| 摘要 |
PURPOSE:To simplify the circuit constitution by applying two-stage switching for four different sound intermediate frequency signals. CONSTITUTION:Input switching circuits 5, 6 consist respectively of filters F1, F2 and F3, F4 and changeover switches S3, S4 and the switches SW3, SW4 are connected to an input signal line to which a sound intermediate frequency signal is applied. Detection circuits 7, 8 of the same constitution are provided respectively with detection transformers T1, T2 and T3, T4 and detection switching circuits 9, 10. The changeover switches S5-S6 are interlocked together. Through the constitution above, four kinds of sound intermediate frequency signals are selected by combining the switching operation of the changeover switches S7 and S3- S6.
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