Function Reference: filt

Function File: sys = filt (num, den, …)

Function File: sys = filt (num, den, tsam, …)

Create discrete-time transfer function model from data in DSP format.

Inputs

num: Numerator or cell of numerators. Each numerator must be a row vector containing the coefficients of the polynomial in ascending powers of z^-1. num{i,j} contains the numerator polynomial from input j to output i. In the SISO case, a single vector is accepted as well.
den: Denominator or cell of denominators. Each denominator must be a row vector containing the coefficients of the polynomial in ascending powers of z^-1. den{i,j} contains the denominator polynomial from input j to output i. In the SISO case, a single vector is accepted as well.
tsam: Sampling time in seconds. If tsam is not specified, default value -1 (unspecified) is taken.
…: Optional pairs of properties and values. Type set (filt) for more information.

Outputs

sys: Discrete-time transfer function model.

Option Keys and Values

’num’: Numerator. See ’Inputs’ for details.
’den’: Denominator. See ’Inputs’ for details.
’tfvar’: String containing the transfer function variable.
’inv’: Logical. True for negative powers of the transfer function variable.
’tsam’: Sampling time. See ’Inputs’ for details.
’inname’: The name of the input channels in sys. Cell vector of length m containing strings. Default names are {'u1', 'u2', ...}
’outname’: The name of the output channels in sys. Cell vector of length p containing strings. Default names are {'y1', 'y2', ...}
’ingroup’: Struct with input group names as field names and vectors of input indices as field values. Default is an empty struct.
’outgroup’: Struct with output group names as field names and vectors of output indices as field values. Default is an empty struct.
’name’: String containing the name of the model.
’notes’: String or cell of string containing comments.
’userdata’: Any data type.

Example

                3 z^-1     
H(z^-1) = -------------------
          1 + 4 z^-1 + 2 z^-2

octave:1> H = filt ([0, 3], [1, 4, 2])

Transfer function 'H' from input 'u1' to output ...

            3 z^-1       
 y1:  -------------------
      1 + 4 z^-1 + 2 z^-2

Sampling time: unspecified
Discrete-time model.

See also: tf.

Package: control