| 摘要 |
PURPOSE:To reduce the size of the transmitter and to realize costdown by eliminating the need for a filter circuit to extract a high frequency signal and a low frequency signal. CONSTITUTION:This transmitter is provided with an operational amplifier 41 comparing a voltage level RFIN of a received signal with a threshold voltage VRF to provide the output of a binary signal, a timer 42 started by using an output signal DIN of the operational amplifier 41 as a trigger to count a reference period T, and counters 43, 44 preserving the count state of the timer 42 as data D1 to decide a read timing of the data. The timer 42 is not expired when it receives a high frequency signal but expired when it receives a low frequency signal. The content of the received data signal is reproduced by reading the state. |
