Does the GRC FFT block re-order its output

GNU Radio
1

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 L.
Principal Investigator, Shirleys Bay Radio Astronomy Consortium

2

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.

3

Josh B. 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 L.
Principal Investigator, Shirleys Bay Radio Astronomy Consortium