tf2zp (Signal Processing Toolbox)

Conversion of transfer function to zero-pole-gain.

Syntax

[z,p,k] = tf2zp(b,a)

Description

tf2zp finds the zeros, poles, and gains of a system in polynomial transfer function form.

[z,p,k] = tf2zp(b,a)

finds the single-input, multi-output (SIMO) factored transfer function form:

given a SIMO system in polynomial transfer function form:

Vector a specifies the coefficients of the denominator in descending powers of s. Matrix b indicates the numerator coefficients with as many rows as there are outputs. The zero locations are returned in the columns of matrix z, with as many columns as there are rows in b. The pole locations are returned in column vector p and the gains for each numerator transfer function in vector k.

The tf2zp function also works for discrete systems, and is part of the standard MATLAB language.

Example

Find the zeros, poles, and gains of the system

b = [2 3];
a = [1 0.4 1];
[z,p,k] = tf2zp(b,a) 
z =
   -1.5000
p =
   -0.2000 + 0.9798i
   -0.2000 - 0.9798i
k =
   2

Algorithm

The system is converted to state-space using tf2ss and then to zeros, poles, and gains using ss2zp.

See Also


`sos2zp`	Conversion of second-order sections to zero-pole-gain.
`ss2zp`	Conversion of state-space to zero-pole-gain.
`tf2sos`	Conversion of transfer function to second-order sections.
`tf2ss`	Conversion of transfer function to state-space.
`zp2tf`	Conversion of zero-pole-gain to transfer function.

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