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Signals and Systems Question & Answers

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This article lists 100+ Signals and Systems MCQs for engineering students. All the Signals and Systems Questions & Answers given below includes solution and link wherever possible to the relevant topic.

A signal is a time-variant and a physical phenomenon. The main intention of the signal is to convey information like the human voice, the voltage on telephone wires, electrical signals, etc. Noise is also a signal but it carries unwanted information.

A system is a device or group of devices that do operations on signals. The system may have one or more inputs and outputs. The inputs of the system are always excitation and the outputs of the system are always the response.

1). The impulse function is denoted by _______
HintThe impulse function denoted by δ(t)
2). The impulse function is _______ when t=0
HintThe impulse function is one when t=0
3). Whenever the amplitude of step function is equivalent to one then that is ______ signal
HintWhenever the amplitude of step function is equivalent to one then that is unit signal
4). When t≥0, the unit signal amplitude must be ________
HintWhen t≥0, the unit signal amplitude must be one
5). When t<0, the unit signal amplitude must be ________
HintWhen t<0, the unit signal amplitude must be zero
6). The discrete-time always indicated with n
HintYes, the discrete-time always indicated with t, for example u(n)
7). Whenever the amplitude of step function is more than one then that is called as ___________ signal
HintWhenever the amplitude of step function is more than one then that is called a step signal
8). The continuous-time always indicated with t
HintYes, the continuous-time always indicated with t, for example u(t)
9). How many inputs does the system have?
HintA system has one or more than one inputs
10). Signal is a _________
HintA signal is a time-variant, and it is a physical phenomenon, and its main intention is to convey information
11). ________ are the examples of signal
HintHuman voice, electrical signals, the voltage on telephone wires, etc are examples of signal
12). The inputs of the system are called _____
HintThe inputs of the system are always excitation
13). In a ______ signal, we can define the value of the signal at any instant of time?
HintIn a continuous signal, we can define the value of the signal at any instant in time
14). In a _________ signal, we can’t define the value of the signal at any instant of time?
HintIn a discrete signal, we can’t define the value of the signal at any instant in time
15). Time scaling won’t work for the ____________ function
HintThe time scaling won’t work for the unit step function
16). The impulse function is _______ when t≠0
HintThe impulse function is zero when t≠0
17). When n=k, δ(n-k) is _______
HintWhen n=k, δ(n-k) is one
18). When n≠k, δ(n-k) is _______
HintWhen n≠k, δ(n-k) is zero
19). The signum function denoted with ______
HintThe signum function denoted with sgn(t), sgn(n)
20). How many outputs does the system have?
HintA system has one or more outputs
21). The outputs of the system are called ________
HintThe outputs of the system is always the response
22). A __________ is an example of the system
HintA communication system, oscilloscopes, modems, etc are examples of the system
23). The standard form of LTI is ___________ Time-Invariant System
HintThe standard form of LTI is Linear Time-Invariant System
24). The unit step signal is denoted with _______
HintThe unit step signal is denoted with u(t) or u(n)
25). ________ are the properties of impulse function
Hintδ(n)-u(n)-u(n-1), f(t) δ(t)=f(0), δ(-t)= δ(t) are the properties of impulse function

