Phase meter using a permuter and matched filter

Abstract

A phase meter precisely measures the phase of two signals with very different frequencies by using a sampler, permuter and a matched filter. The phase meter includes a sampler that samples the fast clock with the slow clock; a permuter that permutes the samples based on the frequencies of the fast and slow clocks; and a matched filter that sums sequences of the samples and generates maximum and minimum phase positions. The maximum and minimum phase positions indicate transition times in the fast clock. The filter can take the average of the minimum and maximum values to determine the phase of the fast clock at the middle point of a cycle. The phase meter can also be used with an interval counter to precisely adjust the transition count used by the interval counter to detect a number of cycles in the interval, and to account for partial cycles that fall within the interval.