[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] USRP producing samples larger than 2^8

From: Eric Blossom
Subject: Re: [Discuss-gnuradio] USRP producing samples larger than 2^8
Date: Wed, 14 Mar 2007 21:13:38 -0700
User-agent: Mutt/1.5.9i

On Wed, Mar 14, 2007 at 07:31:33PM -0700, Chris Stankevitz wrote:
> Hi,
> Should I get samples with a magnitude > 128 from the USRP no FPGA gain?
>  I believe the answer is no.  Take a look at these plots of the data I
> am getting (plot of real portion only):
> http://img157.imageshack.us/img157/8648/plot1gi6.gif
> http://img245.imageshack.us/img245/8528/plot2fp1.gif
> I collected the data using this method:
> ./usrp_rx_cfile.py -d 16 -f 1575420000 -g 0 -N 4000000 file.dat
> Furthermore, I created a test jig which wrote USRP output to stdout and
> verified these spikes are not in the binary file or the binary file
> reader.  I'm using the DBSRX with a GPS antenna and a low noise amplifier.
> Thank you!
> Chris


Does it only occur once, and does it occur in the first 1024 samples?
That is, if you look at, say 1M points, is there only a single

If yes to all 3 questions, then I think you're seeing a known problem
where for some not fully understood reason (but probably related to
failing to properly reinit the FX2 buffers and/or the FPGA) you get
the sinc looking spike.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]