SIST EN 61606-4:2007

Audio and audiovisual equipment - Digital audio parts - Basic measurement methods of audio characteristics -- Part 4: Personal computer

This part of IEC 61606 specifies the basic measurement methods of a linear PCM signal for an audio part of personal computers (PCs) and applies to both desktop and portable computers. The common measuring conditions and methods are described in IEC 61606-1. Specific conditions and methods of measurement for PCs are given in this standard.

Audio- und Audiovisuelle Geräte - Digitale Tonteile - Grundlegende Messverfahren der Audio-Eigenschaften --Teil 4: Personal-Computer

Equipements audio et audiovisuels - Parties audionumériques - Méthodes fondamentales pour la mesure des caractéristiques audio -- Partie 4: Ordinateur personnel

La CEI 61606-4:2005 spécifie les méthodes de mesure de base d'un signal PCM linéaire pour la partie audio des ordinateurs personnel (PC) et s'applique à la fois aux ordinateurs de bureau et portables. Les conditions et méthodes de mesure communes sont décrites dans la CEI 61606-1. Des conditions et méthodes de mesure spécifiques aux PC sont indiquées dans la présente norme. La présente version bilingue (2012-05) correspond à la version anglaise monolingue publiée en 2005-12.

Avdio in avdiovizualna oprema - Digitalni avdio deli - Osnovne merilne metode zvokovnih karakteristik - 4. del: Osebni računalnik (IEC 60606-4:2005)

General Information

• Status: Published
• Publication Date: 28-Feb-2007
• ICS: 33.160.30 - Audio systems
• ICS: 35.160 - Microprocessor systems
• Technical Committee: AVM - Audio, video and multimedia systems and equipment
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Mar-2007
• Due Date: 01-Mar-2007
• Completion Date: 01-Mar-2007
• Ref Project: EN 61606-4:2006 - Audio and audiovisual equipment - Digital audio parts - Basic measurement methods of audio characteristics - Part 4: Personal computer

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61606-4:2007
01-marec-2007
$YGLRLQDYGLRYL]XDOQDRSUHPD'LJLWDOQLDYGLRGHOL2VQRYQHPHULOQHPHWRGH
]YRNRYQLKNDUDNWHULVWLNGHO2VHEQLUDþXQDOQLN,(&
Audio and audiovisual equipment - Digital audio parts - Basic measurement methods of
audio characteristics -- Part 4: Personal computer
Audio- und Audiovisuelle Geräte - Digitale Tonteile - Grundlegende Messverfahren der
Audio-Eigenschaften --Teil 4: Personal-Computer
Equipements audio et audiovisuels - Parties audionumériques - Méthodes
fondamentales pour la mesure des caractéristiques audio -- Partie 4: Ordinateur
personnel
Ta slovenski standard je istoveten z: EN 61606-4:2006
ICS:
33.160.30 Avdio sistemi Audio systems
35.160 Mikroprocesorski sistemi Microprocessor systems
SIST EN 61606-4:2007 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61606-4:2007

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SIST EN 61606-4:2007


EUROPEAN STANDARD
EN 61606-4

NORME EUROPÉENNE
December 2006
EUROPÄISCHE NORM

ICS 35.020; 33.160.30


English version


Audio and audiovisual equipment -
Digital audio parts -
Basic measurement methods of audio characteristics
Part 4: Personal computer
(IEC 61606-4:2005)


Equipements audio et audiovisuels -  Audio- und Audiovisuelle Geräte -
Parties audionumériques - Digitale Tonteile -
Méthodes fondamentales pour Grundlegende Messverfahren der
la mesure des caractéristiques audio Audio-Eigenschaften
Teil 4: Personal-Computer
Partie 4: Ordinateur personnel
(CEI 61606-4:2005) (IEC 61606-4:2005)




This European Standard was approved by CENELEC on 2006-12-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in two official versions (English and German). A version in any other language
made by translation under the responsibility of a CENELEC member into its own language and notified to the
Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61606-4:2006 E

