SIST EN 61041-1:1999

SLOVENSKI STANDARD
01-april-1999
Non-broadcast video tape recorders - Methods of measurement -- Part 1: General
video (NTSC/PAL) and audio (longitudinal) characteristics (IEC 61041-1:1990)
Non-broadcast video tape recorders - Methods of measurement -- Part 1: General video
(NTSC/PAL) and audio (longitudinal) characteristics
Videobandgeräte für den Gebrauch außerhalb des Rundfunks - Meßverfahren -- Teil 1:
Allgemeine Eigenschaften von Video (NTSC/PAL) und Ton (Längsaufzeichnung)
Magnétoscopes hors radiodiffusion - Méthodes de mesure -- Partie 1: Généralités,
caractéristiques vidéo (NTSC/PAL) et audio (enregistrement longitudinal)
Ta slovenski standard je istoveten z: EN 61041-1:1995
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
61041-1
INTERNATIONAL
Première édition
STANDARD
First edition
1990-1%
Magnétoscopes hors radiodiffusion –
Méthodes de mesure
Partie 1:
Généralités, caractéristiques vidéo
(NTSC/PAL)
et audio
(enregistrement longitudinal)
Non-broadcast video tape recorders –
Methods of measurement
Part 1:
General video (NTSC/PAL) and
audio (longitudinal) characteristics
© IEC 1990 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
any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo-
including photocopying and microfilm, without permission in
copie et les microfilms, sans raccord 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
V
PRICE CODE
International Electrotechnical Commission
IEC
Me)RgyHaoogHaR 3neKTpoTexHNVectiaR HOMHCCHR
Pour prix, voir vigueur
catalogue en
• •
For price, see current catalogue

1041-1 ©IEC - 3 -
CONTENTS
Page
FOREWORD 7
Clause
SECTION 1 - GENERAL
1.1 Scope 9
1.2 Normative references 9
1.3 Environment 11
1.4 Magnetic tape 11
1.5 rf
Pe ormance of measurements 11
1.6 Interchangeability test 13
SECTION 2 - VIDEO CHARACTERISTICS, LUMINANCE
2.1 Video test signal - General 13
2.2 AGC operation 13
2.3 Luminance amplitude/frequency response 15
2.4 Luminance non-linear distortion 17
2.5 Luminance
waveform distortion (linear distortion) 19
2.6 Luminance transient tearing 19
2.7 Luminance signal-to-noise ratio 21
2.8 Luminance drop-out compensa on 23
ti
SECTION 3 - VIDEO CHARACTERISTICS,
CHROMINANCE (PAUNTSC)
3.1 Chrominance amplitude/frequency response 27
3.2 Chrominance
signal-to-noise ratio 27
3.3 Chrominance
-to-luminance intermodulation 27
3.4 Luminance-to-chrominance crosstalk 29
3.5 Chrominan
ce-to-luminance displacement 31
3.6 Chrominance
-to-luminance crosstalk 33
SECTION 4 - TIME BASE
4.1 Time base
SECTION 5 - AUDIO CHARACTERISTICS, LONGITUDINAL RECORDING
5.1 Audio test signal - General 33
5.2 AGC operation 35
5.3 Audio characteristics 35

