SIST EN 60244-13:1999

Methods of measurement for radio transmitters -- Part 13: Performance characteristics for FM sound broadcasting

Intended to be used for type tests and acceptance or factory tests.

Meßverfahren für Funksendder -- Teil 13: Übertragungseigenschaften für FM-Tonrundfunk

Méthodes de mesure applicables aux émetteurs radioélectriques -- Partie 13: Qualités de fonctionnement des émetteurs de radiodiffusion sonore à modulation de fréquence

Destinées à réaliser les essais de type ainsi que les essais de réception et les essais en usine.

Methods of measurement for radio transmitters - Part 13: Performance characteristics for FM sound broadcasting (IEC 60244-13:1991)

General Information

• Status: Published
• Publication Date: 31-Dec-1998
• ICS: 33.060.20 - Receiving and transmitting equipment
• Technical Committee: RZV - Radiocommunication
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-1999
• Due Date: 01-Jan-1999
• Completion Date: 01-Jan-1999
• Ref Project: EN 60244-13:1993 - Methods of measurement for radio transmitters - Part 13: Performance characteristics for FM sound broadcasting

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60244-13:1999
01-januar-1999
Methods of measurement for radio transmitters - Part 13: Performance
characteristics for FM sound broadcasting (IEC 60244-13:1991)
Methods of measurement for radio transmitters -- Part 13: Performance characteristics
for FM sound broadcasting
Meßverfahren für Funksendder -- Teil 13: Übertragungseigenschaften für FM-
Tonrundfunk
Méthodes de mesure applicables aux émetteurs radioélectriques -- Partie 13: Qualités
de fonctionnement des émetteurs de radiodiffusion sonore à modulation de fréquence
Ta slovenski standard je istoveten z: EN 60244-13:1993
ICS:
33.060.20 Sprejemna in oddajna Receiving and transmitting
oprema equipment
SIST EN 60244-13:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60244-13:1999

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SIST EN 60244-13:1999

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SIST EN 60244-13:1999

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SIST EN 60244-13:1999

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SIST EN 60244-13:1999

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SIST EN 60244-13:1999
NORME
CEI
INTERNATIONALE
IEC
244-13
INTERNATIONAL
Première édition
STANDARD
First edition
1991-04
Méthodes de mesure applicables aux émetteurs
radioélectriques
Partie 13:
Qualités de fonctionnement des émetteurs de
radiodiffusion sonore à modulation de fréquence
Methods of measurement for radio
transmitters
Part 13:
Performance characteristics for
FM sound broadcasting
© CEI 1991
Droits de reproduction réservés — Copy
right - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized
utilisée sous quelque forme que ce soit et par aucun procédé, in any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and mi crofilm, without permission
microfilms, sans raccord écrit de l'éditeur. in writing from the publisher
Bureau central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève Suisse
Téléfax: [phone] e-mail: inmaiI t iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
U
International Electrotechnical Commission PRICE CODE
IEC
MerktppiaponHas 3nei rporexHNVecnaa
Komuccun
Pour prix, voir catalogue en vigueur
•
For price, see current catalogue

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SIST EN 60244-13:1999
244-13©IEC - 3 -
CONTENTS
Page
FOREWORD
INTRODUCTION 7
Clause
1 Scope 9
2 Normative references 9
3 General terms and definitions 11
4 General conditions of operation 13
5 General conditions of measurement 13
6 General characteristics 15
7 Transmission perf
ormance characteristics 15
8 Unwanted modulation 29
9 Out-of-band emission (Occasional measurement) 37
10 Assessment for transmitter equipped with limiters (Under consideration) 41
11 Special measurement for supplementary signals (Under consideration) 41
Measuring arrangement I
Measuring arrangement II
Annexes (normative)
A CCIR Recommendation 468-4 45
B Extract from CCIR Recommendation 559 59

