61. The quantization noise power N𝑞 (Mean squared value) of the quantization error, with usual notation will be:




Answer: (d)

62. In order to produce ‘100 percent white’ result, the sensitivity of human eye towards Red, Green and Blue must be:

(a) 𝑌 = 0.30 𝑅 +0.59 𝐺 +0.11 𝐵

(b) 𝑌 = 0.60 𝑅 +0.28 𝐺 +0.12 𝐵

(c) 𝑌 = 0.50 𝑅 +0.25 𝐺 +0.25 𝐵

(d) 𝑌 = 0.30 𝑅 +0.60 𝐺 +0.1 𝐵

Answer: (a)

63. Which one of the following methods will be used to transmit teletype on-off keying?

(a) ASK

(b) PSK

(c) PCM

(d) FSK

Answer: (d)

64. For a BPSK modulator with a carrier frequency of 70 MHz and an input bit rate of 10 Mbps , the minimum Nyquist bandwidth will be:

(a) 05 MHz

(b) 10 MHz

(c) 30 MHz

(d) 60 MHz

Answer: (b)

65. The impulse 𝛿(𝑡 ) and unit step function 𝑢(𝑡 ) are related to each other as:

(a) 𝛿(𝑡 )=𝑑𝑢(𝑡 )/dt

(b) 𝛿(𝑡 )= 𝑢(𝑡 )+𝑢(2𝑡 −1)

(c) 𝛿(𝑡 )=∫𝑢(𝑡 )𝑑t

(d) 𝛿(𝑡 )=2.𝑢(𝑡 )

Answer: (a)

66. Signal flow graphs can be used to represent:

(a) Linear systems only

(b) Non-linear systems only

(c) Both linear and non-linear systems

(d) Time-invariant as well as time varying systems

Answer: (a)

67. Consider the second-order feedback system with transfer function:


The breakaway point of root locus of the system at 𝑠 will be:

(a) 1

(b) −1

(c) 1/2

(d) −1/2

Answer: (d)

68. Consider the third-order feedback system whose loop transfer function 𝐿 (𝑠 ) =𝐺(𝑠 )𝐻 (𝑠 ) is defined as:


The value of 𝐾 for which the system is on the verge of instability will be:

(a) 8

(b) 12

(c) 14

(d) 16

Answer: (a)

69. A unity feedback system has:


(a) 05

(b) 10

(c) 15

(d) 20

Answer: (b)

70. The compensator required improving the transient response and margin of stability of a system is:

(a) Lag

(b) Lead

(c) Lag-lead

(d) All of these

Answer: (b)