A system for correcting the phase of a substantially repetitive signal with respect to a known reference timing signal by providing a controlled variable delay of the former, in which a plurality of delay lines having binary ordered delay periods are interconnected by switching means, operating on command, to selectively cascade certain combinations of the delay lines and thereby provide a desired composite delay for each successive cycle of the repetitive signal. The system is particularly suited for providing extended delay range capability for synchronizing the phase of a television signal with a local reference signal. For this purpose, the total composite delay is selected to equal a basic period of repetition of the signal and the switching means interconnecting the delay lines is conditioned to operate during a synchronizing pulse waveform carried by the video signal, thereby avoiding the introduction of undesirable switching transients into those portions of the signal carrying analog picture information. In combination with the switched, binary ordered delay lines, circuitry is shown for developing a digital word signal representing the phase error for each cycle of the repetitive signal.
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