SV: Re: [sdiy] Simulating SW?

[harrybissell]

Hello twin-separated-at-birth... and list :^P

Duh... like my brother said. I've had little or no success at Fourier Analysis
in simulation packages. Sometimes they give what looks to be acceptable
results... other times they are WAY wrong, and obviously so.

Until I know why I won't trust them...

H^) harry

James Patchell wrote:

> I have never used the FFT feature.  I generally avoid them because there
> are a lot of variables that need to be considered.  This is probably a good
> question to be answered by the more mathematically inclined people on the
> list (hint..hint...Magnus...:-)
>
> At 10:20 PM 11/18/2005 +0100, karl dalen wrote:
> >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
> > >
> > > ***************************************************************
> > >
> > >
> > >
>
>          -Jim
> ***************************************************************
> http://www.oldcrows.net/~patchell
>
> ***************************************************************