Control System Toolbox Function Reference

evalfr

Evaluate frequency response at a single (complex) frequency

Syntax

frsp = evalfr(sys,f)

Description

frsp = evalfr(sys,f) evaluates the transfer function of the TF, SS, or ZPK model sys at the complex number f. For state-space models with data , the result is

evalfr is a simplified version of freqresp meant for quick evaluation of the response at a single point. Use freqresp to compute the frequency response over a set of frequencies.

Example

To evaluate the discrete-time transfer function

at , type

H = tf([1 -1],[1 1 1],-1)
z = 1+j
evalfr(H,z)
ans =
  2.3077e-01 +  1.5385e-01i

Limitations

The response is not finite when f is a pole of sys.

See Also
bode        Bode frequency response

freqresp    Frequency response over a set of frequencies

sigma       Singular value response

estim

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