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Recommendation B.131)
TERMS AND DEFINITIONS
The CCITT,
considering
(a) that it is desirable to have, in addition to specific terminology texts
produced by Study Groups, definitions of the general technical terms used in CCI
texts;
(b) that the CCIs are cooperating with the International Electrotechnical
Commission (IEC) in the production of the International Electrotechnical
Vocabulary (IEV) (see CCIR Resolution 66 and CCITT Recommendation A.12),
recommends
(1) that Administrations and recognized private operating agencies of the
CCIs, as well as CCI Secretariats, should use as far as possible, technical terms
in the field of telecommunications with the meaning given in the IEV, the plan of
which is given in Appendix I to this Recommendation;
(2) that general terms common to several Study Groups should be used with
the meaning given in Appendix II to this Recommendation, generally close to the
meaning given in the IEV but adapted for CCI needs.
Note - The definitions given in the IEV Chapters, like those included in
Appendix II, are of a general nature; their purpose is that all Study Groups
should use general terms with the same meaning. In certain cases they may be
slightly different from more complete definitions prepared, or being prepared, by
some Study Groups for their specific needs, but they are not in contradiction
with the latter.
These definitions do not replace definitions contained in CCIR or CCITT
Recommendations (or in the Radio Regulations, the Telegraph and Telephone
Regulations or the ITU Convention) which are to be used in their respective
fields of application.
APPENDIX I
(to Recommendation B.13)
"Telecommunications" chapters of the International
Electrotechnical Vocabulary (IEV)
The IEV is IEC Publication No. 50; it comprises a great number of
chapters, published in separate fascicles. Chapters of the 700 series deal with
telecommunications and are prepared by Joint Working Groups in which CCI experts
take part, coordinated by the JCG (Joint Coordinating Group).
Series 700 Chapters which are dealt with by Joint Working Groups are the
following:
Note: Two and a half pages of a table to Appendix I to Recommendation B.13 are
missing.
1) A similar text will be transmitted to the CCIR as a revision of Recommendation
662.
Fascicle I.3 - Rec. B.13 PAGE1
APPENDIX II
(to Recommendation B.13)
General terminology of telecommunications
(Terms common to CCIR and CCITT)
In order to ensure that telecommunication terms employed by the CCIs have
the same meaning, CMV has collected general terms used in the texts of different
Study Groups together with their definitions.
Note - These terms and definitions in this Appendix have been arranged
according to subject as follows:
1) Forms of telecommunications.
2) Channels, circuits and networks.
3) Use and operation of circuits and networks.
4) Frequencies and bandwidths.
Administrations and Study Groups are invited to comment on these terms and
definitions, and particularly, to forward to CMV their proposals for revision or
for alternative applications, accompanied by appropriate justifications.
When examining these definitions, it should be borne in mind that
Recommendation 573 on radiocommunication vocabulary contains terms relating more
specifically to the CCIR.
The following Notes should also be taken into account:
Note 1 - Definitions of "forms of telecommunication" have been produced by
the CMV in cooperation with the CCI-IEC Joint Coordination Group on Vocabulary
(JCG), to be used by CCIR and CCITT Study Groups.
These definitions of "forms of telecommunication" are of a general nature
and are not in contradiction with definitions of services presently specified by
CCITT and CCIR. Definitions of services are produced by the Study Groups
responsible for these services (mainly CCITT Study Groups I and II for
telecommunication services, CCIR Study Groups 10 and 11 for broadcasting
services).
Note 2 - A number of terms in this Recommendation appear also in Article 1
of the Radio Regulations with a different definition. These terms are identified
by (RR . . ., MOD). Modifications are proposed for two reasons:
a) some Radio Regulations definitions only take into account regulatory
aspects, while the CMV proposes definitions of a technical nature;
b) some Radio Regulations definitions give rise to difficulties of
interpretation, in these cases, modifications or additions proposed by
the CMV may be useful later for draft revisions of the Radio
Regulations definitions in accordance with Recommendation No. 72 of
WARC-79 and Study Programme 1A/CMV.
For regulatory applications, only the terms and definitions in the Radio
Regulations may be used.
