Specifications

dcgain
16-58
16dcgain
Purpose Compute low frequency (DC) gain of LTI system
Syntax k = dcgain(sys)
Description k = dcgain(sys) computes the DC gain k of the LTI model sys.
Continuous Time
The continuous-time DC gain is the transfer function value at the frequency
. For state-space models with matrices , this value is
Discrete Time
The discrete-time DC gain is the transfer function value at . For
state-space models with matrices , this value is
Remark The DC gain is infinite for systems with integrators.
Example To compute the DC gain of the MIMO transfer function
type
H = [1 tf([1 -1],[1 1 3]) ; tf(1,[1 1]) tf([1 2],[1 -3])]
dcgain(H)
ans =
1.0000 -0.3333
1.0000 -0.6667
See Also evalfr Evaluates frequency response at single frequency
norm LTI system norms
s 0= ABCD
,,,()
KDCA
1–
B–=
z 1=
ABCD
,,,()
KDCIA–
()
1–
B+=
Hs
()
1
s 1–
s
2
s 3++
------------------------
1
s 1+
------------
s 2+
s 3–
------------
=