A CIRCUIT FOR PREVENTING DISAPPEARANCE OF COLOR SIGNAL

摘要

In case that the input composite TV(RF) image signal inputs to the synchronous correction circuit(30), the size of the composite image signal is reduced by the resisters(R1)(R2) and the noise is reduced by the capacitor(C1) and resister(R3). At this time, the resistors(R4)(R5)(R6) act like a bias of P type TR(Q1) and the emitter(E) of P type TR(Q1) is connected to the main B+ voltage(12V). Therefore, when the de-noised composite image signal is delivered to the base(B) of TR(Q1). TR(Q1) is turned on and the composite image signal is cut off(CUT). So the output of the collector(C) of TR(Q1) extracts only the synchronous signal.