This circuit is from a 1968 documentation. It generates a non-symmetrical signal with the waveform shown next to the diagram. Transistors are of the time, but modern equivalents can be used.
Using two 567 PLLs, this circuit recognizes two audio tones in sequence providing a signal for a...
We found this transmitter in a documentation on espionage from the 90s. The circuit is...
We find this circuit in a Radio Electronics of July 1984. It consists of the traditional version of 1 A...