Video muting circuit for a video cassette recorder in conjunction with a video camera

摘要

A video muting or fading system for a video cassette device in conjunction with a video camera is specified, this system making it possible that an image appears gradually on the screen at the beginning and is faded out or disappears in each case at the end of the recording so that the optical impression of opening and closing or lifting and dropping of a curtain is conveyed on the screen. The video muting circuit comprises a key input device for selecting a muting function, a device for muting a video signal output by a camera section to a video cassette recording section, a device for dividing the video signal into vertical and horizontal synchronisation signals, and a signal processing device which outputs a control signal to the muting circuit as a ratio to a period which corresponds to the number of horizontal synchronisation signals which is equal to that of the vertical synchronisation signals as input to the signal processing device.