Re: log POWER FFT Output - Samples flipped in frequency

GNU Radio
1

Hello,

I guess it shouldn’t be very difficult to change in order to get the
output
is from -BW/2 to BW/2 instead of [DC BW/2 + -BW/2 DC].
Should I modify my python flowgraph or my “log POWER FFT” hier block?

I just need to flip the samples and I guess there is a recommended way
to
do that. Can numpy.fft.fftshift() do the work?

Many thanks for you help,
Jorge.

On Mon, 19 Jan 2015 08:46:22 -0500, Marcus D. Leech wrote:

That’s normal for FFTW-based FFTs (and a lot of others).

The output goes from:

DC to BW/2
-BW/2 to DC

Where BW is your signal bandwidth.

2

On 01/28/2015 10:03 AM, Jorge G. wrote:

I just need to flip the samples and I guess there is a recommended way
to do that. Can numpy.fft.fftshift() do the work?

Sure, just wrap that into a Python (sync) block. Make sure to operate on
vectors of the correct length! Your itemsize should probably be
fft-length x sizeof(complex).

M