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Unit 1 - Practice Quiz

ECE220

1 A signal is defined as a continuous-time signal if:

A. The variable is discrete.
B. The signal is defined for all values of in a continuous interval.
C. The amplitude of the signal is quantized.
D. The signal is defined only at integer values of .

2 Which of the following notations standardly represents a discrete-time signal?

A.
B.
C.
D.

3 The total energy of a continuous-time signal is defined as:

A.
B.
C.
D.

4 A signal is classified as an Energy Signal if:

A. and
B. and
C. and
D. and

5 A signal is classified as a Power Signal if:

A. and
B. and
C. and
D. and

6 Calculate the average power of the signal .

A.
B.
C.
D.

7 A continuous-time signal is periodic if there exists a positive constant such that:

A. for all
B. for all
C. for all
D. for all

8 The sum of two periodic signals and with periods and is periodic only if:

A.
B. The product is an integer.
C. The ratio is a rational number.
D. The sum is always periodic.

9 A discrete-time sinusoidal signal is periodic only if:

A. is any real number.
B. is a rational number.
C. is an integer.
D. is an irrational number.

10 Which of the following conditions defines an Even Signal?

A.
B.
C.
D.

11 Which of the following conditions defines an Odd Signal?

A.
B.
C.
D.

12 Any signal can be decomposed into an even component and an odd component . The even component is given by:

A.
B.
C.
D.

13 The product of two even signals is:

A. Even
B. Odd
C. Neither even nor odd
D. Zero

14 The product of an even signal and an odd signal is:

A. Even
B. Odd
C. Neither even nor odd
D. Constant

15 Calculate where is an odd signal.

A.
B.
C. $0$
D.

16 Given a signal , the transformation with represents:

A. Time advancement (Shift to the left)
B. Time delay (Shift to the right)
C. Time scaling
D. Time reversal

17 Given a signal , the transformation results in:

A. Expansion of the signal by a factor of 2
B. Compression of the signal by a factor of 2
C. Shifting the signal right by 2
D. Doubling the amplitude

18 For a signal , the operation is known as:

A. Time shifting
B. Amplitude reversal
C. Time reversal (Reflection)
D. Time scaling by 2

19 When performing combined operations , the correct order of operations to obtain from is:

A. Shift by , then scale by .
B. Scale by , then shift by .
C. Shift by , then scale by .
D. Scale by , then shift by .

20 Wait, let's re-evaluate the previous question logic. To get from :

A. 1. Shift by (right). 2. Replace with .
B. 1. Replace with . 2. Shift by (right).
C. 1. Shift by (left). 2. Replace with .
D. None of the above.

21 The unit step function is defined as:

A. 1 for , 0 otherwise
B. 1 for , 0 otherwise
C. 1 for all
D. Undefined at

22 The relationship between the unit impulse and the unit step is:

A.
B.
C.
D. They are unrelated.

23 The Sifting Property of the unit impulse function states that equals:

A.
B.
C.
D. $0$

24 The property simplifies to:

A.
B.
C.
D.

25 The scaling property of the continuous unit impulse function states that is equal to:

A.
B.
C.
D.

26 For discrete time signals, the unit impulse is defined as:

A. 1 for , 0 otherwise
B. for , 0 otherwise
C. 1 for , 0 otherwise
D. undefined

27 The discrete unit step sequence can be expressed in terms of the discrete impulse as:

A.
B.
C.
D. Both B and C

28 Euler's formula relates complex exponentials to sinusoids as:

A.
B.
C.
D.

29 A continuous time real exponential signal is decaying if:

A.
B.
C.
D.

30 The fundamental period of the signal is:

A.
B.
C.
D. It is not periodic

31 Consider the discrete signal . This represents:

A. A unit impulse at .
B. A rectangular pulse of length .
C. A periodic square wave.
D. A ramp function.

32 In the context of software simulation (e.g., MATLAB), a continuous time signal is approximated by:

A. A symbolic variable.
B. A vector of values at discrete sampling intervals.
C. A loop structure.
D. An infinite array.

33 Which MATLAB function is best suited to plot a discrete-time signal?

A. plot()
B. stem()
C. bar()
D. hist()

34 To generate a time vector t from 0 to 10 with a step size of 0.1 in MATLAB, the correct syntax is:

A. t = 0:10:0.1
B. t = 0:0.1:10
C. t = linspace(0, 0.1, 10)
D. t = [0, 10]

35 If is energy signal and is energy signal, then is generally:

A. A Power signal
B. An Energy signal
C. Neither
D. Undefined

36 A signal is called Causal if:

A. for
B. for
C. is defined for all
D.

37 A signal is Anti-causal if:

A. for
B. for
C.
D. It is periodic.

38 The Root Mean Square (RMS) value of a signal over a period is related to Average Power by:

A.
B.
C.
D.

39 Which of the following signals is a Power signal?

A.
B.
C.
D.

40 When simulating the multiplication of two signals x and y in MATLAB (element-wise), the operator used is:

A. *
B. .*
C. ^
D. @

41 The area under the unit impulse function is:

A.
B. 1
C.
D. Undefined

42 What is the result of ?

A. $0$
B. $1$ (almost everywhere)
C.
D. $2$

43 If a signal is shifted by , its magnitude spectrum (frequency content magnitude):

A. Changes in amplitude.
B. Remains unchanged.
C. Is shifted by .
D. Becomes zero.

44 A signal is deterministic if:

A. It can be completely represented by a mathematical equation at any time.
B. Its value cannot be predicted precisely.
C. It has finite energy.
D. It is periodic.

45 The operation in discrete time represents:

A. Interpolation (Upsampling)
B. Decimation (Downsampling)
C. Time Shift
D. Amplitude Scaling

46 Which of the following is true for the complex exponential signal where ?

A. If , it is a growing exponential.
B. If , it is a constant amplitude sinusoid.
C. If , it is an oscillating signal.
D. If , it is a decaying exponential.

47 Compute the value: .

A.
B. 1
C. -1
D.

48 The signal is:

A. Even
B. Odd
C. Neither
D. Both

49 The signal is:

A. Even
B. Odd
C. Neither
D. Both

50 In software simulation, to approximate the integral of a signal sampled with interval , one typically uses:

A. sum(x) * dt
B. diff(x)
C. max(x)
D. mean(x)