bode

Scilab Function
Last update : 25/04/2007

bode - Bode plot

### Calling Sequence

  `bode(sl,[fmin,fmax] [,step] [,comments] )`
  `bode(sl,frq [,comments] )`
  `bode(frq,db,phi [,comments])`
  `bode(frq, repf [,comments])`

### Parameters

- `sl` : `syslin` list (SISO or SIMO linear system) in continuous or discrete time.
- `fmin,fmax` : real (frequency bounds (in Hz))
- `step` : real (logarithmic step.)
- `comments` : vector of character strings (captions).
- `frq` : row vector or matrix (frequencies (in Hz) ) (one row for each SISO subsystem).
- `db` : row vector or matrix ( magnitudes (in Db)). (one row for each SISO subsystem).
- `phi` : row vector or matrix ( phases (in degree)) (one row for each SISO subsystem).
- `repf` : row vector or matrix of complex numbers (complex frequency response).

### Description

Bode plot, i.e magnitude and phase of the frequency response of `sl` .

`sl` can be a continuous-time or discrete-time SIMO system (see `syslin` ). In case of multi-output the outputs are plotted with different symbols.

The frequencies are given by the bounds `fmin,fmax` (in Hz) or by a row-vector (or a matrix for multi-output) `frq` .

`step` is the ( logarithmic ) discretization step. (see `calfrq` for the choice of default value).

`comments` is a vector of character strings (captions).

`db,phi` are the matrices of modulus (in Db) and phases (in degrees). (One row for each response).

`repf` matrix of complex numbers. One row for each response.

Default values for `fmin` and `fmax` are `1.d-3` , `1.d+3` if `sl` is continuous-time or `1.d-3` , `0.5` if `sl` is discrete-time. Automatic discretization of frequencies is made by `calfrq` .

### 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))
    title='(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01)';
    bode(h,0.01,100,title);
    h1=h*syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225))
    clf()
    bode([h1;h],0.01,100,['h1';'h'])

### See Also

`black` , `nyquist` , `gainplot` , `repfreq` , `g_margin` , `p_margin` , `calfrq` , `phasemag` ,