[Discuss-gnuradio] parameters for poly-phase clock sync
Hi, I am trying to use the the poly-phase clock sync. At high S/N levels it works very well but at low S/N (<20dB S/N) it's performance is very bad. Which probably means I have made a mistake somewhere. The parameters I am passing to the module to generate the mother filter are firdes.root_raised_cosine(10,samp_rate*n_filters,symbol_rate,0.35,31*n_filters) where samp_rate = 200 n_filters = 32 (number of filters in the filterbank) symbol_rate = 100 0.35 is the filter's Beta 31 is the length of each filter in the filterbank I have read the book the filter is derived from so I know what it is trying to do but obviously I have messed up somewhere. Thanks - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] GNUradio DVB-S/S2
Hello Dinos, As no one has answered you I will have a try. Physically the USRP can send DVB-S and DVB-S2 the main problem may well be the symbol rate you require to mimic the satellite transponder. As far as Gnuradio S/W is concerned I am not aware of anything that will do what you want at the moment. I have written some DVB-S and DVB-T code and am in the process of writing DVB-S2 code but none support the data services you require. My code is not publicly available as it needs to be cleaned up and made pretty first. Eventually (time frame undecided) I and a group of other Radio Amateurs intend releasing all the code and a companion low cost 1.3 GHz transmitter USB dongle to go with it. Currently the USRP2 is being used as a development platform. - Charles On 02/03/2011 11:32, Dinos Pastos wrote: Hi there Just a quick question related to GNUradio. Is it possible to use USRP2 + WBX + Gnuradio to send DVB-S or S2 signals to a satellite set top box (using a cable) I am trying to emulate an OTA update on a box I have which tunes to a specific Freq/Transponder to download its OS. Please let me know Regards Dino ___ 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] Trying to use gnuradio-companion
Hi All, When I try running gnuradio-companion I get File /usr/local/bin/gnuradio-companion, line 45, in module %gr.version() AttributeError: 'module' object has no attribute 'version' Anyone know what I have done wrong? - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Trying to use gnuradio-companion
On 26/01/2011 19:48, Marcus D. Leech wrote: its importing a really old gnuradio that doesnt have gr.version() in other words, you have multiple gnuradios installed -josh And your PYTHONPATH likely points to the wrong version. Yes you were both right. I have it working now. Thanks. - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Setting UHD kernel buffers
When setting the kernel max buffers for UHD the manual suggests using sudo sysctl -w net.core.rmem_max=new value sudo sysctl -w net.core.wmem_max=new value I have done that on my system and it has made a huge difference to the performance of my software. I can now transmit my DVB-T signal continuously at 10 Ms/s with no dropouts. Unfortunately everytime I reboot my system I have to run the commands again. What is the procedure for making these settings permanent? I am no Linux guru hence the question. I am using Fedora 12. - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] WBX power level
Well I am glad to say my low power problem is fixed. In the end I had to go into my uhd directory do a git pull followed by a make and then a make install. I now have 60 mW on 1.3 GHz. Thanks for the help guys, especially to Jason Abele. - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] WBX power level
- Original Message - From: Jason Abele ja...@ettus.com To: Charles Brain chbr...@btinternet.com Cc: discuss-gnuradio@gnu.org Sent: Monday, June 14, 2010 7:03 PM Subject: Re: [Discuss-gnuradio] WBX power level Hi All, Has anyone measure the power level coming out of their WBX board? Measured on a Gigatronics 8541 microwave power meter connected directly at the back of the USRP2 I am getting (with a CW carrier) 100 MHz about 35 mW 1.3 GHz about 15 mW Ettus quote 50 - 100 mW 1.2 GHz 30 - 70mW 1.2 GHz I know measuring power is notoriously inaccurate but I was wondering what others have found. Setup USRP2 WBX UHD Please try the following command with non-UHD for comparison: usrp_siggen_gui.py -x 250k -i 64 --tx-gain=25 -A 1.0 -f 1.3G You should see about 50mW (17dBm) at 1.30025GHz If you change the final argument to 100M you should see around 80-100mW (19-20dBm) in the tone at 100.25MHz If you can confirm those numbers, perhaps we have a constant scalar missing in either your flowgraph or the UHD code someplace. Thanks Jason Hi Jason, I got the test done this morning (after I re-installed gnuradio 3.2.2 ) Using usrp_siggen_gui.py -x 250k -i 16 --gain=25 -a 1.0 -f 1.3G 60mW @ 1.3 GHz 126mW @ 100 MHz Using my code and UHD (my code modified to write I = 0x7FFF, Q = 0x7FFF) 14.4mW @ 1.3 GHz 33.8 mW @ 100 MHz Using my code and UHD ( my code modified to write I = 0x7FFF, Q = 0x0) 14.8mW @ 1.3 GHz 24.8 mW @ 100 MHz I ran the power meter's self calibration routine before taking the measurements this time and applied the correct frequency correction. Looks like we have a bit missing :-( - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] WBX power level
