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Aide de Scilab >> Traitement du Signal > Identification > mrfit

mrfit

frequency response fit

Syntax

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 weight 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
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Last updated:
Mon Feb 12 19:15:30 CET 2018