Subject: Re: [linux-audio-dev] bandwidth limited waveform generators?
From: Alfons Adriaensen (fons.adriaensen_AT_alcatel.be)
Date: Thu Dec 11 2003 - 14:46:59 EET
On Thu, Dec 11, 2003 at 11:43:02AM +0000, Steve Harris wrote:
> On Thu, Dec 11, 2003 at 12:16:27 +0100, Maarten de Boer wrote:
> > i remember that some time ago there was some discussion about
> > bandwidth limited waveform generators. my question is: did
> > anybody compare the various implementations, and does anybody
> > have an idea what would be the fastest? (square, saw)
>
> I use a set of tables with increasing numbers of partials
> (http://plugin.org.uk/src/util/blo.h, .c) for tri, squ, saw. Its pretty
> basic but it works and its fast. It handles stuff like partial pop-in
> problems for you.
I have anti-aliased dirac pulse (flat amplitude spectrum) and sawtooth
(1/f amplitude spectrum) plugins that will be released probably tomorrow
on the Alsamodular site. A square / rectangle / triangle one is 'under
construction'.
They use interpolated dirac pulses and integrals thereof. Aliases
are below -80 dB for F < Fs/6 (this covers the fundamental frequency
range of most instruments). Memory footprint is very small, and the
code is quite simple and fast.
-- Fons
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