| 摘要 |
PURPOSE:To enable low cost RMC for volume adjustment of audio signal, by using the TV receiver IC decoder for the remote control RMC decoder and providing the muting signal forming circuit. CONSTITUTION:The audio volume adjustment variable resistor R1 is connected between the amplifiers 1 and 3, and the motor 18 is interlocked, and the voltage Er corresponding to the adjustmemt position of the resistor R1 is picked up from the variable resistor R2 to which a given voltage E1 is fed. At the application of power supply, the smplifier 3 is in muting state with the signal Sm from the muting signal forming circuit 21 and the voltage Ec detecting the RMC signal 11 with the decoder 13 using the TV receiver IC is the voltage less than 1/2 of the full power of the amplifier 3. The voltages Ec and Er output the voltage Eh with the comparison at the amplifier 14, and after muting release, the motor 18 is controlled with the control voltage Eh to make variable the resistor R1, allowing to output until the full power of the amplifier 3 with RMC signal. |
