[sdiy] Walsh bank, was: Re: [sdiy] Micro as a Linear to Exponential converter?

[Antti Huovilainen]

On Sat, 15 Aug 2009, Tom Wiltshire wrote:

> Analogously, how many sine waves do you need to make an arbitrary 
> waveform with standard fourier analysis? I've used 64 in my oscillator 
> design, as a compromise between quality and feasibility. I'd say you 
> need at least that many for Walsh synthesis, and probably more, since 
> you're adding functions with sharp edges and that will make the results 
> more crunchy. Double or quadruple this would be better.

You can lower the number of required functions by following the oscillator 
with a tracking lowpass filter. The situation is then analogous to normal 
DA converter.

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
   -- Lt. Cmdr. Ivanova