Multiple frequency digital phase locked loop

Abstract From the Canadian patent

Abstract An improved multiple frequency digital phase-locked loop circuit is described. The improved digital phaselocked loops utilizes a single circuit to effect both phase and frequency adjustments. The multiple frequency digital phase-locked loop effects phase adjustments by selectively combining or subtracting a reference clock signal with a derived programmable clock signal thereby generating a composite digital phase-locked loop clock signal. The multiple frequency provides frequency adjustments by selectively adding or subtracting pulses from the composite clock signal at a rate determined by a programmably controllable clock signal. The improved multifrequency digital phase-locked …