Valuable threshold waveform shaping apparatus

摘要

A waveform shaping apparatus includes a comparing device for comparing a sensor output signal with a threshold voltage to convert the sensor output signal into a waveform shaped signal. The comparing device outputs the waveform shaped signal. The waveform shaping apparatus also includes a frequency-to-voltage converting device for generating the threshold voltage in response to a frequency of the output signal from the comparing device. In the frequency-to-voltage converting device, a clock signal is generated in response to the output signal from the comparing device. The clock signal has a period proportional to a period of the output signal from the comparing device. A counting device is operative for counting pulses in the clock signal generated by the clock signal generating device for every given period, and outputting a signal representing a counted pulse number depending on the frequency of the output signal from the comparing device. A D/A converting device is operative for converting the output signal from the counting device into a voltage signal which depends on the counted pulse number. The threshold voltage is generated in response to the voltage signal generated by the D/A converting device.