1041-1 ©IEC - 5 -
Figure
Page
1 Video test signal: nominal values, ho rizontal line 37
2 Video test signal: vertical field 37
3 Circuit arrangement (clauses 2.2, 2.3, 2.4, 2.5, 3.1, 3.5) 39
4 Test signal for luminance amplitude/frequency response 39
5 Test signal for luminance non-linear distortion (10 steps) 41
6 Test signal for luminance waveform of linear distortion 41
7 Luminance waveform distortion (linear distortion) 43
8 Circuit arrangement: luminance signal-to-noise ratio 45
9 Test signal for luminance signal-to-noise ra tio 45
10 Circuit arrangement: luminance drop-out compensa
tion 47
11 Test signal for luminance drop-out compensation 47-51
12 Test signal for chrominance
amplitude/frequency response 53
13 Circuit arrangement: chrominance
-to-luminance intermodulation 53
14 Test signal for chrominance
-to-luminance intermodulation 53
15 Circuit arrangement: luminance-to-chrominance crosstalk 55
16 Test signal for luminance-to-chrominance crosstalk 55-57
17 Test signal for chrominance-to-luminance displacement 57-59
18 Circuit arrangement: chrominance-to-luminance crosstalk 61
19 Audio test signal level as a function of time 61
20 Circuit arrangement: determination of 0 dB level and of hold time 63
21 Audio amplitude response: determination of 0 dB level 63
22 Audio test signal: determination of hold time 63
23 Audio playback signal: determination of hold time 63
Annex A (normative) - Alte
rnative test signals 65
1041-1 ©IEC - 7 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
NON-BROADCAST VIDEO TAPE RECORDERS -
METHODS OF MEASUREMENT
/PAL)
Part 1: General video (NTSC and audio
(longitudinal) characteristics
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 standard has been prepared by Sub-Committee 60B: Video recording, of IEC Techni-
cal Committee No. 60: Recording.
This is a Part 1 of a series of publications dealing with methods of measurement for non-
broadcast video tape recorders. Other pa rts for video (SECAM) and audio (FM) are under
consideration.
The text of this standard is based on the following documents:
Six Months' Rule Report on Voting
80B(CO)95 80B(CO)110
Full information on the voting for the approval of this standard can be found in the Voting
Report
indicated in the above table.
This part of the standard contains one annex, which is normative.

1041-1 © IEC - 9 -
NON-BROADCAST VIDEO TAPE RECORDERS -
METHODS OF MEASUREMENT
Part 1: General video (NTSC/PAL) and audio
(longitudinal) characteristics
SECTION 1 - GENERAL
1.1 Scope
The methods of measurement described in this International Standard concern the assess-
ormance of non-broadcast video tape recorders of the so-called "colour
ment of the perf
under" type for domestic use.
This standard defines test signals, measurement set-ups and measurement conditions for
non-broadcast video tape recorders of the so-called "colour under" type for domestic use,
so as to make possible the comparison of the results of measurements.
Specifying limiting values of the various quantities for acceptable pe rformance is not an
object of this standard.
The methods of measurement are designed to make possible the assessment of the
performance of the complete recorder by using the input/output terminals of the device.
NOTE - Measuring methods for consumer camcorders (camera-recorders). are under consideration.
1.2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this part of IEC 1041. At the time of publication, the editions indicated were
valid. All standards 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 standards indicated below. Members of IEC and ISO maintain registers of currently
valid International Standards.
1.2.1 IEC 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 386: 1972, Method of measurement of speed fluctuations in sound recording and
reproducing equipment.
IEC 756: 1983, Time base stability of non-broadcast video recorders.
IEC 883: 1987, Measuring method for chrominance signal-to-random noise ratio for video
tape recorders.
- 11 -
1041-1 ©IEC
1.2.2 Other standards quoted
CCIR Recommendation 471, Nomenclature and description of colour bar signals.
Transmission performance of television circuits designed for
CCIR Recommendation 567,
use in international connections.
Definitions of parameters for simplified automatic measure-
CCIR Recommendation 569,
ment of television Insertion test signals.
CCIR Repo Colorimetric standards in colour television.
rt 476,
1.3 Environment
All measurements shall be carried out within the environmental conditions specified by the
manufacturer.
If not otherwise stated by the manufacturer or by the format-standard, the device under
test shall be conditioned for at least three hours before measurement begins. In addition,
an adequate warm-up time shall be used.
The environmental conditions during measurement, at least the temperature and the
relative humidity, shall be reported together with the presentation of the results of
measurements.
1.4 Magnetic tape
The type of magnetic tape used for measurements shall be commonly available and repor-
ted together with the presentation of the results of measurements.
NOTE - By "commonly available" is to be understood the type of magnetic tape recommended by the
manufacturer of the unit being tested.
1.5 Performance of measurements
Unless otherwise stated the measurements shall be carried out by measuring the playback
signal immediately after recording on the same device.
The method of input and output of the signals, i.é. baseband or modulated RF, shall be
reported together with the presentation of the results of measurement.
It is recommended to use baseband input and output of the signals, i.e. via video/audio -
input/output terminals if available. If a modulated RF signal is used for input or output, the
type of modulator or demodulator shall be reported.
If the video tape recorder under test is equipped with external manual controls, e.g.
tracking control, sharpness control, etc., these controls shall be set at mid-position for all
measurements unless otherwise stated.

