Hi. I performed some more tests and report the results on this thread. https://discourse.myriadrf.org/t/glitchy-behavior-gr-limesdr-limesdr-usb-sinewave-test/7022/10?u=vu2tve
I'd love some advice with which I can produce a simple FM modulated sinewave with gnuradio and limesdr. If someone on this mailing list has a limesdr, and some bandwidth to test this out, I'll be more than happy to provide my flowgraphs. Thanks! On Mon, Mar 22, 2021 at 10:10 AM Anish Mangal <anis...@umich.edu> wrote: > So far as I am able to tell with my limited knowledge of limesdr and > gnuradio, it seems like some kind of issue with the right settings to me. > > The gr-limesdr provides a sink block that allows one to use an .ini file > instead of the settings done via the block's settings. I will have access > to the radio in a few days' time and am thinking i'll copy over the .ini > file that was used in sdrangel and use the exact same one in gnuradio and > see what happens. > > On Mon, Mar 22, 2021 at 8:22 AM Cinaed Simson <cinaed.sim...@gmail.com> > wrote: > >> Hi Anish - yes, I removed the LImeSDR block from the flow graph. >> >> I inserted a throttle instead since I didn't have any front end hardware >> available at the time. >> >> I do have a WBFM receiver using gnuradio running on a HackRF which works >> great. >> >> But I'm using low pass filter taps in the complex rational resampler >> which leads the WBFM receiver. >> >> -- CInaed >> >> On 3/20/21 7:52 PM, Anish Mangal wrote: >> >> Hi Cinaed, >> >> But this is without the actual LimeSDR sink block? Or with it? >> >> Because, I can produce a clean sinewave with a HackRF, but not the >> LimeSDR. >> >> On Sun, Mar 21, 2021 at 1:07 AM Cinaed Simson <cinaed.sim...@gmail.com> >> wrote: >> >>> Hi Anish - I think I may have found the problem. >>> >>> When the complex rational resampler is on the out put of the WBFM, it >>> bothered me later that I couldn't see the top of the signal. >>> >>> The scale on QT GUI SINK was clipping the signal but not the >>> computational noise. >>> >>> In the QT GUI SINK, if I set the Y-min to be -99 and Y-max to be 0, the >>> signal looks perfect. >>> >>> And if the receiving RTL dongle has noise while listening, it may be a >>> DC offset problem. >>> >>> -- Cinaed >>> >>> >>> On 3/18/21 6:58 AM, Anish Mangal wrote: >>> >>> Here are two debug logs from LimeSuite GUI. In one, I load the settings >>> that gnuradio does to the limesdr and see the debug log. The other is the >>> settings file which the sdrangel writes. >>> >>> If I diff them, among other differences, this is what I see in the end >>> of the sdrangel-debug-log >>> DEBUG: Selected: VCOL >>> DEBUG: csw 169; interval [166, 172] >>> DEBUG: M=195, N=3, Fvco=1300.000 MHz >>> >>> And this is what I see in the gnuradio-debug-log >>> DEBUG: Selected: VCOM >>> DEBUG: csw 174; interval [171, 177] >>> >>> Now, I'm *very* new to this.. but could it mean that different VCOs are >>> used in both cases, and in the case of gnuradio, it maybe has some issues >>> to stabilize to some freq? >>> >>> On Thu, Mar 18, 2021 at 7:12 PM Christophe Seguinot < >>> christophe.segui...@orange.fr> wrote: >>> >>>> Hi all >>>> >>>> There is something wrong in this simulation. >>>> >>>> Attached is a flowgraph with a selectable Lime SDR Source, and a >>>> RTL-SDR dongle as receiver. I tested this with a Lime SDR Mini. >>>> >>>> - I was suspecting a Lime SDR issue, however this is not so clear. >>>> - As Anish I also tested a const source. >>>> - The flowgraph is running fluently and I dont' see any error >>>> message about transmission to Lime SDR >>>> >>>> Conclusion of my simulations : >>>> >>>> - with a const source (=1) at Lime input : everything is OK, the >>>> received signal is frequency shifted (normal) and the SNR is correct if >>>> LimeSDR Gain is sufficient >>>> - Using ratioanal resampler followed by WBFM Transmit Same reslt, >>>> everything is OK >>>> - First source+ WBFM + Rational resampler (this is a sample