| 摘要 |
PURPOSE:To prevent the generation of noise due to dropout, etc., by supplying an FM-modulated signal to a noise reducing circuit through a de-emphasizing circuit and controlling the noise reducing circuit at the front stage of the de- emphasizing circuit. CONSTITUTION:A signal from a muting circuit 54 is supplied to the de-emphasizing circuit 49 through a low-pass filter 50; and a signal from the de-emphasizing circuit 49 is supplied to a differential amplifier and a signal from the filter 50 is supplied to a detecting circuit 57. In this circuit, the amplifier 55 of the decoder 51 of the noise reducing circuit inputs a de-emphasized signal and the detecting circuit 57 inputs a signal containing a triangular noise component. Consequently, the detecting circuit 57 generates a control signal sensitive to a noise although the decoder 51 has a flat frequency characteristic. |
