| 摘要 |
<p>PROBLEM TO BE SOLVED: To externally and optionally set a gamma correction characteristic by setting two voltage which are the characteristic inflection points of a gamma correction characteristic by means of external variable voltage source and setting the inclination of a characteristic curve of >= the voltage by means of other external variable voltage source. SOLUTION: In an area A where input voltage Vin is >= voltage E1, neither compressing circuit 4 nor compressing and limiting circuit 6 operates, and an amplifier circuit 3 amplifies the voltage Vin gm1×R1 times and outputs it to an output terminal 2. In an area B where the voltage E1 is <Vin<E2, the circuit 4 amplifies the Vin<(gm1x> R<1x> R<2)> /<(> R<1+> R<2)> times and outputs it to the terminal 2. Furthermore, in an area C where voltage E2 is < the Vin, both circuit 4 and 6 operate and amplify the Vin<(1+gm2x> R<3)x(gm1x> R<1x> R<2)> /<(> R<1+> R<2)> times. Therefore, externally applied voltage V2, V3 and V5 are adjusted, and a gamma correction characteristic can inexpensively and optionally be adjusted.</p> |
