# BSNL JTO (CE) Paper 2007 with Solutions Explanations at doorsteptutor. Com Part 6

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76. Amplitude modulation is used for broadcasting because

(A) It is move noise immune than other modulation systems

(B) Compared with other systems it requires less transmitting power

(C) Its use avoids receiver complexity

(D) No other modulation system can provide the necessary bandwidth for high fidelity

77. The maximum phase shift that can be provided by a lead compensator with transfer function

(A)

(B)

(C)

(D)

78. The correct sequence of steps required to improve system stability is

(A) Insert derivative action, use negative feedback, reduce gain

(B) Reduce gain, use negative feedback, and insert derivative action

(C) Reduce gain, insert derivative action, and use negative feedback

(D) Use negative feedback, reduce gain, and insert derivative action

79. Identity slope change at ω = 10 of the magnitude v/s frequency characteristic of a unity feedback system with the following open-loop transfer function

(A)

(B)

(C)

(D)

80. In the feedback control system the loop transfer function is given by

Number of asymptotes of its root loci is

(A) 1

(B) 2

(C) 3

(D) 4

81. In a closed - loop transfer function

(A)

(B)

(C)

(D)

Considering the following statement : In a magic tee

1. The collinear arms are isolated from each other

2. One of the collinear is isolated from the E-arm

3. One of the collinear arm is isolated from the H-arm

4. E-arm and H-arm are isolated from each other. Of these statements

(A) 1 and 2 are correct

(B) 1 and 3 are correct

(C) 1 and 4 are correct

(D) 2 and 3 are correct

83. In 1965 first geostationary satellite was launched called

(A) ANIK

(B) EARLY BIRD (Intel sat - 1)

(C) WESTAR

(D)MOLNIYA

84. When then in two input logic gate we get gate

(A) XOR gate

(B) AND gate

(C) NAND gate

(D) NOR gate

85. In a radio receiver the IF amplifier

(A) Is tuned above the stations incoming frequency

(B) Amplifies the output of local oscillator

(C) Is fixed tuned to one particular frequency

(D) Can be tuned to various isolate frequencies

86. A duplexer is used to

(A) Couple two antennas to a transmitter without interference

(B) Isolate the antenna from the local oscillator

(C) Prevent interference between two antennas connected to a receiver

(D) Use an antenna for reception or transmission without interference.