Specifications

bode
16-22
uses red dashed lines for the first system sys1 and green 'x' markers for the
second system
sys2.
When invoked with left-hand arguments
[mag,phase,w] = bode(sys)
[mag,phase] = bode(sys,w)
return the magnitude and phase (in degrees) of the frequency response at the
frequencies
w (in rad/sec). The outputs mag and phase are 3-D arrays with the
frequency as the last dimension (see “Arguments” below for details). You can
convert the magnitude to decibels by
magdb = 20*log10(mag)
Remark If sys is an FRD model, bode(sys,w), w can only include frequencies in
sys.frequency.
Arguments The output arguments mag and phase are 3-D arrays with dimensions
For SISO systems,
mag(1,1,k) and phase(1,1,k) give the magnitude and
phase of the response at the frequency =
w(k).
MIMO systems are treated as arrays of SISO systems and the magnitudes and
phases are computed for each SISO entry h
ij
independently (h
ij
is the transfer
function from input j to output i). The values
mag(i,j,k) and phase(i,j,k)
then characterize the response of h
ij
at the frequency w(k).
Example You can plot the Bode response of the continuous SISO system
number of outputs
()
number of inputs
()×
length of
w()×
ω
k
mag(1,1,k) hj
ω
k
()
=
phase(1,1,k) hj
ω
k
()∠
=
mag(i,j,k) h
ij
j
ω
k
()
=
phase(i,j,k) h
ij
j
ω
k
()∠
=