Re: gEDA-user: Toporouter Changes

[John Griessen <john@xxxxxxxxxxxxxx>]

Bill Gatliff wrote:

> The geometric autorouter's octilinear output reduces the number of long, 
> parallel traces that might lead to crosstalk.  Your traces are not 
> generally linear so they're even better, but I do still see some long, 
> semi-parallel outputs.  I'm thinking that your output should have better 
> RF performance, 

Some wire pairs being parallel is perfect for that particular case -- it minimizes antenna area they define.
Crosstalk is always a function of which wires, not parallels in general.
So analyzing the output of an autorouter without much human added constraints means too little to me to bother.

What an autorouter that goes to completion can get you that is so valuable is
a way to generate three what-if cases of the same netlist where you set up
different constraints in advance to guide the autorouter.  Comparing those and selecting the best
is highly valuable.  It's a case by case individual thing though.

The next high value thing to do as human input is after a good autorouter run -- you
push parts of the circuit away based on your knowledge of crosstalk susceptibilities.
The best way I've seen to do that is with a DRC correct local autorouter that works like
  a force field that pushes against circuitry in a user-chosen direction and lets it move until it hits
design rule constraints.

John Griessen
-- 
Ecosensory   Austin TX


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user