Abstract: In digital control system, interference, which is mixed in the input signal, has a great influence on the performance of the system. Therefore, processing of input signal has to be done to get useful signal. Finite impulse response (FIR) filter plays an important role in the processing of digital signal. Designing the FIR filter by Matlab can simplify the complicated computation in simulation and improve the performance. By using the methods of window function, frequency sampling and convex optimization techniques, the design of FIR filter has been processed by Matlab. In the view of the designed program of Matlab and I can get the amplitude-frequency characterization. By using the FIR digital filters which have been designed to process the input signal based on the Matlab function, the filtering effect of different digital filters is analyzed by comparing the signalís amplitude-frequency diagrams which have been generated. The experimental results show that the FIR filters designed in this paper are effective. In the view of the designed program of Matlab and I can get the amplitude-frequency characterization. By using the FIR digital filters which have been designed to process the input signal based on the Matlab function, the filtering effect of different digital filters is analyzed by comparing the signalís amplitude-frequency diagrams which have been generated. The experimental results show that the FIR filters designed in this paper are effective.

Keywords: FIR Filter, DSP, FFT, Hanning Window, MATLAB, Taylor Window, Rectangular Window, frequency sampling, amplitude-frequency.