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
<mailto: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
<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
