Re: [Discuss-gnuradio] HELP! Is it a defective USRP1?
Thanks Josh! Problem solved after I adjust the bit rate. One more question, what is the maximum bit rate in USRP1? Also, what is the default sampling rate in benchmark_tx.py and benchmark_rx.py? Based on Nyquist theorem, the sampling rate should be at least twice of the baseband bandwidth, is the bit rate equal to the bandwidth of received signal? or there is something in the middle that I am missing? Thanks, Rachel On Tue, Nov 9, 2010 at 6:29 PM, Josh Blum wrote: > Try a higher rate (spectrally wider symbols). Maybe its an issue of > frequency offset. -Josh > > > On 11/09/2010 02:34 PM, Rachel Li wrote: > >> Hi All: >> >> I am experiencing something strange with USRP1 and already tried a lot of >> approaches to diagnose where the problem is, but no luck so far. >> >> We have two USRP1, each of which has a RXF 2400 daughter board and an >> antenna connected to the Tx/Rx port. When we run benchmark >> (benchmark_tx.py >> and benchmark_rx.py), the packet loss/corrupted rate is very random (from >> 0% >> to 99%). >> >> We've tried several approaches to diagnose where the problem, including >> (1) connect the Tx/Rx ports of two USRP by a SMA connector >> (2) try both sides of the mother board (A and B) , >> (3) use different central frequency from 2.4G to 2.48G, >> (4) adjust the carrier threshold (20 to 50), tx amplitude (0 to 1) and rx >> gain (0 to 90), >> (5) place the radios in different locations, >> (6) use different versions of gnuradio (stable release version 3.3.0 as >> well >> as the latest repository code) >> (7) place a fft sink at the rx to observe the spectrum, I can see the >> signal >> spectrum showing up when tx is transmitting something. >> >> Unfortunately, nothing really helps. >> >> Is it possible that it is a defective USRP? >> >> I really appreciate if anyone of you could guide me with this problem >> because I have a deadline to make in around 2.5 weeks. >> >> Thanks very much! >> >> Rachel >> >> >> >> >> ___ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > ___ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] HELP! Is it a defective USRP1?
Try a higher rate (spectrally wider symbols). Maybe its an issue of frequency offset. -Josh On 11/09/2010 02:34 PM, Rachel Li wrote: Hi All: I am experiencing something strange with USRP1 and already tried a lot of approaches to diagnose where the problem is, but no luck so far. We have two USRP1, each of which has a RXF 2400 daughter board and an antenna connected to the Tx/Rx port. When we run benchmark (benchmark_tx.py and benchmark_rx.py), the packet loss/corrupted rate is very random (from 0% to 99%). We've tried several approaches to diagnose where the problem, including (1) connect the Tx/Rx ports of two USRP by a SMA connector (2) try both sides of the mother board (A and B) , (3) use different central frequency from 2.4G to 2.48G, (4) adjust the carrier threshold (20 to 50), tx amplitude (0 to 1) and rx gain (0 to 90), (5) place the radios in different locations, (6) use different versions of gnuradio (stable release version 3.3.0 as well as the latest repository code) (7) place a fft sink at the rx to observe the spectrum, I can see the signal spectrum showing up when tx is transmitting something. Unfortunately, nothing really helps. Is it possible that it is a defective USRP? I really appreciate if anyone of you could guide me with this problem because I have a deadline to make in around 2.5 weeks. Thanks very much! Rachel ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] HELP! Is it a defective USRP1?
On 11/09/2010 05:34 PM, Rachel Li wrote: > Hi All: > > I am experiencing something strange with USRP1 and already tried a lot > of approaches to diagnose where the problem is, but no luck so far. > > We have two USRP1, each of which has a RXF 2400 daughter board and an > antenna connected to the Tx/Rx port. When we run benchmark > (benchmark_tx.py and benchmark_rx.py), the packet loss/corrupted rate > is very random (from 0% to 99%). > > We've tried several approaches to diagnose where the problem, including > (1) connect the Tx/Rx ports of two USRP by a SMA connector > (2) try both sides of the mother board (A and B) , > (3) use different central frequency from 2.4G to 2.48G, > (4) adjust the carrier threshold (20 to 50), tx amplitude (0 to 1) and > rx gain (0 to 90), > (5) place the radios in different locations, > (6) use different versions of gnuradio (stable release version 3.3.0 > as well as the latest repository code) > (7) place a fft sink at the rx to observe the spectrum, I can see the > signal spectrum showing up when tx is transmitting something. > > Unfortunately, nothing really helps. > > Is it possible that it is a defective USRP? > > I really appreciate if anyone of you could guide me with this problem > because I have a deadline to make in around 2.5 weeks. > > Thanks very much! > > Rachel > My suggestion is that you use a more basic diagnostic. Do both USRPs have roughly the same sensitivity and output power? If you transmit on one, and receive on the other with a FFT, with an attenuator between them, can the Rx side "see" the other side, use increasing levels of attenuation until the Rx can't see the transmitted signal anymore. -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] HELP! Is it a defective USRP1?
Hi All: I am experiencing something strange with USRP1 and already tried a lot of approaches to diagnose where the problem is, but no luck so far. We have two USRP1, each of which has a RXF 2400 daughter board and an antenna connected to the Tx/Rx port. When we run benchmark (benchmark_tx.py and benchmark_rx.py), the packet loss/corrupted rate is very random (from 0% to 99%). We've tried several approaches to diagnose where the problem, including (1) connect the Tx/Rx ports of two USRP by a SMA connector (2) try both sides of the mother board (A and B) , (3) use different central frequency from 2.4G to 2.48G, (4) adjust the carrier threshold (20 to 50), tx amplitude (0 to 1) and rx gain (0 to 90), (5) place the radios in different locations, (6) use different versions of gnuradio (stable release version 3.3.0 as well as the latest repository code) (7) place a fft sink at the rx to observe the spectrum, I can see the signal spectrum showing up when tx is transmitting something. Unfortunately, nothing really helps. Is it possible that it is a defective USRP? I really appreciate if anyone of you could guide me with this problem because I have a deadline to make in around 2.5 weeks. Thanks very much! Rachel ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
