Patent ID: 7432751

Claim:
A circuit for generating a periodic waveform, comprising: a digital phase detector having an input for receiving a multi-bit, discrete-time sampled feedback signal and an output for providing a digital phase error signal indicative of a difference in phase between the multi-bit, discrete-time sampled feedback signal and a digital oscillatory signal; a digital loop filter having an input and an output, the input coupled to the output of the digital phase detector; a VCO having an input and an output, the input coupled to the output of the loop filter; and an ADC having an input and an output, the input coupled to the output of the VCO and the output coupled to the input of the digital phase detector for providing the multi-bit, discrete-time sampled feedback signal, wherein the digital phase detector includes a digital oscillator for generating the digital oscillatory signal, a down converter having a first input for receiving the digital oscillatory signal, a second input for receiving the multi-bit, discrete-time sampled feedback signal, and an output, a phase extractor, having an input coupled to the output of the down converter and an output coupled to the output of the digital phase detector, and a summer coupled in series between the output of the phase extractor and the output of the digital phase detector for effecting an adjustment to the digital phase error signal by a desired, predetermined amount.