| 摘要 |
PURPOSE:To obtain a smooth demodulated voice output removed at its noise by processing a switching noise or the like through a serial circuit consisting of a parallel circuit formed by a resistor and a capacitor and anothr capacitor and processing a noise having a long time width due to drop-out through a muting circuit. CONSTITUTION:A capacitor C2 is connected between a parallel circuit 34 consisting of a capacitor C1 and a resistor R1 and an earth point and a demodulated voice signal (a) is applied to the node between the circuit 34 and the capacitor C2 to process noises having a time width less than a switching noise. The output of a delay circuit 17 is supplied to the other terminal of the circuit 34 through a switch 32 controlled by a holding pulse. The signal (a) applied through the circuit 34 and the delay signal are applied to the non-inversion input point of a buffer amplifier 35. The output of the amplifier 35 is covered at its drop-out haing a long time width by a muting pulse (f) applied froma drop-out detecting circuit and muted smoothly by the time constants of a capacitor C3 and a resistor R2 and a noise-removed and waveform-shaped signal is outputted through a buffer amplifier 37. |