Signals and Systems MCQs with Hints

26). The sgn(t) is equal to one when ______
HintThe sgn(t) is equal to one when t>o
27). The relation between u(t) and sgn() is _______
HintThe relation between u(t) and sgn() is sgn(t)=2u(t)-1
28). The unit ramp signal denoted by ________
HintThe unit ramp signal denoted by r(t) or r(n)
29). The r(t)=t when __________
HintThe r(t)=t when t≥0
30). The r(t)=0 when __________
HintThe r(t)=0 when t<0
31). The unit parabolic signal is zero when _________
HintThe unit parabolic signal is zero when t<0
32). x(t)=A rect (t/T) is a representation of ________
Hintx(t)=A rect (t/T) is a representation of a rectangular signal
33). The sgn(t) is equal to zero when ________
HintThe sgn(t) is equal to zero when t=0
34). The sinc function denoted with _________
HintThe sinc function denoted with sinc(λ)
35). The sampling function denoted with _________
HintThe sampling function denoted with sa(λ)
36). Which one is a normalized function?
Hintsinc is a normalized function
37). The operation on signals perform only on ________
HintThe operation on signals perform only on amplitude or time
38). The sgn(t) is equal to -1 when ___________
HintThe sgn(t) is equal to -1 when t<0
39). ______ operations performed on amplitude
HintScaling, addition, subtraction, multiplication operations performed on amplitude
40). ______ operations performed on time
HintScaling, shifting, reversal operations performed on time
41). For a discrete-time signals time is ______
HintFor discrete-time signals time is discrete
42). For a discrete-time signals amplitude is ______
HintFor discrete-time signals amplitude is continuous
43). Which one is not a normalized function?
HintSampling is not a normalized function
44). For discrete-time signals, both amplitude and time are ____
HintFor discrete-time signals, both amplitude and time are discrete
45). The signal is said to be _______whenever we can define a signal at an instant of time
HintThe signal is said to be deterministic whenever we can define a signal at an instant in time
46). The signal is said to be _______whenever there is un-certainty at any particular instant of time
HintThe signal is said to be non-deterministic whenever there is uncertainty at any particular instant in time
47). The signal is said to be even when it satisfies the condition _______
HintThe signal is said to be even when it satisfies the condition x(t)=x(-t)
48). The sum of two or more even functions, a product of two or more even functions o product of even number and odd functions results ______ function
HintThe sum of two or more even functions, a product of two or more even functions o product of even number and odd functions results even function
49). A signal said to be periodic if it satisfies the condition _________
HintA signal said to be periodic if it satisfies the condition x(t)=x(t+T)
50). The smallest value of T which satisfies the ___________ condition is called the fundamental time period
HintThe smallest value of T which satisfies the x(t)=x(t+T) condition is called the fundamental time period

Signals and Systems MCQs for Students

51). When two periodic sinusoids added then the result is ________
HintWhen two periodic sinusoids added then the result is a sinusoidal signal and it is said to be periodic when two signals of different frequencies are added
52). The signal is said to be odd when it satisfies the condition _____________
HintThe signal is said to be odd when it satisfies the condition x(t)=-x(-t)
53). The sum of two or more odd functions or product of the odd number of odd functions results in ______ function
HintThe sum of two or more odd functions or product of the odd number of odd functions results in odd function
54). _______ methods are used to find whether the signal is periodic or not
HintBoth ratio and GCD methods are used to find whether the signal is periodic or not
55). A signal is said to be a power/energy signal if the total energy/power transmitted is ________
HintA signal is said to be a power/energy signal if the total energy/power transmitted is finite
56). ________ system satisfies the superposition principle
HintLinear system satisfies the superposition principle
57). The system is said to be __________ if its input, output characteristics changes with time
HintIf its input, output characteristics change with time then the system is said to be time-variant
58). The condition for time variance is _____
HintThe condition for time variance is y(n,k)=y(n-k)
59). The system is said to be _______ when it satisfies with linearity and time-variant
HintThe system is said to be a linear time-variant when it satisfies with linearity and time-variant
60). ________ system is a memory less system
HintStatic system is a memory less system
61). A system is said to be _____ if its response is dependent upon the present and past inputs and doesn’t depend upon future input
HintA system is said to be causal if its response is dependent upon the present and past inputs and doesn’t depend upon future input
62). All non-causal systems are _________
HintAll non-causal systems are dynamic
63). All static systems are _____________
HintAll static systems are causal but all causal systems may not be static
64). A system said to be _______ when it produces bounded output for a bounded input
HintA system said to be stable when it produces bounded output for a bounded input
65). The impulse response of a system can be represented with _______
HintThe impulse response of a system can be represented with h(t) or h(n)
66). All finite duration signals with finite amplitude are said to be ______ signal
HintAll finite duration signals with finite amplitude are said to be energy signal
67). All periodic signals are _________ signals
HintAll periodic signals are power signals
68). The continuous impulse is a ________ signal
HintThe continuous impulse is neither energy nor power signal
69). A discrete signal x(n) is said to be periodic when _______
HintA discrete signal x(n) is said to be periodic when x(n)=x(n+N)
70). _____ system is a memory system
HintDynamic system is a memory system
71). In _______ system, the output depends upon future input also
HintIn a non-causal system, the output depends upon future input also
72). The system is said to be _____ when it produces unbounded output for a bounded input
HintThe system is said to be unstable when it produces unbounded output for a bounded input
73). By using __________ we can find the zero state response of the system
HintBy using convolution we can find the zero state response of the system
74). The convolution is a mathematical operation that express _________ relation of an LTI system
HintThe convolution is a mathematical operation that expresses the input and output relation of an LTI system
75). _______ are the properties of convolution
HintCommutative, distributive, associative, shift, convolution with impulse are the properties of convolution

