An Adjustable Improved Window for FIR Filter Design

The window function has a wide range of applications in filter design, signal truncation, information processing, etc., especially in the design of filter using the window function method, the different window functions directly affect the performance and application of the filter, so how to improve the construction of a new window function is of great significance and value for the design of an excellent filter meeting the requirements of use. Based on Blackman window, Kaiser window and its parameters, Chebyshev window, this paper gets an improved adjustable window by multiplying the above Windows and raising them to the power of r. The shape of the window in time domain and frequency domain can change with the change of the adjusting parameter r. By comparing the improved window with common window functions such as Hanning window, Blackman window and so on in image and performance parameters (ripple ratio, main lobe width, etc.), the results show that the improved window has excellent ripple ratio and better roll down ratio when the main lobe width is very close to the general window function. The simulation results show that the filter with improved window design has better passband fluctuation and stopband attenuation, and the improved window is suitable for the cases with high requirements for sidelobe, especially the first side lobe.