| 摘要 |
PURPOSE:To avoid the reception of mis-signal, by transmitting the carrier of the first and second frequency depending of ''1'' and ''0'' of the input signal through the selection of types of information to be transmitted, selecting the information signal at the reception side, transmitting error signal and re-requesting the signal. CONSTITUTION:At transmission side, the synchronizing signal transmission circuit 11 transmits the carrier of the first frequency for a given period, succeedingly the types A,B,C of the information to be transmitted are generated 20...22, they are selected depending on the setting either of FF4...6, and the frequency f1 is delivered with FSK modulation circuit 4 when the input signal is ''1'' and the frequency f0 is delivered with ''0''. On the other hand, at the reception side, the frequency is synchronized with the bit pulse of the transmitter with the synchronizing clock generating circuit, and the signal to the carrier of frequencies f1 and f0 determined with this receiving point, and the types of information is separated. Further, after the information signal transmisstion stage ends, error signal is transmitted from the reception side and retransmission of signal is requested. Thus, the information signal is selected and the reception of error signal can be avoided. |
