Re: [Discuss-gnuradio] Receiver sensitivity of wbx, TVRX.
On 07/17/2010 02:54 PM, naveen nischal wrote: Hi All, Guess it has now become a cliche question. but we have been trying to make a link budget for the usrp and the AO-51 satellite and are looking for some help finding the receiver sensitivity of either the WBX or the TVRX. I have seen the discuss GNU radio archives and found like 50 questions about receiver sensitivity but did not find any answer. so if any of you who have been trying to know the same or do know how it works can help us get some information about it would be greatly appreciated. The reason you didn't find an answer is that there is no answer. It's kind of like asking what the temperature is without specifying when and where the measurement is to be taken. Sensitivity is only a meaningful measurement when you state the type of modulation, error correction coding, data rate, and acceptable error rate. 100 kbits/sec will have better sensitivity than 1 Mbit/sec. BPSK will have better sensitivity than QAM64. Rate 7 convolutional coding will perform better than hamming code. A required BER of 10e-3 will have better sensitivity than a required BER of 10e-6. The ONLY true universal measure of receiver quality is noise figure, and that is what we measure. If you have all the above info plus the noise figure, you can calculate the sensitivity. The TVRX will have a noise figure of 7-10 dB. The WBX noise figure is shown in great detail vs. frequency and vs. gain in the plots at: http://code.ettus.com/redmine/ettus/documents/16 At low frequencies the noise figure is 3 dB. At higher frequencies it rises to about 6 dB. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Receiver sensitivity of wbx, TVRX.
Hi Naveen, Ive been using the TVRX for AO-51 and NOAA APT (Automatic Picture Transmission). I have found that the TVRX is VERY sensitive I have been able to demodulate signals @ ~-115 dB. I always use a preamp at the antenna. My test results can be found here http://www.poes-weather.com/~patrik/AO-51/ and http://noaaport.poes-weather.com:8081/AO-51/ My TVRX is using Microtune 4937 and the tuner spec can be found at http://www.comsec.com/usrp/microtune/4937-DI5-3x8899-2.pdf I have no experience using the WBX. Patrik - Original Message - From: naveen nischal To: Discuss-gnuradio@gnu.org Sent: Sunday, July 18, 2010 0:54 Subject: [Discuss-gnuradio] Receiver sensitivity of wbx, TVRX. Hi All, Guess it has now become a cliche question. but we have been trying to make a link budget for the usrp and the AO-51 satellite and are looking for some help finding the receiver sensitivity of either the WBX or the TVRX. I have seen the discuss GNU radio archives and found like 50 questions about receiver sensitivity but did not find any answer. so if any of you who have been trying to know the same or do know how it works can help us get some information about it would be greatly appreciated. Thanks & Regards, Naveen -- ___ 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] USRP2 with Realtek r8169 Problem
On 07/16/2010 08:30 AM, Soeren Peik wrote: Hi all, I just received my USRP2 and hooked it up to a three month old Thinkpad Edge 13 intel with Realtek ethernet Chipset. System is: Ubuntu 10.04 LTS Lucid Lynx Firmware: txrx_wbx_raw_eth_20100608.bin FPGA-FW: u2_rev3-20100603.bin Daughterboard: WBX When i run the fft application with with sudo usrp2_fft.py -f98e6 I get overruns "SSS" and the GUI hangs. Changing the decimation does not help. The USRP2 is operating as I can clearly see the local FM-Stations in the spectrum. Older Threads suggested problems with inserted pauses. When checking with ethtool I get: Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Link partner advertised link modes: 1000baseT/Half 1000baseT/Full Link partner advertised pause frame use: No Link partner advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: MII PHYAD: 0 Transceiver: internal Auto-negotiation: on Supports Wake-on: pumbg Wake-on: g Current message level: 0x0033 (51) Link detected: yes And with nm-tools I get - Device: eth0 [USRP Link] Type: Wired Driver:r8169 State: connected Default: no HW Address:C8:0A:A9:25:64:5E Capabilities: Carrier Detect: yes Speed: 1000 Mb/s Wired Properties Carrier: on IPv4 Settings: Address: 192.168.10.1 Prefix: 24 (255.255.255.0) Gateway: 0.0.0.0 This looks OK to be. I do not get problems when transmitting. Do you any suggestion for a fix? Unfortunately, I do not have another computer here to try out other setups. Thanks in advance, Soeren ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio I did some more research and kind of fixed the problem. The problem is twofold. The Realtek driver is bad, as mentioned often here in the list. Try to avoid it when you can. I am stuck with it and get very bad performance. However it works with lower data rates, e.g. decimation of 50 or more. Do not run any other programs in parallel. Even by moving the mouse I get dropped packages. The issue of the hanging fft-graph can be fixed by reducing the fft-size to 512 or 256. Then the gui remains responsive. Soeren ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Receiver sensitivity of wbx, TVRX.
