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EUROPEAN STANDARD EN 62121
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2001
ICS 33.160.30
English version
Methods of measurement for minidisc recorders/players
(IEC 62121:2001)
Méthodes de mesure des appareils Messverfahren für MiniDisc-
de lecture et d'enregistrement pour Recorder/Wiedergabegeräte
les minidisques (IEC 62121:2001)
(CEI 62121:2001)
This European Standard was approved by CENELEC on 2001-12-01. 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 three official versions (English, French, 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and 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
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62121:2001 E
Foreword
The text of document 100B/392/FDIS, future edition 1 of IEC 62121:2001, prepared by IEC TC 100,
Audio, video and multimedia systems and equipment, was submitted to the IEC-CENELEC parallel
vote and was approved by CENELEC as EN 62121 on 2001-12-01.
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) 2002-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2004-12-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A and ZA are normative and annexes B and C are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62121:2001 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 62121:2001
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
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
IEC 60065 (mod) 1998 Audio, video and similar electronic EN 60065 1998
apparatus - Safety requirements +corr. June 1999
IEC 60068-2-27 1987 Basic environmental testing procedures EN 60068-2-27 1993
Part 2: Tests - Test Ea and guidance:
Shock
IEC 60268-13 1998 Sound system equipment --
Part 13: Listening tests on loudspeakers
IEC 60651 1979 Sound level meters EN 60651 1994
IEC 60721-3-5 1997 Classification of environmental EN 60721-3-5 1997
conditions
Part 3: Classification of groups of
environmental parameters and their
severities -- Section 5: Ground vehicle
installations
IEC 60958 1989 Digital audio interface EN 60958 1990
IEC 61606 1997 Audio and audiovisual equipment - EN 61606 1997
Digital audio parts - Basic methods of
measurement of audio characteristics
IEC 61909 2000 Audio recording - Minidisc system EN 61909 2000
ISO 532 1975 Acoustics - Methods for calculating--
loudness levels
ISO 1996 Series Acoustics - Description and --
measurement of environmental noise

Publication Year Title EN/HD Year
1)
ISO 3740 Acoustics - Determination of sound--
power levels of noise sources -
Guidelines for the use of basic
standards and for the preparation of
noise test codes
ISO 3741 1999 Acoustics - Determination of sound EN ISO 3741 1999
power levels of noise sources using
sound pressure - Prescision methods
for reverbation rooms
ISO 3743-1 1994 Acoustics - Determination of sound EN ISO 3743-1 1995
power levels of noise sources using
sound pressure - Engineering methods
for small, movable sources in
reverberant fields
Part 1: Comparison method for hard-
walled test rooms
ISO 3743-2 1994 Part 2: Methods for special EN ISO 3743-2 1996
reverberation test rooms
ISO 3744 1994 Acoustics - Determination of sound EN ISO 3744 1995
power levels of noise sources using
sound pressure - Engineering method in
an essentially free field over a reflecting
plane
ISO 3745 1977 Acoustics - Determination of sound--
power levels of noise sources -
Precision methods for anechoic and
semi-anechoic rooms
1)
ISO 3740:2000 is harmonized as EN ISO 3740:2000.

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Première édition
STANDARD
First edition
2001-10
Méthodes de mesure des appareils de lecture
et d'enregistrement pour les minidisques
Methods of measurement for minidisc
recorders/players
 IEC 2001 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
X
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

62121  IEC:2001 – 3 –
CONTENTS
FOREWORD.7
1 Scope and object.9
2 Normative references .9
3 Terms and definitions .11
4 Information required from manufacturers of MD recorders .13
4.1 Introduction .13
4.2 Identification.15
4.3 Mechanical characteristics .15
4.4 Electrical characteristics.15
4.5 Environmental conditions .15
4.6 Mechanical performance requirements .17
4.7 Electrical performance requirements .17
4.8 Results of measurement.17
5 Measuring conditions.17
5.1 Introduction .17
5.2 Environmental conditions .19
5.3 Power supply.19
5.4 Input conditions.19
5.5 Output condition .19
5.6 MD recorder setting.21
5.7 Other conditions .21
5.8 Test disc .21
5.9 Performance claims.23
5.10 Measuring equipment .23
5.11 Additional considerations.27
6 Measurement of mechanical parameters .27
6.1 Shock and vibration resistance.27
6.2 Acoustic noise.33
7 Measurement of electrical parameters .35
7.1 Maximum power consumption.35
7.2 Frequency response.35
7.3 Signal to noise ratio.37
7.4 Dynamic range .41
7.5 Distortion and noise .41
7.6 Channel separation .43
7.7 Deviation of emphasis characteristic .45
7.8 Modulation distortion .49
7.9 Phase difference between channels .51
7.10 Minimum input level.53
7.11 Output voltage.53
7.12 Pitch deviation.55
7.13 Access times .57
7.14 Trackability.59

