OPTICAL TRANSMITTING/RECEIVING DEVICE

摘要

PURPOSE:To transmit and receive a luminous signal without being influenced by an obstacle between a transmitting unit and a receiving unit and the direction of the transmitting unit by controlling the light emission direction of the light transmitting unit with using a slight radio waves according to the indensity of transmission of a transmitting unit. CONSTITUTION:When the obstacle 21 lies between the light transmitting unit and the light receiving unit the emitted light from LEDs 12 and 13 is reflected and absorbed by the obstacle 21 not to be projected in a light receiving element 22, so that the output from a level detector 26 becomes much less than a reference voltage. Therefore, the output from a comparator 27 becomes H and the output having a frequency fH of an FSK modulator 30 is emitted from a transmitting antenna 32 so as to be received in a receiving antenna 16. The FSK demodulator 18 outputs the voltage of H and a control signal decoding circuit 19 shifts two-bit code from 01 to 10 and switches a control switching switch 3 to an output terminal (c). The luminous signals are radiated in different directions from the LEDs 10 and 11 and attenuated with a white wall face A, then reached the element 22 through a reflection path P. And one of the luminous signals is outputted as an audio signal and the other is inputted in the comparator 27 to keep the connection state of the switch 3 with the output.