Re: [Discuss-gnuradio] benchmark_rx n_right always 0

[Tom Rondeau]

On Tue, Jun 5, 2012 at 11:47 AM, Weixian Zhou <address@hidden> wrote:
> I am using benchmark_tx/benchmark_rx to transmit data on 2.41GHz:
> ./benchmark_rx.py -f 2.41G
> ./benchmark_tx.py -f 2.41G
>
> While I can receive packages at the rx end, the n_right field of every
> package is always 0. I know it means the package failed the CRC check. What
> might be the cause? I am using two USRP N210s and daughter boards are
> XCVR2450. The following are the displayed message  at rx end:
> address@hidden:~/Desktop/gnuradio/gr-digital/exales/narrowband$
> ./benchmark_rx.py -f 2.41G
> linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.004.002-128-g12f7a5c9

Hi Weixian,

Remember that these benchmark examples have no error correcting codes
in them, so a single bit error will cause the packet CRC check to
fail. Likely reasons for this include low SNR, nonlinearities in the
receiver/transmitter chain, and multipath channels. You might also
have a frequency offset between the two USRPs that's just a bit
outside of the channel filter's bandwidth such that you are distorting
it enough to cause errors but not so much that many of the bits are
still getting through.

Tom