Composite video signal eliminating synchronising pulse removal circuit - uses two emitter-coupled transistors with base of second fed with black level dependent bias signal

摘要

So as to further develop circuit arrangement comprising two emitter coupled transistors so that the picture signal, forming part of the composite video signal (FBAS-signal), suffers from no distortion and no residual pulse is left over, the latter pulse is compensated by a pulse of opposite polarity taken off from the working (load) resistor (11) in the collector circuit of the first transistor (T1) and supplied to the base of the second transistor (T2). The base of the second transistor (T2) is specif. biased by a voltage dependent on the black level of the BAS-video signal and determining the cut-off voltage at the firts transistor (T1).