| 摘要 |
PURPOSE:To eliminate the discontinuity of a phase in the switching time point, and to eliminate a pulsative noise generated in a reproducing signal by selecting and switching the respective waves to be modulated, after phases of the respective waves to be modulated, which are obtained from two rotary heads have coincides with each other. CONSTITUTION:A voice FM signal which has been brought to sound recording is reproduced by rotary heads 11a, 11b, amplified 12a, 12b, a signal of a prescribed band is fetched by BPFs 13a, 13b, and its amplitude is limited by limiters 14a, 14b, and signals F, G are outputted. when a phase difference of these signals F, G becomes below a prescribed value, a phase difference detector 15 is operated, and its output is provided to an OR gate 22. Also, a control signal for selecting an output of the heads 11a, 11b and obtaining a continuous signal is inputted to an input terminal 19, an output of rise and fall of its signal is provided to the gate 22, an output of the gate 22 is provided as a clock of a D latch 23, and the control signal is applied as a data. In this state, a switch 16 is controlled by an output signal J of the latch 23, the discontinuity of the time for switching the signals F, G is eliminated, and the signals F, G are reproduced by a demodulator 17.
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