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From:	"Chad Parker (parker DOT charles AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Date:	Fri, 26 Aug 2016 18:48:37 -0400
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Subject:	Re: [geda-user] Microwave PCB layout simulation or How to eat all
	your processing power in 3 easy steps
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FWIW, this is something I've thought a lot about also. It would be very
cool, but as with all simulation, to do it and get an answer out that
actually resembles the real world is really hard. There are a lot of
details that have to be taken into account, and then you have to make sure
that your fab gets them all right too when you build the board. You can get
maybe 10% variation in the dielectric constant of FR4, for example. PCB is
not currently aware of many of those details, like board material, layer
thickness, the amount of prepreg between the layers, etc. so you'd still
have to add all that information in somewhere.

I have a situation right now where I'm putting a couple of vias in close
proximity to each other and counting on the parasitic capacitance to couple
in a test signal. I'd love to be able to simulate and get an idea of what
the capacitance actually is. I'll have to build and test it to really
figure it out.

BTW, you need more than just Hyperlynx to do this. You need the specific
Hyperlynx 3D field solver module. My employer has licenses for MG,
including Hyperlynx, but that module is licensed separately (I was just
looking into this last week).

I don't know much about gnucap, but it seems like in order to use it to
simulate a PCB like this, you still need to be able to abstract a circuit
model from the layout, and that's what the fancy, expensive programs do.

--Chad

On Fri, Aug 26, 2016 at 5:15 PM, al davis <ad252 AT freeelectron DOT net> wrote:

> On Fri, 26 Aug 2016 21:45:00 +0200
> "Bert Timmerman (bert DOT timmerman AT xs4all DOT nl) [via geda-user AT delorie DOT com]"
> <geda-user AT delorie DOT com> wrote:
> > So basically you wish for a Hyperlynx exporter for pcb ;-)
>
> Good luck getting Mentor (owner of Hyperlynx) to do that.
>
> What you really need is an exporter to gnucap-Verilog, or a plugin for
> gnucap to read (and write) the pcb format.
>
> If somebody wants to write that gnucap plugin, I will help you do it.
>
>

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<div dir=3D"ltr"><div>FWIW, this is something I&#39;ve thought a lot about =
also. It would be very cool, but as with all simulation, to do it and get a=
n answer out that actually resembles the real world is really hard. There a=
re a lot of details that have to be taken into account, and then you have t=
o make sure that your fab gets them all right too when you build the board.=
 You can get maybe 10% variation in the dielectric constant of FR4, for exa=
mple. PCB is not currently aware of many of those details, like board mater=
ial, layer thickness, the amount of prepreg between the layers, etc. so you=
&#39;d still have to add all that information in somewhere.<br><br>I have a=
 situation right now where I&#39;m putting a couple of vias in close proxim=
ity to each other and counting on the parasitic capacitance to couple in a =
test signal. I&#39;d love to be able to simulate and get an idea of what th=
e capacitance actually is. I&#39;ll have to build and test it to really fig=
ure it out.<br><br></div>BTW, you need more than just Hyperlynx to do this.=
 You need the specific Hyperlynx 3D field solver module. My employer has li=
censes for MG, including Hyperlynx, but that module is licensed separately =
(I was just looking into this last week).<br><div><br></div><div>I don&#39;=
t know much about gnucap, but it seems like in order to use it to simulate =
a PCB like this, you still need to be able to abstract a circuit model from=
 the layout, and that&#39;s what the fancy, expensive programs do.<br><br><=
/div><div>--Chad<br></div></div><div class=3D"gmail_extra"><br><div class=
=3D"gmail_quote">On Fri, Aug 26, 2016 at 5:15 PM, al davis <span dir=3D"ltr=
">&lt;<a href=3D"mailto:ad252 AT freeelectron DOT net" target=3D"_blank">ad252 AT fre=
eelectron.net</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Fr=
i, 26 Aug 2016 21:45:00 +0200<br>
<span class=3D"">&quot;Bert Timmerman (<a href=3D"mailto:bert DOT timmerman AT xs4=
all.nl">bert DOT timmerman AT xs4all DOT nl</a>) [via <a href=3D"mailto:geda-user AT delo=
rie.com">geda-user AT delorie DOT com</a>]&quot;<br>
&lt;<a href=3D"mailto:geda-user AT delorie DOT com">geda-user AT delorie DOT com</a>&gt; =
wrote:<br>
</span><span class=3D"">&gt; So basically you wish for a Hyperlynx exporter=
 for pcb ;-)<br>
<br>
</span>Good luck getting Mentor (owner of Hyperlynx) to do that.<br>
<br>
What you really need is an exporter to gnucap-Verilog, or a plugin for<br>
gnucap to read (and write) the pcb format.<br>
<br>
If somebody wants to write that gnucap plugin, I will help you do it.<br>
<br>
</blockquote></div><br></div>

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