kurmannthomas wrote:
> Thanks to all for their replies...
> Does anyone know about an open source Fixed-Point FFT? Ive found one
> or two, but they only go upto 1024 points, which in my case would be
> 10s of real data @ 100 Samples per second...not that much..I think
> the change to fixed point would be easiest for me since im a
> hardware guy and not specificly a linux prog. :(
Fixed point works only when all the data and intermediate values can be
well represented in the fixed point representation. There are lots of
intermediate values in an FFT, so you have to be careful about the
representation. This is why folks often take the easy way out and use
floating point. But that requires things like floating point hardware if
you want it to be fast.
FFT is an n ln(n) algorithm. Using bigger blocks makes it much slower.
Try just blocking it into smaller sample sizes and using the 1024 code.
You are starting to approach where serious numerical algorithms live, so
be prepared to find a serious FFT programmer to help
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