Note 3 - Terms and definitions relating to reliability have not been
included in this appendix because they usually have rather specific applications.
However, some terms (such as availability, reliability, maintainability) are
currently used by a number of Study Groups. Many terms will be found in
Recommendation G.106 "Concepts, terms and definitions related to quality of
service, availability and reliability".
II.1 Forms of telecommunications
II.1.1 Information, Information, Información
Intelligence or knowledge capable of being represented in forms suitable
for communication, storage or processing.
Note - Information may be represented for example by signs, symbols,
pictures or sounds.
PAGE10 Fascicle I.3 - Rec. B.13
II.1.2 Signal, Signal, Señal
A physical phenomenon one or more of whose characteristics may vary to
represent information.
Note - The physical phenomenon may be for instance an electromagnetic wave
or acoustic wave and the characteristic may be an electric field, a voltage or a
sound pressure.
II.1.3 Transmission, Transmission, Transmisión
The transfer of information from one point to one or more other points by
means of signals.
Note 1 - Transmission can be effected directly, or indirectly, with or
without intermediate storage.
Note 2 - The use of the English word "transmission" in the sense of
"emission" in radiocommunication is deprecated.
II.1.4 Sending, (in telecommunication), Transmission (deprecated in this sense);
Emission (en télécommunication); Emisión (en telecomunicación
The production of a signal at an input port of a transmission line or into
a transmission medium.
Note - In French the term "émission" has other meaning in
radiocommunications, as given in CCIR Recommendation 573.
II.1.5 Communication, Communication, Comunicación
Information transfer according to agreed conventions.
Note - In French and Spanish the corresponding terms "communication" and
"comunicación" have additional specific meanings in telecommunications (see SS
II.3.5 and II.3.2).
II.1.6 Telecommunication, Télécommunication, Telecomunicación
Communication by wire, radio, optical or other electromagnetic systems.
Note - The following definition is given in the International
Telecommunication Convention (Nairobi, 1982) (and RR 4):
Any transmission, emission or reception of signs, signals, writing, images
and sounds or intelligence of any nature by wire, radio, optical or other
electromagnetic systems.
II.1.7 Telephony, Téléphonie, Telefonía
A form of telecommunication primarily intended for the exchange of
information in the form of speech.
Note - This is the definition given in the International Telecommunication
Convention (Nairobi, 1982) (RR 117, MOD).
II.1.8 Telegraphy, Télégraphie, Telegrafía
A form of telecommunication in which the transmitted information is
intended to be recorded on arrival as a graphic document; the transmitted
information may sometimes be presented in an alternative form or may be stored
for subsequent use.
Note 1 - A graphic document records information in a permanent form and is
capable of being filed and consulted; for example, it may take the form of
written or printed matter or a fixed image.
Note 2 - This is the definition given in the International
Telecommunication Convention (Nairobi, 1982) (RR 111, MOD).
Note 3 - Telegraph does not include television or videography.
Note 4 - Moreover, in the Convention and in the RR, the following
restriction is given:
"For the purpose of the Radio Regulations, unless otherwise specified
therein, telegraphy shall mean a form of telecommunication for the transmission
of written matter by the use of a signal code" (RR 111, extract).
Fascicle I.3 - Rec. B.13 PAGE1
II.1.9 Telex (service), (service) Télex, (servicio) Télex
A telegraph service enabling subscribers to communicate directly and
temporarily with each other by means of start-stop apparatus and
telecommunication circuits of the public telecommunication network.
II.1.10 Facsimile, Télécopie, Facsímil
A form of telecommunication for the reproduction at a distance of graphic
documents in the form of other graphic documents geometrically similar to the
original.
II.1.11 Telewriting, Téléécriture, Teleescritura
A form of telecommunication for the purpose of transmitting graphical
information as it is being manually written or drawn and for simultaneously
generating a reproduction at the distant terminal either on a screen or in some
other form.
Note - In cases where the reproduction at the receiving end is in the form
of a graphic document, the term "téléautographie" can be employed in French.
II.1.12 Data, Données, Datos
Information represented in a manner suitable for automatic processing.
