User`s guide

Subreferencing Model Objects
Converting noise channels to measured inp uts loses inform ati on abou t
the variance of the innovations
e. Fo r example, step response due to the
noise channels does not take into consideration the magnitude of the noise
contributions. To include this v ariance information, normalize e such that v
becomes white noise with an identity covariance matrix, where
eLv=
To normalize e, use the following command:
m_GH = noisecnv(m,'Norm')
This command create s a model where u and v are treated as measured
signals, as follows:
yt Gut HLv G HL
u
v
() ()=+=
[]
⎡
⎣
⎢
⎤
⎦
⎥
For example, the scaling by L causes the step responses from v to y to reflect
thesizeofthedisturbanceinfluence.
The converted noise sources are named in a w ay that relates the n oise channel
to the corresponding output. Unnormalized noise s ources e are assigned
names such as
'e@y1', 'e@y2',...,'e@yn ',where'e@yn' refers to the noise
input associated with the output
yn. Similarly, normalized noise sources v,
are nam ed
'v@y1', 'v@y2', ..., ' v@yn'.
Note When you plo t m odels i n the GU I that include noise sou rces, you
can select to view the response of the noise model co rresponding to specific
outputs. For more information, see “Selecting Measured and Noise Channels
in Plots” on page 12-18.
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