| 摘要 |
PURPOSE:To reproduce a picture with high fidelity by controlling the amplification factor of a picture signal amplifier in accordance with the level of a picture signal, which has been varied by a variation of the quantity of light of the light source. CONSTITUTION:A solid scanning element 4 is applied to the variable amplification factor amplifier 6. The peak value of an output signal of the amplifier 6 is held by the peak holding circuit 7, it is compared with the reference voltage from the voltage divider 8 by the error amplifier 9, its error output is fed back to the amplifier 6, and the amplification factor is controlled. In this way, a picture signal level which has been varied by a variation of the quantity of light of the light source is held at a constant value, and a picture signal with high fidelity can be obtained. |