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SIST EN 61606-4:2007
EN 61606-4:2006 - 2 -
Foreword
The text of the International Standard IEC 61606-4:2005, prepared by IEC TC 100, Audio, video and
multimedia systems and equipment, was submitted to the formal vote and was approved by CENELEC as
EN 61606-4 on 2006-12-01 without any modification.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2007-12-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-12-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61606-4:2005 was approved by CENELEC as a European
Standard without any modification.
__________

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SIST EN 61606-4:2007
- 3 - EN 61606-4:2006
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

1) 2) 3)
IEC 60038 (mod) - IEC standard voltages HD 472 S1 1989
+ corr. February 2002
+ A11 1995


1) 3)
IEC 60268-2 - Sound system equipment HD 483.2 S2 1993
Part 2: Explanation of general terms and
calculation methods


1) 3)
IEC 61606-1 - Audio and audiovisual equipment - Digital EN 61606-1 2004
audio parts - Basic measurement methods of
audio characteristics
Part 1: General


1) 3)
IEC 61606-2 - Audio and audiovisual equipment - Digital EN 61606-2 2004
audio parts - Basic measurement methods of
audio characteristics
Part 2: Consumer use


1) 3)
IEC 61672-1 - Electroacoustics - Sound level meters EN 61672-1 2003
Part 1: Specifications




1)
Undated reference.
2)
The title of HD 472 S1 is: Nominal voltages for low voltage public electricity supply systems.
3)
Valid edition at date of issue.

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SIST EN 61606-4:2007

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SIST EN 61606-4:2007


INTERNATIONAL IEC


STANDARD 61606-4





First edition
2005-12


Audio and audiovisual equipment –
Digital audio parts – Basic measurement
methods of audio characteristics –
Part 4:
Personal computer

 IEC 2005  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale V
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

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SIST EN 61606-4:2007
– 2 – 61606-4  IEC:2005(E)
CONTENTS
FOREWORD.4

1 Scope.6
2 Normative references .6
3 Terms, definitions and abbreviated terms .6
3.1 Terms and definitions .6
3.2 Abbreviated terms .8
3.3 Rated values .8
4 Measuring conditions.8
4.1 Environmental conditions .8
4.2 Power supplies.8
4.3 Test signal frequencies .9
4.4 Standard setting .10
4.5 Working setting .11
4.6 Preconditioning .12
5 Measuring instruments .12
5.1 Analogue signal generator.12
5.2 Analogue in-band level meter .12
5.3 Analogue low-pass filter .12
5.4 Analogue weighting filter .12
5.5 Standard medium .12
5.6 Recording medium .13
5.7 Software for digital data evaluation.13
5.8 Short-term distortion meter.14
5.9 Other instruments.14
6 Methods of measurement (digital-in/analogue-out) .14
6.1 Input/output characteristics .15
6.2 Frequency response.16
6.3 Noise characteristics .17
6.4 Distortion characteristics .21
7 Methods of measurement (analogue-in/digital-out) .23
7.1 Input/output characteristics .23
7.2 Frequency response.25
7.3 Noise characteristics .26
7.4 Distortion characteristics .29


Figure 1 – Block diagram for maximum output amplitude measurement .15
Figure 2 – Block diagram for gain difference between channels measurement .16
Figure 3 – Block diagram for frequency-response measurement .16
Figure 4 – Block diagram for signal-to-noise ratio measurement .17
Figure 5 – Block diagram for dynamic range measurement .18
Figure 6 – Block diagram for channel separation measurement.20
Figure 7 – Block diagram for distortion and noise measurement.21
Figure 8 – Block diagram for short-term distortion measurement.22
Figure 9 – Block diagram for maximum allowable input amplitude measurement .23

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SIST EN 61606-4:2007
61606-4  IEC:2005(E) – 3 –
Figure 10 – Block diagram for gain difference between channel and tracking error
measurement.24
Figure 11 – Block diagram for frequency response measurement.25
Figure 12 – Block diagram for signal-to-noise ratio measurement .26
Figure 13 – Block diagram for dynamic range measurement .27
Figure 14 – Block diagram for channel separation measurement.28
Figure 15 – Block diagram for distortion and noise measurement.29
Figure 16 – Block diagram for short-term distortion measurement.30

