Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics

IEC 60027-2:2019 is applicable to telecommunications and electronics. It gives names and symbols for quantities and their units.

Symboles littéraux à utiliser en électrotechnique - Partie 2: Télécommunications et électronique

IEC 60027-2:2019 s'applique aux télécommunications et à l'électronique. Elle donne les noms et symboles des grandeurs et unités.

General Information

Status
Published
Publication Date
07-Jan-2019
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
08-Jan-2019
Ref Project

Buy Standard

Standard
IEC 60027-2:2019 - Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics
English and French language
149 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC 60027-2
Edition 4.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Letter symbols to be used in electrical technology –
Part 2: Telecommunications and electronics
Symboles littéraux à utiliser en électrotechnique –
Partie 2: Télécommunications et électronique
IEC 60027-2:2019-01(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2019 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, 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 writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC

copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite

ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez

les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC

The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes

International Standards for all electrical, electronic and related technologies.
About IEC publications

The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the

latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org

The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,

variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English

committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.

and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary

details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and

once a month by email. French extracted from the Terms and Definitions clause of

IEC publications issued since 2002. Some entries have been

IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and

If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC

La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des

Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC

Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la

plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - Electropedia - www.electropedia.org

webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au

La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en

en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans

comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire

projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.

IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary

Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais

Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et Définitions des

Disponible en ligne et une fois par mois par email. publications IEC parues depuis 2002. Plus certaines entrées

antérieures extraites des publications des CE 37, 77, 86 et
Service Clients - webstore.iec.ch/csc CISPR de l'IEC.
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC 60027-2
Edition 4.0 2019-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Letter symbols to be used in electrical technology –
Part 2: Telecommunications and electronics
Symboles littéraux à utiliser en électrotechnique –
Partie 2: Télécommunications et électronique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 01.060; 33.020 ISBN 978-2-8322-6346-4

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60027-2:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope .............................................................................................................................. 5

2 Normative references ...................................................................................................... 5

3 Terms and definitions ...................................................................................................... 5

4 Introduction to tables ....................................................................................................... 5

5 Quantities and units ......................................................................................................... 6

5.1 General concepts .................................................................................................... 6

5.2 Linear time-independent networks under sinusoidal conditions ............................. 20

5.2.1 General ......................................................................................................... 20

5.2.2 Two-port networks ......................................................................................... 20

5.2.3 n-port networks .............................................................................................. 28

5.3 Line transmission of signals and telephony ........................................................... 34

5.3.1 Quantities and units in line transmission ........................................................ 34

5.3.2 Subscripts for line transmission ..................................................................... 35

5.3.3 Quantities and units in telephony ................................................................... 36

5.3.4 Subscripts for telephony ................................................................................ 36

5.4 Waveguide propagation ........................................................................................ 37

5.4.1 Frequency and wavelength in a waveguide .................................................... 37

5.4.2 Characteristic and normalized impedance and admittance in general............. 38

5.4.3 Impedance and admittance at a point in a substance ..................................... 39

5.4.4 Impedance and admittance at a point in vacuum ............................................ 40

5.4.5 Impedance and admittance of a waveguide ................................................... 41

5.5 Radiocommunications ........................................................................................... 42

5.5.1 General and tropospheric propagation ........................................................... 42

5.5.2 Ionospheric propagation ................................................................................ 45

5.5.3 Antennas ....................................................................................................... 46

5.5.4 Radio links..................................................................................................... 51

5.6 Optical fibre communication .................................................................................. 53

5.7 Television ............................................................................................................. 59

5.8 Dependability ........................................................................................................ 61

5.9 Piezoelectric resonators ........................................................................................ 62

5.10 Semiconductor devices ......................................................................................... 68

5.11 Electroacoustics ................................................................................................... 68

Bibliography .......................................................................................................................... 73

Figure 1 – Conventions concerning signs in electric circuits .................................................. 20

Figure 2 – Conventions for n-port linear networks ................................................................. 28

Figure 3 – Equivalent circuits of a one-port piezoelectric resonator ....................................... 62

---------------------- Page: 4 ----------------------
IEC 60027-2:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LETTER SYMBOLS TO BE USED IN ELECTRICAL TECHNOLOGY –
Part 2: Telecommunications and electronics
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC

Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60027-2 has been prepared by IEC technical committee 25:

Quantities and units.

This fourth edition cancels and replaces the third edition published in 2005. This fourth edition

constitutes a technical revision.

