Horizontal phase lock loop for television

摘要

A horizontal phase lock loop for use in a television receiver comprises first and second loops and a horizontal oscillator which generates a ramp signal at a frequency of twice the line frequency. The first loop locks the oscillator signal to the horizontal synchronization pulses. The oscillator output is sliced and then divided by two to achieve a fifty percent duty cycle drive waveform to the phase detector in the first loop and to a phase detector in the second loop. The second loop includes a variable slicer which operates on the oscillator ramp signal so as to lock the flyback signal generated by the horizontal output stage to the second phase detector's switching waveform. Both loops include a divide-by-two circuit which assures fifty percent duty cycle drive waveforms.