SYSTEM FOR TRANSMITTING CONTROL SIGNAL

摘要

PURPOSE:To transmit plural pieces of control information by one control line by superimposing information comprising a short pulse on a substantial control signal with a microcomputer and providing a separating circuit and a decoder to a receiving side so as to separate the control information and pulse information. CONSTITUTION:A composite signal S1 transmitted from the microcomputer is inputted to a separation circuit 7. The short pulse component included in the signal S1 is attenuated sufficiently by the circuit 7, waveform-shaped by a Schmitt trigger circuit 11 and a substantial control signal DR is reproduced. On the other hand, a differentiating circuit 10 has a time constant suitable for obtaining the rise and fall of a signal CTRL comprising a short pulse train superimposed on the signal S1 and outputs a differetiating pulse S2. This signal S3 is applied to a clock input terminal C of a counter 16 of a decoder 8 and also a pulse T3 obtained via monostable multivibrators 13-15 is applied to a reset teminal R of the counter 16 so as to output count values Q1-Qn of the counter 16.