Thank you for everyone's input. We are aware and taking this very seriously. We tried unsuccessfully to reproduce the issue on multiple devices using both the v3.13.0.3-rc1 tag and head of master. We will continue investigating and report back with any new information.
Regards, Michael On Mon, Oct 29, 2018 at 7:07 AM Lundberg, Daniel via USRP-users < usrp-users@lists.ettus.com> wrote: > I think I am seeing the same or a similar problem using the latest master > (which I think is roughly equivalent to 3.13.0.3 RC1, correct me if I am > wrong) on an N310. > > When I save a signed 16-bit binary file and feed it into the > replay_sample_from_file example, I can only provide it with a full-scale > amplitude of ~8 bits in amplitude (+/- 2^8-1), or I get saturation / > strange corruption of the waveform. Changing the gain does not seem to > have any effect. The N310 is supposed to have a 14-bit DAC, and > conversations with Ettus imply that the replay block is too simple to cause > this, so the problem is probably pretty far upstream? I have described the > problem to Ettus, and they suggested checking most of the things you and I > have already tested (gains, input files, etc…). > > > > *From:* USRP-users <usrp-users-boun...@lists.ettus.com> *On Behalf Of *Serge > Malo via USRP-users > *Sent:* Monday, October 29, 2018 9:55 AM > *To:* sdorm...@eng.ucsd.edu > *Cc:* USRP-users@lists.ettus.com > *Subject:* Re: [USRP-users] Saturation issue with low amplitude (USRP > N310) > > > > Hi all, > > > > any news on this saturation issue concerning the N310 with UHD 3.13.0.3 > RC1? > > I would like to know if Ettus is aware of this problem, and if a new UHD > version is coming with a correction? > > > > Thanks! > > > > Best regards, > > Serge > > > > > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > - - - - - - - - - - - - - > > *Serge Malo * > > CDO & Co-founder, Skydel Solutions > > Cell: 1-514-294-4017 > > www.skydelsolutions.com > > Twitter: @skydelsol <https://twitter.com/skydelsol> > > Avis : Ce message est confidentiel et protégé par le secret professionnel. > Si vous n'êtes pas le destinataire, veuillez informer l'expéditeur par > courriel immédiatement et effacer ce message et en détruire toute copie. / > Notice: This message is confidential and privileged. If you are not the > addressee, please inform the sender by return e-mail immediately and delete > this message and destroy all copies. > > > > > > On Wed, 17 Oct 2018 at 16:53, Ali Dormiani via USRP-users < > usrp-users@lists.ettus.com> wrote: > > Attempt 2. Sorry for breaking mailing list rules with the attachments. > Here is a google drive link to the screenshots, GRC file, and binary files. > (3 MB zip) > > > > > https://drive.google.com/a/eng.ucsd.edu/file/d/1TvmHuEMFb2QpkiMMdiUEW6aVoUfLYayi/view?usp=sharing > > > > We have three sliders in GNUradio. > > > > 1. TX gain > > > > 2. RX gain > > > > 3. Digital Gain (multiply constant block between our binary file and the > UHD block. > > > > We also have one TX connected directly to an RX with a 30 dB analog > attenuation for safety. > > > > Our binary files were generated in MATLAB and are normalized to unity > magnitude. > > > > Attached, please find the GRC file and our binary files. For reference, > the waveform we made is a multitone signal so it should be a bunch of > evenly spaced spikes. I have included some screenshots too. Additionally we > have verified this strange behavior with a spectrum analyzer. > > By playing around with the sliders you can see how narrow the zone is for > good results. Intuitivly it seems like TX and RX gain don't really matter. > They just shift the narrow usability zone for Digital gain. > > > > On Wed, Oct 17, 2018 at 12:45 PM Ali Dormiani <sdorm...