| 摘要 |
PURPOSE:To reproduce a signal with fidelity to an excess optical signal input and to make the service life of a light emitting element long without giving adverse effect onto an infrared ray remote control receiver by solving a problem of interference onto other equipment and near distance inoperation between a transmitter and a receiver in the digital voice signal transmission used for an audio video equipment. CONSTITUTION:The transmitter is configurated such that an operating frequency component of an infrared ray remote controller is attenuated by a low frequency attenuation means 42 of a transmitter 11 and the photoelectric conversion efficiency is controlled by an output signal of a high input impedance photoelectric converter 26 of a receiver 24 is controlled. Through the configuration above, in order to send an optical signal whose operating frequency band component of the infrared ray remote controller is attenuated from the transmitter 11, the adverse effect on the infrared ray remote controller receiver is prevented and since a resistance of a resistor connecting to a photodetector 26 of the receiver 24 is small, the receiver is not saturated against the input of a large optical signal. Moreover, when an excess optical signal is inputted and the receiver is saturated, an output signal of the light receiving section is fed back to control the resistance of the resistor connecting to the photodetector 26, then the signal is reproduced with fidelity. |
