关键词:视频点播;多载波 QAM 调制器;均方根升余弦滤波器;奈奎斯特内插滤波 器;邻道干扰;码间串扰;通用异步收发器 II 华中科技大学博士学位论文 Abstract In this thesis, we analyze the background and features of MC-QAM modulation and show the model of modulation based on quadrature conversion mixer, then present the technology and implementation method for MC-QAM modulation based on the analysis and remark of status. The problems we solved in this thesis include: A procedure to design Root-Raise Cosine (RRC) filters for data transmission application has been described. The proposed algorithm is based on optimal equiripple design technique and the linear equations concluded directly from the requirements of Adjacent Channel Interference (ACI) and Inter-Symbol Interference (ISI). The whole process avoids the numerical ill-conditioning problems because an iterative linear programming technique has been adopted. The two main features that emerge from the proposed algorithm are: (a) ACI reduction, ISI mitigation and lower signal-distortion are obtained, compared to former results. (b) The proposed algorithm is especially favorable for high-order filter designs. A novel architecture for implementing various FIR (Finite Impulse Response) filters expediently in a Field Programmable Gate Array (FPGA) chip has been proposed. The architecture, which utilizes high-speed pipelined Multiple Accumulators, can implement different FIR filters with lowest logic resource usage by considering area-speed tradeoffs. And the base-band shaping filter is taken as example to show how to implement FIR filter with this architecture pare with the traditional architecture for FIR filter. The result reveals that the restriction of synthesis between the area and speed can be much more efficiently optimized by using t
