Signal detecting circuit apparatus.

摘要

A signal detecting apparatus is to obtain hysteresis characteristic at a constant ratio regardless of signal amplitude fluctuations by supplying the threshold level adjusting signal corresponding to the input signal amplitude to the comparison circuit. The threshold value setting signal and the hysteresis adjusting signal is supplied to a comparison circuit through an amplifier and a hysteresis adjusting means having the identical characteristic with the peak hold circuit to set a threshold value and a hysteresis range. Therefore even in the case where the operating characteristic of the amplifier and the peak hold circuit for detecting the peak level of signal amplitude fluctuate, the threshold value and the hysteresis range fluctuation corresponding to the fluctuation. As a result, there can not need the adjustment for resetting the operating characteristic, the threshold value and the hysteresis range in each circuit and thus the time and labor required for adjustment can be further saved.