Signals and Systems MCQs for Interviews

76). The convolution with impulse property states that ________
HintThe convolution with impulse property states that x(t)*δ(t)=x(t)
77). When input signals are scaled by α then the output will be _________
HintWhen input signals are scaled by α then the output will be x(αt)*h(αt)=1/| α| y(αt)
78). ______ are the conditions of Dirichlet
HintThe conditions of Dirichlet are function should be absolutely integrable, and there must be a finite number of maxima and minima in the function, and also there must be a finite number of discontinuous in the function
79). If x(n) is real and even signal then Fourier series coefficient will be ________
HintIf x(n) is real and even signal then Fourier series coefficient will be imaginary and odd, imaginary and even, real and odd, and real and even
80). If the signal that we want to represent in terms of Fourier series is real and even then the fourier series coefficient will be _______
HintIf the signal that we want to represent in terms of Fourier series is real and even then the Fourier series coefficient will be real and even
81). If the signal that we want to represent in terms of Fourier series is real and odd then the Fourier series coefficient will be _______
HintIf the signal that we want to represent in terms of Fourier series is real and odd then the Fourier series coefficient will be imaginary and odd
82). If the signal that we want to represent in terms of Fourier series is imaginary and even then the Fourier series coefficient will be _______
HintIf the signal that we want to represent in terms of Fourier series is imaginary and even then the Fourier series coefficient will be imaginary and even
83). If the signal that we want to represent in terms of Fourier series is imaginary and odd then the Fourier series coefficient will be _______
HintIf the signal that we want to represent in terms of Fourier series is imaginary and odd then the Fourier series coefficient will be real and odd
84). The example of real and even signal is _________
HintThe example of real and even signal is Cos t
85). The example of real and odd signal is _________
HintThe example of real and odd signal is Sin t
86). The example of imaginary and even signal is _________
HintThe example of imaginary and even signal is i cos t
87). The region of convergence _______
HintThe region of convergence decides whether the system is variable or stable and also decides whether the sequence is non-causal or causal
88). A signal x(t) and its Hilbert transform is having _________
HintA signal x(t) and its Hilbert transform is having the same amplitude spectrum, same autocorrelation function, and same energy spectral density
89). How many types of correlations are there?
HintThere are two types of correlations are there they are auto and cross-correlations
90). _______________ function gives measure of match or similarity or coherence between a signal and its time shifted version
HintAuto-correlation function gives the measure of match or similarity or coherence between a signal and its time-shifted version
91). _______________ is the measure of similarity between one signal and the time delayed version of other signal
HintCross-correlation is the measure of similarity between one signal and the time-delayed version of other signals
92). What is the ROC of δ(n)?
HintThe ROC of δ(n) is one
93). What is the ROC of z-transform of δ(n+1)?
HintThe ROC of z-transform of δ(n+1) is Z
94). The analysis of discrete-time LTI system is _____________
HintThe analysis of discrete-time LTI system is Z-transforms
95). ________ sampling works based on the multiplication
HintIdeal sampling works based on the multiplication
96). The noise interference in ideal sampling is ________
HintThe noise interference in ideal sampling is very less
97). The sampling theory is a process to convert ___________
HintThe sampling theory is a process to convert the continuous-time signal into a discrete-time signal
98). How many types of samplings are there?
HintThere are three types of samplings are there they are ideal, natural, and flat top samplings

Read more about Sampling

99). Auto-correlation function of the power signal is maximum at the origin so we can say that _____
HintThe auto-correlation function of the power signal is maximum at the origin so we can say that R(0)≥R(τ)
100). __________ sampling works based on chopping
HintNatural sampling works based on chopping