62121  IEC:2001 – 5 –
Annex A (normative) Test disc requirements.63
Annex B (informative) Table of measurements – Results .77
Annex C (informative) Available test disc .81
Figure A.1 – Sweep signal .75
Table 1 – Acceleration and duration of pulse .29
Table A.1 – Recording signals of the test disc.67
Table A.2 – Composition of the recording signals.75
Table B.1 – Table of measurements – Results .77

62121  IEC:2001 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METHODS OF MEASUREMENT
FOR MINIDISC RECORDERS/PLAYERS
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62121 has been prepared by IEC technical committee 100: Audio,
video and multimedia systems and equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
100B/392/FDIS 100B/424/RVD
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 3.
Annex A forms an integral part of this standard.
Annexes B and C are for information only.
The committee has decided that the contents of this publication will remain unchanged until
2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
62121  IEC:2001 – 9 –
METHODS OF MEASUREMENT
FOR MINIDISC RECORDERS/PLAYERS
1 Scope and object
This International Standard specifies the measuring methods for recording and reproducing
equipment for MiniDiscs that conform to the specifications of IEC 61909.
NOTE 1 For convenience, this recording and reproducing equipment will be referred to as “MD recorder”
hereinafter. The reproducing part of this equipment or equipment with only a reproducing function will be referred
to as “MD player” throughout the text of this standard. If there is no risk of misunderstanding, the term “MD
recorder” will be generally used.
NOTE 2 This standard does not include specifications for listening tests (see IEC 60268-13).
The object of this standard is to list and define the characteristics affecting the performance of
MiniDisc recorders or players, to establish conditions and methods of measurement of those
characteristics, and to standardize the presentation of the results.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. For dated references, subsequent
amendments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60065:1998, Audio,video and similar electronic apparatus – Safety requirements
IEC 60068-2-27:1987, Environmental testing – Part 2: Test – Test Ea and guidance: Shock
IEC/TR 60268-13:1998, Sound system equipment – Part 13: Listening tests on loudspeakers
IEC 60651:1979, Sound level meters
IEC 60721-3-5:1997, Classification of environmental conditions – Part 3: Classification of
groups of environmental parameters and their services, – Section 5: Ground vehicle
installations
IEC 60958:1989, Digital audio interface
IEC 61606:1997, Audio and audiovisual equipment – Digital audio parts – Basic methods of
measurement of audio characteristics
IEC 61909:2000, Audio recording – MiniDisc System.
ISO 532:1975, Acoustics – Methods for calculating loudness levels

62121  IEC:2001 – 11 –
ISO 1996 (all parts), Acoustics – Description and measurement of environmental noise
ISO 3740:1980, Acoustics – Determination of sound power levels of noise sources –
Guidelines for the use of basic standards and for the preparation of noise test codes
ISO 3741:1999, Acoustics – Determination of sound power levels of noise sources – Precision
methods for broad band sources in reverberation rooms
ISO 3743-1:1994, Acoustics – Determination of sound power levels of noise sources –
Engineering methods for small, movable sources in reverberation fields – Part 1: Comparison
method for hard walled test rooms
ISO 3743-2:1994, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering methods for small, movable sources in reverberant fields – Part
2: Methods for special reverberation test rooms
ISO 3744:1994, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering method in an essentially free field over a reflecting plane.
ISO 3745:1977, Acoustics – Determination of sound power levels of noise sources – Precision
methods for anechoic and semi anechoic rooms
3 Terms and definitions
For the purpose of this International Standard, the terms and definitions given in the relevant
clauses pertaining to measurement (see clauses 6 and 7) and the following definitions apply.
3.1
meaning of the expression “designated xxxxx”
the item or value that is designated by a manufacturer based on the reference item or value
EXAMPLE:
Designated recording level: This is the recording level designated by a manufacturer based
on the reference recording level which is indicated on an
attached level meter
3.2
reference frequency
the value is 1 kHz
3.3
reference recording level
the reference for measurements and corresponds to the average music level
It is equal to –12 dB of the full scale signal level of the MiniDisc (= 0,5 V)

