15.1 The Definition of Bode Diagram (Bode图的定义) Ma Magnitude(201gGH(jo) db--decibel (dB) Mdb=201g M 20lgGH(jO) 10 100 (g o) ● ● ● ∠GH(o) 10 @(g o) ● 90° l8015.1 The Definition of Bode Diagram (Bode 图的定义)  (lg) Magnitude (20lg GH( j)   (lg) GH( j) db−−decibel 20lg ( ) 20lg GH j Mdb M = = Mdb (dB) 0.1 1 10 100 0.1 1 10 100 −90 −180