Hiwin D2

D2 Drive User Guide v1.8 3. Operation Principles
HIWIN Mikrosystem Corp. 32
(2) Phase margin
Phase margin is defined as that the angle between the straight line passing through the
gain crossover and the negative real axis of G(jω)-plane, as shown in Fig. 3-9.
Phase margin = PM =

G(jω
g
) -180°.
Fig. 3-9 Phase margin of Nyquist diagram
3.6.2. Bode diagram
The gain margin and phase margin of Bode diagram are given in Fig. 3-10.
Fig. 3-10 Gain margin and phase margin of Bode diagram
40
20
0
-20
-40
-60
-360
0
-90
-180
-270
Gain crossover
g

p

Phase crossover
Gain margin
Phase
margin
)()( dBjG 
(deg)
)
(

j
G

sec)
/
(
rad

sec)
/
(
rad

0
g
 
G
Re
G
j
Im


Plane
j
G


Gain
crossover
 0
1
-1
Phase margin
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