62121  IEC:2001 – 13 –
3.4
maximum recording level
this level is specified as the maximum in the test disc.
It is equal to the full scale signal level of the MiniDisc (= 2,0 V)
3.5
reference source impedance
the impedance designated as the source impedance for the input terminal. An equivalent
resistor should terminate the input terminal as the source impedance during the
measurements
3.6
reference input level
the input level of the reference frequency signal at the input terminal to attain the reference
recording level at a designated attenuation of the recording volume control
3.7
reference load impedance
the impedance designated as the load impedance for the output terminal. An equivalent
resistor should terminate the output terminal as the load impedance during the measurements
3.8
reference output level
the output level at the output terminal that is terminated by the designated load impedance
during the reproduction of the reference recording level signal
3.9
full-scale output level
the output level at the output terminal, terminated by a designated load impedance, during the
reproduction of the maximum recording level signal of the test disc. It corresponds to +12 dB
of the reference or designated output level
3.10
minimum input level
the level of the reference frequency signal at the input terminal to obtain the designated
recording level at the maximum level position of the recording volume control
4 Information required from manufacturers of MD recorders
4.1 Introduction
This information falls into two distinct categories:
a) mandatory information that shall be clearly shown on the MD recorder. The requirements
are indicated by the letter “A” on the right-hand side of the page;
b) optional information which may be given separately, for example, in an instruction manual
relating to and supplied with the MD recorder.
It is essential that mandatory information outside the scope of this standard be given in the
correct location as specified in other relevant standards (for example, for aspects of safety,
see IEC 60065).
62121  IEC:2001 – 15 –
4.2 Identification
4.2.1 Name of manufacturer and/or trade mark A
4.2.2 Model or type and serial number (variants, if any, to be stated) A
4.3 Mechanical characteristics
4.3.1 Dimensions
(inclusive of knobs, connectors and plugs at front and rear sides)
Height mm
Width mm
Depth mm
4.3.2 Total mass kg or g
4.3.3 Special facilities
Operating positions horizontal, vertical or other
System single, multi disc player or recorder,
combination player or recorder, car
portable
Remote control
Programming
4.4 Electrical characteristics
4.4.1 Power supply Volts (V) A
4.4.2 Power frequency Hertz (Hz) A
4.4.3 Power consumption Volt-amperes (VA) for a.c. or W for A
d.c.
4.4.4 Output facilities (digital, analogue, optical or others)
4.5 Environmental conditions
4.5.1 Temperature range
°C
4.5.2 Relative humidity %
4.5.3 Air pressure kPa
62121  IEC:2001 – 17 –
4.6 Mechanical performance requirements
Units For methods of measurement,
see subclauses:
Tolerable shock level m/s 6.1
Tolerable acceleration level m/s 6.1
Maximum acoustic noise dB(A), sones or NR 6.2
4.7 Electrical performance requirements
Units For methods of measurement,
see subclauses:
Maximum power consumption VA for a.c. or W for d.c. 7.1
Frequency response dB 7.2
Signal to noise ratio dB 7.3
Dynamic range dB 7.4
Distortion and noise % 7.5
Channel separation dB 7.6
Emphasis deviation dB 7.7
Modulation distortion % 7.8
Phase difference             ° 7.9
between channels
Minimum input level V 7.10
Output voltage V 7.11
Pitch deviation % 7.12
Access time s 7.13
Trackability mm 7.14
4.8 Results of measurement
The results shall be reported with reference to this standard.
An example is shown in Table B.1.
5 Measuring conditions
5.1 Introduction
To conveniently specify how MD recorders are to be set up for measurement or verification, it
is necessary to define certain conditions under which the measurements shall be made.
Furthermore, these conditions shall be related to specific test discs, specified in annex A.
The following are the basic parameters for the methods of measurement specified in this
standard:
• environmental conditions;
• power supply;
• interface information.
62121  IEC:2001 – 19 –
For the guidance of MD recorder manufacturers, preferred values or ranges are given in
square brackets following each parameter listed bellow:
5.2 Environmental conditions
Ambient temperature
[20 °C ± 2 °C]
Relative humidity [65 % ± 15 %]
Air pressure
[96 kPa ± 10 kPa]
Minimum stabilization time of MD [5 min]
recorder at ambient temperature after
switching on
5.3 Power supply
Type of supply [a.c. or d.c.]
Voltage [within ±1 % of rated value]
Frequency for a.c.
[50 Hz or 60 Hz with a relative tolerance of ±2 %]
Waveform for a.c. [harmonic distortion <2 %]
Waveform for d.c. [ripple <0,1 %]
5.4 Input conditions
5.4.1 Reference frequency
Measuring frequencies for each measurement are selected from:
4 Hz, 8 Hz, 16 Hz, 31,5 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz,
10 kHz, 12,5 kHz, 16 kHz, 18 kHz and 20 kHz.
The reference frequency is 1 kHz unless otherwise specified. 60 Hz and 7 kHz are also used
for the measurement of intermodulation distortion.
The frequency of 400 Hz may also be used for the measurement of trackability.
5.4.2 Reference input level
500 mV r.m.s.
5.4.3 Reference source impedance
Resistor of 1 kΩ with a relative tolerance of ±5 %
5.5 Output condition
5.5.1 Reference load impedance
Resistor of 10 kΩ with a relative tolerance of ±5 %
5.5.2 Reference output level
500 mV r.m.s. on reproducing a test disc that has recorded the reference frequency signal of
the reference recording level.

