Re: gEDA-user: trace calculation

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Thu, Jan 05, 2006 at 08:13:23AM -0800, Larry Doolittle wrote:
> Friends -
> 
> On Thu, Jan 05, 2006 at 11:21:40AM +0100, Karel Kulhavy wrote:
> > Would it be possible to enter material constants and layer ordering into
> > the PCB and then make a function that would display resistance,
> > inductance and capacitance of a track (alone or with reference to
> > infinite groundplane at a different given layer)? You would define
> > starting and ending point and it would calculate the line profile and
> > lengths.
> > 
> > It could work for line-only traces for the beginning.
> > It would make HF design much easier.
> 
> I'm this --> <-- close to making a stab at the line length
> calculation.  If anybody else has started, let me know so
> we can share the work.  What Karel asks for is probably too
> much all at once, but we can work up to it.  Walk before you
> run, etc.
> 
> Basically all I hope to do is find and sum the lengths
> of each segment connecting two points.  Possibly add an
> angle-dependent correction factor for bends, and print
> a warning if any non-45 degree bends show up.  For now
> I don't even need to handle vias -- the critical nets
> that this would be used on most shouldn't use vias.  :-p

Why? Via doesn't have much more inductance than a piece of trace, does
it?

CL<
> 
>      - Larry