calfrq
======

frequency response discretization



Calling Sequence
~~~~~~~~~~~~~~~~


::

    [frq,bnds,split]=calfrq(h,fmin,fmax)




Arguments
~~~~~~~~~

:h Linear system in state space or transfer representation ( `see
  `syslin`_` )
: :fmin,fmax real scalars (min and max frequencies in Hz)
: :frq row vector (discretization of the frequency interval)
: :bnds vector `[Rmin Rmax Imin Imax]` where `Rmin` and `Rmax` are the
  lower and upper bounds of the frequency response real part, `Imin` and
  `Imax` are the lower and upper bounds of the frequency response
  imaginary part,
: :split vector of frq splitting points indexes
:



Description
~~~~~~~~~~~

frequency response discretization; `frq` is the discretization of
`[fmin,fmax]` such that the peaks in the frequency response are well
represented.

Singularities are located between `frq(split(k)-1)` and
`frq(split(k))` for `k>1`.



Examples
~~~~~~~~


::

    s=`poly`_(0,'s')
    h=`syslin`_('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01))
    h1=h*`syslin`_('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225)) 
    [f1,bnds,spl]=calfrq(h1,0.01,1000);
    rf=`repfreq`_(h1,f1);
    `plot2d`_(`real`_(rf)',`imag`_(rf)')




See Also
~~~~~~~~


+ `bode`_ Bode plot
+ `black`_ Black-Nichols diagram of a linear dynamical system
+ `nyquist`_ nyquist plot
+ `freq`_ frequency response
+ `repfreq`_ frequency response
+ `logspace`_ logarithmically spaced vector


.. _freq: freq.html
.. _bode: bode.html
.. _nyquist: nyquist.html
.. _black: black.html
.. _syslin: syslin.html
.. _logspace: logspace.html
.. _repfreq: repfreq.html