Research And Implementation Of DVB-S2 Digital Demodulation Technology

Digital video broadcasting-satellite second generation(DVB-S2)is proposed by the European telecommunications standards institute.As the second generation satellite digital video broadcasting standard,digital video broadcasting-satellite second generation not only has stronger error correction ability and larger transmission capacity,but also has higher flexibility.It has been wildly used in the world as it was released.There have been more in-depth studies in modulation and demodulation fields of digital video broadcasting-satellite second generation by manufacturers from around the world.However,the domestic research starts late and the market competitiveness is insufficient.Therefore,intensive study of digital video broadcasting-satellite second generation is very significant to improve the competitiveness of our country.In this thesis,according to the requirement of actual project and current technical trend,the DVB-S2 digital demodulation technology is studied in the following aspects.1.Overall scheme of the DVB-S2 demodulation system.According to the specification of DVB-S2 modulation system and various factors of channel,the key points of the system design are put forward.2.Symbol synchronization technology.Base on the in-depth study of the new symbol synchronization technology,the overall scheme of the symbol synchronization is proposed.The new cubic interpolation algorithm used in interpolation filter module is introduced.An improved Gardner error detection algorithm is proposed in the timing error estimation module.3.The frame synchronization technology.According to the characteristics of DVB-S2 signal,a differential correlation processing algorithm based on Start of Frame(SOF)and Physical Layer Signaling Code(PLSC)information is given.In order to improve the stability of the frame synchronization module,a synchronous state machine conversion mechanism is designed.4.Carrier synchronization technology.Based on the reality of our country,a new phase error extraction algorithm for the higher-order modulation mode is discussed.The results show that the new scheme not only meets the performance requirements of the carrier synchronization,but also effectively reduces the complexity of the circuit design.5.DVB-S2 decoding technology.In order to reduce the requirement of input Signal Noise Ratio(SNR),a simplified logarithmic likelihood ratio(LLR)implementation technique is used to calculate the soft output information of high-order modulated signals.The high speed channel decoding technology is used to solve the problem of large amount of data and difficulty of decoding,which is verified by simulation.6.The feasibility of using the hardware platform to verify the algorithm.Combined with the demodulation algorithm obtained in the above chapters,the system hardware architecture and performance verification solution of the DVB-S2 demodulator are given.The performance indexes of the DVB-S2 are tested and the results show that the demodulation system can correctly realize the demodulation function.