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SIST EN 60244-13:1999
244-13©IEC - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
METHODS OF MEASUREMENT FOR RADIO TRANSMITTERS
Part 13: Performance characteristics for
FM sound broadcasting
FOREWORD
1) The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National
Committees in that sense.
3) In order to promote international unification, the IEC expresses the wish that all National Committees
should adopt the text of the IEC recommendation for their national rules in so far as national conditions will
permit. Any divergence between the IEC recommendation and the corresponding national rules should, as
far as possible, be clearly indicated in the latter.
This International Standard has been prepared by Sub-Committee 12C: Transmitting
equipment, of IEC Technical Committee No. 12: Radiocommunications.
The text of this standard is based upon the following documents:
Six Months' Rule Report on Voting
12C(CO) 215 12C(CO) 221
Full information on the voting for the approval of this standard can be found in the Voting
Report indicated in the above table.
This new part therefore incorporates all the recommended measurements for FM sound
broadcasting transmitters in a single publication and supersedes all clauses dealing with
FM broadcasting transmitters in the following existing publications:
IEC 244-2, 1969
IEC 244-2A, 1969
IEC 244-2B, 1969
iEC 244-3, 1972
IEC 244-3A, 1971
IEC 244-3B, 1972
IEC 244-4, 1973
Annexes A and B form an integral part of this part of IEC 244.

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SIST EN 60244-13:1999
244- 13©IEC - 7 -
INTRODUCTION
This International Standard is one of a series of parts of IEC 244.
s of IEC 244 are currently under review and several of these will
A number of existing pa rt
be revised or withdrawn. When this process is complete, this series of publications will
comprise one part dealing with general characteristics, with cross-references to relevant
rts, each
CCIR publications* and the Radio Regulations, and a number of specialized pa
dealing with particular types of transmitter.
In most cases references to CCIR publica tions deliberately omit the revision number: it is assumed that reference will
always be made to the later revision of CCIR publications. An excepti
on is made here for Recommendation 468-4,
whose text is reproduced in full in this publica
tion.

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SIST EN 60244-13:1999
244-13©IEC - 9 -
METHODS OF MEASUREMENT FOR RADIO TRANSMITTERS
Part 13: Performance characteristics for
FM sound broadcasting
1 Scope
This International Standard contains the method of measurement to assess the
performance characteristics of frequency modulated transmitters for sound broadcasting.
To assess all other characteristics, this standard needs to be used in conjunction with the
publications quoted in clause 2.
This standard is intended to be used for type tests and acceptance or factory tests.
It is not mandatory to measure all the described characteristics. Additional measurements
may be carried out as an agreement between customer and manufacturer.
The performance characteristics measured in accordance with this standard makes
possible the comparison of the results of measurements made by different observers.
Limiting values for acceptable pe rformance are not covered by this standard but, in
connection with the presentation of measured characteristics, some data are given for
clarity.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and pa
rties to agreements based on this
International Standard are encouraged to investigate the possibility of applying the most
recent editions of the standards indicated below. Members of IEC and ISO maintain regis-
ters of currently valid International Standards.
2.1 !EC publications
215: 1987, Safety requirements for radio transmitting equipment.
Amendment No. 1 (1990).
244-1: 1968,
Methods of measurement for radio transmitters - Part 1: General conditions
of measurement, frequency, output power and power consumption (under revision).
Amendment No. 2 (1989) to IEC 244-1A (1968),
Methods of measurement for radio
transmitters - Part 1: General conditions of measurement, frequency, output power and
power consumption - First supplement: Appendices.

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SIST EN 60244-13:1999
244-13 ©IEC - 11 -
244-12-1: 1989, Methods of measurement for radio transmitters - Pa rt 12: Guideline for
drawing up descriptive leaflets for transmitters and transposers for sound and television
broadcasting - Characteristics to be specified.
244-12-2: 1989, Methods of measurement for radio transmitters - Pa rt 12: Guideline for
drawing up descriptive leaflets for transmitters and transposers for sound and television
broadcasting - Specification sheets.
864-1: 1986, Standardization of interconnections between broadcasting transmitters or
transmitter systems and supervisory equipment - Part 1: Interface standards for systems
using dedicated interconnections.
2.2 CCIR publications
Recommendation 450, Transmission standards for FM sound broadcasting at VHF.
Recommendation 468-4: 1990, Measurement of audio-frequency noise voltage level in
sound broadcasting.
Recommendation 559, Objective measurement of radio-frequency protection ratios in LF,
MF and HF broadcasting.
Recommendation 643, System for automatic tuning and other applications in FM radio
receivers for use with the pilot-tone system.
Report 463, Transmission of several sound programmes or other signals with a single
transmitter in frequency-modulation sound broadcasting.
3 General terms and definitions
3.1 Frequency modulated sound transmitter
The term "frequency modulated sound transmitter" is used in this standard to denote
equipment with a FM radio-frequency output and a baseband frequency input which can
accept monophonic, stereophonic and supplementary service multiplexed signals.
3.2
Description of the transmission systems for FM sound broadcasting
The transmission systems for FM sound broadcasting are laid down in CCiR Recom-
mendation 450.
Supplementary services are described in CCIR Repo
rt 463 and CCIR Recom-
mendation 643.

