Re: [Discuss-gnuradio] Timestamp 'rx_time' in Metadata

[Jeff Long]

rx_time is the time something upstream was received. This could be the 
time of the first sample received by a USRP:


https://gnuradio.org/doc/doxygen/classgr_1_1uhd_1_1usrp__source.html#a8ba918061af928ee7c01e7124580eb82

rx_time could also be the time a packet was received, or could be set by 
other blocks.


There is a utility called gr_read_file_metadata that installs with GR, 
but I haven't tried it yet.


On 01/31/2018 05:37 PM, Zhongyuan Zhao wrote:

Hi

I have several questions regarding the rx_time in the metadata file 
sink, https://gnuradio.org/doc/doxygen/page_metadata.html


1) What is exactly the timestamp? The moment first sample is recorded on 
the hard drive?

2) Is there an example to convert rx_time to readable format?
3) Is there an way to timestamp the IQ data at the moment they are 
generated by USRP?


Thanks.
Zhongyuan Zhao



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[Discuss-gnuradio] Timestamp 'rx_time' in Metadata

[Zhongyuan Zhao]

Hi

I have several questions regarding the rx_time in the metadata file sink,
https://gnuradio.org/doc/doxygen/page_metadata.html

1) What is exactly the timestamp? The moment first sample is recorded on
the hard drive?
2) Is there an example to convert rx_time to readable format?
3) Is there an way to timestamp the IQ data at the moment they are
generated by USRP?

Thanks.
Zhongyuan Zhao
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[Discuss-gnuradio] QT GUI Frequency Sink Noise Floor

[Daigle , Frédéric]

Hi,


I'm an Electrical Engineering Technology teacher and I like to use GNU Radio in 
my classrom for demos and labs.


Today, while trying to explain the relation between the noise floor on a 
frequency sprectrum and the RMS value of the same signal (noise), I realised 
that the QT GUI Frequency Sink noise floor is off.


When I connect a Noise source (amplitude of 1) to a QT GUI Frequency Sink, the 
noise flloor is -33 dB (window = none, fft size = 1024). I was expecting a 
noise floor of -30 dB as 1024 bin means that the 0dB total power is spread in 
1024 bins (which gives -30dB).


For fun, I have switched the flowgraph to WX and used the FFT sink. The noise 
floor on the  WX FFT sink was -30 dB as expected.


Anyone knows where the 3dB different comes from?


Thanks,

Frédéric

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Re: [Discuss-gnuradio] GNU Radio Project Leadership Updates

[Robert McGwier]

Thank you Jonathan.  I hope you have more time to enjoy your airplane and
amateur radio!

Welcome to all the other "old" new people taking on great roles.  We
appreciate it.

Bob


On Wed, Jan 31, 2018 at 3:24 PM, Ben Hilburn  wrote:

