REDUCTION OF CROSS-COLOUR EFFECTS IN PAL (SYSTEM I) COLOUR TELEVISION BY THE USE OF LOW-PASS AND NOTCH FILTERS:subjective tests

摘要

Luminance components of a PAL colour television signal that lie within the fre¬quency band occupied by the chrominance subcarrier and its sidebands are liable to pro¬duce cross-colour effects on the displayed colour picture.nTo mitigate these effects the response/frequency characteristic of the luminance channel of a four-tube colour television camera was modified by including, in turn, a wide-notch filter, a narrow-notch filter (both centred on colour subcarrier frequency) and a 3-6 MHz low-pass filter. This Report presents the results of subjective tests of the effects of these filters on the resolution, cross-colour and colour spreading of a PAL (System I) colour picture;the tests were carried out for two values of decoder chromi¬nance-channel bandwidth. The resolution of the compatible monochrome picture was also examined.