SV: Re: [sdiy] Simulating SW?

[karl dalen]

Thanks for the spice sugestion Jim!
I downloaded it and now trying to use it properly!:)

However i havent simulated before! 
(oh, that was a bad one) :)

When i run the FFT on a single sine wave i get spurious harmonics, first harmo
are displayed 60db below fundamental
and so on.

Is this due to the number of samples in the AC sine
model or the number of FFT points or what?

The more FFT sample points i use the worser the result gets!
Im used to get one spike in the diagram showing the fundamental
and spurious noise a 140db below! And no harmonics!!

And the signal floor are constantly changing due 
to number of FFT sample points set? Really wierd!

KD

--- James Patchell <patchell at cox.net> skrev:

> I use the Linear Technology Switcher Cad...they promote it as a way to 
> simulate switching power supplies, but you can use it as a general purpose 
> SPICE as well...and the best thing...it is free....there are similar 
> packages available from other vendors as well...I think TI also has 
> one.  Take your pick...use the one that works for you.
> 
> http://www.linear.com/company/software.jsp
> 
> 
> At 07:55 AM 11/18/2005 +0000, tom.adam at telenet.be wrote:
> >What simulation software you guys use for trying out new idea's?
> >Or is this "not done".....
> >
> >Looking for a lite version, preferably freeware ;-)
> >
> >Cheers,
> >
> >--
> >Tom Adam
> >The Big Ear
> >http://users.pandora.be/the-big-ear/
> >Check out the download section!
> 
>          -Jim
> ***************************************************************
> http://www.oldcrows.net/~patchell
> 
> ***************************************************************
> 
> 
>