| 摘要 |
PURPOSE:To prevent malfunctions, by providing an AGC circuit in a receiving circuit for remote-control signals and suppressing conventional spectrum components included in the sunlight or the like to take out the accurate remote- control signals. CONSTITUTION:The optical signal generated from a remote-control transmitter is converted to an electric signal by a photodetector D1 and is applied to the gate of an FET Tr1 and is amplified by transistors TRs Tr2-Tr4 and is sent to a transformer t1. Carrier wave components in the remote-control signal are eliminated by the secondary winding of the transformer t1, a capacitor C12, and a diode D3 to take out a required code pulse, and a TR Tr5 of a Schmitt circuit is triggerred by this pulse, and the remote-control signal is taken out from an output terminal T2. At this time, a part of the output of the TR Tr4 is rectified by a diode D4 and is smoothed by a capacitor C15, and a DC feedback signal is applied to the gate of the FET Tr1 to perform an AGC. |
