Digital Audio Broadcasting And The Originator Of The Key Technologies To Achieve - The Eureka-147 Dab System,

This disertation presents research and development work on the European Digital Audio Broadcasting(DAB). An MPEG/DAB audio encoder based on single DSP and a DAB multiplexer based on two DSP plugged in PC are developed. It also presents the design of channel encoder and OFDM (Orthogonal Frequency Divide Multiplex) modulator used in DAB, all based on DSP. Chapter 1 is the general review on the current development of speech/audio encoding and channel encoding&modulation concerning with DAB. Chapter 2 describes research on MPEG-1 audio encoding algroithm and presents a more efficient algorithm by improving the efficiency of suband analysis filter bank and the computation procedure of psycho-acoustics model to determine the masking effects. With the results of this research, an MPEG/DAB encoder based on single DSP—TMS320C31 is developed. Chapter 3 describes the multiplexing mechanism of DAB in detail. An novel structure based on DSP plugged in PC to implement the DAB multiplexer is given. With this structure, an versatile experimental DAB muxer is developed. Chapter 4 investigates the channel encoding and OFDM modulation principle and technique employeed in DAB. The hardware and software architecture for implementing the channel encoder and modulator is researched. A channel encoder based on DSP is described. An more flexible structure of OFDM modulator based on two cascaded DSP — ADSP21020 rather than FFT chips is designed. Finally a summary of this paper together with some review on the prospects of different digital broadcasting techniques is given.