Simulink®

Discrete Transfer Fcn - Implement discrete transfer function

Library

Discrete

Description

The Discrete Transfer Fcn block implements the z-transform transfer function described by the following equations:

where m+1 and n+1 are the number of numerator and denominator coefficients, respectively. num and den contain the coefficients of the numerator and denominator in descending powers of z. num can be a vector or matrix, den must be a vector, and both are specified as parameters on the block dialog box. The order of the denominator must be greater than or equal to the order of the numerator.

Block input is scalar; output width is equal to the number of rows in the numerator.

The Discrete Transfer Fcn block represents the method typically used by control engineers, representing discrete systems as polynomials in z. The Discrete Filter block represents the method typically used by signal processing engineers, who describe digital filters using polynomials in z^-1 (the delay operator). The two methods are identical when the numerator is the same length as the denominator.

The Discrete Transfer Fcn block displays the numerator and denominator within its icon depending on how they are specified. See Transfer Fcn for more information.

Data Type Support

The Discrete Transfer Function block accepts and outputs real signals of type single or double.

Parameters and Dialog Box

Numerator coefficient

The row vector of numerator coefficients. A matrix with multiple rows can be specified to generate multiple output. The default is [1].

Denominator coefficient

The row vector of denominator coefficients. The default is [1 0.5].

Sample time

The time interval between samples. The default is 1. See Specifying Sample Time.

The State Attributes pane of this block pertains to code generation and has no effect on model simulation. See Block State Storage and Interfacing in the Real-Time Workshop^® User's Guide for more information.

Characteristics

Discrete-Time Integrator

Discrete Zero-Pole