plot frequency response matlab
Given a transfer function, the MATLAB function freqz() can be used to
determine the frequency response. The syntax is given by
[h,w]=freqz(A,B,N)
whose parameters are defined as:
h = an output vector containing frequency response
w =an output vector containing normalized frequency values distributed
in the range from 0 to p radians.
B = an input vector for numerator coefficients
A= an input vector for denominator coefficients
N = the number of normalized frequency points used for calculating the
frequency response
wxample:
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Given each of the following digital transfer functions,
1. Plot the poles and zeros on the z-plane.
2. Use MATLAB function freqz() to plot the magnitude frequency response
and phase response for each transfer function.
3. Identify the corresponding filter type, such as lowpass, highpass, bandpass,
or bandstop.
Solution:
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1. The pole-zero plot for each transfer function is demonstrated in Figure
6.20. The transfer functions of (a) and (c) need to be converted into the
standard form (delay form) required by the MATLAB function freqz(), in
which both numerator and denominator polynomials have negative
powers of z. Hence, we obtain
while the transfer functions of (b) and (d) are already in their standard
forms (delay forms).
2. The MATLAB program for plotting the magnitude frequency response
and the phase response for each case is listed
and here figure 6.20:
enjoy