Preventing the production of acceptable recording of video signal by phase shifting a portion of the colour burst

摘要

A copy inhibit system for a PAL or NTSC video signal involves introducing a phase shift into a portion of the colour burst signal. This phase shift prevents a VCR from making an acceptable recording of the video signal. The phase shift may be up to 180°, and may be introduced into bands of video lines. Up to 60% of the colour burst signal may be phase shifted.