Forum: GNU Radio a question about benchmark_rx.py and benchmark_tx.py

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Bill S. (Guest)
on 2008-10-09 21:50
(Received via mailing list)
Hello, everyone!

I am just running a demo program to realize communication between two
usrps using benchmark_rx and benchmark_py under the Python/digital dir.
But when I am trying to use dqpsk modulation scheme, the packets
received are totally wrong. What's wrong with the programs? I am really
confused. Could anybody give me a hint or help me out? Thank you!!!

Bill
Stefan Brüns (Guest)
on 2008-10-09 22:16
(Received via mailing list)
On Thursday 09 October 2008 19:47:10 Bill S. wrote:
> Hello, everyone!
>
> I am just running a demo program to realize communication between two usrps
> using benchmark_rx and benchmark_py under the Python/digital dir. But when
> I am trying to use dqpsk modulation scheme, the packets received are
> totally wrong. What's wrong with the programs? I am really confused. Could
> anybody give me a hint or help me out? Thank you!!!
>
> Bill

I had a problem with different oscillator frequencies on two boards, not
much
but enough for the digital pll in the receiving gnuradio block to lose
tracking.

As a workaround, I used the usrp_fft.py programm as a receiver, and on
the
sending side just a carrier. This way, I could determine the frequency
offset
between the two boards.

Stefan

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