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From: "karl AT aspodata DOT se [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Subject: Re: [geda-user] Active filter
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Comments: In-reply-to "Roger Burghall (roger DOT burghall1 AT btinternet DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
   message dated "Thu, 11 Aug 2022 17:12:46 +0100."
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Roger Burghall:
> I've taken an interest in active filters for a while. (Starting in 1971  to be exact!)
> On GitHub I have the most complex of the programs I wrote to design them.
> Look for r-burg / rbfilter.

Ok, got it.

> I don't know if it still compiles several versions of Ubuntu later, it's written in
> (an early version of) C++.
...

No, there are missing libs, they are considered to "old",
that's the drawback of using gtk et al.

Calc.cpp seems the most interesting one.

> As source material for learning the theory, a long series of excellent articles was
> published in Wireless World in about 1969 to 1971 and it was archived.
> Try https://worldradiohistory.com/UK/Wireless-World/60s/Wireless-World-1969-08.pdf to start.
> Also try "Active Filter Design" by Carson Chen, published by Hayden.

Thanks, I'll look into that.

Regards,
/Karl Hammar