User`s guide

modred
11-143
The last three diagonal entries of the balanced gramians are small, so
eliminate the last three states with
modred using both matched DC gain and
direct deletion methods.
hmdc = modred(hb,2:4,'mdc')
hdel = modred(hb,2:4,'del')
Both hmdc and hdel are first-order models. Compare their Bode responses
against that of the original model .
bode(h,'-',hmdc,'x',hdel,'*')
hs
()
Frequency (rad/sec)
Phase (deg); Magnitude (dB)
Bode Diagrams
−80
−60
−40
−20
0
10
−1
10
0
10
1
10
2
10
3
−200
−150
−100
−50
0