Method for monitoring harmonic wave of electric power by use of electronic computer

Based on TFT method doing such works as signal sampling and conversion, continuous equidistant Fourier operation by computer, measuring time-frequency characteristics of systematic harmonic, etc. Said harmonic monitoring method features that by the interval of said Fourier operation of sampled signals, i.e. step distance in TFT, the time-frequency characteristics of harmonic are real-time measured by computer which automatically regulate operation according to change in voltage, current and harmonic in system, to decreased operated amount and stored data. A portable microcomputer with fewer hardwares is used without magnetic tape recorder.