calfrq - frequency response discretization

Calling Sequence

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

Parameters

• h : SISO linear system (syslin list)
• fmin,fmax : real scalars (min and max frequencies)
• frq : row vector (discretization of interval)
• 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.

Default values for fmin and fmax are 1.d-3, 1.d+3 if h is continuous-time or 1.d-3, 1/(2*h('dt')) if h is discrete-time.

Singularities are located between frq(split(k)) and frq(split(k)+1) 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,spl]=calfrq(h1,0.01,1000);
rf=repfreq(h1,f1);
plot2d(real(rf)',imag(rf)')
 

See Also

bode  black  nyquist  freq  repfreq  logspace