Table 1 – Frequencies used in the measurement .9

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SIST EN 61606-4:2007
– 4 – 61606-4  IEC:2005(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________

AUDIO AND AUDIOVISUAL EQUIPMENT –
DIGITAL AUDIO PARTS –
BASIC MEASUREMENT METHODS
OF AUDIO CHARACTERISTICS –

Part 4: Personal computer


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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 61606-4 has been prepared by IEC technical committee 100:
Audio, video and multimedia equipment and systems.
The text of this standard is based on the following documents:
CDV Report on voting
100/952/CDV 100/1030/RVC

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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SIST EN 61606-4:2007
61606-4  IEC:2005(E) – 5 –
IEC 61606 consists of the following parts under the general title Audio and audiovisual
equipment – Digital audio parts – Basic measurement methods of audio characteristics:
Part 1: General
Part 2: Consumer use
1
Part 3: Professional use
Part 4: Personal computer
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
———————
1
Under consideration.

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SIST EN 61606-4:2007
– 6 – 61606-4  IEC:2005(E)
AUDIO AND AUDIOVISUAL EQUIPMENT –
DIGITAL AUDIO PARTS –
BASIC MEASUREMENT METHODS
OF AUDIO CHARACTERISTICS –

Part 4: Personal computer



1 Scope
This part of IEC 61606 specifies the basic measurement methods of a linear PCM signal for
an audio part of personal computers (PCs) and applies to both desktop and portable
computers. The common measuring conditions and methods are described in IEC 61606-1.
Specific conditions and methods of measurement for PCs are given in this standard.
NOTE 1 The methods described are mostly based on sampling frequencies from 8 kHz to 192 kHz and bit length
from 8 bit to 24 bit.
NOTE 2 This standard describes tests for equipment which has digital input with analogue output and analogue
input with digital output. Digital input data are provided from an internal HDD or other memory media and output
digital data are recorded to an internal HDD or main memories.
NOTE 3 The methods specified in this standard are not applicable to systems incorporating bit-rate reduced
digital audio signals that have data loss or to 1-bit signals. This part does not apply to analogue input with
analogue output and digital input with digital output as described in IEC 61606-1.
NOTE 4 When a CPU in a PC is overloaded by tasks other than those for audio input/output, the PC may fail to
record/reproduce the whole audio data. This standard applies only to the measurement in which input/output data
are recorded/reproduced without such missing data. The performance of a PC with missing audio data may be
evaluated by the short-term distortion measurement although such evaluation is not within the scope of this
standard.
2 Normative references
The following referenced documents are indispensable for the application 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 60038, IEC standard voltages
IEC 60268-2, Sound system equipment – Part 2: Explanation of general terms and calculation
methods
IEC 61606-1, Audio and audiovisual equipment – Digital audio parts – Basic measurement
methods of audio characteristics – Part 1: General
IEC 61606-2, Audio and audiovisual equipment – Digital audio parts – Basic measurement
methods of audio characteristics – Part 2: Consumer use
IEC 61672-1, Electroacoustics – Sound level meters – Part 1: Specifications
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61606-1, as well as
the following, apply.

