| 摘要 |
PURPOSE:To prevent the astable operation of an equalizing circuit by detecting a frame step-out when distortion after equalization is large and fixing the control voltage from a control circuit. CONSTITUTION:A frame step-out detecting circuit and a reset signal generating circuit 20 when detecting a frame step-out generate a reset signal to operate changeover switches 21 and 22 provided in the control circuit. Consequently, the control circuit sends out constant reference voltages Vref1 and Vref2 to the equalizing circuit which uses a recursive filter instead of error signals epsilon1 and epsilon2. Consequently, the fixed reference voltages Vref1 and Vref2 are applied to double balance mixers 5 and 7 in the equalizing circuit, so the equalizing circuit is fixed to flat transfer characteristics. Therefore, even if multipath phasing, etc., having large equalization residuals are inputted, a control signal is stable and the equalizing circuit never operates unstably. |
