Design Of Adaptive Filter Based On FPGA

Compared with analog filter, digital filter has the advantages of high signal to noise ratio, good performance of transition zone, high reliability and expansibility, flexible and convenient design and application. With development of special digital signal processing chip, digital filter CAN achieve performance and processing speed has been greatly improved, the realization of the use of the better performance of digital chip design more complex filter, so that the adaptive filter realization and application become possible, FPGA(field programmable gate array) is a new type of digital signal processing chip, with parallel processing of data and CAN use hardware programming language directly the characteristics of the hardware design, is currently a hot research topic for study of adaptive filter is implemented on FPGA.The Matlab simulation of the adaptive filter, to understand the characteristics of the structure and operation characteristics, and the use of Matlab generating test signals and FPGA simulation software Modelsim joint behavior simulation of FPGA design, then to Altera cyclone IV series chip ep4ce15f17c8 as the carrier of the development board for simulation design, in the design process, make full use of FPGA parallel processing and fast digital signal processing for structural design. On this basis, the following work has been done:The filter needed to fully understand, adaptive transversal filter, adaptive notch filter and FFT transform based on the principle of selection and build a design platform, first in the basic research of current FPGA adaptive transversal filter realization, using modular design method, the structure is divided into single and serial FIR filter module serial LMS weight update module, the design of the two modules and integrated were designed, and simulation experiments, through the parallel call two different modules, each call the four way to design a 16 order filter as an example to illustrate the modular design method, and design of 32 order and 64 order respectively with serial and the processing rate parallel design methods and logic resources call were compared. The results show that the operation rate and parallel call module is proportional to the number, far faster In the whole serial design mode, and for the 64 order all parallel system, greatly improve the design flexibility, reduce the consumption of hardware resources. After the design on this basis, the traditional adaptive trapped wave filter, filter frequency fixed defects, put forward a method of frequency domain transform detection noise characteristic frequency, and CAN change in real time according to the characteristics of noise frequency trapped wave frequency filter design methods, in order to reduce the design complexity and the sign LMS adaptive notch filter algorithm, the characteristic variables of the symbol is determined through the simulation experiment of Matlab. And the noise signal extraction algorithm are introduced and the simulation design, the final design according to frequency noise automatically adjust the trapped wave frequency adaptive notch filter, and on the performance of the filters were Modelsim simulation research, the adaptive notch filter has CAN effectively filter on the frequency of the single frequency noise signal, and does not affect the characteristics of waveforms useful.For the FPGA design of two based on the LMS adaptive algorithm of filter, reflecting the FPGA in the adaptive filter design flexibility and uniqueness, two different types of adaptive filter CAN be respectively applicable to ordinary digital filter CAN not effectively play the role of occasions, also the design method of other types of digital signal processing system based on FPGA implementation has a certain reference value.