| 摘要 |
PURPOSE:&?To obtain a demodulating sound signal without the generation of noise during a changer over by demodulating a sound FM signal reproduced from two heads in an independent demodulating circuit, and gradually adding in an overlapping section to change over to one demodulating sound signal. CONSTITUTION:Switches 4A, 4B are turned on only for a period when sound FM signals 100A, 100B reproduced from heads A, B exist, and are turned off during other period. Therefore, demodulating sound signals 500A, 500B outputted from FM demodulating circuits 3A, 3B indicate conditions as shown in (AJ) and (B). A time t1 shows a time when the switch 4B is turned on and a time t2 shows a time when the switch 4A is turned off, and a time T shows a period during both the signals 500A, 500B are overlapped. The demodulating sound signals 500A, 500B outputted from the circuits 3A, 3B are gradually changed over so as to have a fixed total quantity thereof constantly by a changeover circuit 5 as shown in (C) and (D) and a continuous demodulating sound signal 400 having no noise as shown in (E) is outputted.
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