Signals and Systems Quizzes: Test Your Understanding

Question 1

Which of the following transforms is NOT commonly used in signal analysis?

Accepted Answer

Walsh Transform

Answer

Fourier Transform

Answer

Laplace Transform

Answer

Z-Transform

Question 2

Which signal transform is specifically designed to analyze signals defined at discrete points in time?

Accepted Answer

Z-transform

Answer

Fourier transform

Answer

Laplace transform

Answer

Hilbert transform

Question 3

Which property does NOT apply to the Laplace transform?

Accepted Answer

Frequency-shifting

Answer

Linearity

Answer

Time-shifting

Answer

Convolution

Question 4

Which of these is NOT an application of sonar systems?

Accepted Answer

Predicting the weather

Answer

Underwater navigation

Answer

Detecting underwater objects

Answer

Mapping the ocean floor

Question 5

In a block diagram of a system, what does an arrow represent?

Accepted Answer

A signal path between components

Answer

A physical connection between components

Answer

The type of signal being processed

Answer

The gain or attenuation of the signal

Question 6

In the transfer function of a linear time-invariant (LTI) system, what do the poles and zeros represent?

Accepted Answer

The stability and frequency response characteristics of the system.

Answer

The input and output signals of the system.

Answer

Only continuous-time systems have poles and zeros.

Question 7

In speech processing, which technique is primarily employed to mitigate the effects of background noise?

Accepted Answer

Cepstral analysis

Answer

Fourier analysis

Answer

Wavelet transform

Question 8

In communication systems, the process of combining information-bearing signals with a higher-frequency carrier signal is called:

Accepted Answer

Modulation

Answer

Antenna Radiation

Answer

Multiplexing

Answer

Demodulation

Question 9

For a causal LTI system with impulse response h(t), which statement about its response y(t) is incorrect?

Accepted Answer

The system's response to an impulse input differs from its impulse response.

Answer

y(t) is uniquely determined by h(t) and the input signal x(t).

Answer

The Laplace Transform of y(t) is found by multiplying the Laplace Transform of x(t) by the system's transfer function H(s).

Answer

y(t) is mathematically determined by the convolution of h(t) and x(t).

Question 10

In a feedback control system, the primary purpose of the controller is to:

Accepted Answer

Eliminate any steady-state error.

Answer

Increase the overall system gain.

Answer

Maximize the system's bandwidth.

Answer

Reduce the system's response time.

Question 11

In signal processing, what is the primary goal of using filters?

Accepted Answer

To selectively remove unwanted frequency components, improving the signal-to-noise ratio.

Answer

To increase the signal's amplitude by amplification.

Answer

To intentionally remove specific information from the signal for easier analysis or transmission.

Question 12

Which of the following is NOT a typical application of sonar systems?

Accepted Answer

Measuring atmospheric conditions

Answer

Underwater navigation

Answer

Detecting underwater objects

Answer

Mapping the ocean floor

Question 13

Which of the following properties is **incorrectly** attributed to the Fourier transform?

Accepted Answer

The Fourier transform is a periodic operator.

Answer

The Fourier transform is a linear operator.

Answer

The Fourier transform is a time-invariant operator.

Answer

The Fourier transform is an invertible operator.

Question 14

In the context of feedback control systems, what is the primary objective of feedback?

Accepted Answer

To reduce the system's sensitivity to external disturbances

Answer

To increase the system's overall gain

Answer

To eliminate the need for a controller

Answer

To make the system unstable

Question 15

For analyzing the stability of discrete-time systems, which Z-transform property is crucial?

Accepted Answer

Region of Convergence (ROC)

Answer

Linearity

Answer

Causality

Answer

Time Invariance

Question 16

Which of the following is NOT a typical application of sonar systems?

Accepted Answer

Weather forecasting

Answer

Underwater navigation

Answer

Object detection and imaging

Question 17

Which statement accurately describes the relationship between the Laplace transform and the Fourier transform?

Accepted Answer

The Laplace transform is a more general form of the Fourier transform, accommodating complex-valued signals.

Answer

The Fourier transform is a more general form of the Laplace transform, handling signals of infinite duration.

Answer

The Laplace transform and the Fourier transform are entirely distinct mathematical tools.

Answer

The Fourier transform is a specific case of the Laplace transform obtained by setting the Laplace transform parameter to zero.

Question 18

Which operation on the continuous-time signal **x(t)** will produce a frequency-shifted version of its Fourier transform **X(f)**?

Accepted Answer

Multiply **x(t)** by **e^(j2πf0t)**

Answer

Take the first derivative of **x(t)** with respect to time

Answer

Integrate **x(t)** with respect to time

Answer

Take the absolute value of **x(t)**

Question 19

What is the defining characteristic of a continuous-time signal?

Accepted Answer

Its values are defined over a continuous range of time

Answer

Its values are defined at specific time intervals

Answer

Its amplitude and frequency remain constant

Answer

It exists for a finite duration

Question 20

A system has a bandwidth of 1 kHz. Which time-domain characteristic of a signal will be most affected when the signal passes through this system?

