FM/DRM IBOC Transmitter

Working on something interesting? Share it with the community!

Moderator: robert.ghilduta

Post Reply
jowijo
Posts: 27
Joined: Sun Jan 05, 2014 9:50 pm
Location: Yakima, Washington

FM/DRM IBOC Transmitter

Post by jowijo » Sun Jan 19, 2014 3:33 pm

Hybrid Digital FM Transmitter

Here is a project I have been working on for some time now -- a DRM (DDigital Radio), and FM (Stereo) transmitter "inspired" by HD Radio. Using JACK, you can send both standard analog and digital radio with the BladeRF. The digital decodes in Dream, and the FM works perfectly on every receiver I have tested. Instructions on how to use after the screenshots.

Download & Use


To run this flowgraph, you will need to build gr-drm (Stable branch), and be using GNURadio 3.7 or above. I have tested this on Ubuntu 14, and Arch Linux, and it runs with no issue on my Intel i7 4770k.

[UPDATE 4/13] The latest version of the flowgraph is available right here. (GRC)

INSTRUCTIONS
  • Compile gr-drm and ensure it is working by running the flowgraphs as explained in its readme.
  • Be sure your config.conf has the following in it:

    Code: Select all

    [audio]
    audio_module = jack
  • Open a JACK based GUI like qjackctl,
  • For FM, I use an external FM processor called "Stereo Tool". This generates an MPX signal. You do not have to use this, and if you will not, set the FM Audio source to your preferred sample-rate, and adjust the rational resampler accordingly. (Graph runs at 288sps).
  • Now run the IBOC.grc. In JACK, you should see three inputs: DRM-L, DRM-R, and FM. Connect your music players to it. (For convention, DRM-R, and FM should have the same source; though they don't have to).
Screenshots

Here's a screenshot of the FFT sink showing the IBOC signals. Digital A and B on the right and left, and standard FM in the middle.

Image

...and here is a screenshot from my Windows PC running SDR#. (This is a WAV capture)

Image
__________________

I am very new to GNURadio, so if there is room to make this even more efficient--please let me know. :D
Last edited by jowijo on Sun Apr 13, 2014 1:45 pm, edited 7 times in total.

drmpeg
Posts: 62
Joined: Fri Mar 01, 2013 3:58 am
Location: Silicon Valley
Contact:

Re: WIP: FM/DRM IBOC System. a.k.a "Open HD Radio"

Post by drmpeg » Sun Jan 19, 2014 6:51 pm

You may want to take a look at Clayton's FM transmitter here (in the file multi_tx.grc):

https://github.com/argilo/sdr-examples

Ron

jowijo
Posts: 27
Joined: Sun Jan 05, 2014 9:50 pm
Location: Yakima, Washington

Re: WIP: FM/DRM IBOC System. a.k.a "Open HD Radio"

Post by jowijo » Sun Jan 19, 2014 6:58 pm

Thank you. Had no idea there were BladeRF specific examples like this. Hopefully I can deduct what the problem is using these.

jowijo
Posts: 27
Joined: Sun Jan 05, 2014 9:50 pm
Location: Yakima, Washington

Done.

Post by jowijo » Sat Feb 08, 2014 4:33 pm

I have finally finessed the flowgraph. Sadly, I still cannot communicate with the BladeRF in Arch. It appears to be several upstream issues as documented in my issues with GNURadio and WXPython. As a result, I will be setting up a Wubi installation of Ubuntu to run this over the Blade.

Anyway, OP updated with info and things. Samples should be up for your examination this evening.

jowijo
Posts: 27
Joined: Sun Jan 05, 2014 9:50 pm
Location: Yakima, Washington

Update!

Post by jowijo » Sun Apr 13, 2014 1:13 pm

Fixed the flowgaph and added some use instructions. Check the OP. :)

Post Reply