Comparison of Various Window Functions Used in FIR Filter Designing

In this study, 2-parameter cosh window is modified to improve its spectral characteristic in terms of the ripple ratio by proposing a new additional parameter. It is observed that an increase in the new parameter results in wider mainlobe width and smaller ripple ratio. By choosing the suitable combinations of the two adjustable parameters for the proposed modified window, the optimum windows that yield the minimum ripple ratio for N=51 and N=101 are .found. Simulation results show that the filters designed by proposed 3-parameter Cosh window provide higher quality in terms of the minimum stop-band attenuation for a fixed order, and yield lower order for a fix minimum stop-band attenuation compared to the filters designed by other windows.