gr-dab - GNU Radio Digital Audio Broadcasting module
Copyright (C) Andreas Müller, 2011, Moritz Luca Schmid, 2017
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
This directory (and the resulting tarball) contains a build tree for gr-dab.
gr-dab contains everything needed to get audio from DAB and DAB+
Much of the code was developed as part of "Google Summer of Code 2017" by Moritz Luca Schmid. (the completion of audio reception of DAB and DAB+). His fork can be found here: https://github.com/kit-cel/gr-dab The fork also contains everything needed for transmission of DAB radio. It does however have a number of external dependencies which makes it slightly more tricky to install than this version without TX.
This package requires that gnuradio-core is already installed. It also depends on some GNU Radio prerequisites, such as Boost and cppunit. Additionally it depends on the FAAD2 library. (ubuntu: sudo apt-get install libfaad-dev, fedora: sudo dnf install faad2-devel)
To build gr-dab, run these commands:
$ mkdir build
$ cd build
$ cmake ../
$ make
$ sudo make install
$ sudo ldconfig
After having installed gr-dab, you can play around with GNU radio blocks for gr-dab in GNU Radio Companion, or you can use the tool grdab to start receiving DAB/DAB+ audio using a software defined radio (SDR).
All SDRs supported by gr-osmosdr and which can tune to the DAB frequencies can be used with grdab. It has been verified to work with RTL-SDR, HackRF and USRP B200. grdab can receive both DAB and DAB+ audio.
When connecting a new radio, run:
grdab adjust
This will bring up a GUI where you will see the frequency spectrum and the constellation diagram.
- Drag the channel selector to a valid DAB/DAB+ frequency in your area.
- Adjust the gain sliders such that frequency spectrum looks good. It should be an almost square looking wide signal.
- Adjust the ppm slider until the constellation diagram consists of 4 quite confined dots.
- Then click 'save configuration'
- Your SDR is now calibrated and can be used to receive DAB/DAB+ audio.
The calibration data is stored in the file ~/.grdab/adjustment.yaml. Whenever connecting a new SDR, you will have to repeat the adjustment procedure above.
To see what channels are available on a chosen frequency, run:
grdab info -f <frequency_in_mhz>
When you find a channel, you can start receiving audio with:
grdab receive -f 227.360 --bit_rate 80 --address 204 --subch_size 60 --protect_level 2 --audiorate 48000
where you replace the different options with the output from grdab info for the desired channel. You might have to experiment with a few different values for --audiorate (such as 44100 or 48000). Note that DAB+ is default. To receive classic DAB, add '--classic' an argument.
If you create a file called ~/.grdab/channels.yaml, and list all the channels in your area:
- {name: NRK P1 , frequency: 227.360, address: 204, subch_size: 60, protect_level: 2, bit_rate: 80}
- {name: NRK P2 , frequency: 227.360, address: 384, subch_size: 60, protect_level: 2, bit_rate: 80}
- {name: NRK P3 , frequency: 227.360, address: 444, subch_size: 60, protect_level: 2, bit_rate: 80}
- {name: NRK KLASSISK , frequency: 227.360, address: 564, subch_size: 60, protect_level: 2, bit_rate: 80}
- ...
You can afterward use the grdab ncurses application:
grdab curses
It allows you to select a channel and listen to it:
To allow starting and stopping grdab without having to reinitialize the Software Defined Radio, you can start apps/sdr-zmq-daemon in the background. If you then start grdab with grdab -z, it will start much faster, and you can have multiple instances of grdab running at the same time.