FIR DIGITAL-FILTERS WITH LEAST-SQUARES STOPBANDS SUBJECT TO PEAK-GAIN CONSTRAINTS

This paper was motivated by the numerous applications requiring FIR digital filters with least-squares stopbands subject to maximum-gain constraints. The digital filters presented here can efficiently meet simultaneous specifications on the peak stopband gain and the total stopband energy. The trade-off between these filter performance measures is explored. It is shown that the trade-off is extremely unfavorable for minimax filters designed by the Parks-McClellan computer program [1]. In particular, the stopband energy corresponding to a Parks-McClellan filter can be significantly reduced at the expense of a very small increase in the peak stopband gain. Examples are included.