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A short demonstration of the creation of a live DAB transmission has been performed after the presentation on local DAB broadcasting. It has been done using a average Dell laptop and were consisting of the transmission of: *Live sound from the laptop microphone *Live retransmission of Maxxima webradio *Live retransmission of France Inter *Live retransmission of SWR3 Here are the setup and scripts used ===Hardware=== *Dell Latitude E6400 laptop (Centrino 2 CPU) *USRP1 Universal Software Radio Peripheral with WBX RF daugtherboard (50MHz-2.2GHz) *[[Filter|Mini-circuits bandpass filter]] ===Software=== *Ubuntu Linux 10.04 *Gnuradio 3.3 *Jack open Audio connection kit *arecord (from ALSA utils) *[[Toolame]] open MPEG Layer II encoder *CRC MMBtools open source DAB multiplexer: [[CRC-DabMux]] *Non blocking buffer: [http://www.glines.org/software/bfr bfr] *CRC MMBtools open source DAM modulator: [[CRC-DabMod]] *[[Band 3 baseband player|Baseband USRP1 VHF player]] ===Scripts=== 2 scripts were used in parallel, one for the multiplexer/modulator and the other for getting the sound stream and encode them Script for stream and encode: #!/bin/sh arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug1 |toolame -s 48 -D 4 -b 128 /dev/stdin ./1.ff & arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug2 |toolame -s 48 -D 4 -b 128 /dev/stdin ./2.ff & arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug3 |toolame -s 48 -D 4 -b 128 /dev/stdin ./3.ff & arecord -t raw -f S16_LE -c 2 -r 48000 -D jackplug4 |toolame -s 48 -D 4 -b 128 /dev/stdin ./4.ff & *.ff are FIFO files (names pipes) that were created using "mkfifo" command *"jackplug" are [http://www.alsa-project.org/main/index.php/Asoundrc#JACK_plugin mapping of jack source to ALSA], defined in .asoundrc file in home directory Script for multiplexing, encoding, playout: #!/bin/sh CRC-DabMux -L "MyMux" -A 1.ff -b 128 -i 1 -S -L "LiveMic" -C \ -A 2.ff -b 128 -i 2 -S -L "Maxxima" -C \ -A 3.ff -b 128 -i 3 -S -L "France Inter" -C \ -A 4.ff -b 128 -i 4 -S -L "SWR3" -C \ -O fifo:///dev/stdout |\ CRC-DabMod -f -g1 -r3200000 |\ bfr -p -b 32m -m 8m |\ coinwap_full3.py (bfr is the buffer, coinwap_full3.py is the baseband player) ===Startup procedure=== *Start jack audio server using Jack Control (you need to have install jack audio server and tools) *Launch the 2 scripts. *By default (depending on .asoundrc file) all source will be connected to the laptop microphone *Play the streams of Maxxima, France Inter and SWR3 using any player compatible with jack. In our case we used mplayer. See below: mplayer -ao jack http://maxxima.mine.nu:8000 mplayer -ao jack http://mp3.live.tv-radio.com/franceinter/all/franceinterhautdebit.mp3 mplayer -ao jack http://mp3-live.swr3.de/swr3_m.m3u *Connect the outputs of the different mplayer to the input of the multiplexer using "connectionS" in JACK control

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