| 摘要 |
PURPOSE:To correct the degradation in MTF characteristics automatically with simple constitution by comparing the level half the peak value of an input signal and the impulse waveform of the input signal, comparing the half-amplitude level until the waveform decreases by half from the peak value and a set value and controlling frequency characteristics. CONSTITUTION:The impulse waveform obtained from the output of a differentiating circuit 5 is supplied to a peak holding circuit 13 and a level comparator 14, and the level Vp/2 of 1/2 the peak value Vp detected by the circuit 13 is formed by an attanuator 15 and is supplied to a level comparator 14. The sawtooth waves appearing in the output of a sawtooth wave generating circuit 16 is supplied to a peak holding circuit 17, the output whereof is applied to a subtractor 18. A reference level 19 is is inputted as the other input to the subtractor 18, and a control signal is obtained at the output terminal 12 thereof. |
