Digital phase locked loop stabilization circuitry

Abstract From the Canadian patent

RCA 82,993, Abstract of the Disclosure A digital television receiver includes a first phase locked loop which develops a sampling clock signal that is locked to the horizontal line synchronizing signals components of a composite video signal. A second digital phase locked loop is clocked by the sampling clock signal and develops a digital signal that is phase locked to the color burst signal. This signal is used as a regenerated color subcarrier signal to synchronously demodulate the chrominance components of the composite video signal into and Q color difference signals. To compensate for frequency instabilities in the regenerated subcarrier signal caused by frequency instabilities in the …