Found on a 1964 CQ this circuit is intended for tone frequency change modulation (FSK) telegraphic transmissions. It operates with signals of 2.975 and 2.125 Hz.
Placed near a common receiver, this oscillator is intended to generate a beating signal to receive...
CMOS integrated circuits are sensitive to supply voltages in terms of signal propagation time....
Found in a radio amateur magazine of the 1980s, this circuit uses components that can still be...