... mainlobewidth. On the other hand, to reduce the passband and stopband ripples, the area under208 DESIGN AND IMPLEMENTATION OF FIR FILTERSthe sidelobes should be small. Unfortunately, there is a ... passband, while the remaining zeros provide attenuation for a stopband. For example, we can add a pole at z 1. Thus the transfer functiongiven in (5.2.7) is changed to192 DESIGN AND IMPLEMENTATION ... stopband attenuation (41 dB). In designing a lowpass filter,the Hamming window provides low ripple over the passband and good stopbandattenuation is usually more appropriate for FIR filter design...