@eng.ucsd.edu> > wrote: > > We have three sliders in GNUradio. > > > > 1. TX gain > > > > 2. RX gain > > > > 3. Digital Gain (multiply constant block between our binary file and the > UHD block. > > > > We also have one TX connected directly to an RX with a 30 dB analog > attenuation for safety. > > > > Our binary files were generated in MATLAB and are normalized to unity > magnitude. > > > > Attached, please find the GRC file and our binary files. For reference, > the waveform we made is a multitone signal so it should be a bunch of > evenly spaced spikes. I have included some screenshots too. Additionally we > have verified this strange behavior with a spectrum analyzer. > > By playing around with the sliders you can see how narrow the zone is for > good results. Intuitivly it seems like TX and RX gain don't really matter. > They just shift the narrow usability zone for Digital gain. > > > > > > > > On Wed, Oct 10, 2018 at 6:20 PM Marcus D. Leech via USRP-users < > usrp-users@lists.ettus.com> wrote: > > On 10/10/2018 03:08 PM, Ali Dormiani via USRP-users wrote: > > Hello, > > > > We have the exact same problem. My lab is waiting on some sfp+ cables so > in a few days I will share our screenshots, code, and data binary files in > order to provide this thread with a second example of this issue. For now, > all I can say is this problem is not isolated to your N310 or Windows. > > > > We have two N310's running with the same version of UHD (and GNUradio > 3.7.13.4) on Linux kernel 4.18. By using amplitude sliders in GNUradio we > found that there is a very small and strange gain "Goldilocks" zone around > .002 that gives good results. Going higher starts to raise the noise floor > until all signal definition is gone. > > > > Ali Dormiani > > UCSD Noiselab > > What is your RF gain set to in these examples? Does that change things? > > If you raise things to a level where non-linearity is apparent, does > placing a 10dB attenuator in-line fix it (trying to distinguish between > the transmitter being non-linear, and your receiver/spectrum analyser). > > > > > > On Wed, Oct 10, 2018 at 11:33 AM Mathieu Lizée via USRP-users < > usrp-users@lists.ettus.com> wrote: > > Hi, > > When using the UHD "tx_waveforms" example, I can see that the signal > emitted by my N310 USRP is saturated when it’s not supposed to be. > > Here's a snapshot of the signal when I set the amplitude to 0.003: > .\tx_waveforms.exe --rate 12.5e6 --nsamps 1250000000 --freq 1575.42e6 > --ampl 0.003 --otw sc16 --wave-type SINE --wave-freq 10e3 --channels 2 > > [image: Image removed by sender. tx_waveforms_3e-3_amp] > <https://user-images.githubusercontent.com/15334138/46685506-a7424700-cbc3-11e8-926e-b0da5f416652.png> > > Here's a snapshot of the signal when I set the amplitude to 0.03: > .\tx_waveforms.exe --rate 12.5e6 --nsamps 1250000000 --freq 1575.42e6 > --ampl 0.03 --otw sc16 --wave-type SINE --wave-freq 10e3 --channels 2 > > [image: Image removed by sender. tx_waveforms_3e-2_amp] > <https://user-images.githubusercontent.com/15334138/46685468-9265b380-cbc3-11e8-9ce7-42908cf9bf2e.png> > > As you can see from the pictures above, it seems that there's a saturation > in the signal when the amplitude is set to 0.03 (which is unexpected with > such a small amplitude). We have double-checked with a X300 device, and the > signal is normal in both cases. > > Do you have an idea of what could be wrong, or a suggestion to try on our > side? > > Technical Information: > > - Windows 10 > - USRP N310 > - UHD 3.13.0.3-rc1 > > > > Thank you! > > > > -- > > *Mathieu Lizee* > > *Software Development Intern* > > > > *Skydel Solutions* > > WeWork 5th Floor (Skydel) > > 1275 Av des Canadiens-de-Montreal > > Montreal, QC > > H3B 0G4 > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > > USRP-users mailing list > > USRP-users@lists.ettus.com > > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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