VSWR
Posts: 1
Joined: Sun May 12, 2013 6:23 pm

Q. Rasbery Pi as Digital Radio Mondiale decoder

Sun May 12, 2013 7:55 pm

I wonder if Raspberry Pi can be used as decoder for Digital Radio Mondiale (DRM).
I see some upps written for Linux , Mac and PC . Can this apps be recompiled to work on Raspberry Pi.
The source cod can be found here.
http://sourceforge.net/apps/mediawiki/d ... =Main_Page
The external component (down converter) will need to be build (AM receiver). After that we will need to feed that to sound card to digitize down converted signal then process on Raspberry pi
There is olso link that use USB TV capture card as software define radio. That might be useful.
Like this project:
http://sdr.osmocom.org/trac/wiki/rtl-sdr

Rene_is_I
Posts: 172
Joined: Tue Dec 25, 2012 12:52 pm

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Sun May 12, 2013 8:21 pm

Hi VSWR

I'm not sure how DRM differs from the short wave SDR (modulation, bit rates and so on) , but have you tried searching for SDR on this forum?
May turn up one or two useful things that may be of help.

dynamo_rpi
Posts: 3
Joined: Mon Jul 15, 2013 11:28 am

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Mon Jul 15, 2013 11:51 am

TL;DR it's possible, but the CPU doesn't seem to be able to cope with audio input, audio output and DRM decoding simultaneously.

I managed to compile Dream DRM software version 1.12b on the latest version of Raspbian. I followed these instructions:

https://help.ubuntu.com/community/DREAM_software_radio

Some changes were required for the code to compile properly (in a few places c library includes were omitted and the new libtool required some syntax changes for the bootstraps to work). I built a headless version because I couldn't get it to compile with QT (indeed, 1.12b was the only version I could build without any QT errors, whether in headless mode or not). So the configure command used was:

./configure --disable-qt --disable-hamlib --enable-portaudio

This required portaudio19-dev library to be installed, as the default ALSA audio interface doesn't work in headless mode (it uses QT threads).

First, I overclocked RPi to 1100 Mhz and used the file input mode ( -f) to decode an intermediate frequency wave file, available here:

http://www.winradio.co.uk/home/g303-drm.htm

That worked fine, the audio was decoded without a glitch and was played back through the default HDMI interface onto my TV. That was as far as I got without any trouble.

I have an old USB sound card, which I then used to feed the same wave file being played on my netbook from its audio out to Dream in normal mode. Log output indicated that Dream recognised it as a DRM stream, but no audio was produced, either through HDMI or the USB sound card (whichever I happened to select at the time).

I shut down Dream and recorded this input from the USB sound card using arecord into a wav file. I then used Dream in file input mode once again with this new wav file and it decoded it fine.

So, it appears that RPi doesn't have enough mojo to do everything at once. I'm still investigating whether I can remedy this situation by one or more of:

1) Using jack instead of portaudio
2) Using a different USB sound card
3) Building a newer version of Dream (if I can figure out how to get rid of QT compilation errors in headless build mode).

dynamo_rpi
Posts: 3
Joined: Mon Jul 15, 2013 11:28 am

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Mon Jul 15, 2013 6:28 pm

Update:

Using a different USB sound card didn't work any better. It seems building a newer version of Dream won't do the trick either because of this simple test: running alsaloop -- a program that will send the soundcard input in realtime to sound output -- gives very choppy audio. If I just record audio and play it back later, no choppiness occurs. So the issue really is RPi's ability to handle audio streams going both ways, or indeed doing anything CPU intensive while receiving audio in the background.

I started a related thread here: http://www.raspberrypi.org/phpBB3/viewt ... 29&t=50007

Qljo
Posts: 1
Joined: Sat Apr 18, 2015 5:53 pm

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Sat Apr 18, 2015 6:09 pm

Hello,

Is there any update on the DRM project? I urgently need to build a DRM/DRM+ receiver. Perhaps 2 Raspberries can do, connected via Ethernet?

vinaykushwah24
Posts: 6
Joined: Tue Mar 24, 2015 1:40 pm

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Thu Aug 25, 2016 2:28 am

I am also looking help for DRM using raspberry pi....please someone help.

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braselectron
Posts: 5
Joined: Tue Apr 26, 2016 5:18 pm
Contact: Website

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Sat Nov 03, 2018 4:03 pm

This is the most interesting and helpful project for Digital Radio Broadcast community and for social development around the world.

Can you please consider updating the information about your project ?

I believe that using two Rpi (or more) or the Rpi3 or combining Arduino and RPi we can make the DRM+ receiver work.

Can you please publish here the modifications to Dream for compilation you have tried ?

It could be very helpful, for the ham community, a Github project for the DREAM on RPi to be used for development. Do you agree ?
Last edited by braselectron on Sun Nov 11, 2018 2:45 am, edited 2 times in total.

W. H. Heydt
Posts: 13290
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Sat Nov 03, 2018 5:18 pm

braselectron wrote:
Sat Nov 03, 2018 4:03 pm
This is the most interesting and helpful project for Digital Radio Broadcast community for social development around the world.

Can you please consider updating the information about your project ?

I believe that using two Rpi (or more) or the Rpi3 or combining Arduino and RPi we can make the DRM+ receiver work.

Can you please publish here the modifications to Dream for compilation you have tried ?

I could be very helpful for the community a Github project for the DREAM for RPi to be used for development. Do you agree ?
Given the date of the original post, he had to been using a first generation Pi. That was a single core ARMv6 CPU. The current Pis (Pi3B, Pi3B+) have 4 ARMv8 cores and are roughly 10 times faster. One might well expect a Pi3 class board to be able to handle this.

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braselectron
Posts: 5
Joined: Tue Apr 26, 2016 5:18 pm
Contact: Website

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Sun Nov 11, 2018 3:05 am

DRM and DRM+ are very powerful options for global broadcast.

The news available on the WEB shows that India is embracing this technology as the successor of analog radio broadcast, because its the lower cost option for broadcasters. Also it has many features like images, data and video, very important for emergency transmissions.

The information also shows that a low cost receiver unit is the main drawback which make adoption of this system quite slow.

RPi is a natural candidate to overcome this mile stone. Specially if we could get a PiZero to do the trick, which could lead to a very compact, low cost easy to deploy receiver.

Hope this project catches the attention of the FSF, GNU, Ham and Linux community as a major goal.

Very empowering system.

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startrek.steve
Posts: 386
Joined: Thu Aug 30, 2012 7:19 pm

Re: Q. Rasbery Pi as Digital Radio Mondiale decoder

Thu Nov 22, 2018 11:55 am

Would two pi 3 Plus's have enough grunt to do this?
One on Input and One handling output?
I dabbled with this on my Ubuntu Desktop and never got any output from it.

Steve
Pi 2 running LibreElec Krypton, Pi 2 running Wheezy Desktop, Pi 1 headless Wheezy, downloading Radio, Pi 1 running Picore headless Media Server, Pi Zero to be an Old Time Radio Project. Pi 3 testing. Pi Zero W downloading Radio shows headless.

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