[hpsdr] new architecture - FFT front-end

[Erik Anderson]

Okay, I did just try this with FreeMat.  I chalk up my results to the
unfamiliarity of the program; it sounds like I'm hearing the negative side
of the iFFT results, and I can't understand what I'm saying (i.e.
backwards, fair amount of static), but it's a LOT more readable than I was
expecting.

linky:
https://drive.google.com/a/odysseus.anderson.name/file/d/0B5lP3gUqyXNQelBZSlFxcXM4alk/edit?usp=sharing

On Tue, Sep 9, 2014 at 2:47 PM, Alberto I2PHD <i2phd at weaksignals.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
>
>  On 9/9/2014 11:20 PM, Erik Anderson wrote:
>
>  *To take an extreme example, someone talking for 5sec is not going to
> show up well after an FFT (the voice frequencies are too transient to show
> up in the average) and the resulting frequency information does not carry
> enough data to be able to reproduce the contents of the speech in an iFFT
> operation.*
>
>
> This can easily be checked with Matlab... digitize your 5-second speech
> with one of the many programs that allow to do that, producing a WAV file,
> then import that WAV file into Matlab, compute an FFT of it, do an inverse
> FFT, then playback the resulting data. If your digitization respected the
> Nyquist criterion, what you will hear is indistinguishable from the
> playback of the original WAV file.
>
> --
>
>
>
>
>
> *73 Alberto I2PHD Credo Ut Intelligam *
>
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