The Design And Implementation Of Campus Smart Card System

Speech signal processing is widely applied to communication, voice recognition and synthesis, natural language understanding, multimedia database as well as Internet. Digital filter can be divided into infinite impulse response (ⅡR) digital filter and finite impulse response (FIR) digital filter according to its impulse response of the time domain. FIR digital filter access to a wide range of applications because of convenient description, the system is always stable, easy to implement phase linear features and so on. This paper describes the FIR digital filter the basic knowledge, and combined with concrete examples to introduce the three methods of designing the FIR digital filter——Window function design, Frequency of sampling design, Chebyshev approximation method, presented the three methods of design principles, knowledge, design steps and specific procedures. Modern digital filter can be designed with software or hardware, software approach has the advantage of being very easy to adjust design parameters in accordance with design requirements, greatly reduce the workload, this paper use MATLAB software to design and test FIR digital filter, Meanwhile, it eliminates the noise of speech signal.