In an audio and video recording apparatus, a video signal is separated into a luminance signal and a chrominance signal. The luminance signal is separated into low frequency and high frequency components. The high frequency component signal is subjected to balanced modulation to be thereafter band-compressed...http://www.google.de/patents/US5027222?utm_source=gb-gplus-sharePatent US5027222 - Apparatus for recording audio signals and video signals on a recording medium
