| 摘要 |
PROBLEM TO BE SOLVED: To make reliably detectable signals suddenly generated like detection of insulation deterioration of insulators for transmission lines and make collectable data only needed for the deteriorated part. SOLUTION: After thinning out digital input signals, the wavelet transformation about one measuring frame corresponding to an expected length of a reference waveform is made with delays of every one sample period of the reference waveform, a numerical value table having amplitude values given on frequency- time coordinates from the transformation result is compared (21) with one having a dispersion width given to a numerical value table wherein the reference wave form is wavelet transformed in a memory 17, and if both coincide, the reference waveform is judged to be involved in input signals at the time so that input signals required at the time are taken into a memory 22.
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