This circuit was found in a 90s RF Design. It is an oscillator that can reach 800 MHz, with the frequency controlled by an input voltage.
This configuration of PWM control with the LM317 was found in a Popular Electronics from the 90s....
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in Signetics documentation from the 90's. The circuit performance curve is...