II.1.13 Data communication, Data transmission (deprecated in this sense);
Communication de données; Transmission de données (deprecated in this
sense); comunicación de datos, Transmisión de datos (deprecated in this
sense)
A form of telecommunication intended for the transfer of information
between data processing equipments.
II.1.14 Data transmission, Transmission de données, Transmisión de datos
The conveying of data from one place to another by telecommunication.
Note - The term "data transmission" is deprecated in the sense of "data
communication".
II.1.15 Teleprocessing, teleinformatics; Téléinformatique, Télétraitement;
Teleinformática, Teleproceso
The association of telecommunication and data processing techniques to
process information at a distance.
II.1.16 Television, Télévision, Televisión
A form of telecommunication for the transmision of signals representing
scenes; images of the scenes being reproduced on a screen as they are received.
Note 1 - The received signals may be stored for subsequent display of the
images on a screen.
Note 2 - This form of telecommunication finds major application in
television broadcasting and the word "television" is often used without
qualification to describe this application. The same technique is also used for
industrial, scientific, medical and other applications; such applications are
often referred to as "closed-circuit television".
II.1.17 Still-picture television (SPTV), Télévision à images fixes, Televisión
de imágenes fijas
Television in which the time interval between a displayed picture and the
display of either an updated version of the same picture, or a new picture
forming part of a sequence, exceeds (generally by an appreciable factor) the
usual time interval between pictures.
Note - The question as to whether still-picture television includes
certain modes in teletext, broadcast videography (see S II.1.20), is still under
study.
II.1.18 Telematics (services), Télématique (services de), Telemática (servicios
de)
Telecommunication services supplementing conventional telegraphic or
telephonic services, generally using teleprocessing techniques to permit a user
to receive or send public or private information, or to effect operations such as
file consultation, reservations, commercial or banking transactions.
Examples of telematics services: facsimile, teletex, videography,
telewriting.
Note - Telematics services do not include broadcasting of sound or
television programmes.
II.1.19 Videography, Vidéographie, Videografía
A form of telecommunication in which information, generally in the form of
digital data, is transmitted primarily in order to permit the selection and
display of textual or pictorial information to a user on a visual display unit,
for instance on the screen of a television receiver.
PAGE10 Fascicle I.3 - Rec. B.13
Note - The teletex service and various forms of telegraphy are not forms
of videography.
II.1.20 Teletext, broadcast videography; Vidéographie diffusée, télétexte;
Videografía radiodifundida, teletexto
Videography in which information is broadcast utilizing the means of
transmission used for normal television broadcasting and the desired part of this
information may be selected by any user having suitable equipment.
Note 1 - Information may be transmitted simultaneously with normal
television pictures.
Note 2 - The terms "teletext" and "teletex" refer to two different
concepts.
Note by Secretariat - In CCIR Report 802, S 3.1, CCIR Study Group 11 has
provided the following definition for a teletext service:
"A digital data broadcasting service which may be transmitted either
within the structure of an analogue television signal or by using digital
modulation systems. The service is primarily intended to display text or
pictorial material in two-dimensional form reconstructed from coded data on the
screens of suitably equipped television receivers."
II.1.21 Videotex, interactive videography; Vidéotex, vidéographie interactive,
Videotex, videografía interactiva
Videography in which a telecommunication network is used for transmission
of the user's requirements as well as the answers to his requests.
II.1.22 Teletex (service), (service) Télétex, (servicio) Teletex
A telematics service for text transmission offering additional facilities
to the telex service, in particular further typewriter functions and remote text
processing facilities.
Note - The terms "teletex" and "teletext" refer to two different concepts.
II.1.23 Video-telephony, viewphone, visual telephone; Visiophonie, vidéophonie
(deprecated); Videofonía, videotelefonía
to
to see each other during their telephone conversation.
II.1.24 StillVpicture videoVtelephony, Visiophonie ` images fixes, Videofonma
de imagenes fijas
VideoVtelephony in which the time interval between a displayed picture and
the display of either an updated version of the same picture, or a new picture
forming part of a sequence, exceeds (generally by an appreciable factor) the
usual time interval between pictures.
II.1.25 Teleconference, Tiliconfirence, Teleconferencia
A conference between more than two participants located in two or more
different places and utilizing telecommunication facilities.
