低频段--中频段保持-20db/dec L() L(o)◆ K G()H(@)=- 2)f)= 0 1+@ jo -20 0 y=180°-g9 y=90° Lo) ◆ GU)H(j) L(ao)◆ 迎+2+（巴1 K1+巴 60 40 G(io)H(io)= 1 (op (Uj)2 -20 -20 物 9 0 y=g1 y=-90°+g1 1-(@2 School of Mechanical Engineering ME369-lecture 8.1 Shanghai Jiao Tong University Fal12015 高频段 L(co)◆ G(i@)H(jo)= K R jo L(am)◆ G(j)H(j) j0+2+巴 -20 03 -20 7=90° -60 K 25 L(o)◆ G(j)H(jo)=- jo1+@ y=90°-g 1-@ -20 -40 y=90°-g10=g@ @3 School of Mechanical Engineering ME369-lecture 8.1 Shanghal Jiao Tong University Fall 2015 55 ME369-lecture 8.1 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University 1 1 ( ) ( )     j K G j H j   1 1 180 c tg        γ=90° ( ) ( ) K G j H j j     2 1 ( ) (1 ) ( ) ( )      j j K G j H j   1 1 c tg      2 1 1 3 ( ) ( ) [1 ( ) ] ( ) G j H j j j K j           1 1 2 1 2 90 1 ( ) c c tg             低频段----中频段保持-20db/dec ME369-lecture 8.1 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University (1 ) ( ) ( ) 2     j j K G j H j   1 1 2 2 90 c c tg tg            [1 ( ) ] ( ) ( ) 2 2 2       j j j K G j H j    1 2 2 2 2 90 1 ( ) c c tg            γ=90° ( ) ( ) K G j H j j     高频段