| As an important branch of the modern signal processing, array signal processing has been applied in many fields such as radar,sonar,communication and so on. The performance of antenna array signal processing is deteriorated markedly by channel mismatch,caused by mutual coupling among sensors,unbalance between channels,length of feedback,etc. So the channel mismatch must be equalized before array signal processing for getting high performance.Digital beamforming is an important part in the array signal processing and has a great influence in the subsequent data processing. Broadband multichannel calibration technique and broadband beamforming technique are researched and analyzed deeply in the article.The main contributions of this thesis can be summarized as follows:First, an algorithm of broadband multichannel calibration based on adaptive equalization is studied.The digital filter is synthetized by means of self-adaptive filtering principle, solving amplitude variation and phase shifting mismatching among receiver channels effectively.The approach is applied to the broadband multichannel calibration in EW. The results in this paper show that the algorithm is effective. The realization of digital filter based on FPGA or DSP is a mature technology. So the broadband multichannel calibration can be realized in engineering by designing a specific digital filter.Second, in many cases, it is essential that the array could receive broadband signal without distortion. So the beamformer must have a frequency invariant beam pattern. A method to design a finite impulse response (FIR) filter with specific frequency response by use of adaptive method, and this kind of filter to be used in time-domain broadband beamformer are deeply studied in this paper.The simulation results show that the algorithm is effective.At last, this thesis pays the main attention to the design of broadband array signal processing platform.It presents the design of workflow and working principles, and introduces the important part of the platform. Then the concrete analysis of function modules is presented in order to achieve the functions and indexes of the platform. |
