Abstract: A frequency and phase lock loop is disclosed in which AFC and phase locking functions are completely separated thus permitting signal acquisition range and closed loop bandwidth parameters to be independently established. Interference between phase lock loop (PLL) and automatic frequency control (AFC) signals resulting in the loss of a beat frequency signal for matching VCO and reference signal frequencies is eliminated thus affording enhanced PLL frequency pull-in range.

Abstract: A phasing circuit is described for automatically controlling the phase of an oscillator input to a synchronous detector which demodulates a video signal in a television receiver. A conventional phase locked loop develops an oscillator signal whose phase tracks with variations in the phase of a video intermediate frequency (I.F.) signal applied to the loop. The automatic phasing circuit includes a phase adjustment network for coupling the video I.F. signal to the phase locked loop and for varying the phase of the latter signal input to the loop in response to a phase correction signal. The phase correction signal is preferably developed by a multiplier which senses the video I.F. signal and the input to the phase locked loop and controls the phase adjustment network such that the latter network varies the phase of the video I.F. input to the phase locked loop until the phase of the oscillator signal has a selected phase relationship to the video I.F. signal input to the synchronous detector.

Abstract: A system is described for synchronously detecting a video signal along a selectable detection axis. The system includes a limiter receiving an input video signal and a phase-locked loop for developing an oscillator signal whose frequency is locked to the frequency of the video signal. A phase-adjustment network recieves the oscillator signal from the phase-locked loop for adjusting the phase of the oscillator signal such that it corresponds to the desired axis of detection. A synchronous detector receives the input video signal and the phase-adjusted oscillator signal for detecting the video signal along the selected detection axis.