Patent ID: 6107890
Filing Date: 2000-08-22
Classification: G01R,H03D,H03L

Abstract:
A method of measuring the phase of a pulsed test signal having a variable test signal frequency, the phase being measured with reference to a pulsed reference signal having a substantially constant reference signal frequency, the method comprising the steps of;sampling the test signal at sampling times determined by transition events in the reference signal to obtain a sampled test signal;driving a phase accumulator clocked by the reference signal to generate a pulsed reference state signal having a predetermined frequency which is related to the reference frequency by a fixed ratio other than unity;comparing the reference state signal and the sampled test signal; andoutputting as a result of the comparison a measurement signal representative of a difference in the number of transitions occurring in the reference state signal and the sampled test signal, whereby the measurement signal provides a measure of said phase difference.