sos2zp (Signal Processing Toolbox)

Conversion of second-order sections to zero-pole-gain.

Syntax

[z,p,k] = sos2zp(sos)
[z,p,k] = sos2zp(sos,g)

Description

sos2zp converts a second-order section representation of a given system to an equivalent zero-pole-gain representation.

[z,p,k] = sos2zp(sos)

returns the zeros z, poles p, and gain k of the system given by sos in second-order section form. The second-order section format of H(z) is given by

sos is an L-by-6 matrix that contains the coefficients of each second-order section stored in its rows:

Column vectors z and p contain the zeros and poles of the transfer function H(z):

where the orders n and m are determined by the matrix sos.

[z,p,k] = sos2zp(sos,g)

returns the zeros z, poles p, and gain k of the system given by sos in second-order section form with gain g:

Example

Compute the poles, zeros, and gain of a simple system in second-order section form:

sos = [1  1  1  1  0 -1; -2  3  1  1 10  1];
[z,p,k] = sos2zp(sos)
z =
  -0.5000 + 0.8660i
  -0.5000 - 0.8660i
   1.7808
  -0.2808
p =
   -1.0000
    1.0000
   -9.8990
   -0.1010
k 
    -2

Algorithm

sos2zp finds the poles and zeros of each second-order section by repeatedly calling tf2zp.

See Also


`sos2ss`	Conversion of second-order sections to state-space.
`sos2tf`	Conversion of second-order sections to transfer function.
`ss2zp`	Conversion of state-space to zero-pole-gain.
`tf2zp`	Conversion of transfer function to zero-pole-gain.
`zp2sos`	Conversion of zero-pole-gain to second-order sections.

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