> Hi all!
>
> As usual, there is a lot going on in the project and community, including
> GSOC & SOCIS, GRCon planning, and new development. There are also some big
> changes happening in the project leadership that I want to announce.
>
> First, our Chief Architect and Foundation CTO, Johnathan Corgan, is moving
> into a new role as a Technical Advisor for the project. He will no longer
> be leading the project's technical development, but will remain part of the
> project leadership, sharing his technical knowledge and guidance. Johnathan
> has been a member of the GNU Radio project for 12 years, and served as the
> Project Maintainer for much of that. Additionally, for many years GNU
> Radio's infrastructure only existed because Johnathan paid for them with
> his own funds. Johnathan's contributions and leadership have been critical
> to GNU Radio's tremendous success, and the he deserves significant credit
> for the work he has done for the project and community.
>
> Here's a note from Johnathan, himself, about the change:
>
> I've watched GNU Radio grow from its origins in the enthusiast community
>> to a mainstream tool used extensively for government, academic, and
>> commercial wireless research and applications. To have helped steward its
>> design and implementation over the last decade, especially as an open
>> source project with a purely volunteer community, has put me in contact
>> with many talented and creative developers. Finally, teaching almost a
>> hundred GNU Radio courses and consulting on GNU Radio projects in over a
>> dozen countries has been the highlight of my career.
>>
>> While I will continue to engage with users and provide technical
>> assistance to the GNU Radio project, its forward growth depends on new
>> leadership and commitment. I look forward to seeing what's next.
>>
>
> As Johnathan transitions to his new role, well known developers in the
> community will be taking on expanded responsibilities. Marcus Mueller will
> become the Project Maintainer, responsible for merging, tagging, and
> generally maintaining the codebase. Derek Kozel, Bastian Bloessl, Andrej
> Rode, Philip Balister, and Nate Temple will become Project Officers, taking
> on various development and community efforts to keep the project moving
> forward.
>
> My position leading the project and Foundation remains unchanged, as do
> the roles of Martin Braun (Community Manager, PyBOMBS maintainer,
> Foundation Officer), and Nathan West (VOLK maintainer). While Andrej and
> Derek are expanding their development roles, Andrej will also continue as
> our web & devops infrastructure admin, and Derek will continue to organize
> GRCon18. Felix Wunsch will continue leading GNU Radio's participation in
> GSoC & SOCIS.
>
> Our major priorities in the near-term include integrating the latest pull
> requests, publishing a clear process for community suggestions &
> contributions to the project, and getting to the long-awaited 3.8 release.
> If you're interested in these topics, keep an eye on the list and IRC!
> You'll start to see some announcements and activity very shortly.
>
> We have a strong core team of experienced GNU Radio developers and
> community members, and I'm really excited about the work that will get done
> over the coming months. If you want to get involved, please don't hesitate
> to reach out! We love working with new contributors. And, as always, if you
> have any questions, just let us know.
>
> Lastly, I would like to once again publicly thank Johnathan for all of his
> hard work and contributions as a leader in our community over the last 12
> years!
>
> Happy Hacking,
> Ben
>
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>


-- 
Bob McGwier
Founder, Federated Wireless, Inc
Founder and Technical Advisor, HawkEye 360, Inc
Research Professor Virginia Tech
Chief Scientist:  The Ted and Karyn Hume Center for National Security and
Technology
Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY
Faculty Advisor Virginia Tech Amateur Radio Assn, Trustee K4KDJ
Director of AMSAT
Member of PVRC (Roanoke-Blacksburg), TAPR,  life member of ARRL and AMSAT,
NRVR.ORG (Rocketry)
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[Discuss-gnuradio] GNU Radio Project Leadership Updates

[Ben Hilburn]

Hi all!

As usual, there is a lot going on in the project and community, including
GSOC & SOCIS, GRCon planning, and new development. There are also some big
changes happening in the project leadership that I want to announce.

First, our Chief Architect and Foundation CTO, Johnathan Corgan, is moving
into a new role as a Technical Advisor for the project. He will no longer
be leading the project's technical development, but will remain part of the
project leadership, sharing his technical knowledge and guidance. Johnathan
has been a member of the GNU Radio project for 12 years, and served as the
Project Maintainer for much of that. Additionally, for many years GNU
Radio's infrastructure only existed because Johnathan paid for them with
his own funds. Johnathan's contributions and leadership have been critical
to GNU Radio's tremendous success, and the he deserves significant credit
for the work he has done for the project and community.

Here's a note from Johnathan, himself, about the change:

I've watched GNU Radio grow from its origins in the enthusiast community to
> a mainstream tool used extensively for government, academic, and commercial
> wireless research and applications. To have helped steward its design and
> implementation over the last decade, especially as an open source project
> with a purely volunteer community, has put me in contact with many talented
> and creative developers. Finally, teaching almost a hundred GNU Radio
> courses and consulting on GNU Radio projects in over a dozen countries has
> been the highlight of my career.
>
> While I will continue to engage with users and provide technical
> assistance to the GNU Radio project, its forward growth depends on new
> leadership and commitment. I look forward to seeing what's next.
>

As Johnathan transitions to his new role, well known developers in the
community will be taking on expanded responsibilities. Marcus Mueller will
become the Project Maintainer, responsible for merging, tagging, and
generally maintaining the codebase. Derek Kozel, Bastian Bloessl, Andrej
Rode, Philip Balister, and Nate Temple will become Project Officers, taking
on various development and community efforts to keep the project moving
forward.