62121  IEC:2001 – 21 –
The designated output level of the MD recorder is applicable if this value is not attainable.
5.5.3 Digital output (see IEC 60958)
5.6 MD recorder setting
5.6.1 Designated setting for recording
The recording volume control of the MD recorder under test shall be adjusted to attain the
designated recording level on applying the reference frequency signal of the designated input
level to the input terminal.
5.6.2 Designated setting for reproducing
The output volume control of the MD recorder shall be adjusted to obtain the designated
output level at the output terminal, which is terminated by a designated load impedance, on
reproducing a test disc that has recorded the reference frequency signal of the reference
recording level.
5.6.3 Setting of other controls
The emphasis function(s) and the noise reduction function shall be turned-off (inactive) unless
otherwise specified.
5.7 Other conditions
5.7.1 Recording level
The recording shall be made under the specified setting described in 5.6.1. If recording level
adjustment is needed, the applied signal level itself shall be adjusted at the input without
moving the recording volume control.
5.7.2 Condition for silence signal (no signal) recording
The input terminal of the MD recorder to which no signal is applied shall be terminated by a
resistor equivalent to the designated source impedance for the measurement of signal to
noise ratio, etc.
5.7.3 Measured channel
The measurement of the overall characteristics of the recording and reproducing shall be
made for each channel separately.
The input terminal of the channel that is not under measurement shall be terminated by a
resistor equivalent to the designated source impedance.
5.8 Test disc
The test disc used in the measurement shall conform to annex A.
The blank disc used in the measurement shall conform to IEC 61909.
Available test disks are listed in annex C.

62121  IEC:2001 – 23 –
5.9 Performance claims
The performance claims shall be based on the MD recorder operating under the conditions
specified in clause 5. Unless otherwise specified in 5.2 or 5.3 (for example maximum or
minimum value), a tolerance shall be allocated to each parameter.
If the manufacturer claims power supply voltage tolerances exceeding ±1 %, the character-
istics to be specified shall also be stated for the upper and lower limits of these tolerances.
If variations in the frequency of the power supply, within the tolerances specified by the
manufacturer, have any significant influence on the characteristics to be measured, these
characteristics shall also be stated for the upper and lower limits of the claimed frequency
tolerances.
If harmonics in the a.c. power supply or ripple in the d.c. power supply, within the limits
specified by the manufacturer, have any significant influence on the characteristics to be
measured, those characteristics shall also be stated for the upper limit of the claimed
tolerances of harmonic or ripple content.
5.10 Measuring equipment
5.10.1 Voltmeter
This meter shall measure the true root mean square voltage of an a.c. waveform. But an a.c.
voltmeter with the scaling of the root means square value that measures the average value of
the rectified voltage is applicable for the measurements of sinusoidal waveform voltage.
Accuracy
within ±2 % in the frequency range of 4 Hz to 20 kHz
Range
−100 dB(V) to +20 dB(V)
5.10.2 Oscillator
Frequency range 4 Hz to 20 kHz in sinusoidal waveform
Output voltage not smaller than 2 V
Total harmonic distortion less than 0,001 % in the frequency range of 20 Hz to
20 kHz
5.10.3 Low-pass filter
Pass band 4 Hz to 20 kHz within ±0,3 dB
Attenuation more than 60 dB above 24,1 kHz
Input and output impedance
10 kΩ with a relative tolerance of ±5 %
5.10.4 Band-pass filter
Bandwidth
more than ±10 % of centre frequency within 6 dB
attenuation
Attenuation
more than 50 dB outside of ±20 % of centre frequency
Input and output impedance
10 kΩ with a relative tolerance of ±5 %

