A new and efficient window function for digital FIR filter design

In this thesis, a new window function for digital FIR filter in addition to studied in literature is presented. Some of the well-known and widely used window functions given in the literatures are Kaiser window, Cosine hyperbolic window, Exponential window, Saramaki window, Ultraspherical window, etc. Each window function has advantages and disadvantages compared to their specific application areas. Digital filters are commonly used for application of digital signal processing. The linear phase characteristics of the finite impulse response (FIR) filters make them preferable to infinite impulse response (IIR) filters although their lengths are more. The stability property of FIR filters is the another advantage. There are some methods of designing the FIR filters starting with the given magnitude and/or phase specifications. The one of efficient method for FIR design is to use the Fourier Series. Since the Fourier Series representation of the specified characteristics are infinite and the FIR filters have finite length, to prevent the Gibbs' Oscillations, the window function are used. Briefly, combination of modified Cosh window and Blackman window is proposed in this thesis. Especially, sharper transient and lower magnitude of attenuation are obtained. To find best optimized values, most of mathematical calculations are analyzed, then some specific parameter values are found for proposed window function. Key Words: Finite impulse response (FIR) digital filters, window methods, Blackman window, modified Cosh window.