X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
From: al davis <ad252 AT freeelectron DOT net>
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] PyBIS - A Python based IBIS parser.
Date: Tue, 14 Feb 2012 16:04:04 -0500
User-Agent: KMail/1.13.7 (Linux/2.6.32-trunk-amd64; KDE/4.6.5; x86_64; ; )
References: <CAN0Jx-_077aOKbuuTt7y3Wg7p-8HP9CJB1Zfm9GmvLWP-kXmwg AT mail DOT gmail DOT com>
In-Reply-To: <CAN0Jx-_077aOKbuuTt7y3Wg7p-8HP9CJB1Zfm9GmvLWP-kXmwg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <201202141604.04541.ad252@freeelectron.net>
Reply-To: geda-user AT delorie DOT com

On Tuesday 14 February 2012, Russell Dill wrote:
> I've released a Python based IBIS parser I've created as part
> of a project that I'm working on in the hope that others
> will find it useful, improve on it, and create new projects
> based on it. The parser manages everything in the 5.0
> specification except for AMI files.

I noticed you have a viewer.  One feature that would be useful 
in a viewer is to show the derivatives of the waveforms, without 
smoothing.

The derivatives contain the real information that matters, but 
most of the IBIS people don't realize that.  It is common 
practice to pass a file through the official parser, and if it 
passes, to declare it as good.  They could really use something 
that does more checking than just syntax, and that points out 
problems that may not be apparent on first glance.

To see the significance of the derivatives, remember that the 
derivative of an v/i curve is resistance, the derivative of a 
v/t curve is the change with time.  These are important, not the 
DC static points.

Lots of IBIS files have big errors like negative resistance 
regions and steps in waveforms.  If they are small, they may not 
show on a small plot, but they do have an impact on simulation 
results.