WAVEFORM MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To measure a signal waveform at an optional resolution precision with a low jitter generation. SOLUTION: In this device, a measuring signal having a repeated period is sampled with a sampling signal having a period longer than the repeated period to determine the envelope waveform of the measuring signal, and the signal waveform of the measuring signal is determined from the envelope waveform. This device comprises a frequency signal generator 15 for outputting a frequency signal having a frequency equal to 1/n of the repeated frequency of the measuring signal by use of a reference signal applied to a reference signal input terminal; a phase comparator 14 for detecting the phase difference of the phase of the frequency signal with the phase of the measuring signal and outputting it as a phase difference signal; a voltage control oscillator 17 for generating the reference signal synchronized in phase to the measuring signal on the basis of the phase difference signal outputted from the phase comparator and returning it to the reference signal input terminal of the frequency signal generator; and a sampling signal generating means 18 for generating a sampling signal by use of the reference signal outputted from the voltage control oscillator.