Design Technique of Bandpass FIR filter using Various Window Function

Abstract

Filter is one of the most important part of communication system. Without digital filter we cannot think about proper communication because noise occurs in channel. For removing noise or cancellation of noise we use various type of digital filter. In this paper we propose design technique of bandpass FIR filter using various type of window function. Kaiser window is the best window function in FIR filter design. Using this window we can realize that FIR filter is simple and fast. Keywords: FIR filter, LTI, bandpass filter, MATLAB I. Introduction In different areas digital filter design techniques are widely used. The digital filter consist of both software and hardware implementation. In the digital filter, the input and output signals are digital or discrete time sequence. Digital filters are linear time invariant (LTI) systems which are characterized by unit sample response. These filters are portable and highly flexible. It has minimum or negligible interference noise and other effects. In storage and maintenance digital filters are easier. Digital filters reduce the failure time. Digital filters are categorized in two parts as finite impulse response (FIR) and infinite impulse response (IIR). In comparison to IIR filters, the FIR filters have greater flexibility to control the shape of their magnitude response. According to the frequency characteristics digital filter can be divided-lowpass, highpass, bandpass, and bandstop.The realization of FIR filter is non-recursive in comparison to IIR filter. Bandpass filtering plays an important role in DSP applications. It can be used to pass the signals according to the specified frequency passband and reject the frequency other than the passband specification. Then the filtered signal can be further used for the signal feature extraction. Filtering can also be applied to perform applications such as noise reduction, frequency boosting, digital audio equalizing, and digital crossover, among others.