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Thread-Topic:	[geda-user] Active filter
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Subject:	Re: [geda-user] Active filter
From:	"Roger Burghall (roger DOT burghall1 AT btinternet DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Date:	Thu, 11 Aug 2022 17:12:46 +0100
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Hi Karl
I've taken an interest in active filters for a while=2E (Starting i=
n 1971=C2=A0 to be exact!)
On GitHub I have the most complex of the program=
s I wrote to design them=2E Look for r-burg / rbfilter=2E I don't know if i=
t still compiles several versions of Ubuntu later, it's written in (an earl=
y version of) C++=2E I have a number of other related programs unpublished,=
 on my laptop=2E
I have never used perl, and am occupied with unrelated sof=
tware at the moment, but expect I'll get the chance at some point=2E 

As s=
ource 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=
=2E Try https://worldradiohistory=2Ecom/UK/Wireless-World/60s/Wireless-Worl=
d-1969-08=2Epdf to start=2E

Also try "Active Filter Design" by Carson Chen=
, published by Hayden=2E

I may make a video on my own efforts, in which ca=
se I'll let you know=2E

All the best with you software,
Roger Burghall 


=

=E2=81=A3Get BlueMail for Android =E2=80=8B

On 11 Aug 2022, 16:01, at 16:=
01, "karl AT aspodata=2Ese [via geda-user AT delorie=2Ecom]" <geda-user AT delorie=
=2Ecom> wrote:
> I have been looking into active filters and made this:
>ht=
tp://aspodata=2Ese/git/openhw/bin/act_filter=2Epl
>
>It seems different sou=
rces gives me slightly different values
>and most seem to gloss over the th=
eory makeing it somewhat hard
>to know if the calculations the program does=
 are correct=2E
>
>If you are interested in this, please contact me=2E
>
>R=
egards,
>/Karl Hammar

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<html><head></head><body style=3D"zoom: 0%;"><div dir=3D"auto">Hi Karl<br><=
/div>
<div dir=3D"auto">I've taken an interest in active filters for a whil=
e=2E (Starting in 1971=C2=A0 to be exact!)<br></div>
<div dir=3D"auto">On G=
itHub I have the most complex of the programs I wrote to design them=2E Loo=
k for r-burg / rbfilter=2E I don't know if it still compiles several versio=
ns of Ubuntu later, it's written in (an early version of) C++=2E I have a n=
umber of other related programs unpublished, on my laptop=2E<br></div>
<div=
 dir=3D"auto">I have never used perl, and am occupied with unrelated softwa=
re at the moment, but expect I'll get the chance at some point=2E <br><br><=
/div>
<div dir=3D"auto">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=2E Try <a href=3D"https://worldradiohistory=2Ec=
om/UK/Wireless-World/60s/Wireless-World-1969-08=2Epdf">https://worldradiohi=
story=2Ecom/UK/Wireless-World/60s/Wireless-World-1969-08=2Epdf</a> to start=
=2E<br><br></div>
<div dir=3D"auto">Also try "Active Filter Design" by Cars=
on Chen, published by Hayden=2E<br><br></div>
<div dir=3D"auto">I may make =
a video on my own efforts, in which case I'll let you know=2E<br><br></div>=

<div dir=3D"auto">All the best with you software,<br></div>
<div dir=3D"au=
to">Roger Burghall <br><br><br><br></div>
<div dir=3D"auto"><!-- tmjah_g_12=
99s -->Get <!-- tmjah_g_1299e --><a href=3D"http://www=2Ebluemail=2Eme/r?b=
=3D15919"><!-- tmjah_g_1299s -->BlueMail for Android<!-- tmjah_g_1299e --><=
/a><!-- tmjah_g_1299s --> <!-- tmjah_g_1299e --></div>
<div class=3D"gmail_=
quote" >On 11 Aug 2022, at 16:01, "karl AT aspodata=2Ese [via geda-user AT delori=
e=2Ecom]" &lt;<a href=3D"mailto:geda-user AT delorie=2Ecom" target=3D"_blank">=
geda-user AT delorie=2Ecom</a>&gt; wrote:<blockquote class=3D"gmail_quote" sty=
le=3D"margin: 0pt 0pt 0pt 0=2E8ex; border-left: 1px solid rgb(204, 204, 204=
); padding-left: 1ex;">
<pre class=3D"blue"> I have been looking into activ=
e filters and made this:<br><a href=3D"http://aspodata=2Ese/git/openhw/bin/=
act_filter=2Epl">http://aspodata=2Ese/git/openhw/bin/act_filter=2Epl</a><br=
><br>It seems different sources gives me slightly different values<br>and m=
ost seem to gloss over the theory makeing it somewhat hard<br>to know if th=
e calculations the program does are correct=2E<br><br>If you are interested=
 in this, please contact me=2E<br><br>Regards,<br>/Karl Hammar<br><br><br><=
/pre></blockquote></div></body></html>
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