Re: [Discuss-gnuradio] All packets may lose when running benchmark example in gr-digital/examples/narrowband

[Martin Braun (CEL)]

On Thu, Dec 05, 2013 at 06:47:16PM +0800, Damon wrote:
> When I was running benchmark example in gr-digital/examples/narrowband,
> all packets may lose. The environment is shown below.
> Hardware: USRP N210 with WBX
> Software: GNU Radio v3.7.2.1-62-g6195ff3c and UHD_003.006.000-0-g58f4af97
> 
> The two USRPs are placed close to each other. The example is run by:
> On the TX side: python benchmark_tx.py -f 1.55G -m qpsk -r 200k -M 10
> On the RX side: python benchmark_rx.py -f 1.55G -m qpsk -r 200k
> 
> Sometimes, all packets could be received. Then I restarted test, nothing
> was printed in the terminator on the RX side.
> It looks like a random event. I guess there is something wrong with
> timing synchronizer in the receive path.
> By the way, everything is ok when we do the test with gmsk.

This can happen, it takes a bit of practice to transmit and receive a
clean signal. There lots of reasons this can go wrong: Interference,
non-linear distortions (wrong gain settings)...
GMSK is a bit more robust in these regards.  Nothing to worry about!

MB

-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
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KIT -- University of the State of Baden-Württemberg and
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