Method and apparatus for automatically adjusting the amplitude of a color burst signal

摘要

A novel method effectively adjusts the amplitude of a color burst signal in a chrominance of a composite video signal read by a reproducing head from a magnetic tape. A low pass filtered chrominance signal of 629 KHz obtained from the composite video signal is filtered to detect an original chrominance signal of 3.58 MHz. Also an original color burst signal is extracted from the chrominance signal by using a burst gate pulse generated by a burst gate pulse generator in a video cassette recorder system. The color burst signal is converted to that of a digital value corresponding thereto and comparing an amplitude of the converted color burst signal with a predetermined threshold value to provide a device control signal corresponding to the comparison result. In response to the device control signal, the color burst signal is selectively deemphasized to a predetermined level; and either one of the deemphasized color signal and the extracted color burst signal is selectively outputted.