My position leading the project and Foundation remains unchanged, as do the
roles of Martin Braun (Community Manager, PyBOMBS maintainer, Foundation
Officer), and Nathan West (VOLK maintainer). While Andrej and Derek are
expanding their development roles, Andrej will also continue as our web &
devops infrastructure admin, and Derek will continue to organize GRCon18.
Felix Wunsch will continue leading GNU Radio's participation in GSoC &
SOCIS.

Our major priorities in the near-term include integrating the latest pull
requests, publishing a clear process for community suggestions &
contributions to the project, and getting to the long-awaited 3.8 release.
If you're interested in these topics, keep an eye on the list and IRC!
You'll start to see some announcements and activity very shortly.

We have a strong core team of experienced GNU Radio developers and
community members, and I'm really excited about the work that will get done
over the coming months. If you want to get involved, please don't hesitate
to reach out! We love working with new contributors. And, as always, if you
have any questions, just let us know.

Lastly, I would like to once again publicly thank Johnathan for all of his
hard work and contributions as a leader in our community over the last 12
years!

Happy Hacking,
Ben
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Re: [Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[Marcus D. Leech]

On 01/31/2018 03:16 PM, Sylvain Munaut wrote:

Hi,

* You can just use 0.0 / 0.0 as the default. Those value are only
really used if you don't use the message system and just want a fixed
/ known manually set correction. Once the first message is received,
those value are overwritten

* As stated the time constant is in samples.

* The 'optimize' block only really works when you have some narrow
band signals distributed around the spectrums. It will fail
_miserably_ if you have a single wideband signal centered around DC
...

Cheers,

  Sylvain
Indeed, I find that if I use the osmocom IQ-balance code on radio 
astronomy "signals" that it produces horrible results in interferometry 
applications, as
  it never really "converges", and adds significant long-time-scale 
phase-noise, so I disable it.





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Re: [Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[Sylvain Munaut]

Hi,

* You can just use 0.0 / 0.0 as the default. Those value are only
really used if you don't use the message system and just want a fixed
/ known manually set correction. Once the first message is received,
those value are overwritten

* As stated the time constant is in samples.

* The 'optimize' block only really works when you have some narrow
band signals distributed around the spectrums. It will fail
_miserably_ if you have a single wideband signal centered around DC
...

Cheers,

 Sylvain

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Re: [Discuss-gnuradio] LoRa implementation (resuming an old topic)

[mail]

Hi Alberto,

On 2018-01-31 20:00, Alberto Trentadue wrote:

Back in October 2015 I dropped a question to the list, asking if
anybody had attempted implementing LoRa
modulation using GNURadio. At that time Marcus Muller kindly replied,
suggesting me to take such endeavour.
Unfortunately, such project did not get enough attention and I had to
drop it.

Did anyone else try such thing - just to avoid to reinvent the wheel?


there is a module called `gr-lora` you can find here [0].
There is also at least one presentation about it at GRCon16. You can 
find GRCon videos at the YouTube channel of GNU Radio [1].


Cheers,
Andrej

[0] https://github.com/BastilleResearch/gr-lora
[1] https://www.youtube.com/c/GNURadioProject

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[Discuss-gnuradio] LoRa implementation (resuming an old topic)

[Alberto Trentadue]

Hi all
Back in October 2015 I dropped a question to the list, asking if anybody had 
attempted implementing LoRamodulation using GNURadio. At that time Marcus 
Muller kindly replied, suggesting me to take such endeavour. Unfortunately, 
such project did not get enough attention and I had to drop it.
Now I am dealing with testing LoRa gateways, possibly without the need of LoRa 
client cards. necessarily.  So I would like to use my USRP to make initial LoRa 
test at 868 MHz.
Did anyone else try such thing - just to avoid to reinvent the wheel?
Thank youAlberto
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[Discuss-gnuradio] Call for GRCon18 Committee Volunteers

[Derek Kozel]

Hello,

Regular as clockwork the new year has come and it is time to prepare for
GNU Radio Conference 2018! GRCon17 was another great success continuing
the trend of growing in size and scope. We had 40% more attendees than
in 2016 and 96.9% of attendees who responded to the survey gave the
event a four or five out of five overall rating. The survey also
provided some very useful feedback about what the best parts of the
conference were and how to even better serve the needs and wants of the
community.
Planning GRCon is a significant undertaking, and is only possible each
year because of our community volunteers. You can volunteer at a variety
of levels, taking on whatever responsibilities your time & availability
affords. It's a great experience, and a good opportunity to get more
deeply involved with the GNU Radio project & community.
If you are interested in joining the GRCon18 Committee, or have any
questions, please let us know by emailing gr...@gnuradio.org.
Thanks,
Derek
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Re: [Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[Jeff Long]

1. Add a throttle after the source.

2. You are feeding the optimizer and the balancer from the original 
signal. They need to be connected to the output of the imbalance generator.


