Project descriptionDigital Radio Mondial (DRM) is a standard for broadcast of audio in the frequency bands below 30 MHz. It allows for broadcast of digital radio along with existing analog stations in the AM bands. Near FM-quality audio can be achieved even on the small bandwidths due to the use of cutting-edge audio compression supported by DRM. Several stations broadcast DRM radio mostly in Europe and in particularly in Germany.
The Danish company LIAB shows interest in developing a software defined DRM radio on their microprocessor running Linux. In software defined radio system components traditionally implemented in hardware (e.g. mixers, filters, de-modulators, etc.) are instead implemented in software.
Presently, an experimental processor has been developed in C for execution on a standard PC. It can process and play pre-recorded data down-converted to about 12 kHz and sampled at 48 kHz. The processing includes: frequency tracking, time tracking, equalization, OFDM demodulation, QAM de-mapping, Viterbi decoding, descrambling, etc.
A receiver board has also been purchased, assembled and tried out as a front-end for a PC based solution.
Possible projects could include one or more of the following elements:
a) Development and implementation of fixed point processor based on the running floating point version.
b) Port and adaption to the nanoLIAB microprocessor requiring a fixed point algorithm. This also includes optimization/simplification so that the algorithm can run in real time on the processor with limited resources.
c) Identification of S/N limitations in the presently implemented processor so that it can work on realistic signal-to-noise ratio levels. Possible issues are time tracking and channel estimation.
d) Antenna selection for the DRM front-end, investigation of the needs for an antenna amplifier and performance investigations. This task also combines well with c).
The project is carried in collaboration with: LIAB ApS, and/or Broadcast Service Danmark.