Abstract: A circuit for extracting phase averaged horizontal timing with high noise immunity and for rapidly acquiring a video signal from a composite synchronizing signal generates an output signal at the horizontal sync rate, the output signal having leading edges occurring at the leading edges of the horizontal sync pulses of the composite synchronizing signal. The rate of the output signal is phase averaged by comparing the respective leading edges of the output signal and the composite synchronizing signal within a window centered about the leading edges of the output signal. Difference in the phases of the respective leading edges result in an error signal which is used to adjust the rate of the output signal to obtain coincidence of the respective leading edges. The occurrence of the leading edges of the composite synchronizing signal within the window is used to lock the circuit.

Abstract: A circuit for quantizing television horizontal phase to subcarrier zero crossings has a voltage variable delay circuit to delay the leading edges of incoming horizontal pulses to produce a delayed horizontal pulse output. The corresponding leading edges of the delayed horizontal pulse output are input to the clock input of a flip-flop to store the level of a square wave input which has a given transition (high to low, for example) for each zero crossing of the subcarrier. The stored levels are integrated to produce an error signal which is used to delay the leading edges of the incoming horizontal pulses so that the leading edges of the delayed horizontal pulse output are time quantized within a narrow window at a subcarrier zero crossing.