This edition includes the following significant changes with respect to the previous edition:

a) former Subclauses 3.8 and 3.9 are cancelled and replaced by IEC 80000-13:2008;

b) former Subclause 3.10, now 4.8, is revised in accordance with IEC 60050-192:2015;

c) former Subclause 3.11, now 4.9, is revised in accordance with IEC 60050-561:2014;

d) former Subclause 3.13, now 4.11, is revised in accordance with ISO 80000-8:2007,

IEC 60050-801:1994 and IEC 60050-802:2011;

e) technical and editorial corrections have been carried out, mainly in Subclause 4.1.

f) tables are simplified, mainly by deleting useless columns.
---------------------- Page: 5 ----------------------
– 4 – IEC 60027-2:2019 © IEC 2019
The text of this standard is based on the following documents:
FDIS Report on voting
25/635/FDIS 25/640/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts in the IEC 60027 series, published under the general title Letter symbols to

be used in electrical technology, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 6 ----------------------
IEC 60027-2:2019 © IEC 2019 – 5 –
LETTER SYMBOLS TO BE USED IN ELECTRICAL TECHNOLOGY –
Part 2: Telecommunications and electronics
1 Scope

This part of IEC 60027 is applicable to telecommunications and electronics. It gives names

and symbols for quantities and their units.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.

IEC 60027-1:1992, Letter symbols to be used in electrical technology – Part 1: General

IEC 60027-1:1992/AMD1:1997
IEC 60027-1:1992/AMD2:2005
3 Terms and definitions
No terms and definitions are listed in this document.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Introduction to tables

In this part of IEC 60027, complex quantities are in general denoted by underlining their

symbols. However, this does not constitute a compulsory rule in applications (see

IEC 60027-1).

To avoid any ambiguity, some quantity names are followed by a specific use, enclosed in

angle brackets "<…>" after a comma.

When several symbols are indicated for a given quantity, the first is the preferred symbol and

the others are reserve symbols, unless otherwise stated.

When several units are indicated for a given quantity, the first is the coherent SI unit, unless

otherwise stated. For logarithmic ratios, the first mentioned unit is the decibel.

For quantities defined as a logarithm of the ratio of two power quantities or two root-power

quantities (also known as field quantities), the submultiple decibel (dB) of the bel (B) is

generally used, rather than the neper (Np). The bel is not explicitly mentioned in the tables.

See IEC 60027-3 and ISO 80000-1:2009, Annex C.
---------------------- Page: 7 ----------------------
– 6 – IEC 60027-2:2019 © IEC 2019
5 Quantities and units
5.1 General concepts
Quantity Units
Item
Entry
number
number in Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050

101 101-12-02 signal S A signal is any physical phenomenon whose presence, absence or variation is The unit depends on the

considered as representing information. In general, a signal is a quantity, one or kind of quantity

more parameters of which represent information. constituting the signal
(electric current,
In this document, S and S are used for input and output signals respectively.
1 2
voltage, pressure, etc.).
See IEC 60027-1 for other suitable subscripts.

In cases where the type of signal quantity is known, for example, electric current,

voltage, pressure, etc., use the appropriate symbol.
With respect to capital and lower-case letters, see IEC 60027-1:1992, 2.1.

102 signal power P "s" (lower case, upright) is used as subscript for "signal". watt W

P In signal theory, the term "instantaneous power" is by convention used for the
sig
square of the instantaneous value of a signal. This square is proportional to a
physical power if the signal is a root-power quantity (or field quantity)
(see Note 1 to entry of IEC 60050-103:2009, 103-09-05).
In a physical system, a signal power is always a physical power.
103 signal level L decibel dB
S 1 S
L =10 lg dB= ln Np
L S 2 S neper Np
ref ref
sig
where S and S are two signals of the same kind, S being a reference signal.
ref ref
104 702-07-04 absolute L decibel dB
P 1 P
L =10 lg dB= ln Np
power level;
P 2 P neper Np
ref ref
power level
where P is a power and P is a reference power.
ref
105 702-07-06 absolute decibel dB
U U
L =20 lg dB=ln Np
voltage level;
U U neper Np
ref ref
voltage level
where U is a voltage and U is a reference voltage.
ref
The synonym "voltage level" may be used only where there is no ambiguity.
---------------------- Page: 8 ----------------------
IEC 60027-2:2019 © IEC 2019 – 7 –
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
106 702-07-05 relative decibel dB
L L = L −L
r,x r,x P,x P,0
power level
neper Np
where L and L are the absolute power levels (104) at the measuring point
P,x P,0
and at a reference point, respectively.

