1) In Communication system noise is most likely to effect the signal.
a) At the Transmitter
b) in the channel
c) in the information system
d) at the destination
2) Indicate the false statement.Modulation is used to
a) reduce the bandwidth used
b) separate differing transmission
c) ensure that message may be transmitted over long distance
3) Amplitude modulation is the process of
a) superimposing low frequency over high frequency
b) superimposing high frequency over low frequency
c) carrier interruption
d) frequency shift and phase shift
4) Noise have great importance at high frequency
a) shot noise
b) random noise
c) impulse noise
d) transit time noise
5) INDICATE THE FALSE STATEMENT
(a)hf mixer are generally nosier than hf amplifiers(b)impulse noise voltage is independent of bw
(c)thermal noise is independent of frequency at which it is measured
(d)industrial noise is usually of impulse type
6) THE VALUE OF THE RESISTOR CREATING THERMAL NOISE IS DOUBLED .THE NOISE POWER IS
(a)halved(b)quadrupled
(c)doubled
(d)unchanged
7) ONE OF THE FOLLOWING IS NOT A USEFUL QUANTITY FOR COMPARING THE NOISE PERFORMANCE OF RECEIVERS
(A)i/p noise voltage
(b)equivalent noise resistance
(c)noise temp
(d)noise figure
(A)i/p noise voltage
(b)equivalent noise resistance
(c)noise temp
(d)noise figure
8) INDICATE THE NOISE WHOSE SOURCE IS IN A CATEGORY DIFFERENT FROM THAT OF OTHER THREE
(A)solar noise(B)cosmic noise
(C)atmospheric noise
(D)galgatic noise
9) IN A LOW LEVEL AM SYSTEM ,AMPLIFIERS FOLLOWING THE MODULATED SIGNAL MUST BE
(a)linear(b)harmonic devices
(c)class c amplifiers
(d)non linear devices
10) LEAK TYPE BIAS IS USED IN A PLATE MODULATED CLASS C AMPLIFIER TO
(A)prevent tuned circuit damping
(b)prevent excessive grid current
(c)prevent over modulation
(d)increase the bw
ANSWER KEY
(A)prevent tuned circuit damping
(b)prevent excessive grid current
(c)prevent over modulation
(d)increase the bw
ANSWER KEY
1
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2
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3
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4
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5
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6
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7
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8
|
9
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10
|
B
|
A
|
A
|
D
|
B
|
D
|
A
|
C
|
A
|
B
|
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