Abstract: An optically driven signal generator utilizes optical switches having a common output port and input ports alternately coupled to first and second potentials of opposite polarities. Optical pulses, with interpulse periods commensurate with a desired output frequency, sequentially operate the switches so that electrical signals of opposite polarities are alternately coupled to a common output port in a manner to establish a continuous electrical signal at a frequency that is commensurate with the interpulse periods.

Abstract: A generator of short electromagnetic pulses utilizes a photoconductive switch having metallic strips on a substrate with a gap separation therebetween. A timing circuit provides an electrical signal to the input of the photoconductive switch and a trigger to an optical source causing a short burst of optical energy to illuminate the gap between the metallic strips, thereby causing the photoconductive substrate to provide a low impedance path between the metallic strips and coupling the electrical signal to an output terminal of the photoconductive switch for the duration of the optical pulse. A filter coupled to the output terminal of the switch, via an impedance matching section, selects a signal frequency band for further transmission.

Abstract: A crystal video receiver having CW and pulse detection capability includes a threshold signal generator which switchably provides fixed and noise riding threshold signals, used to determine initial signal detection. Track and hold circuits provide a second threshold, derived from the peak received signal level, for establishing the termination of received video pulses. A pulse width counter is coupled to determine the time a received pulse signal is between the two thresholds and is set to overflow at a predetermined time after the reception of a signal to establish a pulse representative of a received CW signal and to prevent receiver lock up.