Optical analog data link with simple self-test feature

摘要

A communications circuit for optically transmitting analog data signals free of excessive ripple, while having rapid response time. The invention is further characterized by being adapted to provide an immediate indication of the failure of the optical transmission link of the circuit. Commercially available voltage to frequency converter chips are used in conjunction with suitable wiring arrays and in combination with readily available indicator means for constructing the communication circuit of the invention. A V/F converter in the communications circuit is coupled to an offset adjustment means to cause the converter to continuously produce a string of output voltage pulses having a frequency of about 1 Khz responsive to the input analog signal to the converter being zero. The continuous presence of the 1 Khz frequency on the optical transmission link is monitored at the receiving end of the communication circuit and the indicator means is connected to immediately provide an easily detected indication of a failure of the optical transmission link to transmit the 1 Khz frequency pulses.