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244-13
© IEC - 13 -
3.3 Definitions of performance characteristics
These definitions are given in the clauses describing the method of measurement and are
in line with those given in IEC 244-12-1 and IEC 244-12-2.
4 General conditions of operation
-
The FM sound transmitter shall be tested under normal operating conditions at its
rated output power.
- The mains supply and the environmental conditions shall be stated with the mea-
surement results.
- The FM sound transmitter shall be connected to a test load which has an
impedance expressed in terms of return-loss relative to the nominal load impedance of
the transmitter of not less than 26 dB at frequencies within the FM broadcasting band
and 16 dB at frequencies of any measured unwanted frequency outside this band.
5 General conditions of measurement
5.1
Input and output signal arrangements
-
For the purposes of measurement, the input and output signal arrangements are
shown in the form of diagrams given on pages 42 and 43.
-
The impedance of the test equipment, the test object and all connections between
them shall be accurately matched.
- The performance characteristics shall be measured via a directional coupler.
5.2 Measuring equipment
At the input:
-
The modulating signals for the transmitter under test shall be provided by one or
two baseband low distortion generators covering the frequencies up to 100 kHz.
- For stereophony, a stereo coder shall be used. If the transmitter does not
incorporate a stereo coder, an external test stereo coder shall be used.
- If required auxiliary equipment for generating, supplementary signals will be used
(e.g. RDS coder).
At the output:
-
All measurements concerning the transmission performances shall be carried out at
baseband signals, at the output of a test demodulator.
- For stereophony, the signals at the output of a test stereo decoder shall be
measured.
-
For supplementary signals, a test decoder shall be used (e.g. RDS decoder).
NOTE - Because the results of these measurements are critically dependent on the pe
rformance of the
test equipment, it is necessary to check first the overall pe
rf
ormance of the test equipment in the absence
of the transmitter under test.

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244-13 ©IEC
5.3 Modulation and output power conditions
The modulation conditions for each measurement are given in the clauses
-
describing the method of measurement.
The output power is the power of the unmodulated carrier.
All measurements shall be carried out at rated output power.
5.4 Units used
As needed, results may either be given in decibels or as percentages.
6 General characteristics
The method of measurement of the general characteristics of the transmitter such as input
impedance, output power and frequency stability will be described in IEC 244-1 (under
revision).
7 Transmission performance characteristics
Measurement can be performed on baseband signals (at frequencies up to a maximum of
100 kHz) and/or audio-frequency signals (at frequencies up to 15 kHz).
The baseband measurements are made at the multiplex input of the transmitter. The audio
band limiting and pre-emphasis in the transmitter and the de-emphasis in the demodulator
are not in circuit, unless otherwise stated.
The audio-frequency measurements are made at the audio input of the transmitter. The
audio band limiting and pre-emphasis in the transmitter or stereo coder and the
de-emphasis in the demodulator or in the stereo decoder are in circuit, unless otherwise
stated.
7.1 Amplitude/baseband-frequency characteristic
7.1.1 Definition
The amplitude/baseband-frequency characteristic is the variation of the amplitude of the
demodulated signal with frequency for a constant value of the demodulating input signal
voltage, relative to the amplitude at a certain reference frequency.
7.1.2 Measuring arrangement
Measuring arrangement I, page 42, with one signal generator at the input shall be used.
The test demodulator output shall be connected to a spectrum analyser or voltage measu-
ring equipment.
7.1.3 Measurement procedure
- Check that the pre- and de-emphasis filters and band-limiting filters are out of
circuit.
- Adjust the input signal to a specified reference frequency.

