巴特沃兹逼近 (Butterworth) 通带内最平坦滤波器 H(Q2) c2=0|H(0)=max=1 1+ Q2=920 H(iS20 HCQ)H(jQ2 c2=∞|H(∞)=05 一 、巴特沃兹逼近 (Butterworth) ( ) ( ) 1 1 ( ) 2 0 2 =  −            +  = H j H j H j n ( ) 0 2 1 ( ) 0 ( 0) max 1 0 0  =   =  =   =  = = = H j H j H j • 通带内最平坦滤波器 2 1 1 0 0 