Accepted Answer

Frequency components above the bandwidth

Answer

Amplitude

Answer

Duration

Answer

Rise time

Question 21

In which scenario is amplitude modulation (AM) more suitable than frequency modulation (FM)?

Accepted Answer

Long-distance broadcasting

Answer

High-fidelity music transmission

Answer

Mobile communications

Question 22

Which of the following is NOT a fundamental property of linear systems?

Accepted Answer

Time-variance

Answer

Superposition

Answer

Homogeneity

Answer

Causality

Question 23

The impulse response of a system fully characterizes the system's input-output behavior.

Accepted Answer

True

Answer

False

Question 24

Which of the following is NOT a characteristic of continuous-time signals?

Accepted Answer

Discrete-valued

Answer

Periodic

Answer

Aperiodic

Answer

Stochastic

Question 25

The Laplace transform is employed to analyze signals and systems in which domain?

Accepted Answer

s-domain

Answer

Time domain

Answer

Frequency domain

Answer

z-domain

Question 26

A system is considered causal if its impulse response is:

Accepted Answer

Zero for t < 0

Answer

Non-zero for all t

Answer

Zero for t > 0

Answer

Non-zero for t < 0

Question 27

The inverse Laplace transform of 1/(s-a) is:

Accepted Answer

e^(at)

Answer

-at

Answer

-1/a

Answer

s-a

Question 28

A system that produces an output proportional to the integral of its input is called a:

Accepted Answer

Integrator

Answer

Derivator

Answer

Filter

Answer

Delay

Question 29

A signal that has a finite number of values over a finite duration of time is referred to as a:

Accepted Answer

Discrete-time signal

Answer

Continuous-time signal

Answer

Analog signal

Answer

Periodic signal

Question 30

The impulse response of a system is h(t). When the input to the system is x(t), what is the output?

Accepted Answer

y(t) = h(t) * x(t)

Answer

y(t) = h(t) - x(t)

Answer

y(t) = h(t) + x(t)

Answer

y(t) = h'(t) * x'(t)

Question 31

For a system with a transfer function H(s), what is the stability criterion?

Accepted Answer

All poles must be in the left-half of the s-plane

Answer

All poles must be in the right-half of the s-plane

Answer

All zeros must be in the left-half of the s-plane

Answer

All zeros must be in the right-half of the s-plane

Question 32

The Fourier transform of a real-valued signal is:

Accepted Answer

Complex-valued (in general)

Answer

Real-valued

Answer

Imaginary-valued

Answer

Undefined

Question 33

The Laplace transform of a causal signal is:

Accepted Answer

Right-sided

Answer

Left-sided

Answer

Two-sided

Answer

Imaginary

Question 34

The z-transform converges for:

Accepted Answer

|z| < 1

Answer

|z| > 1

Answer

|z| = 1

Answer

All values of z

Question 35

Identify the characteristic that distinguishes continuous-time signals:

Accepted Answer

Values can change continuously with time

Answer

Values exist only at specific moments in time

Answer

Analysis is possible using the Fourier transform

Answer

Finite bandwidth is a property

Question 36

Which of the following is not a property of the discrete-time Fourier transform (DTFT)?

Accepted Answer

Continuous function of frequency

Answer

Applicable for analyzing signals with periodicity

Answer

Periodic in the frequency domain

Answer

Useful in determining system stability

Question 37

Which of the following types of systems is linear, time-invariant, and causal?

Accepted Answer

LTI system

Answer

IIR system

Answer

FIR system

Answer

Nonlinear system

Question 38

What is the unit impulse response of a system?

Accepted Answer

The output of the system when the input is a unit impulse

Answer

The output of the system when the input is a unit step

Answer

The input to the system when the output is a unit step

Answer

The input to the system when the output is a unit impulse

Question 39

Signal processing advancements, like facial recognition and AI, raise ethical and societal concerns. Discuss these implications.

Accepted Answer

Ethical and societal considerations should be considered in developing and using signal processing technologies.

Answer

Advancements in signal processing have no ethical or societal implications.

Answer

Signal processing advancements only benefit society and cannot be misused.

Answer

The ethical and societal implications of signal processing advancements are not relevant to engineers and scientists.

Question 40

What is signal sampling and why is it crucial for digital signal processing?

Accepted Answer

Sampling involves taking discrete measurements of a continuous signal at regular intervals.

Answer

Sampling is only used to convert analog signals to digital signals.

Answer

Sampling is not needed for digital signal processing if the signal is already discrete.

Question 41

Define signal-to-noise ratio (SNR) and explain its importance in evaluating the effectiveness of signal processing systems.

Accepted Answer

SNR is the ratio of signal power to noise power within a system.

Answer

SNR is the difference between the maximum signal amplitude and the maximum noise amplitude.

Answer

SNR is only applicable to analog signal processing systems.

Answer

A higher SNR always indicates a better signal.

Question 42

Which property of a signal indicates how its strength changes over time?

Accepted Answer

Amplitude

Answer

Period

Answer

Frequency

Answer

Phase

Question 43

In digital signal processing, what is aliasing and what are its potential consequences?

