Dab-micro-transmitter For Insertion Of Local Windows

Abstract

By incorporating micro-transmitters into a given DAB-SFN (Digital Audio Broadcasting -Single Frequency Network), service providers are able to replace the information content of a specified single channel inside the predefmed ensemble so that it is of local interest. There must be no interference with neighbouring channels, which must still be receivable within the small radiation field (e.g. 300m3 of the micro-transmitter without loss of information content. The consequent technical problems are analyzed and discussed and measurements are reported which were derived from an experiment set up to demonstrate the operating principle. Conclusions and outlook are given.In DAB digital radio networks based on ETSI 300401 (European Telecommunications Standards Institute) all the transmitters in an SFN broadcast on exactly the same frequency at exactly the same time[l] [2]. In such SFNs it hardly seems possible to provide alternative service and information specific to the various localities [3]. However, this should be possible if micro-transmitters a with very small radiation power are installed creating a so called local window. Thus in the immediate area it is possible to receive the local data from the overwritten channel as well as the original SFN services from the others. Local windows could be applied at bus stops, museums, tourist attractions, and so on [4].