| 摘要 |
PURPOSE:To prevent the malfunction in the reception side by transmitting a digital signal from the transmission side after modulating this signal with a signal whose polarity inversion time length is changed in accordance with the classification of the digital signal. CONSTITUTION:Plural kinds of transmission digital signal are modulated in a modulation control circuit 21 while varying the polarity inversion time by a prescribed extent in accordance with prescribed mode setting in a mode setting operation part 20 of a transmitting part 19 and are transmitted from an LED for transmission. The transmission digital signal is received by an infrared photodiode 24 in a receiving part 23 and is preamplified by a preamplifier 25 and is inputted to a device body 27. The device body 27 is provided with a demodulating means which detects the time length of a discrimination digital signal from the received digital signal to discriminate the classification of the transmission digital signal to generate a mode setting digital signal. Thus, the signal is discriminated accurately in the reception side with the simple constitution to constitute an economical device. This device is suitable for remote control.
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