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.
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