Specifications

evalfr
16-73
16evalfr
Purpose 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
,theresultis
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
ABCD
,,,()
Hf
()
DCfIA–
()
1–
B+=
Hz
()
z 1–
z
2
z 1++
------------------------
=
z 1 j+=