Copyright 2020 - TSR - Tratamiento de la Señal y Radiocomunicaciones

Esther SÁNCHEZ 

MSc. Director: Pablo Angueira

Finish Date: Academic Year 2010-2011

 

MSc. Thesis Description

DRM (Digital Radio Mondiale) is a terrestrial digital radio technology developed and promoted by the DRM Consortium, which is a broadcasting related group of companies and organizations. This technology is standardized to operate in all AM broadcasting bands below 30 MHz. These frequencies are used in long wave, medium wave and shortwave bands.

Actually, we are working on the 26 MHz band which comprises the frequencies between 25.67 MHz and 26.1 MHz. Traditionally, this band was used for international long-distance large-areas coverage by using ionospheric wave refraction, but this type of broadcasting only works when we reach a high ionization level of the ionosphere.

Due to this fact, the 26 MHz band is now being investigated for giving local coverage by using troposfheric wave, as the FM service works. The broadcasting research is complex due to the phenomenoms that appear such as diffraction or multipath.

For making a prediction of DRM signal, we are going to use the ITU-R P.1546 (actually version 3). This recommendation is indicated for frequencies between 30 MHz and 3000 MHz. We work with 26 MHz band, but as it is a high frequency close to 30 MHz, this recommendation may work. The method is based on interpolation/extrapolation from empirically derived field-strength curves as functions of distance, antenna height, frequency and percentage time. The calculation procedure also includes corrections to the results obtained from this interpolation/extrapolation to account for terrain clearance and terminal clutter obstructions.

My work consisted of:

  1. Searching and reading information about 26 MHz broadcasting.
  2. Studying ITU-R P.1546-3.
  3. Studying the matlab implementation of ITU-R P.1546-2.
  4. Making the matlab implementation of ITU-R P.1546-3.
  5. Examining the obtained results.