62121  IEC:2001 – 25 –
5.10.5 Harmonic distortion meter
This meter shall measure residual harmonic and noise components except the fundamental
component.
Indication accuracy
within ±3 %
Minimum measurable value less than 0,001 % (the full-scale is 0,01 %)
Input impedance
more than 100 kΩ
5.10.6 Voltage amplifier
Frequency response flat from 4 Hz to 100 kHz
Amplification about 60 dB
5.10.7 A-weighted filter
This is an audibility compensation filter.
Characteristic defined in IEC 60651
Compensation curve A type
Tolerance type 0
Input and output impedance
10 kΩ with a relative tolerance of ±5 %
5.10.8 Mixed frequency oscillator
This oscillator shall generate a mixed waveform of two sinusoidal signals that are mixed
according to a specified ratio.
Total harmonic distortion of each sinusoidal signal shall be less than 0,001 %.
5.10.9 Intermodulation distortion meter
This meter shall measure the intermodulation distortion of the 7 kHz sinusoidal signal that is
intermodulated by a 60 Hz sinusoidal signal that has 4 times the amplitude of the 7 kHz
signal.
Indication accuracy within ±3 %
5.10.10 Phase difference meter
This meter shall measure the phase difference of sinusoidal signals that have a frequency
range from 20 Hz to 20 kHz within the accuracy of ±1°.
5.10.11 Digital frequency counter
This counter shall be capable of counting the frequency of a 20 kHz sinusoidal signal with an
accuracy of 7 decades.
5.10.12 Spectrum analyzer
Bandwidth at least 200 kHz
Accuracy within ± 20 %
5.10.13 Sound level meter
Type 2 sound level meter (see IEC 60651)

