Fast Fourier Transform help..
 

Can anyone offer us a suggestion on where to find information about FFT in
Excel?

The VBA Analysis Toolpak offers a function called ATPVBAEN.XLA!Fourier .

We'd like to know more about it's parameters and abilities.
We want to convert a time domain force vector into REAL force versus
frequency for the binary data segment.

Fast Fourier Transform help..
 

We'd like to know more about <Fourier parameters and abilities.

Do you have any specific questions? It's a Radix-2 Algorithm only.
Arbitrarily limited to 2^12, or 4096 data points. It's a Subroutine, and
can only be called with data on a worksheet. (Too bad...best to have your
own fft program in vba). VBA editor "debug.print" statements in previous 2
versions caused this to run extremely slow. Fixed in 2007. Can work with
either "i" or "j" complex strings (ie 2+3i or 2+3j).
The frequency domain includes all the data (good for signal processing, etc)
but to do data analysis etc you need to divide by the size of the data.
[for example, use IMDIV( ) ].
Another annoyance for the spreadsheet interface is that blank cells are not
treated as zero. FFt will trigger an error with blank cells.
The algorithm itself is really good though.

--
Dana DeLouis
Windows XP & Excel 2007


"mark" wrote in message
...
Can anyone offer us a suggestion on where to find information about FFT in
Excel?

The VBA Analysis Toolpak offers a function called ATPVBAEN.XLA!Fourier .

We'd like to know more about it's parameters and abilities.
We want to convert a time domain force vector into REAL force versus
frequency for the binary data segment.

Fast Fourier Transform help..
 

Hello, Dana,

I'm the one that posted, but not the one that wanted to use it, so I don't
know the specific question. Thanks for your post. I will pass it along to
the person who wanted it on Monday.

How I got involved is that the company Help Desk has me listed as the local
Excel expert.

Thanks,
Mark