EN 61041-3:1995

SLOVENSKI STANDARD
01-april-1999
Non-broadcast videotape recorders - Methods of measurement -- Part 3: Audio
characteristics for FM recording (IEC 61041-3:1993)
Non-broadcast videotape recorders - Methods of measurement -- Part 3: Audio
characteristics for FM recording
Videobandgeräte für den Gebrauch außerhalb des Rundfunks - Meßverfahren -- Teil 3:
Ton-Eigenschaften bei FM-Aufzeignung
Magnétoscopes hors radiodiffusion - Méthodes de mesure -- Partie 3: Caractéristiques
audio pour l'enregistrement MF
Ta slovenski standard je istoveten z: EN 61041-3:1995
ICS:
33.160.40 Video sistemi Video systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME
CEI
INTERNATIONALE IEC
61041-3
INTERNATIONAL
Première édition
STAN
DARD
First edition
1993-12
Magnétoscopes hors radiodiffusion –
Méthodes de mesure
Partie 3:
Caractéristiques
audio pour l'enregistrement MF
Non-broadcast video tape recorders –
Methods of measurement
Part 2:
Audio characteristics for FM recording
© IEC 1993 Droits
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1041-3 ©I EC:1993 - 3 -
CONTENTS
Page
FOREWORD 7
Clause
SECTION 1: GENERAL
1.1 Scope 9
1.2 Normative references 9
1.3 Test conditions 11
SECTION 2: AUDIO CHARACTERISTICS
2.1 Amplitude/frequency response 13
2.2 Signal-to-noise ratio (AGC off) 13
2.3 Signal-to-noise ratio (AGC on) 15
2.4 Dynamic range (AGC off) 17
2.5 Dynamic range (AGC on) 17
2.6 Harmonic distortion 19
2.7 Channel crosstalk 19
2.8 Channel separation 21
2.9 AGC operation and attack/recovery time 25
2.10 Switching noise 25
2.11 Wow and flutter 27
SECTION 3: CALIBRATION TAPE
3.1 General 27
3.2 Magnetic tape 27
3.3 Recording audio signal 27
3.4 Recording video signal 29
3.5 Presentation 31
Figures
1 Circuit arrangement: Amplitude/frequency response 33
2 Circuit arrangement: Signal-to-noise ratio AGC off; Dynamic range 33
3 Circuit arrangement: Signal-to-noise ratio AGC on 35
4 Circuit arrangement: Harmonic distortion 37

1041-3 © IEC:1993 - 5 —
Clause Page
5 Circuit arrangement: Channel crosstalk AGC off; Channel separation ACG off 37
6 Circuit arrangement: Channel crosstalk AGC on; Channel separation AGC on 37
7 Crosstalk of channel L from channel R 39
8 Crosstalk of channel R from channel L 39
9 Circuit arrangement: AGC operation; Hold time 41
10 Gain curve (out/in response) 41
11 Test signal for attack/recovery time measurement 43
12 Output signal (attack transient) 43
13 Circuit arrangement: Switching noise 45
14 Low-pass filter characteristics 45
15 Input level and audio FM
deviation (modulation) depth for various VTR systems 47
Annex A - Bibliography 49
1041-3 © IEC:1993 - 7 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
NON-BROADCAST VIDEOTAPE RECORDERS -
METHODS OF MEASUREMENT -
Part 3: Audio characteristics for
FM recording
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 cooperation 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, 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.
3) They have the form of recommendations for international use published in the form of standards, 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.
International Standard IEC 1041-3 has been prepared by sub-committee 60B: Video
recording, of IEC technical committee 60: Recording.
The text of this standard is based on the following documents:
DIS Report on voting Amendment to DIS Report on voting
60B(CO)128 60B(CO)141A 60B(CO)145 60B(CO)153
Full information on the voting for the approval of this standard can be found in the reports
on voting indicated in the above table.