Signals and Systems MCQs for Quiz

101). The noise interference in natural sampling is _______
HintThe noise interference in natural sampling is very low
102). If there is no similarity between x(t) and x(t-τ) then autocorrelation will be _______
HintIf there is no similarity between x(t) and x(t-τ) then autocorrelation will be zero
103). If a sequence is purely right-sided sequence or causal then region of convergence is entire z-plane except at __________
HintIf a sequence is purely right-sided sequence or causal then region of convergence is the entire z-plane except at z is equal to zero
104). If a sequence is purely left-sided sequence or anti-causal then region of convergence is entire z-plane except at __________
HintIf a sequence is a purely left-sided sequence or anti-causal then the region of convergence is the entire z-plane except at z is equal to ∞
105). For a two-sided sequence region of convergence is entire z-plane except at __________
HintFor a two-sided sequence region of convergence is entire z-plane except at z is equal to 0 and z is equal to ∞
106). The z-transform for discrete impulse function δ(n) is equivalent to one, for this type of impulse function the region of convergence is entire z-plane ____________
HintThe z-transform for discrete impulse function δ(n) is equivalent to one, for this type of impulse function the region of convergence is entire z-plane including z is equal to 0 and z is equal to ∞
107). The z-transform for discrete impulse function δ(n+1) is equivalent to z, for this type of impulse function the region of convergence is entire z-plane ____________
HintThe z-transform for discrete impulse function δ(n+1) is equivalent to z, for this type of impulse function the region of convergence is entire z-plane including z is equal to ∞ and excluding z is equal to 0
108). The ROC in z-transform indicated as ___________
HintThe ROC in z-transform indicated as a circle
109). The z-transform of a discrete-time signal x(n) is represented by _________
HintThe z-transform of a discrete-time signal x(n) is represented by x(n)↔x(z)
110). _____ sampling works based on a sample and hold
HintFlat top sampling works based on a sample and hold
111). The noise interference in flat top sampling is ______
HintThe noise interference in flat top sampling is high
112). The ZT and DTFT are equal when r is equal to __________
HintThe ZT and DTFT are equal when r is equal to one
113). The ROC is the entire Z-plane for ________ sequence
HintThe ROC is the entire Z-plane for right-hand sequence
114). The z-transform of u(-n) is _______
HintThe z-transform of u(-n) is 1/1-z
115). The white noise spectral density is _____
HintThe white noise spectral density is uniform
116). The frequency-domain representation of time-domain u(t) is __________
HintThe frequency-domain representation of time-domain u(t) is 1/jw+ πδ(ω)
117). The time-domain representation of frequency domain δ(ω) is ______
HintThe time-domain representation of frequency domain δ(ω) is one
118). The state is the group of_________ , which summarizes the history of the system to predict the future values
HintThe state is the group of variables, which summarizes the history of the system in order to predict the future values
119). The smallest set of variables that determines the state of the system are known as ______
HintThe smallest set of variables that determines the state of the system is known as state variables
120). _______ is the vector that contains the state variables as elements
HintState vector is the vector that contains the state variables as elements
121). The advantages of state-space analysis are ______
HintIn state-space analysis, the analysis is done by considering initial conditions, and it is more accurate than transfer function, and the analysis of multi-input and the multi-output system will be made easy by the state space analysis techniques
122). The disadvantages of state-space analysis are ______
HintIn state-space analysis techniques are complex but the process is easy and many computations are required
123). Which signal is used for processing digital signals?
HintA Discrete-time signal is used for processing digital signals
124). The variable of the continuous-time denoted by _______
HintThe variable of the continuous-time denoted by t
125). The variable of the discrete-time denoted by _______
HintThe variable of the discrete-time denoted by n

