[Discuss-gnuradio] Flex2400 and benchmark_rx.py - receiving only fractio
From:
sri ram
Subject:
[Discuss-gnuradio] Flex2400 and benchmark_rx.py - receiving only fraction of packets
Date:
Mon, 24 Dec 2007 14:51:05 -0500
Hi all, I am working with Flex2400 boards and the USRP. I have a question about the digital module (GMSK data transfer). I observe this: When I send 660 packets , I receive less than 400 of them and less than
200 are correct.
I setup two PCs with ubuntu and with an USRP each. The antennas were connected to the TX/RX ports on each USRP and separated around 3.2m. Basic tests such as oscope and fft work fine, with one side sending. Then with
benchmark, on one end I use: ./benchmark_tx.py -f 2.412G --tx-amplitude=20000 -v -r 500k and the other ./benchmark_rx.py -f 2.412G --rx-gain=70 -v -r 500k
For different runs, errors happen and in a typical run I get something like
ok = False pktno = 662 n_rcvd = 355 n_right = 164
I did the following (which did not help) 1) varied rx gain and tx_amplitude over a range 2) checked the frequency 2.412 (using oscope and iwlist) and also changed to other free frequencies
3) repeated experiment at a different time and day The ratio of the pktno to n_rcvd and n_right remains almost the same for different runs. Further, if I send send traffic the other way, I get lesser number of packets (100) correct.
Has anyone seen something like this? Specifically, I am looking at why the RX would receive only a fraction of packets and why only a smaller fraction would pass crc?
Thanks for your help, Sri. P.S. I am attaching the output of the rx side.