62121  IEC:2001 – 27 –
5.11 Additional considerations
5.11.1 Measuring conditions
Unless otherwise stated in the subclause pertaining to the relevant method of measurement,
the conditions specified in clause 5 shall apply.
All measurements described in 7.2 to 7.14 are carried out at the analogue output of the
equipment.
5.11.2 Use of the test disc
All measurements shall be made using specified test discs recorded without pre-emphasis,
unless otherwise specified in the relevant method of measurement.
5.11.3 Reporting of the results
The person who is doing the testing shall:
a) report any deviations from the parameters specified in clause 5;
b) report the test disc and the measurement instruments used;
c) ensure that, before measurement is started, the measurement instruments have
reached stability.
6 Measurement of mechanical parameters
6.1 Shock and vibration resistance
6.1.1 Definition
The recorder insensitivity to direct or indirect mechanical shocks and vibrations as caused by
the supporting surface in the vertical (z-axis) or in the horizontal direction (x- and y-axes) on
the recorder cabinet.
6.1.2 Shock test
MD recorder
Oscilloscope
with test disc
Mechanical
shock table
+z +y
-x +x
Direction of acceleration
-y -z
IEC  1941/01
62121  IEC:2001 – 29 –
Shock table: according to IEC 60068-2-27
Oscilloscope: input A, LF direct;
input B, LF 90° out of phase with A;
x-deflection via input B
MD recorder: line out, left channel, directly connected to oscilloscope inputs A and B
Test signal: 1 kHz left and right, the maximum or the designated recording level
Table excitation: according to IEC 60068-2-27, Figure 2: D = 3 ms, A = variable
The following table gives an extension of Table 1 of IEC 60068-2-27 with g values applicable
for the MD recorder.
Table 1 – Acceleration and duration of pulse
Peak acceleration Correspoinding duration for Corresponding velocity
the nominal pulse change
A
–3
D
ΔΔV = 2/ππ ×× AD ×× 10
ΔΔ ππ ×× ××
g Equivalent m/s ms m/s
n
1 10 3 0,02
2 20 3 0,04
3 30 3 0,06
4 40 3 0,08
550 3 0,1
660 30 1,0
Method
a) For record mode
1) Place the MD recorder horizontally on the shock table.
2) Feed the test signal to the MD recorder and record it.
3) Apply shocks with increasing severity continuously while recording.
4) At the end of the recording, place the MD recorder horizontally on a stable platform.
5) Playback the recorded signal and observe the circle on the oscilloscope.
6) Set the oscilloscope sensitivity of inputs A and B so that a circle is displayed.
7) Observe the circle during shock test run.
8) The distortion of the circle is a measure of the shock influence.
9) It is also advised to listen for audible effects.
10)The test should be repeated three times in all directions (+/−X, +/−Y, +/−Z) for every
severity level.
62121  IEC:2001 – 31 –
b) For playback mode
1) Place the MD recorder horizontally on the shock table.
2) Play TNO 1 of the test disk or equivalent.
3) Apply shocks with increasing severity and observe the circle on the oscilloscope.
4) Set the oscilloscope sensitivity of inputs A and B so that a circle is displayed.
5) Observe the circle during shock test run.
6) The distortion of the circle is a measure of the shock influence.
7) It is advised to also listen for the audible effect.
8) The test should be repeated three times in all directions (+/−X, +/−Y, +/−Z) for each
severity level.
Result
For each direction, give the lowest severity level (in m/s ) resulting in visible distortion of
the circle for each of record and playback modes.
6.1.3 Vibration test
MD recorder Low-pass Distortion
with test disc filter meter
Mechanical
vibration
table
+z +y
-x +x
Direction of acceleration
-y -z
IEC  1942/01
Test signal: 1 kHz, 0 dB, mono-signal, the maximum or the designated
recording level
Acceleration signal: specified noise according to IEC 60721-3-5, Table VI:
– stationary vibration, sinusoidal: frequency range 9 Hz to 200 Hz;
– stationary vibration, random: frequency range 10 Hz to 200 Hz.
Duration: 1 min
62121  IEC:2001 – 33 –
Method
a) For record mode
1) Place the MD recorder horizontally on the vibration table.
2) Feed the test signal to the MD recorder and record it.
3) Apply vibrations of increasing acceleration intensity continuously while recording.
4) At the end of the recording, place the MD recorder horizontally on a stable
platform. Playback the recorded signal and observe the reproduced audio signal to
the point just before the audio sound reproduction is affected by distortion
variations. This limit indicates the conditions between complete error correction and
the beginning of interpolation.
b) For playback mode
1) Place the MD recorder horizontally on the vibration table.
2) Play TNO 53 of the test disk or equivalent and increase the acceleration intensity
continuously up to the point just before the audio sound reproduction is affected by
distortion variations. This limit indicates the conditions between complete error
correction and the beginning of interpolation.
Result
In addition to the disturbance direction (horizontal or vertical), the type of acceleration
signal, the maximum acceleration amplitude (in m/s , peak-to-peak) and the related
frequency (in Hz) or random noise shall be stated for each of record and playback modes.
6.2 Acoustic noise
Definition
The noise generated by the recorder mechanism during various modes of application.
Such modes are:
– disc loading, unloading, disc change action;
– record;
– search within a track, track search, pause and playback.
Block diagram
MD Sound
recorder level-meter
IEC  1943/01
Method
The measurements should be carried out preferably in an anechoic room in order to
minimize the effect of sound reflected by the wall surfaces. A room with a reverberation
time of less than 1 s for frequencies higher than 100 Hz will lead to nearly the same
results, provided the distance between each measuring point and the next reflecting
surface is at least three times the distance of the same measuring point to the sound
source.
The ambient noise (noise without object under test) shall be at least 10 dB lower than the
sound pressure at the measuring point in each frequency band.
Test room parameters shall conform with ISO 3740, ISO 3741, ISO 3743-1, ISO 3743-2,
ISO 3744 and ISO 3745.
62121  IEC:2001 – 35 –
Procedure
1) Place the recorder on a wooden board of 800 mm × 1 200 mm × 20 mm (depth × width ×
thickness) supported by a thin anti-slip layer.
2) Place the microphone of the sound level meter at a distance of 1 m in front of each side of
the recorder and measure the A-weighted sound pressure level (see IEC 60651).
Add a one-third octave spectrum for at least the measuring point with the highest dB(A)
value. This allows the ear-related value to be calculated (see ISO 532) in order to find the
correct NR curve (see ISO 1996).
3) Insert the test disc(s) in the recorder.
4) Measure the recorder noise level at the stated microphone positions and during the
defined modes of application.
5) Repeat the measurement at least three times and calculate the arithmetic mean value.
Result
The one-third octave sound spectrum at the loudest measuring point at a distance of 1 m
to the recorder surface. The noise level per test mode or at least for the highest average
noise level shall be stated in dB(A), sones or NR (see IEC 60268-13).
7 Measurement of electrical parameters
7.1 Maximum power consumption
Definition
The maximum power that the MD recorder or player can draw from the electric supply
during any operation (see IEC 60065).
Method
Using an ammeter, measure the r.m.s. current (I) taken from the electrical supply when
the MD recorder or player is operating under maximum voltage and load conditions.
Result
Maximum power consumption: I × V .
max
For a.c. supplies, the result is quoted in voltamperes, and for d.c. supplies, it is quoted in
watts.
7.2 Frequency response
Definition
The output level as a function of frequency of any given channel for the reproducing
system and also for the overall (recording and reproducing) system, activated by signals
intended for that channel, in reference to the level at the reference frequency.

