| 摘要 |
PURPOSE:To prevent the occurrence of crosstalk based on erroneous signals by providing a switch in an automatic level adjusting circuit of each signal and muting the signal which is not selected. CONSTITUTION:Plural input signals 2A and 2B are selected by a changeover switch 54 and are outputted to a terminal 44 through amplifiers 18 and 42. Outputs of amplifiers 18 and 42 are detected by a detector 26, and the signal level is automatically adjusted by the detection output. A changeover switch 66 which is switched synchronously with said changeover switch is provided between automatic level adjusting volumes 60A and 60B and the detector 26. The changeover switch 66 is switched by a switching circuit 64 to make the volume of the input signal, which is not selected, of zero, and thus, the input signal which is not selected is muted to prevent crosstalk. |
