Contents

SS2FRF

Calculates an LTI Frequency Response Function

Syntax

H = ss2frf(A,B,C,D,w)

Description

This function calculates the frequency-response function of a LTI state-space system that has the following model structure:

$$ \dot{x}(t) = Ax(t) + Bu(t) $$

$$ y(t) = Cx(t) + Du(t) $$

$$ x(0) = x0 $$

or:

$$  x(k+1) = Ax(k) + Bu(k)$$

$$ y(k) = Cx(k) + Du(k) $$

Inputs

A,B,C,D aer the system matrices describing the state-space system. If there is no D-matrix, pass an empty matrix.

w is the vector of complex frequencues at which the frequency response function is to be calculated. Typically, this is for continuous-time systems

$$w = e^{j\omega}$$

and

$$w = j\omega $$

for discrete-time systems.

Outputs

H is the measured frequency response function (FRF). This is a matrix that follows the MATLAB 5 FRF Convention: It is a 3D-array of size l x m x N, in which H(:,:,j) is the FRF at the j th complex frequency.

Uses Functions

ltifrf

See Also

ltifrf