FIR And IIR Digital Filter Designing Based On MATLAB

The main content of this article is designing method of two digital filters through the MATLAB tools. The two digital filters are infinite impulse response (IIR, Infinite Impulse Response) filter and finite impulse response (FIR, Finite Impulse Response) filter, and the input and output signal are digital signals. The traditional design method of digital filter is a tedious and complicated calculation process, and once the design is complete, there is no convenient modification of filter characteristic curve, so it’s very inconvenient. The above disadvantages greatly restrict the development and application of digital filter. While MATLAB and its accompanying toolbox function is very strong, we use the software to design the above-mentioned two kinds of filters, it can be done at any time to take the finished curve and the target filter characteristic curves, in order to make the improvement, saving time and labor, that is very significant advantages.This paper is divided into three parts:the first part is introduction, we introduce the digital signal processing filter function and it’s prospects; in the second part we introduce FIR digital filter design methods using MATLAB, including the window function method, frequency sampling method and optimal equiripple method, and using MATLAB program to design IIR band-pass and low-pass filter, finally we summarize the advantages and disadvantages of the several methods; in the third part we introduce the use of MATLAB to design IIR filter, while we also design IIR band-pass and low-pass filter using MATLAB program.