Accepted Answer

Aliasing creates additional frequencies in the discrete-time signal that were not present in the original continuous-time signal.

Answer

Aliasing is the process of converting a continuous-time signal to a discrete-time signal by sampling it periodically.

Answer

Aliasing has no significant impact on the accuracy or quality of digital signals.

Question 44

Which of the following is NOT a characteristic of a causal system?

Accepted Answer

The system has no memory.

Answer

The output is solely determined by current and past inputs.

Answer

The system exhibits stability.

Answer

The system is invertible.

Question 45

What is the Fourier transform of the unit impulse function?

Accepted Answer

A Dirac delta function

Answer

A unit step function

Answer

A constant value

Answer

A sinusoidal function

Question 46

Which of the following is NOT a type of system response?

Accepted Answer

Nyquist plot

Answer

Impulse response

Answer

Step response

Answer

Frequency response

Question 47

Which property characterizes a stable system?

Accepted Answer

All poles of the transfer function lie in the left half of the complex plane.

Answer

All zeros of the transfer function lie in the right half of the complex plane.

Answer

The impulse response is bounded.

Answer

The step response decays to zero as time approaches infinity.

Question 48

A system with an impulse response of δ(t - t0) is called a:

Accepted Answer

Non-causal system

Answer

Stable system

Answer

Time-invariant system

Answer

Linear system

Question 49

Which of the following is a technique used for analyzing stability of discrete-time systems?

Accepted Answer

Jury stability test

Answer

Root locus

Answer

Fourier analysis

Answer

Laplace transform

Question 50

A system with a transfer function that has all its poles inside the unit circle in the z-plane is:

Accepted Answer

Stable

Answer

Conditionally stable

Answer

Unstable

Answer

Marginally stable

Question 51

Which of the following is NOT a characteristic of a physically realizable system?

Accepted Answer

Output can be predicted before input is applied

Answer

System is causal

Answer

Impulse response is absolutely integrable

Answer

System is stable

Question 52

Which of the following statements accurately describes continuous-time signals?

Accepted Answer

They can be represented graphically for all values of time

Answer

They are characterized solely by their frequency

Answer

They exhibit a periodic nature

Answer

They are only defined at discrete points in time

Question 53

A system exhibits linearity if:

Accepted Answer

The output is directly proportional to the input

Answer

The output is constant regardless of the input

Answer

The output is always negative

Answer

The output is unrelated to the input

Question 54

Which of the following techniques is commonly employed to analyze discrete-time systems?

Accepted Answer

Z-transform

Answer

Wavelet transform

Answer

Laplace transform

Answer

Fourier transform

Question 55

Which of the following systems exhibits causality?

Accepted Answer

A moving average filter

Answer

An ideal differentiator

Answer

A delay line with a negative delay

Question 56

The Fourier transform of a rectangular pulse results in:

Accepted Answer

A sinc function

Answer

An exponential function

Answer

A delta function

Answer

A Gaussian function

Question 57

A system with an impulse response of h(t) = e^(-at)u(t) can be classified as:

Accepted Answer

First-order low-pass filter

Answer

Second-order high-pass filter

Answer

First-order high-pass filter

Answer

Second-order low-pass filter

Question 58

Which of the following is a characteristic of a causal system?

Accepted Answer

Its output is a function of present and past inputs only.

Answer

Stable

Answer

Linear

Answer

Produces an output before the input is applied.

Question 59

Consider a continuous-time system with the input-output relationship y(t) = x(t-2). Which of the following is the impulse response of this system?

Accepted Answer

δ(t-2)

Answer

δ(t+2)

Answer

u(t+2)

Answer

u(t-2)

Question 60

Which of the following operations is NOT linear?

Accepted Answer

Absolute value

Answer

Convolution

Answer

Time reversal

Answer

Differentiation

Question 61

Which of the following sampling rates is sufficient to avoid aliasing for a signal with the highest frequency component of 1 kHz?

Accepted Answer

2 kHz

Answer

0.25 kHz

Answer

1 kHz

Answer

0.5 kHz

Question 62

The sampling theorem states that:

Accepted Answer

The sampling rate must be at least twice the maximum frequency of the signal to avoid aliasing.

Answer

The sampling theorem applies only to periodic signals.

Answer

The sampling rate is independent of the signal frequency.

Answer

The sampling rate can be less than the maximum frequency of the signal.

Question 63

A system is characterized by the following difference equation: y[n] + 0.5y[n-1] = x[n]. Its frequency response is:

Accepted Answer

H(f) = 1/(1 + 0.5e^(-j2πf))

Answer

H(f) = 1/(1 - 0.5e^(-j2πf))

Answer

H(f) = (1 + 0.5e^(-j2πf))

Answer

H(f) = (1 - 0.5e^(-j2πf))

Question 64

Which of the following is an advantage of using the Laplace transform?

Accepted Answer

It transforms linear differential equations into algebraic equations, simplifying their analysis.

Answer

It cannot handle non-linear systems.

Answer

It provides a graphical representation of the signal.

Answer

It is applicable only to periodic signals.