Phase-locked loop

A type II phase-locked loop (PLL). It is shown here demodulating frequency modulation (FM).

Phase Locked Loop (PLL)

This simulates a PLL demodulating FM
The VCO is sinusoidal but can be made a squarewave if needed
Suggested parameters: Sample at 10000Hz,Carrier freq 1000Hz = VCO free running freq
Make baseband freq 8Hz and frequency deviation 100Hz.
Make run time 0.2 second
When you run this you will see the demodulated sinewave (8Hz)
It will have 2fcarrier (2fc) superimposed on top of it (as in a real PLL)

The VCO already has an integrator in the loop (the VCO). We add a second and phase-lead compensation for stability.
This gives a type II PLL.