II.1.26 Audioconference, Audioconfirence, Audioconferencia
A teleconference in which participants are connected by telephone
circuits; the transmission of other signals such as facsimile or telewriting
signals may be possible in addition to speech signals.
II.1.27 Videoconference, Visioconfirence, (vidioconfirence); Videoconferencia
A teleconference in which participants are connected by television
circuits providing for the transmission of animated images in addition to that of
speech and graphic documents.
II.1.28 Telemetry, Telemetering; Tilimesure; Telemedida
A process in which measurements are made at some remote location and the
results are transmitted by telecommunication.
II.1.29 Telecommand, Tilicommande, Telemando
The transmission of signals to initiate, modify or terminate functions of
distant equipment.
II.1.30 Telecontrol, Tiliconduite, Telecontrol
The control of operational equipment at a distance using a combination of
telemetry and telecomand.
II.1.31 Teleguidance, Tiliguidage, Teleguiaje
The guidance and control of distant mobile craft by telecommunication.
II.1.32 Telemonitoring, Tilisurveillance, Telesupervisisn
The observation at a distance by telecommunication of industrial
processes, operational equipment, natural phenomena or individuals.
II.1.33 Remote alarm, Tilialarme, Telealarma
The alerting of a central point by telecommunication to the occurrence of
an unwanted situation or event.
Fascicle I.3 - Rec. B.13 PAGE1
II.1.34 Broadcasting, Tilidiffusion, Teledifusisn
A form of unidirectional telecommunication intended for a large number of
users having appropriate receiving facilities, and carried out by means of radio
or by cable networks.
Note V In English, it should be assumed that Sbroadcasting by radio wavesT
is intended where the word SbroadcastingT is used without qualification, unless
the context indicates the contrary.
Examples: Sound broadcasting or television broadcasting, teletext, the
distribution of time signals and navigational warnings, the distribution of news
from press agencies.
II.1.35 Broadcasting (service), Radiodiffusion, Radiodifusión
Radiocommunication in which transmissions are intended for direct
reception by the general public; these may include sound transmissions,
television transmissions and other types of transmission.
Note - By common usage in French and Spanish the meaning of
"radiodiffusion" and "radiodifusión" is frequently restricted to "sound
broadcasting".
II.1.36 Sound broadcasting (service), Radiodiffusion sonore, Radiodifusión
sonora
A broadcasting service limited to sound programmes.
II.1.37 Television broadcasting (service), Radiodiffusion visuelle,
(Radiodiffusion de) télévision, (Radiodifusión de) Televisión
A broadcasting service of visual programmes with associated sounds.
II.1.38 Cabled distribution; Télédistribution, Câblodistribution (Canada),
distribución por cable
A form of telecommunication for the distribution of television or sound
programmes over networks of cables to a number of users.
Note - Some systems may transmit other signals and provide return
channels.
II.2 Channels, circuits and networks
II.2.1 (Transmission) channel, Voie (de transmission), Canal (de transmisión)
A means of transmission of signals in one direction between two points.
Note 1 - Several channels may share a common path; for example each
channel is allocated a particular frequency band or a particular time slot.
Note 2 - In some countries the term "communication channel" or its
abbreviation "channel" is also used to mean "telecommunication circuit", i.e. to
encompass the two directions of transmission. This usage is deprecated.
Note 3 - A transmission channel may be qualified by the nature of the
transmitted signals, or by its bandwidth, or by its digit rate; for example:
telephone channel, telegraph channel, data channel, 10 MHz channel, 34 Mbit/s
channel.
II.2.2 Telephone-type channel, Voie de type téléphonique, Canal de tipo
telefónico
A transmission channel suitable for the transmission of speech but which
is used for the transmission of other signals.
II.2.3 (Telecommunication) circuit, circuit (de télécommunication), circuito (de
telecomunicación)
A combination of two transmission channels permitting transmission in both
directions between two points, of the signals exchanged between the same
terminals
Note 1 - If the telecommunication is by nature unidirectional, e.g.
long-distance television transmission, the term "circuit" is sometimes used to
designate the single transmission channel providing the facility, but this usage
is deprecated.
telegr
telegraph circuit, data circuit, digital circuit.
