Re: Ringing in the Holidays (sort of)

[RUMSEY IAN SCOTT <rumsey@ucsub.colorado.edu>]

Franz-
	I have an extremely rough understanding of Prony's method, so I
may be able to point you in the right direction.  The way I see it,
Prony's method approximates the signal you have with the impulse response
of some digital filter over that time span.  To extrapolate the signal,
the full impulse reponse of the filter is calculated.  The accuracy of
the approximation depends on the number of poles and zeroes used in the
digital filter representation (I think).  If you have MATLAB,
I think there is a Prony's method function in the signal processing
toolbox.  The book I looked in was Statistical Digital Signal Processing
and Modeling by Monson H. Hayes, John Wiley & Sons, 1996.
	I hope this helps.  Maybe someone with a little more expertise
will be able to supplement what I've told you.

-Ian Rumsey
University of Colorado

On Sun, 29 Nov 1998, Franz Gisin wrote:

> Does anybody have any experience using Prony's method (or any of it's
> derivatives and/or equivalents) to extrapolate highly oscillatory LC FDTD
> analysis results.
> 
> We are modeling plane wave coupling into electronic enclosures through
> apertures here at San Francisco State University, and have a number of cases
> were the plane wave, after it has passed through the aperture into the
> enclosure itself, rings to no end.  In some cases, we are up to 30,000 time
> steps, and a rough "visual extrapolation" indicates that we would have to go
> past 100,000 time steps before the ringing has decayed to a sufficiently small
> value.
> 
> Thanks,
> 
> Franz Gisin
> 
> -- 
>