Hi All, Has anyone measure the power level coming out of their WBX board? Measured on a Gigatronics 8541 microwave power meter connected directly at the back of the USRP2 I am getting (with a CW carrier) 100 MHz about 35 mW 1.3 GHz about 15 mW Ettus quote 50 - 100 mW 1.2 GHz 30 - 70mW 1.2 GHz I know measuring power is notoriously inaccurate but I was wondering what others have found. Setup USRP2 WBX UHD - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] WBX power level
- Original Message - From: Philip Balister phi...@balister.org To: Charles Brain chbr...@btinternet.com Cc: discuss-gnuradio@gnu.org Sent: Saturday, June 12, 2010 4:54 PM Subject: Re: [Discuss-gnuradio] WBX power level Is your flowgraph delivering the maximum amplitude to the USRP? Philip I am not using gnuradio I am using C++ code that talks directly to the USRP2 using the UHD interface and I have it writing 0x7FFF to the I channel and 0 to the Q channel. I also tried 0x7FFF to both I and Q with similar results. - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Carrier leakage on transmit
3 - Measure the amplitude of the TX DC offset as received by the RX (in this case at -1 MHz). Iteratively adjust your I TX DC offset number until you get to the lowest power you can see. Then do the same for Q. If it still isn't low enough, do I again. Matt Hi Matt, Are the settings for the I and Q adjustments independent or do I have to iterate between them for the lowest error? Also if I am sending a 0 amplitude signal can I simply AM detect the received signal to measure the dc error value? Finally what is the simplest way to synchronise receive, so I can make sure I am associating a particular DC offset error with a corrected transmitted block? I can see the carrier going up and down on the Analyser but my routine comes up with some silly values. I think it is because I have the routine out of sync. Sorry for the dumb questions :-) - Charles setup WBX, USRP2, UHD ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Carrier leakage on transmit
Hi, Is there any way of calibrating out or mitigating the carrier at the WBX tx frequency? I am sending a wideband signal and the carrier (which I assume is due to dc coupling in the WBX) is at a significant level compared to my signal. - Charles Kit USRP2 - WBX - UHD http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Carrier leakage on transmit
Hi Johnathan, You can offset the carrier with UHD by passing a 2nd parameter in the set_tx_freq call. Unfortunately it only seems to work with small offsets, far too small to take it outside the passband of my signal. :-( It was not so much of a problem with my DVB-S code but I am now playing with DVB-T and I can see it in the middle of the ODFM waveform swamping the pilot tones. I think some form of calibration routine is going to be necessary. I guess I will just have to be patient and wait. - Charles - Original Message - From: Johnathan Corgan jcor...@corganenterprises.com 'set_lo_offset', which will adjust the analog LO in frequency and to your desired tuned frequency. I'm not sure what the equivalent function in the UHD is; it may not be implemented yet. This at least lets you move the spurious carrier outside the passband of your transmit signal. In order to fully remove it, either DC offset trimming would need to be implemented in the FPGA, or host code/firmware written to tweak the built-in DAC DC offset compensation. I've done the former for clients, and it works well. Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Carrier leakage on transmit
Hi Johnathan, I tried an offset of 10 MHz and the output on the spectrum analyser looks frazzled, it no longer looked clean. Funnily enough the satellite receiver still managed to lock to the signal. I am fiddling about with an anti aliasing filter at the moment but when I have that sorted I will try some other offset values. In my last post I should have said OFDM not ODFM. - Charles - Original Message - From: Johnathan Corgan I haven't had the opportunity to try recent versions of UHD; I'll get to that this week. But you should be able to move the LO at least 10-12 MHz away. Your feedback on the TX side issues you've encountered have already been very useful, thanks. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Carrier leakage on transmit
Well I have had another look at the offset stuff. What seems to be happening is that when you apply an offset you have to scale back the max IQ values being sent to the USRP2. I get this situation. No LO offset, great raised cosine shaped QPSK signal Add LO offset, QPSK signal looks awful. Reduce IQ signal amplitude QPSK signal again looks good and I can see the LO offset on the spectrum analyser. I have also noticed that when I try OFDM the unwanted rubbish on either side of my OFDM signal changes with LO offset. There seems to be an interaction in there somewhere probably to do with the complex mixer in the FPGA. I have not ruled out my own code yet but it seems unlikely. - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] UHD tx phenomenon
Hi, Sorry for the subject line but I couldn't think of what else to call it. I have been using the UHD in my application and while adding the facility to my GUI to transmit different symbol rates I noticed that when I am transmitting samples and send a tx_set_rate command strange things happen. The output becomes distorted and the Ethernet activity drops. When I go back to the original tx_rate most times it recovers. Are there any known problems with the UHD concerning rate changes while sending? - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Which version of UHD firmware should I be using?