107 702-08-03 noise A noise is any variable physical phenomenon, generally a quantity, apparently The unit depends on the

not conveying information and which can be superimposed on, or combined with, kind of quantity

n a wanted signal. constituting the noise
(electric current,
Concerning upper and lower-case letters, see IEC 60027-1:1992, 2.1.
n voltage, pressure, etc.).
"n" (lower case, upright) is used as subscript for "noise".
In cases where the type of noise quantity is known, use the appropriate symbol
(for example, I, i for electric current) with n as subscript (e.g. I , i ).
n n
108 103-09-05 power w(f) watt per W/Hz
spectral hertz
P = wf( )d f
density,
or noise>
where f is the frequency and P is the total power.
In signal theory, the term "instantaneous power" is by convention used for the
square of the instantaneous value of a signal or noise. This square is

proportional to a physical power if the signal or the noise is a root-power (or field

quantity). See Note 1 to entry of 103-09-05 in IEC 60050-103:2009.
In a physical system, the power spectral density is always a physical power
spectral density.

109 power N The power spectral density (108) is frequency-independent: watt per W/Hz

spectral w(f) = N hertz
density of
white noise
110 702-08-51 equivalent U Applies to a one-port network. volt V
noise
U is an RMS voltage.
voltage n
---------------------- Page: 9 ----------------------
– 8 – IEC 60027-2:2019 © IEC 2019
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
111 702-08-52 equivalent Applies to a one-port network. ohm Ω
noise
resistance; U
R =
4 kT ∆f
ref
noise
resistance
is the equivalent noise voltage (110), k is the Boltzmann constant, T
where U
n ref
is a reference temperature and ∆f is the frequency bandwidth (154) considered.
The synonym "noise resistance" may be used only where there is no ambiguity.
112 702-08-54 spot noise T(f) Applies to a one-port network. kelvin K
temperature f is frequency.
113 702-08-55 mean noise Applies to a one-port network. kelvin K
temperature
114 702-08-56 equivalent Applies to a two-port network. kelvin K
T ( f )
spot noise f is frequency.
temperature
115 702-08-58 mean Applies to a two-port network. kelvin K
equivalent
The synonym "mean noise temperature" may be used only where there is no
noise
ambiguity.
temperature;
mean noise
temperature
116 702-08-57 spot noise Applies to a two-port network. one 1
Ff()

factor The noise factor is the ratio of the exchangeable power spectral density (108) of

output noise to the power spectral density that would be present at the output if

the only source of noise were input thermal noise at a reference temperature
ref
Tf()
Ff() 1+
ref
where T ( f ) is the equivalent spot noise temperature (114).
For exchangeable power, see IEC 60050-702:1992, 702-07-11.
---------------------- Page: 10 ----------------------
IEC 60027-2:2019 © IEC 2019 – 9 –
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
117 702-08-57 spot noise decibel dB
F ( f ) 1
F f = 10 lg Ff dB = ln Ff Np
figure ( ) ( ) ( )
neper Np
F ()f
where is the spot noise factor (116).
In English, "noise factor" is generally used for the arithmetic expression and
"noise figure" is used for the logarithmic expression. See IEC 60050-702:1992,
702-08-57, Note 2.
In French, "facteur de bruit" is generally used in both cases.
118 702-08-59 mean noise Applies to a two-port network. one 1
factor;
F 1+
noise factor
ref
where T is the mean equivalent noise temperature (115) and T is a reference
ref
temperature.
The synonym "noise factor" may be used only where there is no ambiguity.
119 702-08-59 mean noise decibel dB
F 1
FF10 lg dB ln F Np
figure;
neper Np
noise figure
where F is the mean noise factor (118).
In English, "noise factor" is generally used for the arithmetic expression and
"noise figure" is used for the logarithmic expression. See IEC 60050-702:1992,
702-08-59, Note 2.
In French, "facteur de bruit" is generally used in both cases and the adjective
"logarithmique" is omitted in practice.
The synonym "noise figure" may be used only where there is no ambiguity.
120 702-08-61 signal-to- k Signal power (102) divided by noise power. one 1
noise ratio;
In practice, the symbol S/N is generally used.
SNR
---------------------- Page: 11 ----------------------
– 10 – IEC 60027-2:2019 © IEC 2019
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
121 702-08-61 signal-to- K decibel dB
Kk= 10 lg dB = ln k Np
noise
SN SN SN
neper Np
logarithmic
ratio
where k is the signal-to-noise ratio (120).
In practice, the term "signal-to-noise ratio" and the symbol S/N are generally
used.
122 103-07-17 growth Example: decibel dB/s
coefficient per
Np/s
σ t
second
ut = u e sin ω t
( )
neper
where u(t) is a sinusoidal function of time t, with angular frequency ω and per
second
amplitude .
123 103-05-24 damping δ =−σ decibel dB/s
coefficient per
Np/s
where is the growth coefficient (122).
second
neper
per
second
124 103-07-16 complex s second s Special units are only
s =σ + jjω =−+δω
angular to the used when the real and
power imaginary parts are
frequency;
where is the angular frequency, is the growth coefficient (122) and δ is
ω σ
of treated separately.
complex
the damping coefficient (123).
minus
frequency
one
---------------------- Page: 12 ----------------------
IEC 60027-2:2019 © IEC 2019 – 11 –
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
125 131-15-20 transfer H The unit of the quantity
Ss()
function H is the quotient of the
Hs() =
unit of s (t) by the unit
Ss()
of s (t).
and S , respectively, are the complex representations of the input and
where S
1 2
output signals, respectively, as functions of the complex angular frequency s
(124).
The complex quantities are generally the Laplace transforms of the time-varying
quantities:
Lst()
H =
Lst()