Note 3 V Such characteristics of the transmission channels as bandwidth,
digit rate, may be different in the two directions of transmission.
Note 4 V In telephony, usage of the term Stelephone circuitT is generally
limited to a telecommunication circuit directly connecting two switching centres.
II.2.4 TelephoneVtype circuit, Circuit de type tiliphonique, Circuito de tipo
telefsnico
A pair of associated telephoneVtype channels permitting transmission in
both directions between two points.
II.2.5 (Frequency) channel, Canal (de friquences), Canal (de frecuencias)
PAGE10 Fascicle I.3 - Rec. B.13
Part of the frequency spectrum intended to be used for a transmission of
signals and which may be defined by two specified limits, or by its centre
frequency and the associated bandwidth, or by any equivalent indication.
Note 1 V A frequency channel may be timeVshared in order to allow
communication in both directions by simplex operation.
Note 2 V The use of the term SchannelT to mean Stelecommunication circuitT
is deprecated.
Note 3 V The term SradioVfrequency channelT used in radiocommunication is
defined in CCIR Recommendation 573.
II.2.6 Link, Liaison, Enlace
A means of telecommunication with specified characteristics between two
points.
Note V The type of the transmission path or the capacity is normally
indicated, e.g. radio link, coaxial link, broadband link.
II.2.7 PointVtoVpoint communication, Communication point ` point, Comunicacmon
punto a punto
Communication provided by a link between two specified fixed points.
II.2.8 PointVtoVmultipoint communication, Communication point ` multipoint,
Comunicacisn punto a multipunto
Communication provided by links between one specified fixed point and a
number of specified fixed points.
II.2.9 PointVtoVarea communication, Communication point ` zone, Comunicacisn
punto a zona
Communication provided by links between one specified fixed point and any
number of nonspecified points located in a given area.
Note V When pointVtoVarea communication involves unidirectional links from
a single fixed point to a number of points, this type of communication is
commonly referred to as SbroadcastingT (see ' II.1.34).
II.2.10 Telecommunication network, telecommunication system (United States of
America); Riseau de tilicommunication; Red de telecomunicacisn
All the means of providing telecommunication services between a number of
locations where equipment provides access to these services.
II.2.11 (Telecommunication) terminal, Terminal (de tilicommunication), Terminal
(de telecomunicacisn)
o
one or more specific services.
Note V The term may be qualified to indicate the type of service or user,
e.g. Sdata terminalT, Ssubscriber's terminalT.
II.2.12 Subscriber's line, subscriber loop; Ligne d'abonni, ligne de
rattachement; Lmnea de abonado, bucle de abonado
A link between equipment in a subscriber's premises and the
telecommunication centre providing the required services.
II.2.13 Port (of a network), Acchs (d'un riseau), Porte (term not to be used in
this sense); Puerta (de una red)
A termination through which signals can enter or leave a network.
II.2.14 Transmission path, Trajet de transmission, Trayecto de transmisisn
The course taken by a signal during its transmission between two points.
II.2.15 Interface, Interface, Interfaz
A boundary between two systems or between two parts of the same system,
defined by the specification of suitable characteristics, usually for the purpose
of ensuring format, function, signal and interconnection compatibility at the
boundary.
Note V An interface may be defined, for example, at a plug and socket
connection, at the aperture of an antenna or between layers of a hierarchical
system.
II.2.16 Distribution link, Liaison de distribution, Enlace de distribucisn
A link for the transmission of sound or television broadcasting programmes
to the users, generally from a programme production centre, when no further
postVproduction processing is intended.
II.2.17 Primary distribution link, Liaison de distribution primaire, Enlace de
distribucmon primaria
The part of a distribution link from a programme production centre to
either a broadcast transmitting centre or the headVend of a cabled distribution
network.
II.2.18 Secondary distribution link, Liaison de distribution secondaire, Enlace
Fascicle I.3 - Rec. B.13 PAGE1
de distribucisn secundaria
The part of a distribution link from the headVend of a cabled distribution
network to the users.
II.2.19 Contribution link, Liaison de contribution, Enlace de contribucisn
A link for the transmission of sound or television broadcasting signals to
a programme production centre.