Hello, I am a bit confused, there seems to be two versions of the UHD firmware a Raw Ethernet version and a UDP version. I am about to try and move my USRP2 application to UHD and I was wondering which version I should be using? I have a USRP2 and a WBX board. - Charles http://www.g4guo.blogspot.com/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Which version of UHD firmware should I be using?
Thanks Tim, I wanted to make sure I was backing the right horse. I have flashed the UHD UDP version and can ping it from my host. Next I have to figure out how to build all the UHD utils. I will have a look back at past emails to see if I can figure it out. - Charles http://www.g4guo.blogspot.com/ - Original Message - From: Tim Pearce timothy.pea...@gmail.com To: Charles Brain chbr...@btinternet.com Cc: discuss-gnuradio@gnu.org Sent: Sunday, May 09, 2010 12:03 PM Subject: Re: [Discuss-gnuradio] Which version of UHD firmware should I be using? Charles, If your looking to move applications to the long term solution you probably want : UHD with UDP ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] How to use the UHD API?
Hi, Well I can now find my usrp2 using uhd_find_usrps. After sorting out how to have 2 Ethernet connections on my PC and sending things to the right interface and getting my firewall to play ball :-) What I now want to do is to configure the WBX set the interpolation ratio and then start streaming samples to the usrp2 directly from my C++ application. I am looking for an example of how to do this. I have looked at simple_usrp.hpp but I am not sure how to use it. I think it describes the API rather than a load of virtual functions I have to implement. All this is a bit outside my comfort zone at the moment. - Charles http://www.g4guo.blogspot.com/ - Original Message - From: Josh Blum j...@joshknows.com To: discuss-gnuradio@gnu.org Sent: Sunday, May 09, 2010 4:52 PM Subject: Re: [Discuss-gnuradio] Which version of UHD firmware should I beusing? I should have added some notes when I put up the download link. For FPGA, get the UDP FPGA image. For firmware, get the UHD image (there is only one). ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] how to decide the number of taps of RRC filter
This is what I use http://www-users.cs.york.ac.uk/~fisher/mkfilter/racos.html - Charles - Original Message - From: Yan Nie yn...@uwo.ca To: discuss-gnuradio@gnu.org Sent: Monday, April 26, 2010 10:55 PM Subject: [Discuss-gnuradio] how to decide the number of taps of RRC filter Dear all, I'm trying to transmit a sequence with code rate of 3kHz. How to decide the number of taps of RRC filter? Or is there any good reference talking about how to calculate the number of the taps? Thank you so much in advance! Regards, Yan ___ 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] Hardware sampling rates
Hi, Would it be possible (now)/( or in the future) to be able to change the sampling rate of the DAC in the USRP2 using an external clock? I am working on stuff that is pushing what is possible in software and not having to add extra overhead simply to do up/down interpolation to get to something that divides into 100M would be really useful. I have tried the fractional interpolator and it just sucks too many CPU cycles. - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] using sig_source_c on a USRP2
Hello again Brian, Well here is the screen shot. http://www.chbrain.dircon.co.uk/usrp2_signal.jpg The sample rate was set to 20 M, the frequency to 5 MHz and the interpolation to 20. The WBX carrier was set to 1 GHz I am sure I have done something wrong - Charles - Original Message - From: Brian Padalino bpadal...@gmail.com To: Charles Brain chbr...@btinternet.com Cc: discuss-gnuradio@gnu.org Sent: Sunday, February 21, 2010 7:55 PM Subject: Re: [Discuss-gnuradio] using sig_source_c on a USRP2 You should definitely be able to see something at 1.001GHz, but any residual DC offset will also cause a spike at 1.000GHz when using a vector modulator. What's your resolution bandwidth set at on your spectrum analyzer? Can you post a link to a screen shot or two? Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] using sig_source_c on a USRP2
The problem has now been solved. I had assumed the USRP2's DAC sample rate of 400 MS/s was the rate I had to interpolate to. Not so, it should be 100/s MS/s. Thanks all - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] using sig_source_c on a USRP2