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SIST EN 61606-4:2007
61606-4  IEC:2005(E) – 7 –
3.1.1
personal computer
PC
personal computer which is designed to be used by one person at a time
NOTE 1 A PC does not include optional sound cards or any board or drive installed by the user after purchase.
NOTE 2 A PC may be used by more than one person when it is used with network computers.
3.1.2
standard input signal amplitude
input analogue signal amplitude which corresponds to the digital full-scale level:
– analogue input terminal: 2 V r.m.s.
– microphone terminal: 100 mV r.m.s.
3.1.3
standard output signal amplitude
output analogue signal amplitude which corresponds to the digital full-scale level:
– analogue output terminal: 2 V r.m.s.
NOTE If the EUT cannot output the amplitude of 2 V r.m.s., 1 V r.m.s. may be used for the measurement. In that
case, measured data should be indicated with the measured voltage.
– headphone terminal: maximum output amplitude
3.1.4
normal measuring amplitude
analogue signal amplitude equal to 1/10 of the standard input signal amplitude
3.1.5
normal source impedance
impedance which is connected to the analogue input terminals of the EUT:
– analogue input terminal: 2,2 kΩ
– microphone terminal: 600 Ω
3.1.6
normal load impedance
load impedance which is connected to the output terminals of the EUT:
– load of analogue output terminal: 22 kΩ
– load of headphone terminal: 32 Ω
– load of speaker terminals: 8 Ω or equal to the impedance of internal speakers
3.1.7
factory setting
default setting of EUT as defined by the manufacturer
3.1.8
standard medium
internal storage medium which provides digital test data at the standard setting and should be
a hard disk drive (HDD) working on the EUT
NOTE If the EUT is not equipped with a HDD, another memory medium which is used as a main memory may be
used. In this case, it should be stated with the results.
3.1.9
recording medium
internal data storage medium on which audio playback data are recorded for the analogue-
in/digital-out measurement and should be a hard disk drive (HDD)
NOTE If the EUT is not equipped with a HDD, another memory medium which is used as a main memory may be
used.

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SIST EN 61606-4:2007
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3.1.10
working medium
internal storage medium from which digital test data are provided at the working setting
NOTE This medium should be a main data source when audio signal is played on the EUT, such as a compact
disc (CD).
3.2 Abbreviated terms
EUT equipment under test, which is a PC in this standard
AC alternating current
r.m.s. root-mean square
LPCM linear pulse code modulation
LSB least significant bit

3.3 Rated values
For a full explanation of these terms, see IEC 60268-2. The following are rated conditions for
digital audio equipment which should be specified by the manufacturer:
• rated supply voltage;
• rated supply frequency;
• rated digital input word length;
• rated sampling frequency(ies).
4 Measuring conditions
4.1 Environmental conditions
The following environmental conditions with the indicated tolerances shall be used:
– air pressure: 96 kPa ± 10 kPa
– ambient temperature: 15 °C to 35 °C
– relative humidity: (60 ± 15) %
4.2 Power supplies
An a.c. power supply or a battery shall be used. If a battery is used, it should be stated with
the results.
4.2.1 Supply voltage
Rated a.c. power supply voltage, as specified in IEC 60038, shall be used. The tolerance of
the supply voltage should be ±10 % or less.
4.2.2 Frequency(ies)
AC power supply frequency(ies) specified by the manufacturer shall be used. The tolerance of
the frequency should be +2 %, –4 % or less.
4.2.3 Noises at the power supply output
Noises at the power supply output should be less than the amplitude which affects the result
of measurement.

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SIST EN 61606-4:2007
61606-4  IEC:2005(E) – 9 –
4.2.4 Battery
Only the battery designed for the EUT or built in the EUT shall be used.
4.3 Test signal frequencies
The frequency of the test signal shall be selected from the values in Table 1. In catalogues
and other documents, where precision is not required or implied in the description, it is
permitted to use the nominal values shown in this table. Unless otherwise specified, the
reference frequency for measurements shall be 997 Hz, which may be stated in non-critical
contexts, as 1 kHz.
Table 1 – Frequencies used in the measurement
Dimensions in Hz
Actual frequency
Nominal
f = f = f = f = f = f = f = f = f = f =
s s s s s s s s s s
frequency
8 000 11 025 16 000 22 050 32 000 44 100 48 000 88 200 96 000 192 000
4 4 4 4 4 4 4 4 4 4 4
8 7 7 7 7 7 7 7 7 7 7
16 17 17 17 17 17 17 17 17 17 17
32 31 31 31 31 31 31 31 31 31 31
63 61 61 61 61 61 61 61 61 61 61
125 127 127 127 127 127 127 127 127 127 127
250 251 251 251 251 251 251 251 251 251 251
500 499 499 499 499 499 499 499 499 499 499
1 000 997 997 997 997 997 997 997 997 997 997
2 000 1 999 1 999 1 999 1 999 1 999 1 999 1 999 1 999 1 999 1 999
– – – – – – – – –
3 700 3 677
–
4 000 4 001 4 001 4 001 4 001 4 001 4 001 4 001 4 001 4 001
– – – – – – – –
5 100 5059 5059
– – – – – – – – –
7 400 7 351
– – –
8 000 7 993 7 993 7 993 7 993 7 993 7 993 7 993
– – – –
10 000 10 007 10 007 10 007 10 007 10 007 10 007
– – – – – – – – –
10 100 10 141
– – – – – – –
12 500 12 503 12 503 12 503
– – – – – – –
14 717 14 717
14 700 14 717
– – – – –
16 000 16 001 16 001 16 001 16 001 16 001
– – – – – – – –
18 000 17 987 17 987
– – – – –
20 000 – 19 997 19 997 19 997 19 997
– – – – – – – – –
20 300 20 269
– – – – – – – – –
22 000 22 079
– – – – – – – –
30 000 29 989 29 989
– – – – – – – –
35 000 34 981 34 981
– – – – – – –
40 000 40 429 40 429 40 429
– – – – – – – –
–
44 000 44 159
– – – – – – – – –
50 000 49 999
– – – – – – – – –
70 000 70 001
– – – – – – – – –
80 000 79 999
– – – – – – – – –
88 000 88 301

