DIGITAL PHASE DIFFERENCE DETECTION DEVICE AND FREQUENCY SYNTHESIZER EQUIPPED WITH SAME

摘要

A digital phase difference detection device is equipped with: a delay circuit (10) that cumulatively delays first signals and generates signals for each delay amount; a flip-flop group (20) that latches the delay amount signal in synchronization with a second signal; an edge detector (30) that, in response to the output from the flip-flop group, detects a first phase difference between the rise of the first signal and either the rise or fall of the second signal, and detects a second phase difference between the fall of the first signal and either the rise or fall of the second signal; a storage circuit (40) that stores the first and second phase differences; and a normalization circuit (50) that calculates the period of the first signal from the difference between past first and second phase differences stored in the storage circuit and the difference between first and second phase differences newly detected by the edge detector, and normalizes the phase difference of the first and second signals on the basis of the period of the first signal.