| 摘要 |
PURPOSE:To attain the transmission with high S/N by ORing exclusively a signal retarding a received FM signal for a prescribed time and the received FM signal so as to lower the lower limit of an oscillated frequency at the transmission side. CONSTITUTION:An input signal is inputted to a delay circuit 2 retarding a signal by tapprox.=1/(4.fmax) via a buffer 1. An exclusive OR circuit 3 ORs exclusively the input signal and an output signal of the circuit 2. Thus, the output signal of the circuit 3 consists of the frequency component twice that of the received FM signal B and its low frequency component. Thus, even when the lower limit of the oscillation frequency at the transmission side is lowered, no distur bance is given to the demodulation wave being the low frequency component. But the duty of the signal inputted to the exclusive OR is kept to 50%.
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