[sdiy] Novation peak NCOs

[James J. Clark]

Regarding the 24MHz issue, the documents that I have read on the Peak 
(https://uk.novationmusic.com/peak-explained) only say that the DAC is 
oversampled to 24MHz, which is pretty typical for sigma-delta style audio 
DACs these days. Its a way to get high bit widths - typically 16 or 24 
bits. It does NOT mean that the signal processing is done at 24MHz. In 
fact the "peak-explained" document specifically says that the wavetable 
waveforms are band-limited before being stored in the table, to avoid 
aliasing. This wouldn't be necessary if the signal path was running at 
24MHz.

I would guess that the signal path is running at whatever the DAC sample 
rate is (which is not 24MHz - that is just the master 1-bit clock rate).

They call this the "New Oxford Oscillator". I don't see what is 
particularly new about this. Maybe there was an old Oxford oscillator?

In any case, the Cylonix Cyclebox (and the Cylonix-Intellijel 
Shapeshifter) is an FPGA design and DOES run the signal path at 24MHz and 
has all the nice properties that other posters have mentioned, such as 
inaudible aliasing and ability to do artifact-free FM (and also 
complicated nonlinear operations which would otherwise cause heaps of 
aliasing). And this was released back in 2010...

Regards,
Jim
www.cylonix.com