Signals and Systems MCQs for Exams

126). ____________ is the process of reconstruction from its sampled output
HintInterpolation is the process of reconstruction from its sampled output
127). The nquist rate of sin4000πt is _____
HintThe nquist rate of sin4000πt is 4000Hz
128). The maximum frequency of sin4000πt is _____
HintThe maximum frequency of sin4000πt is 2000Hz
129). The nquist rate of sin200πt is _____
HintThe nquist rate of sin200πt is 200Hz
130). The nquist rate of sin(400t)*sinc(600t) is _____
HintThe nquist rate of sin(400t)*sinc(600t) is 400 samples/sec
131). A ________ is a frequency selective network
HintA filter is a frequency selective network
132). An LTI system acts as a _______
HintAn LTI system acts as a filter
133). The nquist rate of cos(2000πt)*sin(6000πt) is _____
HintThe nquist rate of cos(2000πt)*sin(6000πt) is 6000 samples/sec
134). Filters allow transmission of signals in a __________________
HintFilters allow transmission of signals in a certain band of frequencies and out of the band that frequencies will be rejected
135). Whichever the frequencies is allowed by the LTI system or the filter is called _________
HintWhichever the frequencies are allowed by the LTI system or the filter is called pass-band
136). In _______ band, a certain band of frequencies are is allowed and rest of the frequencies are allowed by the filter
HintIn stop-band, a certain band of frequencies are is allowed and the rest of the frequencies are allowed by the filter
137). How many types of filters are there?
HintThere are five types of filters are there they are high-pass, low-pass, band-stop, band-pass, and all-pass

Read more about Filters

138). The nyquist rate of sinc(200t)*sinc(600t) is _____
HintThe nyquist rate of sinc(200t)*sinc(600t) is 600 samples/sec
139). The change of input signals shape when it is transmitted through a system is called _________
HintThe change of input signals shape when it is transmitted through a system is called distortion
140). If one input and one output is given to the system then that system is called ______
HintIf one input and one output is given to the system then that system is called a single input single output system
141). The ratio of Fourier transform of the output signal to the Fourier transform of the input signal is called ____________
HintThe ratio of Fourier transform of the output signal to the Fourier transform of the input signal is called transfer function
142). If two or more inputs and two or more outputs are given to the system then that system is called ______
HintIf two or more inputs and two or more outputs are given to the system then that system is called multiple inputs multiple outputs system
143). The maximum frequency of sinc(200t)*sinc(600t) is _____
HintThe maximum frequency of sinc(200t)*sinc(600t) is 300Hz
144). Which one is a transformation technique?
HintFourier series, Fourier transform, Z- transform all are transformation techniques
145). The Fourier series, and Fourier transform is given by a french mathematician John Batiste Joseph Fourier in _________
HintThe Fourier series and Fourier transform is given by a french mathematician John Batiste Joseph Fourier in 1768-1830

Read more about Fourier Series and Fourier Transform

146). The periodic signals ________ time signals
HintThe periodic signals may be continuous and discrete-time signals
147). How many types of Fourier transforms are there?
HintThere are two types of Fourier transforms are there they are continuous-time and discrete-time Fourier transforms
148). The nyquist rate of sinc(400t)*sinc(600t) is _____
HintThe nyquist rate of sinc(400t)*sinc(600t) is 1000 samples/sec
149). How many types of Fourier series are there?
HintThere are two types of Fourier series are there they are continuous-time, and discrete-time Fourier series
150). Which transform is only for a continuous-time?
HintLaplace transform is only for a continuous time

