Base - Band Study On The Shaping Filter And Channel Digital Receiver Technology

This paper investigates the problems about the base-band signal shaping and the multi-rate signal processing of the radio-frequency signal. Firstly, the paper gives the mathematical model of the shaping-filter functions and discusses their transmission characteristics. Secondly, the methods to realize the shaping-filter are introduced, which include the FIR algorithm, the FFT-IFFT algorithm and the symbol sliding-window algorithm. The genetic algorithm (GA) is used to optimize the filter coefficients. Computer simulation shows the GA is effective in the filter's design. In addition, the paper presents filter multi-phase structure for the shaping-filter design and its FPGA implementation, where multipliers can be omitted by using the look-up table of the filter coefficients ROM . Test of the prototype circuit board shows the method is perfect. Finally, two important theories of the multi-rate signal processing, interpolation and decimation, are discussed. The paper also gives their computer simulation results and FPGA implementation.