Re: [Discuss-gnuradio] RFNoc and data rates

[Nicolas Cuervo Benavides]

Hi Sylvain,

Sorry for reviving a relatively old issue. I see that you mentioned some tweaking to be done on the fft block when the signal are weak. I'm currently working on an application using this RFNoc blocks and I'm having that problem: I'm calculating the power received at my radio and below some power level all my samples are mapped to zero. I'm migrating this power calculation from a previous GNURadio host implementation, and so far I haven't been able to determine where is that tweaking to be done. Needless to say that I'm new in the RFNoC part of SDR.

Would it be possible to elaborate a little bit more on the matter?

Thank you in advance!

Regards,

Nico

On Wed, Sep 23, 2015 at 10:10 AM, Sylvain Munaut <address@hidden> wrote:

Hi,

>> My question is, is this possible using current RFnoc blocks?, with for
>> example an average block?

One thing worth considering is the internal precision.

I'm not familiar with the requirement for RA but I assume if you do a
lot of averaging it's to get rid of the noise and dig out very weak
signals.
The current average block might not have enough internal precision for
your needs and might need to be tweaked a bit.


>> Also wondering if a 8k channel FFT block might be expected in RFNoc
>> anytime soon?

Most of the blocks currently assume that 1 vector / fft size = 1
packet. And packets have to fit within the MTU, so with 4 bytes per
sc16 sample, that's 2048 which is the current limit. And I think even
the internal RFNoC fifos are sized with this MTU size in mind.

So for larger FFTs you'll need other mechanism to synchonize the FFT
boundaries, like the EOB flag.

Cheers,

  Sylvain

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Nicolás Cuervo Benavides

Handy: +49 157 70476855

Electric and Electronic Engineering department.

Electronic Engineering

Universidad Nacional de Colombia

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Student M.Sc. Information and Communication Technology

Karlsruher Institut für Technologie

Karlsruhe, Baden Würtemberg, Germany