sync separator - video signal + sync separator = sync signal

July/august 1984 A video signal + sync separator = sync of a video signal. When supplied signal with a composite video signal of at least 0.5 the circuit outputs This little circuit can separate the quite a respectable (9 V p p ) synchron- synchronization section from the rest ization signal. This is eminently suitable for use with the video effect circuit (video D/A) described elsewhere in this issue. The basis of the circuit is a com- parator consisting of two transistors, the inverting input (T2) of which is connected to a fixed d.c. voltage. When the input signal at the non- inverting input (the base of T1) falls below the voltage set at the base of T2 (about 3.6 V) transistor T1 switches off and T2 conducts. If a video signal is applied to the input the d.c. voltage setting of T1 will be slightly higher than that of T2. On top of this the base setting circuit of T1 contains a clamping diode which will only allow a very small change in the negative direction (roughly 0.4 V). T...