Modification to exponential window and its applications in signal processing

Abstract

In this paper, exponential window is modified to improve its spectral parameters in terms of ripple ratio and sidelobe roll-off ratio by introducing an additional parameter. It is observed that an increase in the value of new parameter gives wider mainlobe width and smaller ripple ratio with larger sidelobe roll-off ratio. By selecting the suitable combinations of the two adjustable parameters, spectrum design equations are empirically obtained for proposed modified window for window length N=51.Simulation results shows that proposed modified window provides higher sidelobe roll-off ratio compared to well known Kaiser, cosh and exponential windows for same window length. Also, it gives less window coefficient compared to all above windows for same ripple ratio and mainlobe width which shows the computational efficiency of window. Moreover, the application of the proposed modified window in image processing and FIR filter design are presented. Digital FIR filter designed by modified window provides higher far-end stopband attenuation compared to Kaiser, cosh and exponential windows and also gives better minimum stopband attenuation compared to cosh and exponential windows. It also gives good contrast ratio by proper selecting adjustable window parameters in the field of image processing.