Figure 3.24 plots the Kaiser window and its transform for . Note how increasing causes the side-lobes to fall away from the main lobe. The curvature at the main lobe peak also decreases somewhat.
Figure 3.25 shows a plot of the Kaiser window for various values of . Note that for , the Kaiser window reduces to the rectangular window.
Figure 3.26 shows a plot of the Kaiser window transforms for . For (top plot), we see the dB magnitude of the aliased sinc function. As increases the main-lobe widens and the side lobes go lower, reaching almost 50 dB down for .
Figure 3.27 shows the effect of increasing window length for the Kaiser window. The window lengths are from the top to the bottom plot. As with all windows, increasing the length decreases the main-lobe width, while the side-lobe level remains essentially unchanged.
Figure 3.28 shows a plot of the Kaiser window side-lobe level for various values of . For , the Kaiser window reduces to the rectangular window, and we expect the side-lobe level to be about 13 dB below the main lobe (upper-lefthand corner of Fig.3.28). As increases, the dB side-lobe level reduces approximately linearly with main-lobe width increase (approximately a 25 dB drop in side-lobe level for each main-lobe width increase by one sinc-main-lobe).