MCQ in Feedback and Control Systems Part 2 | Engineering Board Exam

This is the Multiple Choice Questions in Feedback and Control Systems Part 2 of the Series as one of the Electronics Engineering Examination topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

MCQ Topic Outline included in ECE Board Exam Syllabi

9. Feedback and Control Systems

• MCQ in Block Diagram Representation and Signal Flow Graphs
• MCQ in LTI Systems and Transient Analysis
• MCQ in System Modeling and Transfer Function
• MCQ in Poles and Zeros, Root Locus, and Stability Analysis
• MCQ in Poles and Zeros, Root Locus, and Stability Analysis

Continue Practice Exam Test Questions Part 2 of the Series

⇐ MCQ in Control Systems Part 1 | Engineering Board Exam

Choose the letter of the best answer in each questions.

51. A control system working under unknown random action is called

A. computer control system

B. digital data system

C. stochastic control system

D. adaptive control system

52. The first order control system, which is is well designed, has a

A. small bandwidth

B. negative time constant

C. large negative transfer function pole

D. none of the above

53. Zero-order hold used in practical reconstruction of continuous-time signals is mathematically represented as a weighted-sum of rectangular pulses shifted by:

A. any multiples of the sampling interval

B. integer multiples of the sampling interval

C. one sampling interval

D. 1 second intervals

54. Sampling can be done by:

A. impulse train sampling

B. natural sampling

C. flat-top sampling

D. all of the mentioned

55. The first step required to convert analog signal to digital is :

A. sampling

B. holding

C. reconstruction

D. quantization

56. Sampling is necessary :

A. in complex control systems

B. where high accuracy is required

C. non automated control systems

D. automated control system

57. ______ is a sampling pattern which is repeated periodically

A. single order sampling

B. multi order sampling

C. zero order sampling

D. unordered sampling

58. Aliasing is caused when:

A. sampling frequency must be equal to the message signal

B. sampling frequency must be greater to the message signal

C. sampling frequency must be less to the message signal

D. sampling frequency must be greater than or equal to the message signal

59. The signal is reconstructed back with the help of

A. zero order hold circuits

B. extrapolations

C. signal is reconstructed with zero order holds and extrapolations

D. signal is not reconstructed

60. A control system working under unknown random actions is called ______.

A. computer control system

B. digital data system

C. stochastic control system

D. adaptive control system

61. Zero initial condition for a system means

A. input reference signal is zero

B. zero stored energy

C. no initial movement of moving parts

D. system is at rest and no energy is stored in any of its components

62. The first order control system ,which is well designed has a

A. small bandwidth

B. negative time constant

C. large negative transfer function pole

D. none of the above

63. A zero order hold is used with sampled data system to

A. make it critically damped

B. reconstruct the sampled signal

C. improve the stability of the system

D. convert it to a continuous system

64. A controller is basically a ______.

A. sensor

B. comparator

C. amplifier

D. clipper

65. Z and Laplace transform are related by:

A. s = ln z

B. s =ln z/t

C. s =z

D. s= t/ln z

66. What is the z-transform of the signal x[n] = anu(n)?

A. x(z) =1/z-1

B. x(z) = 1/1-z

C. x(z) = z/z-a

D. x(z) = 1/z-a

67. Which one of the following rules determine the mapping of s-plane to z-plane?

A. right side of the s-plane maps into outside of the unit circle in z-plane

B. left half of s-plane maps into inside of the unit circle

C. imaginary axis in s-plane maps into the circumference of the unit circle

D. all of the mentioned

68. Assertion (A): The z-transform of the output of the sampler is given by the series. Reason (R): The relationship is the result of the application of z = e-sT, where T stands for the time gap between the samples.

