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---------------------- Page: 1 ----------------------
NORME CEI
INTERNATIONALE IEC
60883
INTERNATIONAL
Première édition
STAN DARD
First edition
1987-04
Méthode de
mesure du rapport signal à bruit
aléatoire de chrominance pour
magnétoscopes
Measuring method for chrominance
signal-to-random noise ratio for
video tape recorders
© IEC 1987 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 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: [email protected] IEC web site http: //
CODE PRIX Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
IEC MelcayHapoaHae 3lleiTpOTexHH4ecKaR HOMHCCHA
Pour prix, voir catalogue en vigueur
• • For price, see current catalogue
---------------------- Page: 2 ----------------------
3
1987 883 © IEC
CONTENTS
Page
FOREWORD 5
5
PREFACE
7
INTRODUCTION
Clause
7
1. Scope and object
7
2. Chrominance signal-to-random noise measurement
7
2.1 Test signal
signal-to-noise ratio 9
2.2 Chrominance
11
2.3 Chrominance noise measurement circuit
13
2.4 Recommended filtering
15
2.5 Calibration
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883©IEC1987 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MEASURING METHOD FOR
CHROMINANCE SIGNAL-TO-RANDOM
NOISE RATIO FOR VIDEO TAPE RECORDERS
FOREWORD
1)
The formal decisions or agreements of the I E C 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 inte
rnational use and they are accepted by the National Committees in that
sense.
3) In order to promote international unification, the I E C expresses the wish that all National Committees should adopt the text of
the I E C recommendation for their national rules in so far as national conditions will permit. Any divergence between the I E C
recommendation and the corresponding national rules should, as far as possible, be clearly indicated in the latter.
4)
The I E C has not laid down any procedure concerning marking as an indication of approval and has no responsibility when an
item of equipment is declared to comply with one of its recommendations.
PREFACE
This standard has been prepared by Sub-Committee 60B: Video Recording, of IEC Technical
Committee No. 60: Recording.
The text of this standard is based on the following documents:
Six Months' Rule
Report on Voting
60B(CO)69
60B(CO)78
Further information can be found in the Repo
rt on Voting indicated in the table above.
---------------------- Page: 4 ----------------------
– 7
883 O IEC 1987
MEASURING METHOD FOR CHROMINANCE SIGNAL-TO-RANDOM
NOISE RATIO FOR VIDEO TAPE RECORDERS
INTRODUCTION
When reproducing colour pictures on a video tape recorder, changes in colour occur caused partly
by the recording method (conversion of the subcarrier) and partly by the equipment (tape, tape
recorder).
Scope and object
1.
This standard describes a technique for measuring the impairment of a TV picture due to
random noise in a colour signal. It should be realized that other mechanisms can be present which
introduce impairments that appear to be caused by random noise, but are not measured by this
technique.
Other techniques are necessary for measuring parameters such as moiré, time base error and
cross-colour.
The values which result from this measurement method make it possible to compare different
video tape recorders, recording systems and video tapes for the random noise characteristics.
This standard is intended for use with all IEC recognized video recording formats.
2. Chrominance signal-to-random noise measurement
This method is suitable for PAL and NTSC colour video signals.
2.1
Test signal
2.1.1 The suggested test signal is an all-red signal which has been made to correspond with the
following colour bar test pattern: colour bar 100/0/75/0 (test pattern
b of CCIR Recommendation
471) for 625/50 PAL system and 75/7.5/75/7.5 (test pattern c of CCIR Recommendation 471) for
525/60 NTSC
...