| 摘要 |
PURPOSE:To reduce an influence for picture signals due to noise superimposed by reset pulse and improve an S/N ratio by controlling the reset pulse amplitude which is applied to the CCD image sensor through reverse-amplified output of the difference between standard voltage and DC voltage proportional to the reset pulse amplitude. CONSTITUTION:When the reset pulse amplitude amplitude which is sent to the CCD image sensor varies and becomes less than a prescribed value, an output voltage of detecting circuit 13 is lowered and the difference between the output voltage of the detecting circuit 13 and the output voltage of DC electric power source is increased, resulting in increasing the output voltage of an error amplifier 14. Consequently, the voltage which is applied to a pulse amplitude control terminal 12a of pulse circuit 12 is increased, an output pulse amplitude of the circuit 12 is enlarged, and the decrease of reset pulse amplitude is compensated. Also, when the reset pulse amplitude is increased, the same compensating operation is made. Thus a negative feedback loop, i.e. detecting circuit 13 error amplifier 14 pulse circuit 12 detecting circuit 13, stabilizes the reset pulse amplitude to reduce the influence of noise superimposed by reset pulse.
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