file >>>> found on LimeSDR website >>>> - the spectrum is not correct (look like a modulated signal >>>> - the received signal magnitude is not constant >>>> - >>>> *BUT the send signal on the Time Sink look like correct. ( I.E =1+j0 as >>>> for others sources, whitout any glicht) * >>>> >>>> How can we further investigate this? >>>> >>>> >>>> On 18/03/2021 13:13, Anish Mangal wrote: >>>> >>>> And, if I try the attach gnuradio file, which is just a constant source >>>> of value '1' going to the limesdr sink block, I actually see a sine-ish >>>> wave without the glitchy behavior. >>>> >>>> On Thu, Mar 18, 2021 at 5:31 PM Anish Mangal <anis...@umich.edu> wrote: >>>> >>>>> I tried your grc and got the same result. >>>>> >>>>> See the waveform's envelope in this oscilloscope capture. Note the >>>>> timebase. >>>>> >>>>> https://drive.google.com/file/d/1b7PnpmvFfdQTDIwALuOzb22AzeffzR2w/view?usp=sharing >>>>> >>>>> This isn't happening in SDRAngel. >>>>> >>>>> On Thu, Mar 18, 2021 at 3:49 AM Cinaed Simson <cinaed.sim...@gmail.com> >>>>> wrote: >>>>> >>>>>> I moved the rational resampler block from the output side to the >>>>>> input side of the WBFM. >>>>>> >>>>>> The output of WBFM block needs to match the input of your LimeSDR. >>>>>> >>>>>> I don't have the LimeSDR software installed so I couldn't look inside >>>>>> the sink block. >>>>>> >>>>>> -- Cinaed >>>>>> >>>>>> P.S - yes, you can post GRC's on the mailing list - they're text >>>>>> based. >>>>>> >>>>>> >>>>>> On 3/17/21 4:14 AM, Anish Mangal wrote: >>>>>> >>>>>> I linked >>>>>> <https://drive.google.com/file/d/1xQz1Kp_feAO1YrZRXXnMF25XEGgqVPSw/view?usp=sharing> >>>>>> the grc file in the original email. Attaching it here as well. (Don't >>>>>> know >>>>>> if the mailing list allows attachments) >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Mar 17, 2021 at 1:40 PM Cinaed Simson < >>>>>> cinaed.sim...@gmail.com> wrote: >>>>>> >>>>>>> >>>>>>> Hi Anish - since this is a gnuradio mailing list, the starting point >>>>>>> would be to post your GRC - which is an yaml or text file. >>>>>>> >>>>>>> -- Cinaed >>>>>>> >>>>>>> On 3/16/21 11:19 PM, Anish Mangal wrote: >>>>>>> >>>>>>> Hi! Any pointers to where I can start debugging this? >>>>>>> >>>>>>> Maybe run gnuradio-companion in debug mode? >>>>>>> Do more simpler tests? >>>>>>> Any other suggestions? >>>>>>> >>>>>>> I have a HackRF One and will try the exact same comparison there too >>>>>>> ... SDRAngel & grc >>>>>>> >>>>>>> On Mon, Mar 15, 2021 at 7:32 PM Anish Mangal <anis...@umich.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> To properly explain the issue I'm facing, I recorded a video >>>>>>>> showing Oscilloscope waveforms. >>>>>>>> >>>>>>>> >>>>>>>> https://drive.google.com/file/d/11anGShu-I3NhL9Jet6YAiyBprvwP4kDc/view?usp=sharing >>>>>>>> >>>>>>>> The gnuradio flowgraph is here: >>>>>>>> >>>>>>>> https://drive.google.com/file/d/1xQz1Kp_feAO1YrZRXXnMF25XEGgqVPSw/view?usp=sharing >>>>>>>> >>>>>>>> The various versions of the software/hardware involved are the >>>>>>>> following. >>>>>>>> >>>>>>>> gnuradio-companion: 3.8.2.0 (Python 3.6.9) >>>>>>>> gr-limesdr: branch gr-3.8 (last commit >>>>>>>> 47511dd58de1695b70e1028366411bada85eb60f) >>>>>>>> sdrangel: 4.12.1 >>>>>>>> OS: Linux Mint 19.1 >>>>>>>> CPU: Intel© Core™ i7-4900MQ CPU @ 2.80GHz × 4 >>>>>>>> RAM: 16GB >>>>>>>> H/w: Thinkpad T440p >>>>>>>> >>>>>>>> tl;dr >>>>>>>> I'm trying a simple test to create a sinewave output from a WFM >>>>>>>> modulator block. If there is no audio input, its WFM modulated signal >>>>>>>> should be a simple sinewave. If I test this with SDRAngel, I see a >>>>>>>> clean-ish actual sinewave in time domain on the oscilloscope. But if I >>>>>>>> try >>>>>>>> to do the same with gnuradio, it seems to produce a glitchy signal. >>>>>>>> >>>>>>>> Could I have any advice on what I might be doing wrong? >>>>>>>> >>>>>>>> Thanks, >>>>>>>> Anish // VU2TVE >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>> >>
