| 摘要 |
PURPOSE:To prevent generation of abnormal sound due to the 2nd signal by bringing the reception side into the standby state until the 2nd signal is a normal signal and receiving the signal after a prescribed time is elapsed in switching the signal from the 1st signal to the 2nd signal. CONSTITUTION:When a switch S1 is thrown to the position of +VCC power supply while a reproducing head LB is switched to a head LA, the voltage level of a time constant circuit RA.CA rises, transistors (TR)Q12, Q13 are turned on, a TRQ9 is driven, a differential amplifier consisting of TRs Q5, Q6 is operated and a speaker SP is brought into the silent state. Then a TRQ11 is turned on succeedingly, a TRQ7 is driven, the differential amplifier comprising the TRs Q5, Q6 is inoperative, the differential amplifier comprising TRs Q1, Q2 is operative and a signal obtained by the reproducing head LA is reproduced by the speaker SP.
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