Scilab Function
Last update : 25/05/2004

svplot - singular-value sigma-plot

### Calling Sequence

  `[SVM]=svplot(sl,[w])`

### Parameters

- `sl`: `syslin` list (continuous, discrete or sampled system)
- `w`: real vector (optional parameter)

### Description

computes for the system `sl=(A,B,C,D)` the singular values of its transfer function matrix:

                 G(jw) = C(jw*I-A)B^-1+D
    or
                 G(exp(jw)) = C(exp(jw)*I-A)B^-1+D
    or
                 G(exp(jwT)) = C(exp(jw*T)*I-A)B^-1+D

evaluated over the frequency range specified by `w`. (T is the sampling period, `T=sl('dt')` for sampled systems).

`sl` is a `syslin` list representing the system `[A,B,C,D]` in state-space form. `sl` can be continous or discrete time or sampled system.

The `i`-th column of the output matrix `SVM` contains the singular values of `G` for the `i`-th frequency value `w(i)`.

    SVM = svplot(sl)

is equivalent to

    SVM = svplot(sl,logspace(-3,3))  (continuous)

    SVM = svplot(sl,logspace(-3,%pi)) (discrete)

### Examples

    x=logspace(-3,3);
    y=svplot(ssrand(2,2,4),x);
    xbasc();plot2d1("oln",x',20*log(y')/log(10));
    xgrid(12)
    xtitle("Singular values plot","(Rd/sec)", "Db");

### Author

F.D; ;