| 摘要 |
PURPOSE:To eliminate a transient noise generated in a muting part by a noise reducing circuit by muting a sound signal muted at a joint of a track, in a muting period including the previous muting period, after passing the noise reducing circuit. CONSTITUTION:Delaying circuits 13, 14 of the first controlling circuit 11a are triggered by a leading edge part of a head switching signal, and the circuit 13 and the circuit 14 form a signal having a pulse width which is shorter than by tau1 time than the head switching signal, and a signal having a pulse width which is shorter by tau1 time than a two piece portion of the head switching signal, respectively. Delaying circuits 15, 16 are triggered by a leading edge part of an output of inversion circuits 13a, 14a, form a pulse which is continued for 2tau1 time, and supply it to a muting circuit 11. A delaying circuit 18 of the second controlling circuit 12a is triggered by a leading edge part of the first control signal inverted by an inversion circuit 17a, and forms a pulse which is continued until before tau2 time of the first inverted control signal which comes in the next time. A delaying circuit 19 is triggered by a trailing edge part of the first control signal, forms a pulse which is continued for tau2 time, and supplies it to a muting circuit 12. |
