Re: [linux-audio-dev] Diode wave shaper (LADSPA plugin)?

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Subject: Re: [linux-audio-dev] Diode wave shaper (LADSPA plugin)?
From: Erik de Castro Lopo (erikd-lad_AT_mega-nerd.com)
Date: Mon Aug 16 2004 - 12:49:36 EEST

On Mon, 16 Aug 2004 10:54:04 +0200
Stanley Jaddoe <linux-audio-dev_AT_terabytemusic.cjb.net> wrote:

> Hi,
>
> I'm trying to convert an existing analog (hardware) synth to an open source
> softsynth.
> One of the components of the analog synth is a diode wave shaper. The
> schematic is included (diode.jpg). The Inputs 2, 3, ... n and its resistors
> are optional.
>
> I'd like to know if there's a LADSPA plugin

Possibly, but I'm not too familiar with what is available in LADSPA.

> (or even better: a DSP IIR recurrence relation)

Nope, not possible with a linear recurrence relationship.

> which emulates the included schematic as close as
> possible. Unfortunately, I don't have the EE background required to do this
> myself.

Its actually rather simple (first year EE):

    static inline double
    diode_clip (double input, double clip_level /* should be positive */)
    { if (input > clip_level)
            return clip_level ;
        if (input < -clip_level)
            return clip_level ;
        return input ;
    }

Erik 

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  Erik de Castro Lopo  nospam_AT_mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
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