where Ls (t) and Ls (t) are the Laplace transforms of the signals s (t) and s (t)

1 2 1 2
and t is time.
126 transfer gain The unit is the same as
G()ω
GH(ωω) = (j )
for H.
where H (σω+ j ) is the transfer function (125).
127 transfer The unit is the
A()ω AG()ωω= 1 / ()
attenuation reciprocal of the unit of
G(ω)
where is the transfer gain (126).

128 transfer If the transfer function H (125) is of dimension one (see IEC 60050-112:2010, one 1 Special units are only

exponent 112-01-13): used when the real and
imaginary parts are
HG(jωω) ( )exp[−=jB(ω)] exp[Γ (ω)]
treated separately.
Γ AB− j (see 129 and 130).
See also image transfer coefficient (IEC 60050-131:2002, 131-15-25).
129 logarithmic A decibel dB
A 20 (lg e) Re ()ΓΓdB Re () Np
transfer
neper Np
attenuation
where Γ is the transfer exponent (128) and e is the base of the natural
logarithm.
In practice, "transfer attenuation" is used.
---------------------- Page: 13 ----------------------
– 12 – IEC 60027-2:2019 © IEC 2019
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
130 phase radian rad
B(ωω) = Im(ΓH) = − arg (j )
change; 1° = rad
degree
ϕ 180
where is the transfer function (125) and Γ is the transfer exponent
H (σω+ j )
phase shift
(128).
131 voltage one 1
a =
attenuation U
factor
where U and U are two voltages. Subscripts 1 and 2 can for example designate
1 1
the input port and the output port, respectively, of a two-port network. The
inverse of the voltage attenuation factor is the voltage gain factor (133).
In practice, "voltage attenuation" is used.
132 logarithmic
decibel dB
A A =20 lg a dB=ln a Np
U U U U
voltage
neper Np
attenuation
where is voltage attenuation factor (131). When the logarithmic voltage

attenuation is negative, its absolute value is the logarithmic voltage gain (134).

In practice, "voltage attenuation" is used.
133 voltage gain one 1
g U
U 2
g =
factor
where U and U are two voltages. Subscripts 1 and 2 can, for example,
1 1

designate the input port and the output port, respectively, of a two-port network.

The inverse of the voltage gain factor is the voltage attenuation factor (131).
In practice, "voltage gain" is used.
134 logarithmic decibel dB
G G =20 lg g dB=ln g Np
U U U U
voltage gain
neper Np
where g is the voltage gain factor (133). When the logarithmic voltage gain is
negative, its absolute value is the logarithmic voltage attenuation (132).
In practice, "voltage gain" is used.
---------------------- Page: 14 ----------------------
IEC 60027-2:2019 © IEC 2019 – 13 –
Quantity Units
Item
Entry
number
number in
Name Symbol Definition and remarks Name Symbol Remarks
IEC 60050
135 702-02-10 power loss S instead of P in the case of apparent powers. one 1
Use subscript
factor;
power a =
attenuation 2
factor

Subscripts 1 and 2 are used to designate the power of a signal at two points, for

example, input and output of a two-port network, or th
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.