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Adjust the input level so that the frequency deviation of the transmitter has a
-
specified value.
- Vary the frequency of the modulating signal either manually or continuously by
sweeping up to 76 kHz (some specifications ask for up to 100 kHz).
- Keep the input level constant.
- Measure the level of the demodulator output signal as a function of the modulation
frequency.
- If required, repeat the procedure for other values of frequency deviation.
7.1.4 Presentation of the results
- The results may be presented as a table or a graph relative to the amplitude of the
output at reference frequency. The frequency deviation at reference frequency shall be
stated.
7.2 Baseband-frequency demodulation
7.2.1 Introduction
The method of intermodulation measuring is based on the method using two signals with
frequencies f1 and f2 and equal amplitudes with a frequency difference f 2 - f1 = 1 kHz. The
1 2) as the second order pro-
products of interest are the difference tone of 1 kHz and (f + f
1 kHz), as the
ducts and the tones 1 kHz below f1 , (f1 - 1 kHz), and 1 kHz above f2 (f2 +
third order products. The lowest frequency for f1 shall be 3 kHz.
7.2.2 Definition
The second order (third order) intermodulation level is the ratio, expressed as a per-
centage or in decibels, between (1) the arithmetic sum of the r.m.s. values of the second
order (third order) intermodulation component and (2) the arithmetic sum of the r.m.s.
values of the wanted components at the demodulator output, for a modulation signal
consisting of two tones of equal amplitude, generated within the baseband and spaced
1 kHz apart.
7.2.3 Measuring arrangement
Measuring arrangement I, page 42, shall be used. Two baseband generators are
connected to the input of the transmitter. The isolation between the output of the gene-
rators shall be at least 40 dB. The spectrum analyser is connected to the output of the
demodulator.
7.2.4 Measuring procedure
- out of
Check that the pre- and de-emphasis filters and band-limiting filters are
circuit.
Adjust one input signal to frequency f1.
Adjust the other input signal f2
to a frequency 1 kHz higher.
- Adjust both input signals to the same level, so that one modulating signal gives
50 % of the specified deviation value of the transmitter under test.

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244-13 Uo IEC
- Vary the input frequencies up to 76 kHz keeping the input frequency spacing at
1 kHz and the frequency deviation constant (some specifications ask for measurements
up to 100 kHz).
- Measure for a number of discrete frequencies the r.m.s. values of the second order
and third order intermodulation components and the r.m.s. values of the wanted
components at the output of the demodulator from the spectrum analyser.
- If required, repeat this procedure for other values of the frequency deviation.
NOTE - Another value other than 1 kHz may be used for the frequency difference fd = f2 – f1.
7.2.5 Presentation of the results
Components falling outside the frequency range shall not be taken into account.
The values of levels of each intermodulation component shall be given as a percentage or
in decibels relative to the arithmetic sum of the wanted components. The results shall be
2 frequency. The
presented in the form of tables or graphs as a function of the highest f
frequency deviation shall also be stated with the results.
7.3 Amplitude/audio-frequency characteristic
7.3.1 Definition
The amplitude/audio-frequency characteristic is the variation of the amplitude of the
demodulated/decoded signal with frequency for a constant value of the input signal
voltage, relative to the amplitude at a ce rtain reference frequency.
7.3.2 Measuring arrangement
In the case of monophony, arrangement I, page 42, shall be used.
In the case of stereophony, arrangement I1, page 43, shall be used; measurements are
first performed using the A input of the coder and the A output of the decoder, then
repeated using the B input of the coder and the B output of the decoder.
In both cases, one signal generator at the input shall be used. The test demodulator
output shall be connected to a spectrum analyser or voltage measuring equipment.
7.3.3 Measurement procedure
- Check that the appropriate pre- and de-emphasis filters are in
circuit.
- Adjust the input signal to a specified reference frequency.
- Adjust the input level at reference frequency so that the frequency deviation at
15 kHz does not exceed the maximum rated deviation (75 kHz or 50 kHz).
- Vary the frequency of the modulating signal either manually or continuously by
sweeping up to 15 kHz.
-
Keep the input level constant.

