| 摘要 |
PURPOSE:To perform stable transmission and reception by obtaining a synchronizing signal, synchronizing with a received data signal, from the received signal regardless of the state of a transmitted data signal. CONSTITUTION:When a switch 3 is controlled by a data signal, the output of the switch 3 is made into an FSK signal, frequency-modulated into a frequency (n) or (m) times the oscillation frequency of a quartz oscillator 4 synchronizing with a data pulse signal, and then sent to a reception side. The received FSK signal is demodulated by a frequency discriminator 10 into data signal pulses, which are outputted 12 via a buffer amplifier 11. Part of the FSK signal is brought under switch control by the output of the discriminator 10, so the output frequency of a switch 15 is held equal to that of the oscillator 4. Consequently, the output frequency of a voltage-controlled oscillator 17 is equalized to that of the oscillator 4 and the output of the oscillator 17 is outputted from a terminal 20 synchronizing with a data signal outputted from a buffer amplifier 19 to a terminal 12. |
