| 摘要 |
PURPOSE:To improve the processing speed and to reduce the burden of hardware at the time of the extraction of a peak value, etc., by providing a polarity converting means which performs an input waveform signal that it contains only signal components of the positive polarity. CONSTITUTION:A pitch extracting analog part 102 obtain six kinds of waveform signals by removing higher harmonic components from six kinds of outputs from a hexa-pickup 110 through a low-pass filter. Further, six kinds of zero- cross signal pulses which go up to a high level or down to a low level each time the amplitudes of the waveform signals change in sign are generated. They are outputted to a pitch extracting digital part 103. Consequently, only one kind of power value signal is generated and used corresponding to one input waveform signal (positive waveform signal). Thus, the required signal is reduced to one-half as compared with two kinds of a conventional example. Namely, the speed of time-division processing and the hardware scale of a memory, e.g. a shift register and a RAM are both reducible in half as compared as those of the conventional example. |