1041-1 © IEC -13 -
1.6 Interchangeability test
The interchangeability within the IEC standard concerning the device under test shall be
confirmed, i.e. the characteristics of the signals recorded on tape and the track pa ttern
shall comply with the standard.
The procedure is under consideration.
SECTION 2 - VIDEO CHARACTERISTICS, LUMINANCE
2.1 Video test signal - General
Unless otherwise stated the characteristics of the synchronizing signal and the character-
signal shall be in accordance with the CCIR television standard
istics of the chrominance
relevant to the recorder under test.
The nominal value of the peak-to-peak amplitude of the composite video signal, i.e. from
sync tip to white level, shall be 1,0 V.
The nominal value of the amplitude of the picture signal, i.e. from blanking level to white
level, shall be:
0,7 V for 625 lines/50 Hz systems;
0,714 V for 525 lines/60 Hz systems.
The nominal value of the amplitude of the picture signal shall be regarded as 100 % when
defining signal amplitudes in percent (see figure 1).
Unless otherwise stated all test signals shall include in each field at least eight lines of
100 % white in order to ensure correct operation of the automatic gain control. These lines
shall be located at the end of the vertical blanking area (see figure 2 and note below).
The active field period shall contain the specific picture test signal for measurement of the
video characteristics.
Unless otherwise stated the test signal shall be identical in each horizontal line of the ac-
tive field period, i.e. regarding amplitude, frequency, phase, timing, etc.
Unless otherwise stated the rise time and the fall time of the test signal shall be not less
than 2T.
NOTE - Alternative test signals using white reference in each line are shown in annex A (figures A.1, A.2,
A.3 and A.4). See also CCIR Recommendations 471-1 and 569-2, and Report 476-1.
2.2 AGC operation
2.2.1 This measurement determines the reaction of the automatic gain control to
deviations of the amplitude of the input signal from the nominal value.
2.2.2 The circuit arrangement shall be as shown in figure 3.

1041-1 ©IEC - 15 -
2.2.3 The test signal shall be a monochrome staircase signal without a chrominance
burst as shown in figure 5.
The following test signals shall be used sequentially:
a) the amplitude of the test signal from sync tip to white shall be changed by ±6 dB
while the ratio of the amplitude of the synchronizing signal to the amplitude of the
picture signal shall be nominal;
b) the amplitude of the synchronizing signal shall be changed by ±6 dB while the ampli-
tude of the picture signal shall be nominal;
the amplitude of the picture signal shall be changed by ±6 dB while the amplitude of
c)
the synchronizing signal shall be nominal.
2.2.4 The output signal shall be measured on an oscilloscope. The measurements shall
be made for each condition a), b), c) in 2.2.3.
The deviation of the following signal levels from the corresponding nominal signal levels
during playback shall be measured as a percentage of the nominal levels:
the amplitude of the output signal from sync tip to white;
1)
2) the amplitude of the synchronizing signal.
2.2.5 The results of measurement shall be reported in a table as shown hereafter:
Variation (%
Parameter
a b c
Amplitude of output signal from sync tip
+/- +/- +/-
to white
+/-
Amplitude of synchronizing signal +/- + / -
2.3 Luminance amplitude/frequency response
2.3.1 This measurement determines the amplitude/frequency response of the luminance
channel, i.e. the amplitude of the output signal relative to a reference level as a function of
frequency.
2.3.2 The circuit arrangement shall be as shown in figure 3.
2.3.3 The test signal shall be a sine-wave multiburst signal with or without a chrominance
burst according to figure 4 (see note to clause 2.1).
The chrominance burst shall be switched off if the multiburst signal of the playback signal
is affected by the activated chrominance
channel of the device under test.

