Patent ID: 7268825

Claim:
Apparatus for frequency and phase locking a clock signal to an incoming video signal, comprising: a system clock for generating a clock signal for frequency and phase locking to the incoming video signal; a digitizer for digitizing the incoming video signal to yield a digitized color sub-carrier burst component; a numerically controlled oscillator clocked by the system clock for generating a phase lock signal for locking to the incoming video signal; a logic unit for sensing a static phase offset magnitude from an ideal 90° phase offset between the digitized color sub-carrier burst component and the numerically controlled oscillator output signal and for generating a compensating offset in accordance with the static phase offset signal for input to the system clock to drive the static offset to zero; and a color frame logic circuit for detecting phase alignment between a sync edge and the color sub-carrier burst component for determining the composite video input color frame sequence and for generating at least one pulse for resetting the numerically controlled oscillator.