1041-3 © IEC:1993 -9-
NON-BROADCAST VIDEOTAPE RECORDERS -
METHODS OF MEASUREMENT -
Part 3: Audio characteristics for
FM recording
Section 1: General
1.1 Scope
This part of IEC 1041 concerns the measurement of overall characteristics of the FM audio
recorded using slanted tracks similar to those used for recording of the video information.
The main characteristics of such a recording system are: two channels, high fidelity and
the use of companders for noise reduction.
1.2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this pa rt of IEC 1041. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this pa rt of IEC 1041 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. Members
of IEC and ISO maintain registers of currently valid International Standards.
IEC 94-3: 1979, Magnetic tape sound recording and reproducing systems - Part 3:
Methods of measuring the characteristics of recording and reproducing equipment for
sound on magnetic tape
Amendment No. 2 (1988)
IEC 268-1: 1985, Sound system equipment - Part 1: General
IEC 268-3: 1988,
Sound system equipment - Part 3: Amplifiers
IEC 268-8: 1973, Sound system equipment - Part 8: Automatic gain control devices
IEC 386: 1972, Method of measurement of speed fluctuations in sound recording and
reproducing equipment
IEC 574-4: 1982, 4:
Audio-visual, video and television equipment and systems - Pa rt
Preferred matching values for the interconnection of equipment in a system
IEC 843: 1987, Helical-scan video tape cassette system using 8 mm magnetic tape -
Video 8
1041-3 ©I EC:1993 - 11 -
IEC 1053-1: 1991,
Helical-scan video tape cassette system using 12,65 mm (0,5 in)
magnetic tape on type beta format - FM audio recording - Pa rt 1: 625 lines - 50 field
systems
IEC 1053-2: 1991,
Helical-scan video tape cassette system using 12,65 mm (0,5 in)
magnetic tape on type beta format - FM audio recording - Pa
rt 2: 525 lines - 60 field
systems
IEC 1054: 1991,
Helical-scan video tape cassette system using 12,65 mm (0,5 in)
magnetic tape on type VHS - FM audio recording
1.3 Test conditions
1.3.1 The FM audio signal and the video FM signal shall be recorded simultaneously.
1.3.2 The video signal applied to the videotape recorder shall be a 100/0/75/0 colour
bars one with an amplitude of 1 Vpp.
1.3.3 For the determination of the reference input level a specified calibration tape
(see 3.1) is required, a section on which a sine wave of 400 Hz is recorded using a
frequency deviation as defined in the relevant standard for the VTR system to which the
equipment under test belongs (see note below). The reference recording frequency
deviation shall be determined by the following procedures.
1.3.3.1 If adjustable record gain controls are provided on the equipment, they shall be
adjusted at preset middle position. The input level applied to the VTR shall be adjusted so
that the output voltages Vo
derived from recording and reproducing are the same as the
output voltages Vc derived from reproducing a section of the specified calibration tape
described above.
1.3.3.2 If adjustable record gain controls are not provided on the equipment, the input
level shall be adjusted so that the output voltages Vo derived from recording and
reproducing are the same as the output voltages VV derived from reproducing a section of
the specified calibration tape described above.
1.3.4 The peak recording level corresponds to 100 % modulation depth (frequency
deviation according to the relevant specification).
1.3.5 The input level required for the 0 VU indication is different for each VTR system.
1.3.6 The audio characteristics shall be measured at each tape speed specified for the
VTR under test.
NOTE – The reference input level corresponds to the following modulation depth:
• 33 % for beta and VHS systems according to IEC 1053-1, 1053-2 and 1054.
• 60 % for 8 mm video system according to IEC
843.
Figure
15 shows the above-mentioned parameters in comparison.

