly connecting two switching devices or exchanges, together with associated
25、terminating equipment. A telecommunication circuit may permit transmission in both directions simultaneously (duplex), or not simultaneously (simplex). A telecommunication circuit that is used for transmission in one direction only is sometimes referred to as a unidirectional telecommunication circu
26、it. A telecommunication circuit that is used for transmission in both directions (whether simultaneously or not) is sometimes referred to as a bidirectional telecommunication circuit. 1008 interface 408 F: jonction (interface) S: interfaz The common boundary between two associated systems. 2 Recomme
27、ndation 6.701 (0393) ITU-T RECMN*G=701 93 = 4662591 0583329 123 1009 congestion F: encombrement/engorgement S: congestin Congestion is the conditions that exists in a network if the capacity needed for the instantaneous traffk exceeds the bandwidth available in the network. 2.2 Digital signais 2001
28、digit F: lment numrique S: dgito A member selected from a finite set. NOES 1 In digital transmission, a digit may be represented by a signal element, being Characterized by the dynamic nature, discrete condition and discrete timing of the element, for example it may be represented as a pulse of spec
29、ified amplitude and duration. In equipment used in digital transmission, a digit may be represented by a stored condition being characterized by a The context of the use of the term should be such as to indicate the radix of notation. (The meaning of “digit” in In telephone subscriber numbering, a d
30、igit is any of the numbers 1, 2, 3 . . . 9 or O forming the elements of a 2 specified physical condition, for example it may be represented as a binary magnetic condition of a ferrite core. Notes 1, 2 and 3 translates into French as “lment numrique”.) telephone number (Recommendation Q.10 i). (This
31、meaning of “digit” translates into French as “chiffre”.) 3 4 2002 binary figure F: chifie binaire S: cifra binaria One of the two figures (that is, O or 1) used in the representation of numbers in binary notation. 2003 binary digit (bit) F: lment binaire (bit) S: dgito binario (bit) A member selecte
32、d from a binary set. NOTES 1 2 Bit is an abbreviation for binary digit. In the interest of clarity, it is recommended that the term “bit” should not be used in two-condition start-stop modulation instead of “unit element”. 2004 octet F: octet S: octeto A group of eight binary digits or eight signal
33、elements representing binary digits operated upon as an entity. 2005 code word character signal F: mot de code signal de caractre S: palabra de cdigo seal de carcter A set of signal elements representing the quantized value of a sample in PCM. NOTE - In PCM, the term “PCM word” may be used in this s
34、ense. Recommendation 6.701 (03/93) 3 2006 digital signai 1051 F: signal numrique S: seal digital A discretely timed signal in which information is represented by a number of well-defined discrete values that one of its characteristic quantities may take in time. NOTE - The term may be qualified to i
35、ndicate the digit rate, for example: “140 Mbit/?, digital signal”. 2007 signai element F: lment de signal S: elemento de seal A part of a digital signal, characterized by its discrete timing and its discrete value, and used to represent a digit. 2008 digit position F: position dun lment de signal, p
36、osition dun lment numrique S: posicin de dgito The position in time or space into which a representation of a digit may be placed. 2009 n-ary digital signal F: signal numrique n-aire S: seal digital n-aria 1 A digital signal in which each signal element has one of n permitted discrete values. 2010 r
37、edundant digital signal F: signal numrique redondant S: seal digital redundante The signal that is produced by encoding a given signal in accordance with a reiindant line CO-:. 201 1 redundant n-ary signal F: signal n-aire redondant S: seal n-aria redundante A digital signal whose elements can assum
38、e n discrete states where the average equivalent binary content per signal element is less than log2 n. NOTE - The relative redundancy R, of an n-ary digital signal, is given by: R=l- rd . log2n rd e logZn where rd is the symbol rate of the R-ary signal and re is the equivalent bit rate. This may al
39、so be expressed in terms of the number of binary digits which can be transmitted by an element of a particular line code. Examples are: AMI (37% redundant), 1 binary digit per element; 4B3T (16% redundant), 1.33 binary digit per element. 20 12 pseudo n-ary signai F: signal pseudo n-aire S: seal sedo
40、 n-aria A redundant n-ary digital signal that is derived from a m-ary digital signal without change of the line digit rate. NOTE - An alternate mark inversion signal is an example of a pseudo-ternary signal, Le. R = 3, m = 2. 4 Recommendation 6.701 (03/93) ITU-T RECVN*G.701 93 M 4862591 0583333 883
41、I 2014 line digit rate symbol rate F: dbit numrique en ligne dbit de symboles S: velocidad digital de linea velocidad de smbolos I The number of signal elements of the line signal transmitted per unit time. NOTES 1 2 unit interval. The baud is usually used to quantify this, one baud being equal to o
42、ne single element per second. Modulation rate is the term used in telegraphy and data communication; it is the reciprocal of the duration of the 2013 digit rate F: dbit numrique S: velocidad digital The number of digits per unit time. NOTES 1 2 An appropriate adjective may precede the word “digit”,
43、for example, binary digit rate. In the interests of clarity it is recommended that this term should not be used to express the symbol rate on the line. 20 15 equivalent binary content F: contenu binaire quivalent S: contenido binario equivalente The number of binary digits strictly necessary to conv
44、ey the same information as a defined number of signal elements in a given digital signal. 2016 equivalent bit rate F: dbit binaire quivalent S: velocidad binaria equivalente The value of the bit rate strictly necessary to convey the same information in the same time as a given digital signal at a gi
45、ven digit rate. 2017 significant instant, significant instant of a digital signal F: instant signiJcatiJ instant significatif dun signal numrique S: instante significativo, instante signijcativo de una seal digital The instant at which a signal element commences in a discretely-timed signal. 20 18 u
46、nit interval F: intervalle unitaire S: intervalo unitario (o intervalo unidad) The nominal difference in time between consecutive significant instants of an isochronous signal. 2019 decision instant, decision instant of a digital signal F: instant de dcision, instant de dcision dun signal numrique S
47、: instante de decisin, instante de decisin de una seal digital The instant at which a decision is taken as to the probable value of signal element of a received digital signal. 2020 decision circuit F: circuit de dcision S: circuito de decisin A circuit that decides the probable value of a signal el
48、ement of a received digital signal. Recommendation 6.701 (03193) 5 ITU-T RECMN*G-70L 73 = 48b259L 0583332 7LB W 202 1 regeneration F: rgnration S: regeneracin The process of receiving and reconstructing a digital signal so that the amplitudes, waveforms and timing of its signal elements are constrai
49、ned within specified limits. 2022 regenerator F: rgnrateur S: regenerador A device that performs regeneration. 2023 regenerative repeater F: rpteur rgnrateur S: repetidor regenerativ0 A repeater that regenerates digital signals. NOTES 1 2 A regenerative repeater may operate in one or both directions of transmission, and the term may be qualified by Repeater is defined in Recommendation G.601. “unidirectional” or “bidirectional” as appropriate. 2024 jitter F: gigue S: fluctuaci
