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.
The integrated circuit used in this regulator is not very common today. The circuit is from old...
With the micro voltage regulator shown in the figure, we can design a power supply for small...
We find this circuit in a 1980s documentation. The integrated ones are of the time and their...