METHOD OF DETECTING REPETITIVE FREQUENCY OF MEASURED SIGNAL, SAMPLING APPARATUS USING THE SAME, AND WAVEFORM OBSERVATION SYSTEM

摘要

A method of detecting repetitive frequency of a measured signal includes steps of assuming a repetitive signal of the measured signal obtained by a conventional method as tentative repetitive frequency of the measured signal in order to highly accurately detect waveform repetitive frequency of the measured signal even if a fluctuation in frequency is observed in the measured signal, detecting a variation in frequency of a specific signal obtained when the measured signal is sequentially sampled with sampling frequency comprising frequency largely varied from the tentative sampling frequency to cause folding of frequency in sampling, calculating an error included in a sampling number based on the detected variation in frequency of the specific signal and a variation of the sample number indicating how many times the frequency folding has occurred when the measured signal contains the fluctuation in frequency, and correcting the tentative repetitive frequency of the measured signal based on the error included in the sample number, thereby calculating normal repetitive frequency of the measured signal.