62121  IEC:2001 – 37 –
Block diagrams
a) For the reproducing system
Test disc MD player Voltmeter
IEC  1944/01
b) For the overall (recording and reproducing) system
MD
Oscillator Voltmeter
recorder
IEC  1945/01
Test frequencies
4 Hz, 8 Hz, 20 Hz, 31,5 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz,
10 kHz, 12,5 kHz, 16 kHz, 18 kHz and 20 kHz.
Methods
a) For the reproducing system
Play the test disc and reproduce the fixed frequency test signals (from the 3rd to the 19th
track of the test disc) for the frequency response measurement.
The output level deviation from the designated output level of the reference 1 kHz signal
as a function of frequency is plotted.
b) For the overall system
Record the test frequency signals of the designated input level for the frequency response
measurement.
Play this recorded disc and plot the output level deviations from the designated output
level of the reference 1 kHz signal as a function of frequency.
Results
The frequency response of each channel is the maximum deviation, quoted in decibels,
relative to the 1 kHz reference signal. It should be presented as a graph or table for both
the reproducing system and the overall system.
The measurement shall be made for both audio channels.
7.3 Signal to noise ratio
7.3.1 Signal to noise ratio for the reproducing system
Definition
The ratio of the reproduced reference signal of the maximum level to the weighted noise
level when reproducing the digital silence signal (0000)H.
Block diagram
Low-
MD A-weighted
Test disc Voltmeter
pass
player filter
filter
IEC  1946/01
Test frequency
1 kHz
62121  IEC:2001 – 39 –
Method
Reproduce the 1 kHz signal of the maximum recording level (1st track of the test disc).
Note the voltmeter reading A (reference level), in decibels.
Reproduce the digital silence level signal (0000)H (21st track of the test disc).
Note the voltmeter reading B, in decibels.
Result
The A-weighted signal-to-noise ratio of a channel shall be expressed as:
S/N = (A − B) dB
The measurement shall be made for both audio channels.
7.3.2 Signal to noise ratio for the overall system
Definition
The ratio of the reference signal level to the weighted noise level plus 12 dB when
reproducing the signals in a test disc. The reference signal and the silence signal are
recorded successively in the disc.
12 dB is the level difference between the maximum and the reference recording level.
Block diagram
MD Low-pass A-weighted
Oscillator Voltmeter
recorder filter filter
R
IEC  1947/01
NOTE R is a resistor equal to the designated source impedance of the MD recorder.
Test frequency
1 kHz
Method
1) Record the 1 kHz reference signal of the reference recording level for some duration.
Then switch the input terminal from the oscillator to the resistor and continue the recording
operation for no-signal recording.
2) Reproduce the recorded reference signal. Note the voltmeter reading A (reference level),
in decibels.
3) Reproduce the portion of the silence signal (no signal) recorded. Note the voltmeter
reading B, in decibels.
Result
The weighted channel signal-to-noise ratio shall be expressed as:
S/N = (A − B + 12) dB
The measurement shall be made for both audio channels.

62121  IEC:2001 – 41 –
7.4 Dynamic range
Definition
The total signal level of distortion and noise relative to the reproduced reference
frequency signal of maximum recording level.
The measuring signal level should be –60 dB of th
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