Forum: GNU Radio Does the GRC FFT block re-order its output

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558c40b97bd1af8d912424757714bda9?d=identicon&s=25 Marcus D. Leech (Guest)
on 2009-01-26 01:25
(Received via mailing list)
Does the GRC output block re-order output?   I'm puzzled with respect to
what I'm seeing.

My normal expectation is that, given an FFT buffer of size N, that on
output

buf[0] to buf[N/2] = DC to nyquist
buf[N/2] to buf[N] = -nyquist to DC

But that isn't what I'm seeing in GRC FFT output.   Clues?

--
Marcus Leech
Principal Investigator, Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
4252201ac30d6dd44d8090ce1070e35f?d=identicon&s=25 Josh Blum (Guest)
on 2009-01-26 21:55
(Received via mailing list)
Send the generated python code so we can see how the fft block is
created.

Marcus D. Leech wrote:
> Does the GRC output block re-order output?   I'm puzzled with respect to
> what I'm seeing.
>
> My normal expectation is that, given an FFT buffer of size N, that on output
>
> buf[0] to buf[N/2] = DC to nyquist
> buf[N/2] to buf[N] = -nyquist to DC
>

Seems correct.
558c40b97bd1af8d912424757714bda9?d=identicon&s=25 Marcus D. Leech (Guest)
on 2009-01-26 22:01
(Received via mailing list)
Josh Blum wrote:
> Send the generated python code so we can see how the fft block is
> created.
>
Never mind.  It was my own problem, nothing to do with GRC.    Carry
on.  Nothing to see here.

--
Marcus Leech
Principal Investigator, Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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