| 摘要 |
PURPOSE:To appropriately compensate dropouts even if many dropouts are generated by setting up the limit level of a limiter so that an output of an amplifier exceeds the limit level when the dropouts exceeding prescribed density are detected. CONSTITUTION:A frequency-modulated audio RF signal is amplified by an amplifier 1 and inputted to a band-pass filter 2 to extract an audio carrier component and the amplitude of the extracted component is limited by a limiter 3. The amplitude-limited signal is demodulated by a demodulator 4 and outputted through a switch 5. A dropout compensating signal taken out through a level detector 6, a comparator 7, a standard voltage 7', and a pulse width expanding circuit 8 is applied to the switch 5 to turn the switch 5 off during the signal is outputted and also integrated by a low-pass filter 10. A signal corresponding to the generation density of dropouts is inputted to the amplifier 1 to control the amplifier 1 so that the output of the amplifier 1 exceeds the limit level of the limiter 3. |
