IEC 62121 pdf download Methods of measurement for minidisc recorders/players
1 scope and object
This International Standard specifies the measuring methods for recording and reproducingequipment for MiniDiscs that conform to the specifications of lEC 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 referredto as “MD player”throughout the text of this standard. lf there is no risk of misunderstanding, the term “MDrecorder” 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 ofMiniDisc recorders or players, to establish conditions and methods of measurement of thosecharacteristics, and to standardize the presentation of the results.
The following normative documents contain provisions which,through reference in this text,constitute provisions of this International Standard. For dated references,subsequentamendments to,or revisions of,any of these publications do not apply. However，parties toagreements based on this International Standard are encouraged to investigate the possibilityof applying the most recent editions of the normative documents indicated below.For undatedreferences, the latest edition of the normative document referred to applies. Members of lECand lSo 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 loudspeakerslEC 60651:1979,sound level meters
IEC 60721-3-5:1997，Classification of environmental conditions – Part 3: Classification ofgroups of environmental parameters and their services,- Section 5: Ground vehicleinstallations
lEC 60958:1989,Digital audio interface
IEC 61606:1997，Audio and audiovisual equipment – Digital audio parts – Basic methods ofmeasurement of audio characteristics
IEC 61909:2000,Audio recording – MiniDisc System.
ISO 532:1975,Acoustics – Methods for calculating loudness levels
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 – Precisionmethods 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: Comparisonmethod for hard walled test rooms
ISO 3743-2:1994，Acoustics – Determination of sound power levels of noise sources usingsound pressure – Engineering methods for small, movable sources in reverberant fields – Part2: Methods for special reverberation test rooms
ISO 3744:1994，Acoustics – Determination of sound power levels of noise sources usingsound pressure – Engineering method in an essentially free field over a reflecting plane.
ISO 3745:1977,Acoustics -Determination of sound power levels of noise sources – Precisionmethods for anechoic and semi anechoic rooms
3Terms and definitions
For the purpose of this International Standard, the terms and definitions given in the relevantclauses pertaining to measurement (see clauses 6 and 7) and the following definitions apply.
meaning of the expression “designated xxXXX”
the item or value that is designated by a manufacturer based on the reference item or valueEXAMPLE:
Designated recording level: This is the recording level designated by a manufacturer based
on the reference recording level which is indicated on anattached level meter
reference frequencythe value is 1 kHz
reference recording level
the reference for measurements and corresponds to the average music levellt is equal to -12 dB of the full scale signal level of the MiniDisc (= 0,5 V)