Digitally controlled phase locked loop system

In a television signal processing system, apparatus comprising:

• a source of television signals including a horizontal line synchronizing signal component;
• signal separation means, coupled to said source, for separating the horizontal line synchronizing signal component from said television signals;
• first phase comparison means, coupled to said signal separation means for generating a first phase difference signal representing the difference in phase between said separated horizontal line synchronizing signal and a first oscillatory signal;
• means, coupled to said first phase comparison means and responsive to said first phase difference signal for generating a first frequency control signal;
• digital signal generation means including a digital oscillator responsive to said first frequency control signal for generating a plural-bit sampled data digital oscillatory signal having a frequency which varies about a nominal frequency by amounts determined by said first frequency control signal;
• second phase comparison means, coupled to said digital signal generation means for generating a second phase difference signal representing the difference in phase between a single-bit digital signal, representing a predetermined bit of said plural-bit sampled-data digital oscillatory signal, and a second oscillatory signal;
• means, coupled to said second phase comparison means and responsive to said second phase difference signal for generating a second frequency control signal;
• a variable oscillator, responsive to said second frequency control signal for generating an analog oscillatory signal having a frequency determined by said second frequency control signal;
• and
• frequency dividing means coupled to said variable oscillator for dividing the analog oscillatory signal provided thereby in frequency by first and second predetermined factors to generate said first and second oscillatory signals.