Chroma burst detection system

摘要

A video cassette recording (VCR) playback system includes circuitry for separating the components of a video signal to produce luminance information and color-under information. The separated color-under information is applied to the input of a variable gain control amplifier the output signal from which includes burst information at color-under carrier frequency during burst intervals. The output signal from the variable gain amplifier is applied to a rectifying circuit which is enabled during the burst interval. The burst information at color-under carrier frequency is rectified during the burst interval and peak detected to produce a control voltage which is applied to the variable gain control amplifier for controlling its gain.