| 摘要 |
PURPOSE:To pevent malfunction, by inhibiting the reception in a transmitting part when a control signal is tansmitted from the transmitting part. CONSTITUTION:The light receiving output obtained in a photodetector provided in the transmitting part is supplied to a counter 84 through an amplifier 83. Counted contents of the counter 84 are tansferred to a latch 86 through a decoder 85. The output of the amplifier 83 is supplied to the latch 86 through a monostable multivibrator 87. The monostable multivibrator 87 has a pulse width corresponding to the unit time of the control signal, and as the result, data is transferred to the latch 86 after the unit time from the arrival of the first pulse. Since the output of the monostable multivibrator 87 is supplied to an AND circuit 21 through an inverter 90, the transmission from a light emitting diode 26 is not peformed during the unit time. The QC output of a counter 18 is supplied to a monostable multivibrator 91, and the output is supplied to an enable terminal of the counter 84. Since the QC output forms window pulses for transmission, the counter 84 stops the counting operation and the control signal is not received when the transmission from the light emitting diode 26 is performed. |
