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

1. The unit step response of an L.T.I. system is the convolution of a step signal and it’s ________**a) Impulse response**

b) Ramp response

c) Parabolic response

d) Time response

2. What is the output of the following code?

conv([1 2],[3 4])

**a) [3 10 8]**

b) [8 10 3]

c) [3 8]

d) [4 6]

3. What is the working of the conv2() command?**a) 2-d convolution**

b) 1-d convolution

c) 3-d convolution

d) n-d convolution

4. What is the output of the following code?

conv([1;3],[1;3])

**a) A column vector of 1 6 9**

b) A row vector of 9 6 1

c) A row vector of 1 6 9

d) A column vector of 9 6 1

5. What is the output of the following code?

conv(3,9)

**a) 27**

b) 3

c) 9

d) Error

6. What is the output of the following code?

conv[1 2]

a) Error in input**b) Error in []**

c) 2

d) 0

7. What is the output of the following code?

>>p=conv([ones(1,100)],[ones(1,100)]); >>x=[1:1:199]; >> plot(x,p)

**a) A triangular pulse**

b) A step pulse

c) A sinusoid

d) Error

8. What is the length of the output?

p=conv([ones(1,150)],[ones(1,150)]);

**a) 299**

b) 298

c) 300

d) Error

9. What is the dimension of the output?

conv([1;2],[1;2])

**a) 1*3**

b) 1*4

c) 1*2

d) 2*2

10. What is the output of the following code?

conv([1],[2;3])

**a) A column vector of 2 and 3**

b) A column vector of 3 and 2

c) A row vector of 3 and 2

d) A row vector of 2 and 3

11. What is the output of the following code?

conv({1 2},{3 4})

**a) Error**

b) 6 8

c) 3 8

d) 3 10 8

12. What is the shape output of the following code?

p=conv([ones(1,100)],[ones(1,50)])

**a) A trapezoid**

b) A rectangular pulse

c) A triangular pulse

d) Error

13. What is the peak value of the output graph from the following code?

>>q=conv([1 2],[2 1]); >> plot([0 1 2],q)

**a) 5**

b) 4

c) 1

d) Error

14. The output of p=conv([ones(1,50)],[ones(1,100)]) and p=conv([ones(1,100)],[ones(1,50)]) are same.**a) True**

b) False

15. The signal get shifted by 1 units in time due to the following code: conv([ 1 2 3],[ 0 1 0 ]).**a) True**

b) False

16. After what instant in time will the signal output become zero?

p=conv([ones(1,100)],[ones(1,50),zeros(1,50)]);

a) 150**b) 149**

c) 151

d) Error

17. For a causal L.T.I. system, the impulse response is 0 for _________**a) t<0**

b) t=0

c) t>0

d) Always

18. The convolution of a discrete signal with itself is _________**a) Squaring the signal**

b) Doubling the signal

c) Adding two signals

d) is not possible

19. The convolution of a function with an impulse function delayed to an instant 3 in time results in ____________

a) An advance in the function by 3 units in time

b) The function itself**c) A delay in the function by 3 units in time**

d) Cannot be determined

20. What is the output of the following code?

a=con([1 2],[1 2]); b=cconv([1 2],[1 2]);

**a) a=b**

b) a<b

c) a>b

d) a!=b

21. A continuous signal can be represented as the product of an impulse function and the signal itself.**a) True**

b) False

22. What is the output of the following code?

cconv([1 2],[0 1 0])

**a) [0 1 2 0]**

b) [1 2 0 0]

c) [1 2 0 0]

d) [0 0 1 2]

23. What is the Scope value if the signal generator has a frequency of 2 Hz only?**a) An attenuated signal of same frequency**

b) The entire signal at the same frequency

c) The entire signal at reduced frequency

d) An attenuated signal at reduced frequency

24. What is the output of the following code?

P=tf([1 2],[3 4]); Q=tf([1 2],[3 4]); Z=P.Q;

**a) Z is the response of the system whose pole is at s=-4/3**

b) Z is the response of the system whose pole is at s=4/3

c) Z is the response of the system whose poles are at s=-4/3 & s=+4/3

d) Z is the response of the system whose zeros are at s=-4/3

25. What is the inverse laplace transform of Z from the following?

P=tf([1],[1 0 0]); Q=tf([1],[1 0]); Z=P.Q;

a) t^{2}**b) t ^{2}/2**

c) t

^{3}

d) Error

26. What is the output of the following code?

P=tf([1 2],[3 4]); Q=tf([1 2],[3 4]); Z=P.Q; ilpalace(Z)

**a) Error**

b) t

c) t^{2}

d) Cannot be determined

27. What is the output of the following code?

conv[1 2]

a) Error in input**b) Error in []**

c) 2

d) 0