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)); fresp=repfreq(G,w); Gid=frfit(w,fresp,4); frespfit=repfreq(Gid,w); bode(w,[fresp;frespfit]) |  |  |
frequency response fit
sys=frfit(w,fresp,order) [num,den]=frfit(w,fresp,order) sys=frfit(w,fresp,order,weight) [num,den]=frfit(w,fresp,order,weight)
positive real vector of frequencies (Hz)
complex vector of frequency responses (same size as w)
integer (required order, degree of den)
positive real vector (default value ones(w)).
stable polynomials
sys=frfit(w,fresp,order,weight) returns a bi-stable transfer function
G(s)=sys=num/den, of of given order such that
its frequency response G(w(i)) matches fresp(i), i.e.
freq(num,den,%i*w) should be close to fresp.
weight(i) is the weight given to w(i).
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)); fresp=repfreq(G,w); Gid=frfit(w,fresp,4); frespfit=repfreq(Gid,w); bode(w,[fresp;frespfit]) | | |