A Study Of Detecting Algorithm Of Direct Sequence Spread Spectrum Signal And The Realization With FPGA

This paper begins with the principle of the spread spectrum communication,introduces some common pseudo noise codes, such as m sequence and Gold sequence. Then emphasizes the theory of some common filter in the communication systems, including shaping filters—raised cosine filter, interpolation filter—CIC filter, Farrow filter and so on. For Farrow filter’s property, it is more flexible to convert one sampling rate to another sampling rate than the common interpolation filter( begins with interpolation, followed by extraction), especially when signal’s sampling frequency is close to the sampling rate of the whole systems. Then gives the simulation results with Matlab. In the Chapter 4, which is important chapter in this paper, some brief introductions to the principle of algorithms of the square frequency doubling, the variances hop by hop and the method of fourth mean power are given with emphasizes on the simulations and comparison of each algorithms, and chooses the fourth mean power algorithm as the realization of the DSSS signal detecting. Then this paper followed by the hardware realization,which is realized by the fourth mean power algorithm as mentioned before. The hardware platform is ISE 12.1 and the simulation software is Modelsim 6.5. Finally, it proves that the fourth mean power algorithm is suitable for this item.