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[Discuss-gnuradio] Large number of overflows...
From: |
Ian Holland |
Subject: |
[Discuss-gnuradio] Large number of overflows... |
Date: |
Mon, 12 Apr 2010 13:52:01 +0930 |
Hi All
I am trying a modified example of the digital-bert routines, for
communication between 2 USRP2s, and notice that I am getting a very
large number of overflows (SSSS....) even with decimation rate at the
receiver of 20, and 4 samples per symbol (sometimes even with 20
samples/symbol). If I don't get overflows (as has occurred when I used
20 for decimation as well as 20 for samples/symbol in one instance), I
am able to capture the demodulated bits as 111111111111111111111111...,
as expected for the example. However, with overruns, which seem to occur
more for lower samples per symbol and/or lower decimation values, I get
a large number of bit errors.
My receiver flowgraph is of the form:
USRP2 Source --> RRC Filter --> Costas Loop --> Mueller and Muller Synch
--> Complex to Real --> Binary Slicer --> Descrambler --> File Sink.
The transmitter flowgraph uses the same blocks as per
digital-bert/transmit_path.py, but with a USRP2 sink.
I am transmitting over-the-air, and clocks are not synchronised between
Tx and Rx.
I have a gigabit Ethernet link, and 2 x 2 GHz CPUs in my PC, which is
running Ubuntu 9.10.
Can anyone suggest why I am getting so many over-runs, and how I could
get around this problem?
Thanks
Ian.
- [Discuss-gnuradio] Large number of overflows...,
Ian Holland <=
- Re: [Discuss-gnuradio] Large number of overflows..., Matt Ettus, 2010/04/22
- RE: [Discuss-gnuradio] Large number of overflows..., Ian Holland, 2010/04/22
- Re: [Discuss-gnuradio] Large number of overflows..., Josh Blum, 2010/04/22
- Re: [Discuss-gnuradio] Large number of overflows..., Matt Ettus, 2010/04/22
- Re: [Discuss-gnuradio] Large number of overflows..., Marcus D. Leech, 2010/04/23
- Re: [Discuss-gnuradio] Large number of overflows..., Johnathan Corgan, 2010/04/23
- RE: [Discuss-gnuradio] Large number of overflows..., Ian Holland, 2010/04/23