Re: gEDA-user: File instead of SPICE voltage source?

[Shahab Sanjari <sanjari@xxxxxxxxxxxxxxxxxxx>]

Yes,
The file exists before. a large one. near 30,000 samples each 1ms apart, 
produced by a data acquisition system.
like this:

  0.0000    14.65
  0.0010   -10.99
  0.0020   -26.86
  .
  .
  .
  29.9920   -73.24
  29.9930   -105.0
  29.9940   -78.13

The original file was comma separated, I removed them with a SED script.

my experiment with PWL and spice ( my last email ) was successful, but 
it was slow.
I am new to splines, but the idea is interesting, since it shows the 
behavior of the original analog signal better than a PWL.

How is this possible with GNU-CAP?

in the case of a quadratic or cubic spline, what value should I choose 
for transient analysis step size?

regards,
Shahab.


al davis wrote:
> On Sunday 01 May 2005 04:55 pm, Shahab Sanjari wrote:
>
> > This one is somehow off topic, actually a general question
> > about SPICE simulation, but I thought I'd better ask it here.
> >
> > Is it possible to tell the SPICE, that a voltage source
> > doesn't generate according to a fix function, but rather
> > reads a file from hard disk which has data in it? For example
> > an ASCII file that has two columns separated with tabs or
> > space, one for time and the other for amplitude. I could then
> > feed this into my custom made filter to check the output.
>
>
> Gnucap will do it the same way another poster said to do it with 
> Spice, and some other ways too.  
>
> With gnucap, you can also do it through a .model statement.  
> When you do it this way, you can pick the order of 
> interpolation up to 3.  1 is PWL, 2 is quadratic splines, 3 is 
> cubic splines.  You can also set the boundary conditions.  
> There is no limit on the number of points.
>
> It will take about 5 lines of code to add exactly the feature 
> you are looking for.  If you want to try it I can do it this 
> weekend.
>
> Does the file exist completely before running the simulation?  
> Or is the file being created as the simulation runs?

--

Shahab Sanjari  (sanjariathrzdottu-darmstadtdotde)