| 摘要 |
PURPOSE:To automatically switch a broadcasting signal at a desired time interval by providing a forced selecting circuit to select and output forcibly the prescribed circuit of plural electronic volume circuits regardless of the output of a timer circuit. CONSTITUTION:A timer circuit 1 outputs 1 or plural switching signals to switch at the time interval set beforehand. In accordance with these switching signals, two plural electronic volume circuits 4 and 5 are successively selected and two outputs are increased and decreased. In accordance with the output of these two increasing decreasing electronic volume circuits 4 and 5, a signal adjusting circuit 6 increases, decreases and outputs two corresponding input signals. After the output signal is outputted through an amplifier to a speaker 8, two signals are simultaneously increased and decreased and a smooth sound is replaced. At the process in which such a switching action of a broadcasting signal is successively executed, when a forced selecting circuit 12 functions, the prescribed circuit of the electronic volume circuits 4 and 5 can be selected and outputted regardless of the timer output. Thus, a prescribed broadcasting signal can be continuously selected.
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