| 摘要 |
PURPOSE:To make the operator at a remote location recognize the control state, by returning a signal indicating the control state to a remote operation transmitter from a device to be operated. CONSTITUTION:When a keyboard 3 in a transmitter for remote operation 2 is operated, a control signal generating circuit 5 is driven and when a remote control signal is transmitted to a receiver main body 1 via a light emitting diode 6, this signal is received at a photodetector 7 and a reception circuit 8 and conducted to a sound volume control voltage generating circuit 9. A sound volume control signal obtained from the circuit 9 is applied to a reception sound volume control circuit 10 as a control signal and also applied to a varactor diode 16 in the transmitter 1 to FM-modulate the oscillation frequency of the transmitter in reponse to the control signal level. This FM modulation signal is demodulated at a frequency discriminator 22 in the transmitter 2 and applied to a voltage detection circuit 24. Thus, any of light emitting element groups 4 is illuminated in response to the sound volume control state. |
