Thanks for your email Eric, no, there is no underrun or overrun, the CPU usage is really low (even with the loggin activated), i am running it on a i7 processor.
you usually get a much sharper constellation, don't u? On Tue, Apr 7, 2009 at 8:34 PM, Eric Blossom <e...@comsec.com> wrote: > On Tue, Apr 07, 2009 at 11:07:54AM -0700, Paco Garcia wrote: > > > > Dear All, > > > > I am trying to demod a qpsk from another USRP but with the setup below I > get > > a really noisy constellation: > > > > http://img231.imageshack.us/img231/2465/screenshotysh.png > > > > The 2 USRPs are connected via a SMA cable with 40 db attenuators and DC > > blocker. > > I have also played with the costas alpha, samples per symbol, gain mu, > > frequency fine tunning and this is the best result I can get. > > > > ./benchmark_tx.py -m dqpsk -f 1.25G -m dqpsk --tx-amplitude=10000 -r 1M > -M > > 99999999 --excess-bw=0.35 > > ./benchmark_rx.py -r 1M -m dqpsk --log --costas-alpha=0.05 -S 4 --verbose > -r > > 1M --gain-mu=0.01 --excess-bw=0.35 -f 1.25G > > > > Thanks for your help. > > Are you getting overruns ("uOuO") on the rx side? > If so, try running at a lower data rate, say 500k. > > Eric >
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