BladeRF astronomical interferometer

Working on something interesting? Share it with the community!

Moderator: robert.ghilduta

jynik
Posts: 455
Joined: Thu Jun 06, 2013 8:15 pm

Re: BladeRF astronomical interferometer

Post by jynik » Wed May 25, 2016 8:49 am

Hi David,

Excellent - I know I definitely look forward to seeing your progress. Thank you for sharing your project with everyone here!

I need to think about how to expose this functionality in gr-osmosdr so that you could access it from within a flowgraph.

In the meantime, perhaps [this approach](https://github.com/Nuand/bladeRF/wiki/b ... of_Samples) will let you start processing samples in your flowgraph while configuring things with the CLI? Let me know if you have any questions!

- Jon

dlonard
Posts: 13
Joined: Sat Aug 31, 2013 1:48 pm

Re: BladeRF astronomical interferometer

Post by dlonard » Thu May 26, 2016 6:06 am

Jon,

Thanks, the FIFO approach looks like it might be the way to go. Should have some results soon.

David

jynik
Posts: 455
Joined: Thu Jun 06, 2013 8:15 pm

Re: BladeRF astronomical interferometer

Post by jynik » Sat May 28, 2016 12:52 pm

David,

No problem! Let me know if you have any questions or need clarification on anything.

Another up and coming item that may be of interest to you is the SoapyMultiSDR module for SoapySDR. I've chatted a bit with the author, Josh, about bladeRF support with this synchronization trigger, so ideally it'd be nice and seamless. If you're familiar with GNU Radio flowgraphs, I expect that you'd feel right at home in Pothos (which supports SoapySDR backends).

Cheers,
Jon

dlonard
Posts: 13
Joined: Sat Aug 31, 2013 1:48 pm

Re: BladeRF astronomical interferometer

Post by dlonard » Mon May 30, 2016 3:45 pm

Jon,

I've been able to get synchronized reception from my three BladeRFs with the latest FX3 firmware, FPGA images and bladeRF-cli, following the write-ups on how to get this going. The FIFO approach that you suggested works well, with the caveat that the temp files for each BladeRF grow very large, so sustained recording is still not possible yet. I expanded the GnuRadio FIFO flowgraph to read the three temp files and it worked fine.

Below, I've got an example for a configuration for my radios to trigger only as receivers and have attached the scripts used to control each radio. Each radio was activated in separate terminals using the commands listed below. (File paths and serial #'s will differ).

MASTER
bladeRF-cli -d '*:serial=33' -s ~/gnuflow/aipy/140mhz/synch/master.txt -i
trigger j71-4 rx fire ******when ready

SLAVE 1
bladeRF-cli -d '*:serial=be' -s ~/gnuflow/aipy/140mhz/synch/slave1.txt -i

SLAVE 2
bladeRF-cli -d '*:serial=69' -s ~/gnuflow/aipy/140mhz/synch/slave2.txt -i


I'm going to check out SoapySDR. Seamless multi-radio triggering would be very cool.

David
Attachments
slave2.txt
Set up 2nd slave BladeRF
(670 Bytes) Downloaded 730 times
slave1.txt
Set up 1st slave BladeRF
(671 Bytes) Downloaded 737 times
master.txt
Set up Master BladeRF
(662 Bytes) Downloaded 722 times

jynik
Posts: 455
Joined: Thu Jun 06, 2013 8:15 pm

Re: BladeRF astronomical interferometer

Post by jynik » Fri Jun 03, 2016 2:38 pm

dlonard wrote: The FIFO approach that you suggested works well, with the caveat that the temp files for each BladeRF grow very large, so sustained recording is still not possible yet. I expanded the GnuRadio FIFO flowgraph to read the three temp files and it worked fine.
If files are growing large, I think we may have some miscommunication or have something I have to do a better job clarifying here... let's figure that out.

The idea is that bladeRF-cli is writing to and GNU Radio is reading from a Unix Named Pipe (or "FIFO") --- not an actual file on disk or in a RAM-based filesystem.

This should be created with mkfifo.

Let me know if I've clarified anything or only added more confusion.

- Jon

livingstone_ray
Posts: 1
Joined: Tue Aug 29, 2017 7:55 am

Re: BladeRF astronomical interferometer

Post by livingstone_ray » Tue Aug 29, 2017 8:22 am

hi there.

i have the comments and i am i have a coupling of questions regarding the clock and sample synchronization.

firstly, i am doing an OFDM SIMO wireless system and i am trying to perform clock synchronization and sample alignment at the 2 BladeRF RX boards to ease the burden of synchronization at the software level for my diversity combining. i have followed David's work on the configuration of master receiver and slave receiver, in my case which is only two boards, so what i am trying to do is first configure the master and slave with the scripts attached below, then i run my GNU Radio flow graphs which has osmocom Source blocks which set the gains and everything else, then with the GNU Flow graph running i fire the trigger using "trigger j71-4 rx fire" from the master console, the issue is i am receiving anything at all, so my question is when i configure the boards using the bladerf -cli first and then run GNU Radio flow graphs, does my osmocom Source blocks overwrite the settings i did before with bladerf -cli?, which could be the reason why i cant fire the trigger and i cant receive anything.

secondly, if i am correct regarding the above, how can i make the clock and sample settings using bladerf -cli and then just receive the samples as i normally would from the osmocom Source block of the receiver?, i am aware of the FIFO approach but i dont have enough memory to store temp files as i am running GNU Radio from a 30 Gb Ubuntu partition that i dual booting with windows 10 on my laptop. maybe Jon you could explain a little more about how the FIFO approach actually works if i am incorrect.

thanks.
Attachments
SIMO_Slave.txt
(403 Bytes) Downloaded 125 times
SIMO_Master.txt
(395 Bytes) Downloaded 119 times

Post Reply