MATLAB® and Its Applications in Engineering: [Based on MATLAB 7.5 (R2007b)]

11.6. Zeros, Poles and Pole–Zero Map of a Transfer Function

The command tf2zp is used to obtain the zeros z, poles p and gain k of the transfer function defined by its numerator and denominator polynomials, n and d, respectively. The syntax is given as follows:

[z, p, k] = tf2zp(n, d);

To obtain the transfer function, as a ratio of two polynomials, if the zeros z, poles p and gain k are given, the MATLAB command zp2tf is used as follows:

[n, d] = zp2tf(z, p, k);

The command pzmap(n,d) can be used to plot the pole–zero map of a given transfer function, and the command printsys(n,d,'s') prints the transfer function as a ratio of two polynomials in the variable s. The above commands are illustrated in the following examples.

Example 11.10.