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244-13 ©IEC
- Measure the level of the demodulator or decoder output signal as a function of the
modulation frequency.
- If required, repeat the procedure for other values of frequency deviation.
NOTE - For a pre-emphasis with a time constant of 50 µs the pre-emphasis at 15 kHz is 13,6 dB.
7.3.4 Presentation of the results
The results shall be presented as a table or a graph relative to the amplitude of the output
at reference frequency. The frequency deviation at reference frequency shall be stated.
7.4 Audio-frequency harmonic distortion
7.4.1 Definition
The harmonic distortion factor is the ratio, expressed as a percentage or dB, between (1)
the r.m.s. value of the sum of the second order and all higher harmonics and (2) the r.m.s.
value of the sum of the fundamental and all harmonics at the demodulator/decoder output,
for sinusoidal modulation signals up to 7,5 kHz.
7.4.2 Measuring arrangement
In the case of monophony, arrangement I, page 42, shall be used.
In the case of stereophony, arrangement II, page 43, shall be used; measurements are
first performed using the A input of the coder and the A output of the decoder, then
repeated using the B input of the coder and the B output of the decoder.
In both cases, the output of the demodulator or decoder is connected to a distortion meter
having sufficiently wide bandwidth.
7.4.3 Measurement procedure
Check that the appropriate pre- and de-emphasis filters are in circuit.
Adjust the input signal to a specified reference frequency.
Adjust the input level so that the frequency deviation of the transmitter has a
specified value.
- Vary the input frequency from 40 Hz to 7,5 kHz, keeping the frequency deviation
constant.
- Measure for a number of discrete frequencies the distortion in the output signal
from the demodulator or decoder.
- If required, repeat the procedure for other values of the frequency deviation.
7.4.4 Presentation of the results
The results shall be presented in the form of a table and expressed as a percentage or in
decibels as a function of the modulation frequency. The frequency deviation shall also be
stated with the results.

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7.5 Audio-frequency intermodulation
7.5.1 Introduction
The method of measuring intermodulation is based on the method using two signals with
frequencies f1 and f2
and producing equal frequency deviation with a frequency difference
f2 -
f = 1 kHz. The products of interest are the difference tone of 1 kHz and (f 1 f2)
+ as
the second order products and the tones 1 kHz below f 1 , (f1 - 1 kHz), and 1 kHz above f2,
(f2 + 1 kHz), as the third order products. The lowest frequency for f 1
shall be 3 kHz.
7.5.2 Definition
The second order (third order) intermodulation level is the ratio, expressed as a
percentage or in decibels, between (1) the arithmetic sum of the r.m.s. values of the
second order (third order) intermodulation components and (2) the arithmetic sum of the
r.m.s. values of the wanted components at the demodulator/decoder output, for a
modulation signal consisting of two tones generated within the audio-frequency band and
producing equal frequency deviation, spaced 1 kHz apart.
7.5.3 Measuring arrangement
In case of monophony, arrangement I, page 42, shall be used.
In case of stereophony, arrangement II, page 43, shall be used; measurements are first
performed using the A input of the coder and the A output of the decoder, then repeated
using the B input of the coder and the B output of the decoder.
In both cases, two generators are connected to the input of the transmitter. The isolation
between the outputs of the generators shall be at least 40 dB. The spectrum analyser is
connected to the output of the demodulator or decoder.
7.5.4
Measurement procedure
Check that the appropriate pre- and de-emphasis filters are in circuit.
Adjust one input signal to frequency f1.
Adjust the other input signal f2
to a frequency 1 kHz higher.
Adjust both input signal levels so that one modulating signal gives 50 % of the
specified deviation value of the transmitter under test.
- Vary the input frequencies up to 15 kHz keeping the input frequency spacing at
1 kHz and the frequency deviations due to each input signal constant.
- Measure for a number of discrete frequencies the r.m.s. values
(U) of the second
order and third order intermodulation components and the r.m.s. values
of the
(U)
wanted components at the output of the demodulator or decoder.
- If required, repeat this procedure for other values of the frequency deviation.
NOTE - Another value than 1 kHz may be used for the frequency difference f
d = f2 — f.
7.5.5
Presentation of the results
Components falling outside the frequency range shall not be taken into account.