If a sweep signal is used in the measurement, the sweep frequency range is from 16 Hz to
1/2 × f .
s

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4.4 Standard setting
4.4.1 Standard input condition for the EUT
4.4.1.1 Analogue signal input condition
4.4.1.1.1 Microphone Input
Signal amplitude: normal measuring amplitude
Source impedance: normal source impedance
4.4.1.1.2 Analogue Input
Signal amplitude: normal measuring amplitude
Source impedance: normal source impedance
4.4.1.2 Digital signal Input condition
The test digital signal shall be recorded on the standard medium.
Input signal level: normal measuring level
4.4.2 Standard output condition for the EUT
4.4.2.1 Analogue output condition
4.4.2.1.1 Voltage output and headphone output condition
Signal amplitude: 1/10 of standard output signal amplitude
Load impedance: normal load impedance
4.4.2.1.2 Power output condition
Signal amplitude: 1/10 of maximum output amplitude
Load impedance: normal load impedance
4.4.2.2 Digital output condition
The digital signal that is obtained from an analogue input signal shall be recorded on the
recording medium.
Output signal level: –20 dB
FS
4.4.3 Hardware condition
4.4.3.1 Standard medium setting
To prepare the measurement, test signals shall be recorded on the standard medium. These
recorded signals are used for an input test signal.
The signal format and accuracies are specified in 4.6.1 of IEC 61606-1.
4.4.3.2 Other hardware settings
All settings shall be set according to the factory setting except for the settings, such as
hardware volume control, necessary for certain specific measurements.

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SIST EN 61606-4:2007
61606-4  IEC:2005(E) – 11 –
4.4.4 Software condition
4.4.4.1 Audio playback and recording software
A factory setting software should be used for audio reproduction and recording.
4.4.4.2 Display setting
All settings shall be set according to the factory setting.
Contents displayed on the screen shall be limited to those which are necessary for the
measurement, and other contents (for example, a background picture or video) should not be
displayed.
4.4.4.3 Other software
It is not necessary to activate any other software except for factory setting software if this
exists.
4.4.5 Setting of level controls
4.4.5.1 Analogue-in/digital-out case
4.4.5.1.1 Analogue level control
The analogue level control shall be adjusted so that an input analogue signal of 997 Hz and
the normal measuring amplitude is converted into a digital output level of –20 dB . If the
FS
EUT is not equipped with an analogue level control, the measurement may be performed at
the default gain.
4.4.5.1.2 Digital level control
Level controls provided in the digital domain shall be adjusted to 0 dB.
4.4.5.2 Digital-in/analogue-out case
4.4.5.2.1 Digital level control
Level controls provided in the digital domain shall be adjusted to 0 dB.
4.4.5.2.2 Analogue level control
The analogue level control shall be adjusted so that an input digital signal of 997 Hz and the
normal measuring level is converted into the output of normal measuring amplitude. If the
EUT is not equipped with any analogue level control, the measurement may be performed at
the default gain.
4.5 Working setting
Digital test data sha
...