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

[Shahab Sanjari <sanjari@xxxxxxxxxxxxxxxxxxx>]

It works!

since my data was in a file with two columns the first being time the 
other amplitude, with a SED script I added a "+" at the front of every line.

$> sed -e 's/.*/ + &/' ./oldfile > ./newfile

then I added the header and footer.

then with a small deck like this:

test circuit
.include data.dat
r1 1 0 500
.tran 1m 10
.end

and the commands:
$> spice3 -b test.cir -r raw.file
$> nutmeg raw.file
and
plot v(1)

I could plot the values like a charm!

:-)

Only the whole calculation process took about 10min of over 95% of CPU 
usage on my ThinkPad-T22-900MHz, since the data contained 30,000 samples 
each 1ms apart!
And this was only plotting, i.e. display voltage over a resistor. I plan 
to feed the signal into a filter!


bests,
Shahab.


Daniel Nilsson wrote:
> On Sun, May 01, 2005 at 10:55:18PM +0200, Shahab Sanjari wrote:
>
> > Hi,
> >
> > 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.
>
>
> I don't think there is a direct way to accomplish what you're looking
> to do here, but there is a slight variant that I normally use. You
> don't specify which SPICE version you are using, so the following idea
> might need some tweaking but in general what I do is to create a file
> with the voltage time pairs (one per line) and then include this file
> in the top level spice netlist. For example, create a file that looks
> like this:
>
> + 0e-9  1
> + 1e-9  1.1
> + 2e-9  2.1
> + 3e-9  3.1
>
> etc...
>
> Then it's easy to script a solution that adds a few lines at the top
> and bottom of the file so that it looks like this:
>
> Vsource pos_node neg_node pwl (
> + 0e-9  1
> + 1e-9  1.1
> + 2e-9  2.1
> + 3e-9  3.1
> )
>
> I use this in HSPICE, I hope it is supported in ngspice as well but
> you might need to tweak this somewhat.
>
> Then simply include this file in the toplevel netlist and you should
> be good to go.
>
> HTH
>
> --
> Daniel Nilsson

--

Shahab Sanjari  (sanjariathrzdottu-darmstadtdotde)