| 摘要 |
PURPOSE:To improve and stabilize an accuracy in a control throughout a wide range by providing plural sharpness control circuits and successively superimposing the plural sharpness control circuits according to a residual distortion in an equalizing output. CONSTITUTION:The sharpness control circuits 21, 22 respectively control the frequency/amplitude characteristic of an input signal according to a control signal. A control circuit 23 generates the control signal according to the residual distortion in the equalizing output and controls so as to successively superimpose the plural sharpness control circuits 21, 22 and operate. Accordingly, in the respective sharpness control circuits 21, 22, the control can be executed only by using a part small in the change ratio of the sharpness to a change in a control voltage of a Q control characteristic. Thereby, a control accuracy can be improved throughout a wide range and a stable control can be executed.
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