Hi All, Guess it has now become a cliche question. but we have been trying to make a link budget for the usrp and the AO-51 satellite and are looking for some help finding the receiver sensitivity of either the WBX or the TVRX. I have seen the discuss GNU radio archives and found like 50 questions about receiver sensitivity but did not find any answer. so if any of you who have been trying to know the same or do know how it works can help us get some information about it would be greatly appreciated. Thanks & Regards,Naveen ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] ATSC decoding - Zero Output Problem - Update
Hi all, I did some investigations regarding the zero output problem: First of all I installed gnuradio 0.9 on an old Red Hat 9 installation and made tests with the files from http://comsec.com/data/README. As the 0.9 ATSC DTV decoder works fine, I took the intermediate save files (*.rxout, can be obtained when using the log function) and used them as input for the version 3.x ATSC decoder. It turned out that everything works fine if I use the 0.9 output after the bit timing loop (bt_*.rxout) as input for the 3.x frame sync block. Further, if I use the 0.9 fpll output as input for the 3.x bit timing loop nothing happens (zero output). So I guess the problem can be isolated to the bit timing loop. I still do not fully understand the code, so I hope someone can help me to further isolate the problem. If we can fix this we would finally have a working gnuradio ATSC receiver again! Regards Klaus -Ursprüngliche Nachricht- Von: discuss-gnuradio-bounces+klaus.hueske=tu-dortmund...@gnu.org [mailto:discuss-gnuradio-bounces+klaus.hueske=tu-dortmund...@gnu.org] Im Auftrag von Klaus Hueske Gesendet: Donnerstag, 24. Juni 2010 09:52 An: discuss-gnuradio@gnu.org Betreff: Re: [Discuss-gnuradio] ATSC decoding Hi Stephen, Did you make progress with this zero byte output problem? Anyway, I'm wondering if the ATSC receiver implementation will work at all with the current version of Gnuradio. It looks like parts of the original ATSC implementation that was working with Gnuradio 0.9 have been adapted to be used in Gnuradio 2.0, but now we have 3.2.2. Anyone here who can verify that the provided code can decode ATSC signals? Thanks Klaus --- On Mon, Apr 19, 2010 at 8:12 PM, Stephen Branch wrote: >Hello everyone, > >I am part of Auburn University's Software Defined Radio Senior Design >team, > >Software being used: >Ubuntu v.9.10 on xfs partition >GNURadio v.3.3 (git) >Xine > >Available hardware: USRP1, USRP2, WBX daughterboard, TVRX daughterboard > >We followed the instructions in ./gnuradio/gr-atsc/src/python/README to >no >success. > >Using the FFT we found 507.25M to have a strong signal. According to >http://en.wikipedia.org/wiki/North_American_broadcast_television_freque ncie s#UHF_band > this is channel 20. >And according to >http://www.fcc.gov/fcc-bin/tvq?state=AL&call=&arn=&city=&chan=14&cha2=6 9&se rv=&type=0&facid=&list=2&dist=&dlat2=&mlat2=&slat2=&dlon2=&mlon2=&slon2= &siz e=9 > this is WCOV from Montgomery, Alabama. >So we do have the correct video carrier frequency, which I assume is >the >frequency we want to record and decode into a video. > >Question #1) Is the video carrier the one that carriers the video, or >would it >be the ATSC carrier? > >We then used: >./usrp_rx_cfile.py -s -d 10 -g 20 -f 507.25e6 atsc_data_6-4m_complex >./interp_short.py atsc_data_6-4m_complex ./xlate.py >./fpll.py >./btl-fsd.py >./viterbi-out.py test.mpeg > >Problems: >/tmp/atsc_pipe_5 never fills with data. >The output file, 'test.mpeg' is empty. > >Question #2) What do we need to fix to get /tmp/atsc_pipe_5 to fill. >Question #3) What do we need to fix to get temp.mpeg to fill. > >Thank you, >Bobby Black & Stephen Branch >addr...@hidden (please do not blank out this email) >black85 @ auburn . edu > >Bobby Black >Auburn University >addr...@hidden >(334) 804-4826 ___ 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
