calfrq

Scilab Function
Last update : April 1993

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`,