[hpsdr] new architecture - FFT front-end

[David Bridgham]

On 9/4/14, 10:40, Erik Anderson wrote:
> (*) An FFT is fundamentally calculating an approximation (average
> intensity of a frequency over the frame) so there is some information
> loss when calculating an FFT.

I've been considering this since I read it, trying to figure out where
the loss of information is with an FFT.  Obviously it's only looking at
a window of the much larger set of input samples but I think an Inverse
FFT really ought to return the samples in that window accurately.  I
suppose there's always a little loss due to the finite precision
arithmetic from fixed sized numbers but beyond that, where is the
information loss?

One DSP course I took described DFT as a change of basis in Hilbert
space.  Changing bases should always be a reversible function, I would
think.



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