A. both a and r are true and r is correct explanation of a

B. both a and r are true but r is not correct explanation of a

C. a is true but r is false

D. a is false but r is true

69. Inverse z-transform of the system can be calculated using:

A. partial fraction method

B. long division method

C. basic formula of the z-transform

D. all of the mentioned

70. If the z transform of x(n) is X(z) =z(8z-7)/4z²-7z+3, then the final value theorem is :

A. 1

B. 2

C. ∞

71. Difference equation model results in:

A. sampled-data systems

B. numerical analysis of continuous time systems

C. continuous time feedback systems

D. both a & b

72. Which of the following is an advantage of Laplace transform method

A. it gives solution in frequency domain only

B. it gives total solution more systematically

C. initial conditions are incorporated in the very first step

D. both b & c

73. Analysis of control system by Laplace transform technique is not possible for

A. discrete time systems

B. linear systems

C. time invariant systems

D. unstable continuous time systems

74. Z-transform is used in:

A. continuous optimal control problem

B. discrete optimal problem

C. control systems

D. none of the mentioned

75. Unit step response of the system described by the equation y(n) +y(n-1) =x(n) is:

A. z²/(z+1)(z-1)

B. z/(z+1)(z-1)

C. z+1/z-1

D. z(z-1)/z+1

76. Difference equation model results in:

A. sampled-data systems

B. numerical analysis of continuous time systems

C. continuous time feedback systems

D. both a and b

77. For relative stability of the system which of the following is sufficient?

A. gain margin

B. phase margin

C. both a and b

D. magnitude

78. Stability of a system implies that :

A. small changes in the system input does not result in large change in system output

B. small changes in the system parameters does not result in large change in system output

C. small changes in the initial conditions does not result in large change in system output

D. small changes in the initial conditions result in large change in system output

79. Linear mathematical model applies to :

A. linear systems

B. stable systems

C. unstable systems

D. all of the mentioned

80. With feedback _____ reduces.

A. system stability

B. system gain

C. system stability and gain

D. damping

81. Asymptotic stability is concerned with:

A. a system under influence of input

B. a system not under influence of input

C. a system under influence of output

D. a system not under influence of output

82. A linear time invariant system is stable if :

A. system in excited by the bounded input, the output is also bounded

B. in the absence of input output tends zero

C. both a and b

D. system in excited by the bounded input, the output is not bounded

83. If a system is given unbounded input then the system is:

A. stable

B. unstable

C. not defined

D. linear

84. If the impulse response in absolutely integrable then the system is :

A. absolutely stable

B. unstable

C. linear

D. stable

85. If root of the characteristic equation has positive real part the system is :

A. stable

B. unstable

C. marginally stable

D. linear

86. The use of sampled data control system are:

A. for using analog components as the part of the control loop

B. for time division of control components

C. whenever a transmission channel forms a part of closed loop

D. none of the mentioned

87. Jury’s test determines whether the roots of a polynomial lie:

A. close to unit circle

B. within the unit circle

C. outside the unit circle

D. on the unit circle

88. The transformation technique in which there is one to one mapping from s-domain to z-domain is

A. approximation of derivatives

B. impulse invariance method

C. bilinear transformation method

D. backward difference for the derivative

89. Parallel form of realization is done in

A. high speed filtering applications

B. low speed filtering applications

C. both a and b

D. none of the above

90. In cascade form of realization, how many bits should be used to represent the FIR filter coefficients in order to avoid the quantization effect on filter coefficients?

A. 5 to 10

B. 12 to 14

C. 20 to 24

D. 28 to 40

91. How is the sampling rate conversion achieved by factor I/D?

A. by increase in the sampling rate with (i)

B. by filtering the sequence to remove unwanted images of spectra of original signal

C. by decimation of filtered signal with factor d

D. all of above

92. In the cascaded form of realization, the polynomials are factored into

A. product of 1st-order and 2nd-order polynomials

B. product of 2nd-order and 3rd-order polynomials

C. sum of 1st-order and 2nd-order polynomials

D. sum of 2nd-order and 3rd-order polynomials

93. Open loop transfer function of a system having one zero with a positive real value is called.

A. zero phase function

B. negative phase function

C. positive phase function

D. non-minimum phase function

94. Consider the function F (s)= 5/s(s²+3s+2), the initial value of f(t) is:

A. 5

B. 5/2

C. 5/3

D.0

95. In a closed loop for which the output is the speed of the motor, the output rate control can be used to:

A. limit the speed of the motor

B. limit the torque output of the motor

C. reduce the damping of the system

D. limit the acceleration of the motor

96. The transfer function of any stable system which has no zeros or poles in the right half of the s-plane is said to be:

A. minimum phase transfer function

B. non-minimum phase transfer function

C. minimum phase frequency response function

D. minimum gain transfer function

97. State model representation is possible using _________

A. physical variables

B. phase variables

C. canonical state variables

D. all of the above

98. Conventional control theory is applicable to ______ systems

A. siso

B. mimo

C. time varying

D. non-linear

99. The transfer function for the state representation of the continuous time LTI system: dq(t)/dt=Aq(t)+Bx(t) Y(t)=Cq(t)+Dx(t) is given by

A. c(si-a)-1b+d

B. b(si-a)-1b+d

C. c(si-a)-1b+a

D. d(si-a)-1b+c

100. The system which works on the initial condition without any input applied to it is called as :

A. homogeneous system

B. non homogeneous system

C. linear system

D. non linear system

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