[sdiy] "AVR synthesizer"

[Antti Huovilainen]

On Tue, 15 Feb 2005, Jaroslaw Ziembicki wrote:

> What would be interesting is a 2nd order variable state filter - with
> switchable "low pass", "band pass", "high pass", and "band stop"
> outputs. No big problem with implementing - assuming an ATmega
> is being used...

SVFs are problematic in digital domain. To guarantee stability at zero 
resonance, you need to use 4x oversampling or limit the cutoff to 5khz 
(assuming 44khz samplerate).

Antti

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