II.3 Use and operation of circuits and networks
II.3.1 Connection, Channe de connexion, Cadena de conexisn
A temporary association of transmission channels or telecommunication
circuits, switching and other functional units set up to provide for the transfer
of information between two or more points in a telecommunication network.
II.3.2 (Complete) connection; Channe de connexion complhte, (Chemin de)
communication; Cadena de conexisn completa, (camino de) comunicacisn
A connection between users' terminals.
Note - In French and in Spanish, the terms "communication" and
"comunicación", have also a more general meaning (see S II.1.5).
PAGE10 Fascicle I.3 - Rec. B.13
II.3.3 Switching (in telecommunication), Commutation (en télécommunication),
Conmutación (en telecomunicación)
The process of temporarily associating functional units, transmission
channels or telecommunication circuits for the purpose of providing a desired
telecommunication facility.
II.3.4 Call attempt (by a user), (Tentative d') appel (par un usager), (Tentativa
de) llamada (por un usuario)
A single sequence of operations made by a user of a telecommunication
network trying to obtain the desired user, terminal or service.
Note - This definition differs slightly from the definition of the same
term which appears in CCITT Recommendation P.10 (S 21 - Telephone calls
description).
II.3.5 Call, Communication, Comunicación
The establishment and use of a complete connection, following a call
attempt.
Note - In French and in Spanish, the terms "communication" and
"comunicacíon", have also a more general meaning (see S II.1.5).
II.3.6 Conversation (in telecommunication), Conversation (en télécommunication),
Conversación (en telecomunicación)
An exchange of information between terminals.
II.3.7 Code, Code, Código
A system of rules defining a one-to-one correspondence between information
and its representation by characters, symbols or signal elements.
II.3.8 Modulation, Modulation, Modulación
A process by which a quantity which characterizes an oscillation or wave
follows the variations of a signal or of another oscillation or wave.
Note - Modulation may be intentional or unintentional.
II.3.9 Carrier, Porteuse, Portadora
An oscillation or wave, usually periodic, some characteristic of which is
intended to be constrained by modulation to follow the values of a signal or of
another oscillation.
II.3.10 Carrier (component), (Composante) porteuse, Portadora (componente)
In a modulated oscillation or wave, the spectral component having the
frequency of the periodical oscillation or wave prior to modulation.
II.3.11 Multiplexing, Multiplexage, Multiplexación
A reversible process for assembling signals from several separate sources
into a single composite signal for transmission over a common transmission
channel; this process is equivalent to dividing the common channel into distinct
channels for transmitting independent signals in the same direction.
II.3.12 Demultiplexing, Démultiplexage, Demultiplexación
A process applied to a composite signal formed by multiplexing, for
recovering the original independent signals, or groups of these signals.
Note - Demultiplexing may be partial, for instance for extracting a group
from a supergroup of telephone channels.
II.3.13 Multiple access, Accès multiple, Acceso mltiple
Any technique whereby a number of terminals are able to share the
transmission capacity of a link in a predetermined manner or in accordance with
traffic demand.
Fascicle I.3 - Rec. B.13 PAGE1
II.3.14 Space division, Répartition spatiale, División espacial
A technique whereby a separate individual transmission path is used for
each transmission channel for example in multiplexing, switching or multiple
access operations.
II.3.15 Time division, Répartition temporelle, División en el tiempo
A technique whereby a separate distinct recurrent time interval is used
for each transmission channel, for example in multiplexing, switching or multiple
access operations.
II.3.16 Frequency division, Répartition en fréquence, répartition
fréquentielle, Distribución en frecuencia
A technique whereby a separate distinct frequency band is used for each
transmission channel, for example in multiplexing, switching or multiple access
operations.
II.3.17 Code division, Répartition en code, División por código
A technique whereby orthogonal signals are used to provide distinct
transmission channels, for example in multiplexing, switching or multiple access
operations; such signals being distinguishable even when they share the same
frequency bands and the same time intervals.
II.3.18 Simplex, half duplex (deprecated); Simplex, à l'alternat, semi-duplex
(deprecated in this sense); Símplex, semiduplex
Designating or pertaining to a method of operation in which information
can be transmitted in either direction, but not simultaneously, between two
points.
