[sdiy] Digital VCO

[Richard Wentk]

At 05:39 24/04/2006, Eric Brombaugh wrote:
>The current design is sinewave output only. Other waveforms are possible 
>(square/triangle/sawtooth), but the PSoC doesn't have the computational 
>horsepower to do bandlimited waveforms, so there will be some audible 
>aliases if these are used. Also, the 8-pin PSoC I'd like to use only has 2 
>unused pins, so the number of realtime control options are limited.

One way to do bandlimited waveforms is to precalculate them and select them 
dynamically based on the frequency.

Splicing can be an issue, but if you're working with a fairly low-res DAC 
ultimate quality isn't such an issue.

>I'm interested in any thoughts / suggestions from the list on this idea. 
>Is this worth pursuing, or am I deluded? :)

Sounds like an interesting project. The big advantage with digital is that 
it's trivially easy to turn a digital VCO into a digital VCLFO with a cycle 
time that goes as low as you want.

Richard