Signals and Systems MCQs with Answers

151). Which transform is only for a discrete-time?
HintZ-transform is only for a discrete-time
152). _________ are for the analysis purpose
HintFourier series and Fourier transforms are for the analysis purpose
153). _________ transforms are for the design purpose
HintLaplace and z-transform are for the design purpose
154). The number of cycles per second is a ________
HintThe number of cycles per second is a frequency
155). How much time taken by the signal is called the _____________
HintThe time taken by the signal is called the fundamental time period
156). In T seconds one cycle has finished and in one second how many cycles has finished means _____
HintIn T seconds one cycle has finished and in one second how many cycles has finished means 1/T cycles
157). _________ is also used to calculate the power and phase constant of a particular harmonic present in the expansion
HintFourier series is also used to calculate the power and phase constant of a particular harmonic present in the expansion
158). There are _______ Fourier series methods
HintThere are three Fourier series methods they are trigonometric, complex, and polar, harmonic Fourier series methods
159). The system output y(t)=x(t),if t=0 then the output is dependent on _______
HintThe system output y(t)=x(t),if t=0 then the output is dependent on present input
160). The system output y(t)=x(t-1),if t=0 then the output is dependent on _______
HintThe system output y(t)=x(t-1),if t=0 then the output is dependent on past input
161). The system output y(t)=x(t+1),if t=0 then the output is dependent on _______
HintThe system output y(t)=x(t+1),if t=0 then the output is dependent on future input
162). The power of energy signals is equivalent to _______
HintThe power of energy signals is equivalent to zero
163). The energy of power signals is equivalent to _______
HintThe energy of power signals is equivalent to infinity
164). The real and complex exponential signal can be defined in __________
HintThe real and complex exponential signal can be defined in both discrete and continuous-time
165). __________ are the examples of systems
HintElectrical circuits, mechanical systems, chemical and biological systems, etc are the examples of systems
166). If f(t)=f(t+T) then the signal is ________
HintIf f(t)=f(t+T) then the signal is continuous-time signal
167). If f(t)=f(-t) then the signal is said to be ________
HintIf f(t)=f(-t) then the signal is said to be even
168). Interconnection patterns are of _________ types
HintInterconnection patterns are of three types they are serial, parallel, and feedback interconnections
169). __________ is an example of an invertible system
Hinty(t)=αx(t) is an example of an invertible system
170). If distinct inputs lead to distinct outputs then the system is said to be ___________
HintIf distinct inputs lead to distinct outputs then the system is said to be invertibility
171). The system is said to be linear if it satisfies the ________ properties
HintThe system is said to be linear if it satisfies the scaling and additivity properties
172). The speech signal is the example of ___________ dimensional signal
HintThe speech signal is an example of a one-dimensional signal
173). ______ is an example of multi-dimensional signal
HintImage is an example of a multi-dimensional signal
174). Which signal has infinite duration?
HintPower signal has infinite duration
175). _____ are the elementary signals
HintStep function, impulse function, and ramp function are the elementary signals

Signals and Systems MCQs for Engineers

176). Which one is an example of causal systems?
Hinty[n]=x[n]+1/2x[n-1] is an example of causal systems
177). In ________ system the value of the present output depends on past/future input
HintIn a memory system the value of the present output depends on past/future input
178). ______ system consists of delay elements, differentiation, integration, in their equation
HintDynamic system consists of delay elements, differentiation, integration, in their equation
179). Which one is an example of a non-causal system?
Hinty[n]=x[n+1]+1/2x[n-1] is an example of a non-causal system
180). In ________ system the value of the present output depends on present input
HintIn a memory less system the value of the present output depends on the present input
181). The sampling rate of telephony is around _______
HintThe sampling rate of telephony is around 8KHz
182). The bandwidth of telephony is around _______
HintThe bandwidth of telephony is between 300-3400Hz
183). The bit rate of telephony is around _______
HintThe bit rate of telephony is around 2.4-64 Kbit/sec
184). The sampling rate of high fidelity music is around _______
HintThe sampling rate of high fidelity music is around 44.1KHz
185). The bandwidth of high fidelity music is around _______
HintThe bandwidth of high fidelity music is around 5Hz-20KHz
186). The standard audio rate of compact rate is around _________
HintThe standard audio rate of compact rate is around 44.1KS/s
187). The standard audio rate of a DVD system is around _________
HintThe standard audio rate of a DVD system is around 96KS/s
188). The data rate of FM radio is ______
HintThe data rate of FM radio is 88.2KB/sec
189). The frequency band of FM radio is between _____
HintThe frequency band of FM radio is between 0.002-11KHz
190). The sampling rate of AM radio is around _______
HintThe sampling rate of AM radio is around 11.025KHz
191). The data rate depends on ________
HintThe data rate depends on available bandwidth, the level of the signals we use, and the quality of the channel
192). The average frequency of human voices is _________
HintThe average frequency of human voices is 125Hz to 8KHz
193). How many ways are there to represent discrete-time signals?
HintIn three ways the discrete-time signals are represented are a functional, tabular method of representation and sequence representation
194). Which system doesn’t have feedback?
HintNon-recursive system doesn’t have feedback
195). Which one is an example of a recursive system?
Hinty(n)=x(n)+y(n-2) is an example of a recursive system
196). Which one is an example of a non-recursive system?
Hinty(n)=x(n)+x(n-1) is an example of a non-recursive system

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