frequency phase plot
phaseplot(sl) phaseplot(sl, fmin, fmax) phaseplot(sl, fmin, fmax, step) phaseplot(frq, db, phi) phaseplot(frq, repf) phaseplot(.., comments)
A siso or simo linear dynamical system, in state space, transfer function or zpk representations, in continuous or discrete time.
real scalar: the minimum frequency (in Hz) to be represented.
real scalar: the maximum frequency (in Hz) to be represented.
real scalar: the frequency discretization step (logarithmic scale)). If it is not specified the algorithm uses adaptative frequency steps.
a character string vector: the legend label to be associated with each curve. Optional value is the empty array.
a row vector or an n x m array: The frequency discretization in Hz.
an n x m array: the magnitudes corresponding to
frq. This argument is not used, it only
appears to make phaseplot have the same
syntax as gainplot and
bode.
an n x m array: the phases in degree corresponding to
frq. The phaseplot
function plots the curves phi(i,:) versus
frq(i,:)
an n x m complex array. The
phaseplot function plots the curves
phase(repf(i,:)) versus
frq(i,:)
This function draws the phase of the frequency response of a system. The system can be given under different representations:
phaseplot(sl,...) case
sl can be a continuous-time or
discrete-time SIMO system given by its state space,
rational transfer function (see syslin) or zpk representation. In case of
multi-output the outputs are plotted with different
colors.
In this case the frequencies can be given by:
the lower and upper bounds in Hz
fmin,
fmax and an optional
frequency step step. The
default values for fmin and
fmaxare
1.e-3,
1.e3 if
sl is continuous-time or
1.e-3,
0.5/sl.dt (nyquist
frequency) if sl is
discrete-time. If the step
argument is omitted the function use an
adaptative frequency step (see calfrq).
a row vector or a 2D array
frq which gives the
frequency values in Hz. 2D array can be used
for multi-output systems if one wants to
have different frequency discretization for
each input/output couple.
phaseplot(frq,...) case
This case allows to draw frequency phase plots for previously
computed frequency responses. The frequency response can be
given either by it's complex representation
repf or by it's magnitude phase
representation db,
phi.
frq and repf must
be row vectors or n x m arrays (each row represent an
input/output couple).
The datatips tool may be used to display data along the phase curves.
s=poly(0,'s') h1=syslin('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01)) h2=syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225)) clf();phaseplot([h1;h2],0.01,100,.. ["$\frac{s^2+18 s+100}{s^2+6.06 s+102.1}$"; "$\frac{s^2+3.02 s+228.01}{s^2+27 s+225}$"]) title('Phaseplot') |  |  |
| Version | Description |
| 5.4.0 | Function phaseplot introduced. |
| 6.0 | handling zpk representation. |