We find this circuit in American documentation from the 1980s. It consists of a frequency folder using a varicap. The capacitors and coils depend on the frequency of operation.
In the figure we have the circuit of an amplifier for alternating signals with 10 times gain,...
Frequencies up to just over 100 kHz can be obtained with an oscillator based on one of the four...
With this circuit it is possible to regulate a source of up to 9 A using 3 LM350. The integrated...