II.3.19 Duplex, full duplex (deprecated); Duplex, bilatéral simultané; Dplex
Designating or pertaining to a mode of operation by which information can
be transmitted in both directions simultaneously between two points.
II.3.20 Unidirectional; Unilatéral, unidirectionnel, simplex (term deprecated
in this sense); Unidireccional, unilateral
Pertaining to a link where the transfer of user's information is possible
in one preassigned direction only.
Note - This term should not be used to describe the direction of call
set-ups.
II.3.21 Bidirectional; Bilatéral, bidirectionnel, duplex (term deprecated in
this sense); Bidireccional, bilateral
Pertaining to a link where the transfer of users' information is possible
simultaneously in both directions between two points.
Note 1 - The transmission channel capacity and signalling rate are not
necessarily the same in both directions.
Note 2 - This term should not be used to describe the directions of call
set-ups.
II.3.22 One-way; à sens unique, spécialisé (term deprecated in this sense); de
sentido nico
Pertaining to an operational mode in which the call set-ups always occur
in one direction.
Note - This term should not be used to describe the direction of transfer
of users' information.
II.3.23 Both-way; A double sens, mixte; De doble sentido
d
directions.
Note 1 V The amount of traffic flowing is not necessarily the same in both
directions.
Note 2 V These terms should not be used to describe the direction of
transfer of users' information.
Note 3 V The term StwoVwayT is sometimes used in English in place of
SbothVwayT; this usage is not recommended.
PAGE10 Fascicle I.3 - Rec. B.13
II.4 Frequencies and bandwidths
II.4.1 Frequency band, Bande de fréquences, Banda de frecuencias
A continuous set of frequencies lying between two specified limiting
frequencies.
Note - A frequency band is characterized by two values which define its
position in the frequency spectrum, for example, its lower and upper limiting
frequencies.
II.4.2 Frequency bandwidth, Largeur de bande (de fréquences), Anchura de banda
(de frecuencia)
The quantitative difference between the limiting frequencies of a
frequency band.
Note 1 - The term "bandwidth" is usually associated with a qualification,
for example:
- baseband bandwidth;
- necessary bandwidth;
- bandwidth of an amplifier or other device.
Note 2 - A bandwidth is defined by a single value and does not depend upon
the position of the band in the frequency spectrum.
II.4.3 Baseband, Bande de base, Banda de base
1) The frequency band occupied by one signal, or by a number of multiplexed
signals intended to be conveyed by a radio transmission system or a line
transmission system.
Note 1 - In the case of radiocommunication, the baseband signal
constitutes the signal modulating the transmitter.
Note 2 - The following definition proposed by the JCG in IEV Chapter 702,
was also found to be acceptable.
2) That frequency band occupied by one signal or by a number of multiplexed
signals at specified input and output points of a transmission system.
Note 1 - In the case of a radiocommunication, the baseband is that band
which is occupied by the signal modulating the transmitter.
Note 2 - When the transmission involves multiple modulation, it is
generally considered that the baseband is that band occupied by the signal which
is applied to the first modulation stage and not the band occupied by an
intermediate modulated signal.
II.4.4 x dB bandwidth (of a signal), Largeur de bande ½à x dB╗, Anchura de banda
entre puntos a ½x dB╗
The width of a frequency band such that beyond its lower and upper limits
any spectral line or any power spectral density of the spectrum of a signal is at
least x dB lower than a 0 dB reference level specified for the type of signal
considered.
II.4.5 Frequency departure, écart de fréquence, déviation de fréquence (term
deprecated in this sense); desajuste de frecuencia
An unintentional frequency separation from a stated frequency.
II.4.6 Frequency shift, Déplacement de fréquence, Desplazamiento de frecuencia
An intentional frequency change produced by modulation, or an
unintentional change due to a natural phenomenon.
II.4.7 Frequency drift, Dérive de fréquence, Deriva de frecuencia
An undesired progressive and slow change in frequency with time.
II.4.8 Frequency offset, Décalage de fréquence, Separacíon de la frecuencia
modula
modulation.
Note V A frequency offset may be effected, for example, as a means of
avoiding or minimizing interference.
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