phasemag

Scilab Function
Last update : 21/12/2005

phasemag - phase and magnitude computation

### Calling Sequence

  `[phi,db]=phasemag(z [,mod])`

### Parameters

- `z`: matrix or row vector of complex numbers.
- `mod`: character string
  - `mod='c'`: "continuous" representation between -infinity and +360 degrees (default)
  - `mod='m'`: representation between -360 and 0 degrees
- `phi`: phases (in degree) of `z`.
- `db`: magnitude (in Db)

### Description

`phasemag` computes the phases and magnitudes of the entries of a complex matrix. For `mod='c'``phasemag` computes `phi(:,i+1)` to minimize the distance with `phi(:,i)`, i.e. it tries to obtain a "continuous representation" of the phase.

To obtain the phase between -%pi and %pi use `phi=atan(imag(z),real(z))`

### Examples

    s=poly(0,'s');
    h=syslin('c',1/((s+5)*(s+10)*(100+6*s+s*s)*(s+.3)));
    [frq,rf]=repfreq(h,0.1,20,0.005);
    scf();
    plot2d(frq',phasemag(rf,'c')');
    scf();
    plot2d(frq',phasemag(rf,'m')');

### See Also

`repfreq`, `gainplot`, `atan`, `bode`,