Ok I will try that. Just for your information, throttle or not, it works in both cases on the Nutaq Zepto Le 2016-06-15 17:15, "Nick Foster" <bistrom...@gmail.com> a écrit :
> One clue for you is already being printed out for you in the TX flowgraph > image. Get rid of the throttle block. > > The RX time domain plot looks actually pretty healthy. It's showing a > frequency offset, which is normal for unsynchronized devices. > > The constellation plot needs to happen after timing and phase recovery, or > it will show useless garbage. Because your PSK demod is happening all in a > single, monolithic block, you don't get access to the constellation. If you > put a timing recovery block and a Costas loop block in front of the QT GUI > sink, and set their parameters appropriately, you should be able to get a > decent constellation plot. > > --n > > On Wed, Jun 15, 2016 at 1:26 PM Olivier Goyette < > olivier.goyett...@gmail.com> wrote: > >> I'm giving a copy of the email I just sent to Ettus Research. I think >> that it's been a hardware problem since the beginning but i'm waiting for >> their response. >> >> Check it out, maybe some of view have already seen this kind of bug >> >> >> *************************E-mail***************************************************** >> >> Hi ! >> >> >> >> My name is Olivier and I’m actually working with your USRP N210 and >> GNURadio Companion. It’s been a couple of week since I started using your >> equipment and yet, I already had issues with it. Doing a simple >> modulation/demodulation seems impossible and everything I came up with >> until now, suggest me that it’s a hardware problem. So, I took quite a lot >> of pictures for you to see what’s wrong and I’ll share the links to my >> dropbox so it will be easier like that. >> >> >> >> What I’m trying to do is a PSK mod and demod. I know it works because one >> of my colleague is using a Nutaq Zepto SDR and he’s been using the same >> flowgraph as mine in an other project and it works perfectly. So, what we >> did is the following setup : >> https://www.dropbox.com/s/ottq341sob5z90r/Actual_setup.jpg?dl=0 >> >> >> >> The upper radio represents the TX link (WBX card) and the one at the >> bottom represent the RX link (SBX card). >> >> >> >> This is the flowgraph on the TX radio : >> https://www.dropbox.com/s/ir5ehp6caiy525a/TX_side.jpg?dl=0 >> >> >> >> This is the flowgraph on the RX radio : >> https://www.dropbox.com/s/tl95cwbstwzl4r8/RX_side.jpg?dl=0 >> >> >> >> What we’re trying to do is to transmit a video stream from one computer >> to another. Unfortunately, on the RX computer, the file supposedly >> containing the video is empty (0 bytes when you right click on it and go to >> the properties panel). >> >> >> >> This is the TX spectrum : >> https://www.dropbox.com/s/pzsn8oo74sgrehp/TX_spectrum.jpg?dl=0 and this >> is the spectrum when you look at it with a spectrum analyser : >> https://www.dropbox.com/s/5bks7aksih8ctzh/TX_MDO_spectrum.jpg?dl=0 >> >> >> >> This is the RX spectrum : >> https://www.dropbox.com/s/dlsovfxovv4n9tm/RX_spectrum.jpg?dl=0 >> >> >> >> This is the TX time domain graph : >> https://www.dropbox.com/s/q25sbjukyzsyymz/TX_time_domain.jpg?dl=0 >> >> >> >> This is the RX time domain graph : >> https://www.dropbox.com/s/qetgf0cr4s7d5hb/RX_time_domain_1.jpg?dl=0 >> >> >> >> This is the TX constellation : >> https://www.dropbox.com/s/gflb0f65oa0m1rl/TX_constellation.jpg?dl=0 >> >> >> >> This is the RX constellation : >> https://www.dropbox.com/s/4j0hnhl97v2uj7g/RX_constellation.jpg?dl=0 >> >> >> >> What seems strange to me is the time domain graph at RX. It’s like if the >> imaginary part and the real part of the signal were modulated onto whatever >> signal that appears to be there. I tried my RX link on one of the other >> radio I have and look at the result : >> https://www.dropbox.com/s/f1al75vgo5z2wcf/RX_time_domain_2.jpg?dl=0 . >> The time domain is completely different but still it is a SBX card and I >> haven’t touch any settings in my flowgraph to keep consistency. >> >> >> >> So, now I’m asking for your help because my knowledge is pretty basic >> with this equipment and I’d like to have your input about that. >> >> >> >> For your information, I did reload the firmware and the bitfile into the >> FPGA before sending this email so it’s not necessary to ask me to do it. >> >> >> >> I sincerely hope this will lead somewhere as I’m out of options right now. >> >> >> Thank you for your time and have a nice day ! >> >> 2016-06-15 13:58 GMT-04:00 Marcus Müller <marcus.muel...@ettus.com>: >> >>> Hi Olivier, >>> >>> what does this mean: >>> >>> The 1st file contains only '1' and the other only '0'. >>> >>> How did you generate these files. Without knowing better, I'd say this >>> is a case for our File Format FAQ: >>> >>> >>> http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#What-is-the-file-format-of-a-file_sink-How-can-I-read-files-produced-by-a-file-sink >>> >>> Best regards, >>> Marcus >>> >>> On 06/15/2016 12:25 AM, Olivier Goyette wrote: >>> >>> This is non sense seriously. This is my flowgraph : >>> <https://www.dropbox.com/s/4cfptq5419kvyhz/file_source.png?dl=0> >>> https://www.dropbox.com/s/4cfptq5419kvyhz/file_source.png?dl=0 >>> >>> When I send only zeros '0', this is what I get : >>> <https://www.dropbox.com/s/aipf6wsj5ekwxnb/zeros.png?dl=0> >>> https://www.dropbox.com/s/aipf6wsj5ekwxnb/zeros.png?dl=0 >>> >>> When I send only ones '1' this is what I get : >>> <https://www.dropbox.com/s/g38hgrtc7s6exyt/ones.png?dl=0> >>> https://www.dropbox.com/s/g38hgrtc7s6exyt/ones.png?dl=0 >>> >>> When I interleave both ones and zeros '1' & '0' , this is what I get : >>> https://www.dropbox.com/s/a1cfs0tebmywz0l/interleave.png?dl=0 >>> >>> What's wrong seriously ? If I can't even modulate properly, how am I >>> suppose to make this work ? >>> >>> 2016-06-14 9:54 GMT-04:00 Olivier Goyette <olivier.goyett...@gmail.com>: >>> >>>> Hi >>>> >>>> I have a problem. On my first setup, I use 2 file source. The 1st file >>>> contains only '1' and the other only '0'. The 2 file sources go through a >>>> selector and end up in a CPFSK mod block. When I run this, switching from >>>> '1' to '0' makes the frequency drift from + to - FSK_deviation like it >>>> should do normally. Now, when I use a unique file source containing '1' and >>>> '0' (actually I wrote up the alphabet in a file) and I run this, this is >>>> what I get : >>>> https://www.dropbox.com/s/4tdswnmp79lj67c/unique_file_source.png?dl=0 >>>> . Any Idea why it's doing this. Is it the rate of transmission that does >>>> this, like if it was to fast ? >>>> >>>> my setup : >>>> https://www.dropbox.com/s/snamjalklskfdzh/single_file.png?dl=0 >>>> >>>> Thank you >>>> >>> >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing >>> listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >
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