- 17 -
1041-1 ©IEC
The reduced amplitude of the multiburst signal is essential because of pre-emphasis and
clipping circuits in use.
Signals having amplitudes greater than those of the frequency bursts shall therefore not
be used.
2.3.4 The output signal shall be measured on an oscilloscope.
be 40 % of the amplitude of the 100 % white output
The reference level V shall
ref (a)
ing level to white level.
picture signal, i.e. from blank
The peak-to-peak amplitude V of each frequency burst of the output signal shall be
related to the reference level V to obtain the amplitude/frequency response A:
ref(a)
VP_P
A (dB) = 20 Ig
Vref (a)
The method of defining the amplitude/frequency response by stating the resolution of a
certain number of horizontal lines shall not be used.
2.3.5 The results of measurement shall be reported in a table showing the frequency in
MHz and
A in dB.
2.4 Luminance non-linear distortion
2.4.1 This measurement determines the non-linear distortion of the luminance channel,
i.e. the deviation of grey levels between blanking level and white level of the output picture
signal in relation to the grey levels of the input picture signal.
2.4.2 The circuit arrangement shall be as shown in figure 3.
2.4.3 The test signal shall be a monochrome staircase signal of 5 to 10 steps without a
chrominance burst according to figure 5.
The nominal amplitude of the steps shall be 100 %/no where no is the maximum number of
steps.
The grey level of the nth step of the test signal shall be:
Vtn
= (n x100±2)%
Vtn
2.4.4 The output signal shall be measured on an oscilloscope.
The reference level V
shall be the amplitude of the 100 % white output picture signal,
ref (b)
i.e. from blanking level to white level.

1041-1 ©IEC -19 -
on of the nth step of the output signal, i.e. from blanking level to the nth
The amplitude V
V
grey level, shall be measured as a percentage of the reference level
ret (b)
The non-linear distortion of the luminance channel shall be calculated as the percentage
NL (n) of the deviation of the nth output grey level Von from the nth test signal grey
level
Vtn:
NL (n) = Von - Vtn (percent)
2.4.5 The results of measurement shall be given in a table showing the number n of the
step and the percentage NL (n) of the deviation.
2.5 Luminance waveform distortion (linear distortion)
2.5.1 This measurement determines the distortion of a bar and of a 2T pulse caused by
the luminance channel.
2.5.2 The circuit arrangement shall be as shown in figure 3.
2.5.3 The test signal shall be in accordance with figure 6 (see note to clause 2.1). The
following two conditions of the test signal shall be used:
a) the amplitude of the bar and the 2T pulse shall be 50 %;
the amplitude of the bar and the 2T pulse shall be 100 %.
b)
2.5.4 The output signal shall be measured on an oscilloscope.
The waveform distortions shall be calculated as shown in figures 7.1 to 7.4.
2.5.5 The results of measurement shall be listed in the order given by figures 7.1 to 7.4
for the two test signal conditions described in 2.5.3.
2.6 Luminance transient tearing
2.6.1 High-amplitude transients with small rise times may cause malfunctioning of the
FM-demodulator causing incorrect levels of the output signal, e.g. black or white stripes.
2.6.2 The circuit arrangement is under consideration.
2.6.3 The test signal shall be a square-wave signal having an amplitude of 100 % and a
rise/fall time of T. The frequency shall be in the range from 200 kHz to 250 kHz.
2.6.4 The measurement of transient tearing is under consideration.
2.6.5 The presentation of the results of measurement is under consideration.

