| 摘要 |
PURPOSE:To suppress an unnecessary output during arrival of no signal by performing adequate FS demodulation by excluding a noise signal of lower than a prescribed level under automatic level control by detecting a reception level. CONSTITUTION:Received signal 1, inputted to waveform shaping circuit 4 via band-pass filter 2 and amplifying circuit 3, is converted into a rectangular wave, and through gate circuit 5, demodulator 6 performs FS democulation. On the other hand, level detecting circuit 7 and gain control circuit 8 exercise level control to make the output of amplifier 3 nearly constant. Once a low-level noise is inputted, switch circuit 9 closes gate circuit 5. |
