归首士学 NORTHWESTERN POLYTFCHNICAL UNTVERSITY §5.2 幅相频特性( Nyquist)(6) §5.2.1典型环节的幅相频率特性 (6)振荡环节G(s) s2+250n+on +2E (s-x1)(S-12) G(o) G(j0)=1∠0° +j22 G(jo)=0∠-180 2+[25-P 0,5 =0.85 =0 25 ∠G=- arctan =0.3§5.2 幅相频率特性 ( Nyquist )(6) ⑹ 振荡环节 2 2 2 2 [1 ] [2 ] 1 n n G w w w w 2 2 1 - 2 arctan n n G w w w w §5.2.1 典型环节的幅相频率特性 2 2 2 2 ( ) n n n s s G s w w w ( ) 2 1 1 2 n n s s w w n n j G j w w w w w 1 2 1 ( ) 2 2 G( j0) 10 G( j) 0 180 ( )( ) 1 2 2 w s s n