METHOD FOR DETECTING VIDEO SIGNAL LEVEL AND VIDEO SIGNAL LEVEL DETECTION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To detect a level of a video signal with a simple configuration without the need for a special measurement device. SOLUTION: Part of a received video signal is branched by a branching device 2 and a pedestal clamp circuit clamps the branched output at a pedestal level. Then a diode D1 detects an output of a transistor TR 1 biased at the pedestal level to detect only a synchronizing signal. Then the input level of the video signal is detected by detecting a level of the detected synchronizing signal.