Injection locking [1] can not only improve oscillator frequency stability and phase noise, but act as a selective frequency divider as well [2][3 ... and 10 respectively without any component values ...

That’s where the digital to analog ... buffer circuit, and we get a beautiful sawtooth out the other side. If you want to filter it, you can. It knocks down some of the high frequency noise ...

The diode’s two wires go to an analog ... My circuit includes a voltage divider and potentiometer for adjusting that voltage, which controls the oscillator’s output frequency.