mrfit

frequency response fit

Calling Sequence

sys=mrfit(w,mag,order)
[num,den]=mrfit(w,mag,order)
sys=mrfit(w,mag,order,weight)
[num,den]=mrfit(w,mag,order,weight)

Arguments

:w positive real vector of frequencies (Hz) : :mag real vector of frequency responses magnitude (same size as w) : :order integer (required order, degree of den) : :weight positive real vector (default value ones(w)). : :num,den stable polynomials :

Description

sys=mrfit(w,mag,order,weight) returns a bi-stable transfer function G(s)=sys=num/den, of of given order such that its frequency response magnitude abs(G(w(i))) matches mag(i) i.e. abs(freq(num,den,%i*w)) should be close to mag. weight(i) is the weigth given to w(i).

Examples

w=0.01:0.01:2;s=`poly`_(0,'s');
G=`syslin`_('c',2*(s^2+0.1*s+2),(s^2+s+1)*(s^2+0.3*s+1)); // syslin('c',Num,Den);
fresp=`repfreq`_(G,w);
mag=`abs`_(fresp);
Gid=mrfit(w,mag,4);
frespfit=`repfreq`_(Gid,w);
`plot2d`_([w',w'],[mag(:),`abs`_(frespfit(:))])

See Also

• cepstrum cepstrum calculation
• frfit frequency response fit
• freq frequency response
• calfrq frequency response discretization