| 摘要 |
PURPOSE:To eliminate the noise contained in the signal with high accuracy without having a complicated constitution, by giving the differential waveform shaping to the output of a solid state image pickup device (CCD) and then detecting and holding the peak of the output signal. CONSTITUTION:A clearing switch 21 is temporarily turned on, and the potential is set VG at a point (c). The output signal supplied from a CCD (not shown in the diagram) receives the differential shaping with a time constant formed by a capacitor C10 and a resistance R10 and then receives a conversion of impedance through an amplifier 20 to be applied to a diode D1. For the output of the amplifier 20, only the voltage in the direction allowed to the polarity of the diode D1, and the peak level of the signal is held by a capacitor C11. The switch 21 is turned on again before the differential wave of a reset waveform, i.e., the transient switching noise of the CCD signal is supplied. Thus the noise contained in the signal is eliminated. A diode D2 prevents the transient voltage to the signal in the direction where the differential waveform is not required. |
