| 摘要 |
PURPOSE:To perform muting control easily without using any new transmission system by multiplexing and transmitting a muting signal with a sound volume control signal by remote control from an insulated signal system, and extracting the muting control signal and performing muting control during channel switching on a reception side. CONSTITUTION:A remote control receiving circuit 1 receives a signal from a remote control transmitter and applies a sound volume control pulse A corresponding to sound volume control to an insulated connection circuit 5. The output of the circuit 5 is applied to a muting circuit 22 through an LPF13 and an attenuator 14 to control an audio signal. A channel specifying signal B from the circuit 1 is applied to a channel selecting circuit connected to a keyboard 2 to output a channel mode signal D from the circuit 3, and during the period of the signal D, a muting control signal E is applied from a muting control signal generating circuit 4 to the circuit 5. Then, the signal A is superposed on the signal E by the circuit 5 and the signal E is detected by a muting signal detecting circuit 15; and the circuit 22 is controlled by a muting control signal E' from the circuit 15 to facilitate muting control. |
