| 摘要 |
PURPOSE:To suppress the noise of a dark part even on a bright screen and to improve regenerating quality by controlling the amplitude of a required video signal in accordance with that of a brightness signal. CONSTITUTION:A brightness signal A with 2 stage levels is delayed by delay lines 13, 17 and reflected by an amplifier 5 and an operational amplifier 14 and an outline signal is obtained by the operational amplifier 14 to form an outline signal C with a prescribed amplitude through an amplifier 15. On the other hand, a brightness signal B is adjusted at its level and amplitude by a clamp circuit 21 and a gain control amplifier 22 and then a control signal D is formed through an inversional amplifier 25. The control signal D is applied to clippers 31, 32 through a level shifter 34 to set up a clip level and outline signals E, F are formed from the outline signal C. These outline signals E, F are synthesized by an operational amplifier 35, an outline signal controlled at its amplitude is supplied to an adder 6 and synthesized with the brightness signal B delayed by the delay line 13 and amplified by the amplifier 5 to obtain a brightness signal H. In said constitution, the size of the amplitude of the outline signal can be controlled by that of the brightness signal and the picture quality of a reproduced image can be improved.
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