| 摘要 |
PURPOSE:To perform effective remote operation by superposing and transmitting voltage pulses to the cable from an indoor device to an outdoor device, and detecting that by the outdoor device and switching the supply destination of the power source for the local oscillator in the outdoor device to either of the 1st and the 2nd local oscillators. CONSTITUTION:The power supply circuit 11 of the indoor device 10 sends a pulse outputted from a voltage pulse generating circuit 12 to the outdoor device 14 through the power cable 13. Then, the device 14 detects the transmitted voltage pulse by a detecting circuit 16. The voltage pulse, on the other hand, drives a stabilized power circuit 15, whose output is supplied to either of the 1st and the 2nd local oscillation circuits 33 and 34 through a power source switching circuit 17. In such a case, the switching is carried out on the basis of the output of the circuit 16, which uses a differentiating circuit. Then, the circuit 17 uses, for example, an FF circuit and an initializing circuit 18 connected to the circuit 17 specifies one local oscillator at the time of power-on operation from the device 10. |
