Frequency analyzer

To get a better feel of the stability of the VCO I wrote a small program that analyzes the export from logic 2 and measures the frequency everytime we get a positive zero crossing.

 As not to spoil the fun, here is the DCO:

 The DCO is fairly stable, with a deviation of around 0.5Hz for most cycles when running at 880Hz, or 0.06%.

Now, as for the VCO...

 

Here we get a frequency variation of around 50Hz when running at 2920Hz, or 1.7%, almost 30 times worse than the DCO. This definitely has to be inspected more closely.