Re: [Discuss-gnuradio] OLPC

[Mathias Coinchon]

As in the DRM (digital radio mondiale) specification the signal are generally maximum 20kHz wide but 10kHz is the most commonly used nowadays.

So the actual cheap way to receive DRM (Digital Radio Mondiale) transmission is to use the soundcard at A/D with an external tuner. With this it is also possible to decode any narrowband signal such as AM for example.

The external tuner can either be a traditional LW/MW/SW radio with a modification consisting of a downconverter of the IF to 12kHz:
Example of receiver modifications: http://www.drmrx.org/receiver_mods.html
Mixer/downconverters available at: http://www.sat-schneider.de/DRM/DRM.htm

There are also some tuner directly giving a 12kHz IF output:
- Elektor kit: http://www.elexs.de/drm.htm
- Coding technologies Digital traveller (include usb soundcard and FM receiver): http://www.codingtechnologies.com/products/digtrav.htm

So a first step would be to port the open source Dream software DRM receiver on the OLPC: http://drm.sourceforge.net/

Regarding high sampling rate A/D, would it be possible to use the A/D of a analog video acquisition device and plug it on an cheap external tuner such as the one used on the USRP TVRX daughterboard ?

Mathias