Hello, I have been playing around with the USRP2, mainly to get a feeling for how much data I can pass across the Ethernet. I have noticed something odd When I use sig_source_c with a sample rate of 20 Ms/s and a frequency of 1 MHz with the WBX board set to 1 GHz and the interpolation set to 20 I would have expected the output on the HP 8592L to be at 1.001 GHz but it is at 1 GHz. I have tried various combinations of sample rate and frequency and can make little sense of what is happening. When I use the audio sink and use sig_source_f it works exactly how I expected. What am I doing wrong ? - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] using sig_source_c on a USRP2
Hello Brian, Sorry it is not possible to get a screen shot at the moment mainly because I have turned everything off for the day and not having a GPIB i/f on the analyser I would have to find my video digitiser and take a snapshot from the video out. I can see the residual at 1 GHz it is just that the main signal is not where I was expecting it. The signal is 30 db above the residual. When I set the frequency to 10 MHz for example the main signal is at about +2 Mhz above the residual (from memory). I thought I might be doing something wrong or using something that was not supported. The documentation is fairly sparse and even more so on the USRP2. The USRP2 sinks don't have the same naming format as those for the USRP1 i.e sink_32fc vs sink_c which confuses me. - Charles - Original Message - From: Brian Padalino bpadal...@gmail.com To: Charles Brain chbr...@btinternet.com Cc: discuss-gnuradio@gnu.org Sent: Sunday, February 21, 2010 7:55 PM Subject: Re: [Discuss-gnuradio] using sig_source_c on a USRP2 You should definitely be able to see something at 1.001GHz, but any residual DC offset will also cause a spike at 1.000GHz when using a vector modulator. What's your resolution bandwidth set at on your spectrum analyzer? Can you post a link to a screen shot or two? Brian ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Some help required piping samples to the USRP2/WBX
Hello, I am trying to write a python script which will allow me to take some 16 bit IQ samples from a file and write them out to my USRP2/WBX. The background is that I am trying to implement what has been done on here http://www.m0dts.co.uk/datv_live.htm but instead taking the output of gbDVB piping it through an app I am writing (to do the raised cosine filtering) then piping that to the USRP2 Unfortunately GnuRadio is a bit daunting at the moment especially finding what various things are especially as some usrp blocks don't seem to exist for the usrp2 or their input formats are different. What I need to do is set the tx frequency to 1249 MHz select the correct antenna output then pipe samples from the input file to the usrp2 sink. Any pointers would be most useful. Be gentle - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] USRP2 WBX selecting the antenna
Well I am pleased to say that the txrx_wbx.bin firmware from Jason's git seems to work on my USRP2 - WBX combination. These SD cards are strange, I have two identical SD cards same manufacturer (Kingston) size etc. One works and one does not on the USRP2. On both cards the USRP2 lights come on as expected but the USRP2 can't be seen on one of them. Oh well. - Charles ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] USRP2 WBX selecting the antenna
I assume it will be in /releases/usrp2-bin/trunk - Charles We haven't posted the USRP2 firmware which supports the WBX yet. Look for it later today. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] USRP2 WBX selecting the antenna
Hello, I just got my USRP2 and WBX today and am trying to test it. find_usrps finds it, and usrp2_fft.py produces a spectrum display but when I generate a low level signal I don't see it on the display. I have looked at the schematic and it seems to indicate I have not selected the antenna input but I can't figure out how to do it. usrp_fft.py will take an antenna selection but usrp2_fft.py does not. Can someone tell me what to do next, I have searched the email archive and can't find an answer to this obvious question. - Charles aka G4GUO ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
