Medium wave DRM field trials in Brazil – Some daytime and nighttime results in urban environment

The Digital Radio Mondiale (DRM) system broadcasts audio in the frequency band below 174 MHz [1] and [2]. In this experiment in urban areas in Brazil, a hybrid signal composed of an analog AM signal and a digital DRM30 signal, with the same content, were broadcasted in diurnal and nocturnal transmissions. This paper describes the experimental setup, which employs the spectral shaping technique in simulcast transmission [14], and presents some results of medium wave propagation measurements campaigns that are being carried out in Brazil. The experiment is part of a series of field trials that are being conducted by the Brazilian Government which includes campaigns at MW, HF and VHF frequency bands.

► Field trials of DRM system in medium wave band were carried out in Brazil.
► Measurements of field intensity, audio quality and signal-to-noise ratio.
► Simulcast transmission of DRM signal and analog signal.
► Spectral shaping technique was employed during theses trials.