1041-3 ©I EC :1993 – 13 -
Section 2: Audio characteristics
2.1 Amplitude/frequency response
2.1.1 This measurement determines the maximum deviation of overall characteristics
from flat response within a specified frequency range.
2.1.2 The circuit arrangement shall be as shown in figure 1.
2.1.3 The test signal shall be a sine wave of 1 000 Hz with a superimposed sine-wave
sweep covering the frequency range from 20 Hz to 20 kHz.
The input level of the 1 000 Hz sine wave applied to the VTR shall be the reference input
level as defined in 1.3.3.1 and 1.3.3.2.
The input level of the sine-wave sweep to the VTR shall be 20 dB below the 1 000 Hz
sine-wave input level.
2.1.4 The output playback signal shall be measured by a spectrum analyser disregarding
the 1 000 Hz spectral component.
2.1.5 The amplitude/frequency response within the frequency range of 20 Hz to 20 kHz
shall be calculated with respect to the amplitude of 400 Hz.
2.1.6 The presentation of the results, that is the maximum positive and negative
differences from the response at 400 Hz, shall be reported in dB for channel L and
channel R respectively.
Preferably these ratios are to be presented graphically as a function of frequency
[see 21.1.2 5) of IEC 268-3].
2.2 Signal-to-noise ratio (AGC off)
2.2.1 This measurement determines the ratio of the output level at playback of an audio
signal recorded at reference recording level, to the output noise level at playback of a
recording without input signal.
2.2.2 The circuit arrangement shall be as shown in figure 2.
2.2.3 Two recordings shall be made under the following conditions:
1) The test signal shall be a sine wave of 400 Hz.
The input level applied to the VTR shall be the reference input level as defined
in 1.3.3.1.
2) No audio signal shall be applied to the VTR.
S2.
The audio input of the VTR shall be terminated by a shielded resistor of 600
The adjustable record control shall be in the same position as determined above
in 2.2.3 1).
1041-3 ©IEC:1993 – 15 –
2.2.4 The output playback level V0 shall be measured by a true r.m.s. meter according
to 6.2.1 of IEC 268-1.
For the noise measurement (Vn) the meter shall be preceded by a filter having A weighting
characteristics with tolerance type 1 according to IEC 268-1, appendix A.
The signal-to-noise ratio S/N shall be the ratio of the output level V 0 at playback of
recording according to 2.2.3 1) to the output noise level Vn at playback of recording
according to 2.2.3 2).
Vo
S/N = 20 Ig (dB)
Vn
2.2.5 The presentation of the results, that is the signal-to-noise ratio, shall be reported in
dB for both channel L and R respectively.
2.3 Signal-to-noise ratio (AGC on)
2.3.1 This measurement determines the ratio of the output level at playback of an audio
signal recorded at the reference recording level, to the output noise level at playback of
recording without input signal, when the tested VTR has no facility to switch off the AGC.
2.3.2 The circuit arrangement shall be as shown in figure 3.
2.3.3 A recording shall be made under the following conditions:
• The test signal shall be a burst sine wave of 400 Hz.
• The duration t 1 of the gate pulse (figure 3b) shall be equal to the hold time
previously measured (see 2.9).
• The input level V1 (figure 3a) applied to the VTR shall be the reference input level
as defined in 1.3.3.2.
2.3.4 The peak-to-peak output playback level V shall be measured by an oscilloscope.
n
• The r.m.s. noise level V (figure 3e) shall be measured by a true r.m.s. meter
according to IEC 268-1 through a filter having A weighting characteristics with
tolerance type 1 according to. IEC 268-1.
• The signal-to-noise ratio S/N shall be the ratio of the output level V 0 (figure 3c) to
the noise level VnT at playback of a recording according to 2.3.3.
V0
S/N = (20 Ig 9 (dB)
VnT
where Vn T = Vn x
1041-3 ©I EC:1993 – 17 –
2.3.5 The presentation of results, that is the signal-to-noise ratio, shall be reported in
decibels for both channels L and R respectively.
2.4 Dynamic range (AGC off)
2.4.1 This measurement determines the ratio of the maximum output level to the output
noise level of a recording made without input signal. The maximum output level is reached
at a total harmonic distortion of 3 %.
2.4.2 The circuit arrangement shall be as shown in figure 2.
2.4.3 Two recordings shall be made under the following conditions:
1)
The test signal shall be a sine wave of 400 Hz.
The input level applied to the VTR shall be increased by equal steps from the reference
input level to that which provides a total harmonic distortion of 3 % in the playback
output signal Vm.
The reference input level is defined in 1.3.3.1.
2) No audio signal shall be applied to the VTR. The audio input of the VTR shall be
terminated by a shielded resistor of 600 U.
The adjustable record gain controls shall be in the same position as determined
in 1.3.3.1.
2.4.4 The output playback level Vm shall be measured by the same r.m.s. meter as
mentioned in 2.2.4.
2.4.5 The dynamic range DR shall be defined as the ratio of the output level Vm at
playback of the recording according to 2.4.3 1) to the noise level Vn at playback of the
recording according to 2.4.3 2). Vn is derived from the measurement made in clause 2.2.
V
m
DR = 20 Ig  (dB)
V
n
2.4.6 The presentation of results, that is the dynamic range, shall be reported in decibels
for both channels L and R respectively.
2.5 Dynamic range (AGC on)
The dynamic range is the difference between the peak programme output level and the
weighted noise output level.
In case of non-switchable AGC and noise reduction system it is difficult to measure the
value of the dynamic range by using a quasi-static test signal.
An appropriate test method is still under investigation and will be implemented later.

1041-3 ©I EC:1993 –19 –
2.6 Harmonic distortion
2.6.1 This measurement determines the total harmonic distortion using the reference
recording level.
2.6.2 The circuit arrangement shall be as shown in figure 4.
2.6.3 The test signal sh
...