Research Of RDS/RBDS Demodulation Algorithm

The main target of this thesis is description the de-modulation algorithm of the RDS (Radio Data System) system in FM radio and further research in this topic. Generally, International RDS implementation standard is based on analog circuit which leads to super large consummation. This thesis investigates a method to implement RDS system based on digital circuit, and meet general international standard's requires. At the same time, because of the advantage of the digital circuit, such as low power consummation, high speed, so this IP (intellectual property) has more really application purports.RDS is a communications protocol standard from the European Broadcasting Union for sending small amounts of digital information using conventional FM radio broadcasts. The RDS system standardizes several types of information transmitted, including time, track/artist info and station identification. RDS has been standard in Europe and Latin America since the early 1990s. RBDS (Radio Broadcast Data System) is the official name used for the U.S. version of RDS. There is no basic difference between these two versions. China use European standard RDS.The de-modulation method this thesis descripts can cover those two standards, and did a detail research on every step of the procedure.1. Expound the function of the RDS, and emphasis the modulation and demodulation of the general international standard.2. Expound the implementation structure and RDS block type.3. Based on the standard, improve the system. Propos a efficient structure, including filter design (such as CIC filter, lattice wave digital filter),de-modulation method and Manchester coding (decoding).4. In further investigation, propose a new de-modulation algorithm which is based on the wave shape in time domain. They are Peak-Peak detect and Passing 0 detect. Both of them have the advantage on cutting calculation resource in CPU.The final result shows that structure is fully agree with the general requires, and the product will be sold in the market this year. Meanwhile, the improved de-modulation method has forecast meaning, and gives a way to improve the current system.