Design And Implementation Of Wide-band Beamforming System Based On SOPC

Beamforming is one of the array signal processing techniques which are popular andwidely used in many fields recently. The main function of this technique is performing aspatial filter for the received signal to overcome the signal interference from some orientationand enhance the signal energy from specified direction. Wideband signals can carry moretarget information and have weaker correlation characteristics in reverberation backgroundthan those narrowband signals. So wideband beamforming technology is developing rapidly.Due to the large amount of computation and data, the higher demand has been put forward inthe aspects of storage capacity, transmission capacity, processing capabilities and displayability. And it is also the difficulty of engineering applications.Currently, the traditional way of wideband beamformer’s implementation is to achievebeamforming operation by using large scale programmable logic device and the digital signalprocessing chip, and the processing results which are trasmission to the computer via the buswill be stored, processed, displayed and analyzed. It may increases the system’s complexity,the debugging’s difficulties and also the operation’s period. In this article we presents adisplay and control platform for the wideband beamforming system based on SOPC(SystemOn Programmable Chip). The multi-channel wideband beamforming processes can beachieved at real-time, at the same time, peripheral device such as VGA and PS/2wasexpanded in the FPGA, and a display and control system was built to show the input andoutput data based on Nios Ⅱ software processor. Compared to traditional approach, thismethod makes full use of the advantage of FPGA parallelism and scalability, all the functionsof data processing, displaying and controlling were achieved within a single processor. Thiscompact structure is reliable for a sonar system, and also provides a new way for the signalprocessor. The main research content can be summarized as follows:First of all, this article introduces the common method of wideband beamformingincluding the basic principles and structure of the time domain and frequency domainbeamforming methods. The model of the wideband beamformer is put forward, with focusingon the pinciple of fractional delay filter based on the maximum flat. And then we make thesimulation on the computer to show the effectiveness of this theory.Secondly, the wideband beamforming algorithm based on maximum flat is programmedby the Verilog HDL in the QuartusⅡ software. After the certification through the simulationin the Modelsim, it was transplanted into FPGA hardware platform for real-time implementation. And the actual results were analyzed by comparing to the the theoreticalsimulation.Again, the platform of displaying and controlling has been designed on the SOPC. Themain work of this part includes development of self-defined peripheral devices such as VGAand PS/2, the transplant from μC/GUI embedded interface to Nios Ⅱ, the design ofhuman-computer interface,as well as the graphics of coordinate transformation display onthe interface after the transfomation from three-dimensional to two-dimensional.Finally, the test and debug of the entire system has been carried out after every part iscerticificated valid. It can verify the correctness and effectiveness of the systemimplementation, as well as the stability of the SOPC system.