Patent ID: 7977992
Filing Date: 2011-07-12
Classification: H03B

Abstract:
1. A phase generator, comprising: a delay element configured to receive an input signal and configured to delay the input signal by a predetermined amount to develop a delayed version of the input signal; a logic element configured to receive the input signal and the delayed version of the input signal, the logic element configured to produce a signal dependent on a phase difference between the input signal and the delayed version of the input signal; a circuit configured to generate an analog reference signal independent of an output of the logic element and having a fixed amplitude; an analog amplitude comparator configured to receive the output of the logic element and the analog reference signal, the analog amplitude comparator configured to generate a control signal that is dependent on the amplitude difference between the output of the logic element and the analog reference signal, where the control signal is applied to the delay element to determine the delay applied to the input signal; and a frequency detector configured to affect the control signal in response to the delay between the input signal and the delayed version of the input signal.