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 <mailto: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
o the spectrum is not correct (look like a modulated signal
o the received signal magnitude is not constant
o *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
<mailto: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
<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 <mailto: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
<mailto: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 <mailto: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
<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
<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
