Front End Design Of The Receiver For Digital Audio Broadcasting

Digital broadcasting will be the dominant broadcasting system in the future. Digital Radio Broadcasting (DAB) is a broadband, nearly CD quality, digital broadcasting, suit for terresestrial and satellite broadcasting. DRM (Digital Radio Mondiale) is a flexible digital sound broudcasting system for terrestrial broadcasting in bands below 30MHz.The front end in a digital broadcasting receiver means the part of circuit that converting RF analog signal to baseband digital data stream. It is the key part that determines the performance of the receiver. This thesis gives analysis of the requirements for the front end and research on the crucial problems in front end designing. The mixer circuit architecture has been designed, word length of A/D converter and AGC reqirements discussed, simulation of OFDM demodulation influenced by linearial distortion of the channel is given, that will be help for the filter design of DRM front end. The simulcast of DRM system has also been analysed.The front end circuit of DAB receiver has been designed by using U2731B, which is an ASIC for DAB system. The DAB receiver has been examined by the ministry of information industry, the performance parameter of fornt end circuit exceeded requirements.The DRM programmable digital down-convertor (PDC) based on the concept of software radio has been designed also. The analog part in the fornt end of DRM receiver is made from AM radio and the digital part is designed to be a PDC which could satisfied with the multi-mode and multi-band requirements of DRM system. An FPGA test circuit that was the main part of DRM test receiver has also been designed to verified the PDC.