ABSTRACT
Digital filter is a device made up by digital multiplier, adder and self-timer. Its function is to operate and process the numeric code of the inputting discrete signal, in order to change the signal spectrum.Based on this reality of wide application of digital filter in the actual design, this paper analyzes the basic theories, characteristics, design methods of the digital filter comprehensively, especially discusses the design of finite impulse response filter thoroughly. It introduces the definition, classification, design and implementation of the filter. In the design method, it introduces the basic steps of the design of digital filter and MATLAB. It mainly research the design principle of FIR digital filter and three design methods including window function method, frequency sampling method and equal ripple optimal approximation. Through a specific example, it goes on simulation analysis and establishes a graphical user interface (GUI).
Keywords: Finite impulse response,Window function method, Frequency sampling method, Equality ripple approach method and MATLAB
