Z Transform

MATLAB

This set of MATLAB Multiple Choice Questions & Answers (MCQs) focuses on “Z Transform”.

1. What is the output of the following code?

ztrans(1,z)

a) 1/z-1
b) 1/z+1
c) z/(z-1)
d) z/(z+1)

2. What is the output of the following code?

syms n;ztrans(2^n,z)

a) z/(z-2)
b) z/(z+2)
c) z/(2-z)
d) z/(2+z)

3. What is the output of the following code?

ztrans('[1 0 1 0 1]',z)

a) [ z/(z – 1), 0, z/(z – 1), 0, z/(z – 1)]
b) [ z/(z + 1), 0, z/(z – 1), 0, z/(z – 1)]
c) [ z/(z – 1), 0, z/(z – 1), 0, z/(z -+1)]
d) [ z/(z + 1), 0, z/(z – 1), 0, z/(z + 1)]

4. What is the output of the following code?

>>syms s;
>> ztrans('n',s)

a) s/(s-1)2
b) ns/(s-1)2
c) s/(ns-1)2
d) Error

5. What is the output of the following code?

>> ztrans('n',s)

a) s/(s-1)2
b) ns/(s-1)2
c) Error
d) s/(s+1)2

6. What is the output of the following code?

ztrans([1,2,3 4*z],z)

a) [ z/(z – 1), (2*z)/(z – 1), (3*z)/(z – 1), (4*z)/(z – 1)2]
b) [ z/(z + 1), (2*z)/(z + 1), (3*z)/(z + 1), (4*z)/(z – 1)2]
c) [ z/(z – 1), (2*z)/(z – 1), (3*z)/(z – 1), (4*z)/(z + 1)2]
d) [ z/(z – 1), (2*z)/(z – 1), (3*z)/(z – 1) (4*z)/(z – 1)2]

7. The R.O.C. of impulse function is _________
a) The entire z-plane
b) Interior to the unit circle |z|=1
c) Exterior to the unit circle |z|=1
d) Between the unit circle |z|=1 and |z|=∞

8. What is the output of the following code?

ztrans(exp(2*n),z)

a) z/(z – exp(2))
b) z/(z – exp(-2))
c) z/(z + exp(-2))
d) z/(z + exp(2))

9. The bilateral Z-transform ranges from ____________
a) -∞ to ∞
b) 0 to ∞
c) -∞ to 0
d) Does not exist

10. The R.O.C. of a unit step function is __________
a) |z|>|1|
b) Entire z plane except z=0
c) Entire z plane except z=∞
d) Does not exist

11. What is the relationship b/n laplace transform and z-transform of a function?
a) Impulse invariant transformation
b) z=e-sT
c) s=jw
d) s=σ

12. If σ<0, the point in the z plane lies __ of the circle |z|=1.
a) Interior
b) Exterior
c) On the circumference
d) Nowhere near

13. What is the T in the relation z=esT?
a) Sampling Period
b) Time Period
c) Normal Period
d) Average Period
.

14. The Z-transform is only for discrete signals.
a) True
b) False

15. The Z-transform doesn’t follow the linearity principle.
a) True
b) False

16. The unit delay operator can be thought of in the z-domain as ___________
a) Multiplication by z-1
b) Multiplication by z
c) Multiplication by z-2
d) Multiplication by z2

17. The convolution of a signal in time domain can be viewed as __________
a) Multiplication in z-domain
b) Squaring in z-domain
c) Doubling the signal in z-domain
d) Convolution in z-domain

18. The impulse response of a discrete time system is the inverse Z-transform of the transfer function of the system in z-domain.
a) True
b) False

19. What will be seen in the scope if the step time is 1 second in the following Simulink Model?

a) A unit step signal delayed by 2 units in time
b) u[n-3]
c) A ramp function
d) An impulse function

20. What will be seen in the scope if the step time is 0 seconds in the following Simulink Model?

a) A unit step signal delayed by 2 units in time
b) u[n-3]
c) A ramp function
d) An impulse function

21. What will be seen in the Scope if the step time is 0 seconds in the following Simulink Model and the limit of x axis is n=10?

a) A delayed ramp function
b) r[n-1]
c) r[n-2]
d) Error

22. How much does the delay change, if the step time is taken as two units in time, in r(t-m), in scope 1 and 3?

a) 1 and 3
b) 2 and 3
c) 3 and 1
d) Error

23. This is the output of scope1.

What is the transfer function1?
a) z/(z-1)2
b) z2/(z-1)2
c) A parabola
d) A impulse function

24. The Discrete Transfer Fcn1 is using a ramp function.

a) True
b) False

25. What will be seen in the scope?

a) A ramp function
b) A step function
c) A parabola
d) A hyperbola

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