Sorry I reread your original email, ... you're now using settings where the there are no more (or very few) USRP overruns? Is that correct?
Yes. When using smaller fusb_nblock and fusb_block_size parameters, I don't see any 'uO' when running the script.
In that case it's not the overruns, it's the detector. I suspect there is too much noise or the gain is set wrong. What reason do you have to believe that 20% packet loss is not expected? What's the SNR?
I was under the impression that when using a cable to connect TX and RX boards, the SNR should be very high and the BER or PER should be close to 0. Could it be that the SNR is too high and the signal is saturated? I tried using antennas instead. The packet loss ratio is about the same as as when I'm using a direct antenna cable. That's why I believed the loss is not due to the physical channel. (can't be 100% sure with this kind of logic though) I don't know how to measure the SNR with existing GNU Radio blocks. Is there any fast ways to do this?
Especially at large symbol rates (like 2MHz), there is no reason to expect that the error performance would be 0% packet loss without actually knowing the SNR.
That's usually due to insufficient channel coherence bandwidth. That shouldn't be the case for the antenna cable. Many thanks, -Michael -- Hsin-Mu (Michael) Tsai Ph.D. Student Electrical and Computer Engineering Department Carnegie Mellon University E-Mail: [EMAIL PROTECTED] Web: http://www.ece.cmu.edu/~hsinmut/ Office: +1-412-268-4639 _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio