APPARATUS FOR DETECTING NON-STANDARD IMAGE SIGNAL OF TV

摘要

The circuit detects non-standard video signal and prevents malfunction of detecting by stopping generating output of detection when noise exceeds a reference level. It includes a differential detector (10) for detecting the difference between current sync. and 1-field-previous sync., a signal level down section (32) for reducing the pedestal level detected by a pedestal level detector (31) to its signal level, an area integrating section (50) for integrating the output of the signal level down section (32), and a switching section (20) for switching normal video signal from the differential signal detector (10) and noise removed video signal.