| 摘要 |
PURPOSE:To obtain a vibration signal only of its component by knocking by providing a gate means which allows a knocking signal to pass through obtained from an output signal of a cylinder internal pressure detecting means. CONSTITUTION:An output of a piezoelectric type cylinder internal pressure sensor 1 is input to a band pass filter 12 and a low pass filter 15 via an I/V converter 11. An output waveform, obtained passing through the band pass filter 12, generates a waveform overlapping both a noise signal and a knocking signal. The output waveform of the band pass filter 12 is applied to a gate circuit 13, passing through it while a timer 17 outputs an output pulse, and a knocking discriminating circuit 14 extracts a knocking signal component to be discriminated. |
