COMSATS INSTITUE OF INFORMATION TECHNOLOGY
Digital Signal Processing
Lab#7
Z-Transform and Pole-Zero Plotting
Marks:- 10
Objective:
By the end of this lab students will be able to:
Determine Z-Transform of any signal
Find inverse Z-Transform of the signal
Plot Pole-Zero diagrams.
Pre-Lab Tasks:
Some Useful MATLAB Commands:
freqz: can be used to plot the magnitude and phase of system response. Also it is
used to find Frequency response of any system.
tf2zp: This function is used to find poles and zeros of a rational z-transform
expressed as ratios of polynomials in descending powers of z.
zp2tf: It is used as inverse process of above function.
zplane: This function plots zeros and poles.
residuez: It can be used to develop the partial-fraction expansion of a rational z-
transform and to convert a z-transform expressed in a partial-fraction form to its
rational form.
impz: The inverse of a rational z-transform can be readily calculated using this
function.
filter: This command can also be used for calculating inverse of z-transform.
sptool: Signal Processing Tool - Graphical User Interface. sptool opens the sptool
window which allows you to import, analyze, and manipulate signals, filters, and
spectra.
In Lab Tasks
Task 1:
Matlab Code:
b=[0 1 1 ]
a= [1 -2 +3] % -ve powerz of z are on right n other on left
roots(a)
roots(b)
zplane(b,a); %gives zeros,poles
