| 摘要 |
PURPOSE:To secure the optimum working state of each circuit by setting the working conditions of a pre-holding circuit and a muting circuit independently of each other after setting each drop-out detecting level. CONSTITUTION:The reproduction signal given from a head 1 is turned into an FM sound signal via BPF 3 and delivered via a pre-holding circuit 5, a muting circuit 6 and a noise reduction circuit 7 after demodulation 4. While a drop-out detecting circuit 8 supplies a D0 detection pulse to the circuit 5 when the level of the FM sound signal is lower than the detection level. Thus said detection pulse is pre-held. A drop-out detecting circuit 9 also produces the D0 detection pulse. Then the control signal delayed by a time constant circuit 10 is supplied to the circuit 6 for execution of a muting action. |
