Television receiver raster blanking system

摘要

A cathode ray tube raster in a television receiver is blanked for selected channels chosen to receive audio information by a bias circuit coupled to a video signal source connected to a cathode ray tube wherein the bias circuit provides a given bias potential to the cathode ray tube when a modulated picture carrier signal is detected and a different bias potential blanking the raster of the cathode ray tube when an unmodulated picture carrier signal is detected.