| 摘要 |
PURPOSE:To prevent the undesirable noise from being applied to the aural output by generating the pulse signal corresponding to the noise, inhibiting the output of the aural signal during the period of generation of the pulse signal, and obtaining the output inerpolated with the aural signal before inhibition. CONSTITUTION:HF amplification 1 is given to the amplitude modulation wave signal of the radio frequency supplied through antenna 1a, and IF obtained through frequency conversion 2 is amplified through IF transformers 3, 5 and 7. Thus, signal detection 8 is carried out. The output of circit 8 is set to a proper gain at the variable resistor 12 via gate circuit 9 and capacitor 10 and then delivered after the aural amplification through low-frequency amplifier 12. Here, if the noise is supplied, the amplitude modulation wave signal branched off through capacitor 15 is detected (16) and the greater part of the noise passes through BPF17 to undergo pulse shaping 18. And the aural signal is attenuated largely and transmitted to gate circuit 9 to block the output of the reproduced modulation wave signal. Instead, the aural signals stored in capacity 10 before inhibition are interpolated to avoid application of the undesirable noise to the aural output. |