1041 -1 ©IEC - 21 -
2.7 Luminance signal-to-noise ratio
2.7.1 This measurement determines the noise behaviour of the luminance channel. The
influence of the chrominance channel is determined by measuring with and without
chrominance burst.
2.7.2 The circuit arrangement shall be as shown in figure 8.
2.7.3 The test signal shall be a black and white signal according to figure 9 (see note to
clause 2.1). The following two conditions of the test signal shall be used:
a) test signal without chrominance burst;
b) test signal with chrominance burst.
2.7.4 The noise superimposed on the 50 % grey level of the output signal shall be
measured by a noise meter having the following characteristics:
The noise meter shall have a gating function in order to guarantee noise measurement in
the flat po ion of the 50 % grey level.
rt
The measuring instrument shall be preceded by the following band-limiting filters:
a) low-pass filter according to CCIR Recommendation 567, annex II, with:
fc
= 5 MHz for 625 lines/50 Hz systems;
fc = 4,2 MHz for 525 lines/60 Hz systems, recalculated from CCIR Recommen-
dation;
b) high-pass filter according to CCIR Recommendation 567, annex Ill, with
fc = 100 kHz;
c) chrominance sub-carrier notch filter;
d) weighting network according to CCIR Recommendation 567, annex 11, switchable
on/off.
The meter shall read the r.m.s. value, Vrms , of the noise.
The reference level V shall be the amplitude of the 100 % white output picture signal,
ref (c)
i.e. from blanking level to white level.
The signal-to-noise ratio S/N is defined as:
Vref (c)
S/N (dB) = 20 Ig
Vrms
2.7.5 The results of measurement, i.e. the unweighted and weighted values of S/N (dB),
shall be stated for the test signals as defined in items a) and b) of 2.7.3.

1041-1 ©1EC - 23 -
2.8 Luminance drop-out compensation
2.8.1 Drop-outs are mainly caused by particles on the su rface of the tape increasing the
distance between head and tape, which results in a decrease of the output voltage of the
reading head.
This measurement determines the ability of the luminance playback channel of the VTR to
compensate for drop-out.
2.8.2 The circuit arrangement shall be as shown in figure 10.
2.8.3 The test signal shall be derived from a special prerecorded test tape.
The artificial drop-outs shall be achieved by reduction of the recording current during
cert
ain time periods. The rise/fall time of the envelope of the recording current shall be
approximately 2µs.
The
recording current shall be the optimum recording current except for
the drop-out periods.
Two kinds of test signal are required for the following measurements:
a)
Measurement of drop-out compensation level and switching noise
The test signal shall be a 50 % white level. In a ce
rtain number of non-successive lines
a black information shall be inserted according to figure 11a.
During a period of 20 ps symmetrical to the black information the recording current
shall be reduced to achieve a reduced output voltage from the playback head. The
number of special lines shall be at least three.
The output voltage of the playback head during the drop-out period compared with the
output voltage during periods of optimum current recording shall be:
10 dB in the first special line;
20 dB in the second special line;
30 dB in the third special line.
b)
Measurement of frequency characteristic and time behaviour
The test signal (figure 11b) shall be a 50 % white level superimposed with a sine-wave
having a peak-to-peak amplitude of 40 %.
The frequency of the sine wave shall be 0,5 MHz in the first half of the active line
period and 2,0 MHz in the second half.
In ten successive lines the recording current shall be suppressed by more than 26 dB
over a period of 20 ps symmetrical to the point of switching from 0,5 MHz to 2,0 MHz
(see figure 11b).
Both test signals a) and b) described above may be combined in an active field period. An
example is given in figure 11c.

-----------------
...