3. Whatever the scale of magnitude is in the imbalance generator, 1.0 is 
too small to see on the time plot.


4. The time plots will look different if the phase is rotated, so 
different is not necessarily wrong.


5. Add a slider to control magnitude, and you can see the optimizer adjust.



On 01/31/2018 09:21 AM, kokosz wrote:
This is exactly what I am doing, but restored signal looks very weird 
(its real part is close to zero). I have attached example *grc file 
showing the problem.


Dnia 31 stycznia 2018 12:34 Jeff Long  napisał(a):

If you put 0 in the manual fields and wire

  src->optimize->iqbal

and

  src->iqbal

it seems to work fine. Do you have a GRC file?

"period" is some sort of time constant, in samples. If you set it to
samp_rate, optimization will happen within a second. Smaller values for
faster response up to a point.

On 01/31/2018 05:54 AM, kokosz wrote:

Dear all,

It looks like IQ imbalance is causing problems in my
application, as I
was able to simulate real-world-like problems after adding "IQ
Imbalance
Generator" to my GRC flowgraph. So, after simulating this
imbalance, I
wanted to get rid of it with the help of "IQ Bal Optimize" and
"IQ Bal
Fix" combo. Unfortunately, I can't get it work.

As far as I understand, "IQ Bal Optimize" is automatically
detecting
settings (i.e. magnitude and phase correction values) for "IQ
Bal Fix"
and pass it to the latter block via message connection called
"iqbal_corr". Is this is true, I don't understand why I have to
manually
set "Magnitude" and "Phase" in "IQ Bal Fix" (otherwise I cannot
run the
flowgraph because of empty fields). I think that these fields
were meant
for making manual fix possible, but when using "IQ Bal
Optimize"/"IQ Bal
Fix" combo, message connection should be all what is necessary,
right?
Also, because of lack of detailed documentation, I am not sure
how to
interpret "Period" field in IQ Bal Optimize - what units are
expected here?

I am using GRC v3.7.11, compiled from source files few days ago.




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Re: [Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[kokosz]

This is exactly what I am doing, but restored signal looks very weird
(its real part is close to zero). I have attached example *grc file
showing the problem.




  Dnia 31 stycznia 2018 12:34 Jeff Long 
willco...@gmail.com napisał(a):


   If you put 0 in the manual fields and wire

   src-optimize-iqbal

 and

   src-iqbal

 it seems to work fine. Do you have a GRC file?

 period is some sort of time constant, in samples. If you set it to
 samp_rate, optimization will happen within a second. Smaller values for
 faster response up to a point.

 On 01/31/2018 05:54 AM, kokosz wrote:

 Dear all,

 It looks like IQ imbalance is causing problems in my application, as I
 was able to simulate real-world-like problems after adding IQ Imbalance
 Generator to my GRC flowgraph. So, after simulating this imbalance, I
 wanted to get rid of it with the help of IQ Bal Optimize and IQ 
Bal
 Fix combo. Unfortunately, I cant get it work.

 As far as I understand, IQ Bal Optimize is automatically detecting
 settings (i.e. magnitude and phase correction values) for IQ Bal Fix
 and pass it to the latter block via message connection called
 iqbal_corr. Is this is true, I dont understand why I have to 
manually
 set Magnitude and Phase in IQ Bal Fix (otherwise 
I cannot run the
 flowgraph because of empty fields). I think that these fields were meant
 for making manual fix possible, but when using IQ Bal 
Optimize/IQ Bal
 Fix combo, message connection should be all what is necessary, right?
 Also, because of lack of detailed documentation, I am not sure how to
 interpret Period field in IQ Bal Optimize - what units are expected 
here?

 I am using GRC v3.7.11, compiled from source files few days ago.




