Software And Virtual Radio Simulation Of Digital AM Broadcasting System

Software and Virtual Radio SimulationOf Digital AM Broadcasting SystemCandidate Yu Chunhua,Supervisor Wu LenanDepartment of Radio Engineering, Southeast University, China The topic of this paper is mainly about the DRM(Digital Radio Mondiale) system which works as a transitional form from analogue broadcasting to digital broadcasting, with the help of current medium and short wave transmitter, the system can transmit low bit rate signal with very narrow bands characterized by 4.5/5kHz single sideband and 9/10kHz double sideband. In this way, not only can it guarantee the acoustic fidelity of FM or CD, but also can ensure the simulcast with the original analogue broadcasting. In addition, it saves frequency resource and reduces emission power. Besides, the wireless channel is a time-variant and multi-path channel below 30MHz. OFDM (Orthogonal Frequency Division Multiplex) technique, on which DRM system is based, features with high bandwidth efficiency and robustness to multi-path channel. The research in this paper about OFDM refers to the construction model and key technology such as source coding, channel coding, etc.With Mento Carlo simulations method, Matlab emulation is established. Random data, speech and picture files are passed through the DRM system testing platform, with 64QAM, 16QAM or 4QAM different mapping methods, rate compatible punctured convolution codes and 2D Wiener filter channel estimation so that different methods are at hand to choose. By use of Visual C++ under Windows XP operating system, a platform on virtual radio is designed in condition that 2 PCs replace DRM transmitter, DRM channel and DRM receiver, respectively. In this way, data can be recorded, coded, transmitted, and played, and provides a good demo platform for Chinese medium and short wave digital AM broadcasting test.