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The values of levels of each intermodulation component shall be given as a percentage or
in decibels relative to the arithmetic sum of the wanted components. The results shall be
presented in the form of tables or graphs as a function of the highest frequency. The
f2
frequency deviation shall also be stated with the results.
7.6 Cross-talk attenuation (stereophonic separation)
7.6.1
Introduction
Cross-talk can be caused by linear or by non-linear distorsion. Some specifications will
give both separately. The combination of linear and non-linear cross-talk is measured as
cross-talk attenuation or stereophonic separation.
Cross-talk components may appear as unwanted single frequencies.
See also 8.2.2.
7.6.2 Definition
Cross-talk attenuation is the ratio, expressed in decibels of the r.m.s. voltage at the output
of the modulated stereo channel to the r.m.s. value of the sum of the linear and non-linear
cross-talk components and the noise at the output of the unmodulated stereo channel.
7.6.3 Measuring arrangement
Measuring arrangement
Il, page 42, shall be used.
The audio generator is connected to one of the two inputs (A or B) of the stereo coder
which supplies the modulating signal to the transmitter. An r.m.s. voltmeter is connected
successively to outputs A and B of the stereo decoder (the distortion meter can be used
as a level meter).
7.6.4 Measurement procedure
- Check that the appropriate pre- and de-emphasis filters are
in circuit.
Adjust the input signal to 40 Hz at the A input of the stereo coder.
Adjust the input signal level for the specified frequency deviation.
Vary the input frequency between 40 Hz and 15 kHz keeping the frequency
deviation constant.
-
Measure, for a number of discrete frequencies, the voltage at the A output of the
decoder (wanted output signal) and then the voltage at the B output (output signal due
to cross-talk).
- The same procedure is repeated with the input signal applied to the B channel and
measuring the cross-talk in the A channel.
- Repeat, if required, the procedure for other values of frequency deviation.

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7.6.5 Presentation of the results
The values of the cross-talk are expressed in decibels referred to the wanted channel
output and presented in the form of a table or graph as a function of the input frequency.
The frequency deviation shall also be stated with the results.
7.7 Linear cross-talk
7.7.1 Definition
Linear cross-talk is the ratio, expressed in decibels, of the r.m.s. voltage of a modulating
signal at a given frequency at the output of the modulated channel, to the r.m.s. value of
the fundamental frequency cross-talk component at the output of the unmodulated
channel.
7.7.2
Measuring arrangement
Measuring arrangement ll, page 43, shall be used. The arrangement at the input is the
same as that described in 7.6.3.
Instead of a voltmeter, a spectrum analyser or a selective voltmeter is connected
successively to the two outputs (A and B) of the decoder.
7.7.3 Measurement procedure
The measurement procedure is identical to that given in 7.6.4. The value of the
fundamental frequency component (wanted and unwanted) displayed on the spectrum ana-
lyser shall be measured.
7.7.4
Presentation of the results
The values of the linear cross-talk shall be expressed as described in 7.6.5.
7.8 Non-linear cross-talk
7.8.1 Introduction
Non-linear cross-talk may be caused by harmonic distorsion of the M signal (A + B)/2
above 7,5 kHz of the input signal and intermodulation products between M and
S = (A -B)/2 signals of the multiplex signal.
This method of measurement covers both. When a distinction between the two is
necessary, another method of measurement is needed (under consideration).
7.8.2 Definition
Non-linear cross-talk is the ratio, expressed in dB, of the r.m.s. voltage of a modulating
signal of a given frequency at the output of the modulated channel, to the r.m.s. value of
the sum of the components at the output of the unmodulated channel at frequencies other
than that of the modulating signal.

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7.8.3 Measuring arrangement
Measuring arrangement II, page 43, shall be used as in 7.6.3, except that a distortion
meter is connected successively to the two outputs (A and B) of the decoder.
7.8.4 Measurement procedure
The measurement procedure is similar to that given in 7.6.4. For the wanted channel
output, the distortion meter is switched to measure level and for the unwanted channel
output, the distortion meter is switched to measure these components, except at input
frequency (the fundamental of the modulating signal is rejected, in order to eliminate the
effect of linear cross-talk).
7.8.5 Presentation of the results
The values of the non-linear cross-talk shall be expressed as described in 7.6.5.
8 Unwanted modulation
8.1 Introduction
Unwanted modulation of the transmitter output signal may be present within the band
occupied by the output channel and is determined by measuring random noise, periodic
noise, and unwanted single-frequency components in the demodulated signal. Periodic
noise includes hum and other unwanted single-frequency components which may be
produced by different causes, particularly by frequency generating processes and by
mutual influence of either stereophonic channels or the audio signals and the supple-
mentary signals. The unwanted modulation may be frequency or amplitude modulation.
8.2 Unwanted frequency modulation
8.2.1 Random noise
8.2.1.1 Definition
Random noise (FM noise) is expressed in terms of audio signal-to-noise ratio.
Audi
...