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iqbal_test.grc
Description: application/gnuradio-grc
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Re: [Discuss-gnuradio] gnu radio installation on Mac via MacPorts

[Michael Dickens]

Thanks for reporting back, Vipin, and your creative solution. Sometimes
starting over is the way to go ;)
A strange note: the "rev-upgrade" logfile was clean; no errors or issues
found beyond the usual innocuous ones. I've no idea why port thought uhd
was broken the final run-through.
Anyway: Good catch on the gpsd issue; I'm glad we got it fixed quickly! You're 
very welcome for the support! - MLD
On Wed, Jan 31, 2018, at 2:28 AM, Vipin Sharma wrote:
> Ok, I tried another attempt by completely removing the MacPorts and
> restarting. This time it worked!> sudo port -fp uninstall installed
> sudo rm -rf /opt/local /Applications/DarwinPorts
> /Applications/MacPorts /Library/LaunchDaemons/org.macports.*
> /Library/Receipts/DarwinPorts*.pkg
> /Library/Receipts/MacPorts*.pkg
> /Library/StartupItems/DarwinPortsStartup
> /Library/Tcl/darwinports1.0 /Library/Tcl/macports1.0
> ~/.macports> 
> sudo port selfupdate


> 


> sudo port install gnuradio  


> 


> 


> I got segmentation fault when I tried this:


> uhd_fft -f 868M -s 10M


> 


> but then after trying 


> 


> sudo port select --set python python27


> 
> uhd_fft works fine.
> 
> Thanks for your support!



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Re: [Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[Jeff Long]

If you put 0 in the manual fields and wire

  src->optimize->iqbal

and

  src->iqbal

it seems to work fine. Do you have a GRC file?

"period" is some sort of time constant, in samples. If you set it to 
samp_rate, optimization will happen within a second. Smaller values for 
faster response up to a point.


On 01/31/2018 05:54 AM, kokosz wrote:

Dear all,

It looks like IQ imbalance is causing problems in my application, as I 
was able to simulate real-world-like problems after adding "IQ Imbalance 
Generator" to my GRC flowgraph. So, after simulating this imbalance, I 
wanted to get rid of it with the help of "IQ Bal Optimize" and "IQ Bal 
Fix" combo. Unfortunately, I can't get it work.


As far as I understand, "IQ Bal Optimize" is automatically detecting 
settings (i.e. magnitude and phase correction values) for "IQ Bal Fix" 
and pass it to the latter block via message connection called 
"iqbal_corr". Is this is true, I don't understand why I have to manually 
set "Magnitude" and "Phase" in "IQ Bal Fix" (otherwise I cannot run the 
flowgraph because of empty fields). I think that these fields were meant 
for making manual fix possible, but when using "IQ Bal Optimize"/"IQ Bal 
Fix" combo, message connection should be all what is necessary, right? 
Also, because of lack of detailed documentation, I am not sure how to 
interpret "Period" field in IQ Bal Optimize - what units are expected here?


I am using GRC v3.7.11, compiled from source files few days ago.




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[Discuss-gnuradio] How to use IQ Bal Optimize/Fix?

[kokosz]

Dear all,   It looks like IQ imbalance is causing problems in my application, 
as I was able to simulate real-world-like problems after adding IQ 
Imbalance Generator to my GRC flowgraph. So, after simulating this 
imbalance, I wanted to get rid of it with the help of IQ Bal Optimize 
and IQ Bal Fix combo. Unfortunately, I cant get it work.   As 
far as I understand, IQ Bal Optimize is automatically detecting 
settings (i.e. magnitude and phase correction values) for IQ Bal Fix 
and pass it to the latter block via message connection called 
iqbal_corr. Is this is true, I dont understand why I have to 
manually set Magnitude and Phase in IQ Bal Fix 
(otherwise I cannot run the flowgraph because of empty fields). I think that 
these fields were meant for making manual fix possible, but when using IQ 
Bal Optimize/IQ Bal Fix combo, message connection should be all 
what is necessary, right? Also, because of lack of detailed documentation, I am 
not sure how to interpret Period field in IQ Bal Optimize - what 
units are expected here?   I am using GRC v3.7.11, compiled from source files 
few days ago.
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