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Free download in PDF Digital Modulation Techniques Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(21)
Run Length Encoding is used for
[A]
Correction of error in multiple bits
[B]
Bit error correction
[C]
Reducing the repeated string of characters
[D]
All of the above
(22)
Parity check bit coding is used for
[A]
Error detection
[B]
Error correction and detection
[C]
Error correction
[D]
None of the above
(23)
Parity bit coding may not be used for
[A]
Error in more than single bit
[B]
Which bit is in error
[C]
Both a & b
[D]
None of the above
(24)
For a (7, 4) block code, 7 is the total number of bits and 4 is the number of
[A]
Information bits
[B]
Redundant bits
[C]
Total bits- information bits
[D]
None of the above
(25)
Interleaving process permits a burst of B bits, with l as consecutive code bits and t errors when
[A]
B ≤ 2tl
[B]
B ≥ tl
[C]
B ≤ tl/2
[D]
B ≤ tl
(26)
The code in convolution coding is generated using
[A]
EX-OR logic
[B]
OR logic
[C]
AND logic
[D]
None of the above
(27)
For decoding in convolution coding, in a code tree,
[A]
Diverge right when a bit is 0 and diverge left when the bit is 1
[B]
Diverge upward when a bit is 0 and diverge downward when the bit is 1
[C]
Diverge downward when a bit is 0 and diverge upward when the bit is 1
[D]
Diverge left when a bit is 0 and diverge right when the bit is 1
Answer: Diverge upward when a bit is 0 and diverge downward when the bit is 1
(28)
A linear code
[A]
Minimum hamming distance between two code words is equal to weight of any non zero code word
[B]
Sum of code words is also a code word
[C]
All-zero code word is a code word
[D]
All of the above
(29)
Graphical representation of linear block code is known as
[A]
Pi graph
[B]
Matrix
[C]
Tanner graph
[D]
None of the above
(30)
Synchronization of signals is done using
[A]
Transmitter and receiver connected to master timing source
[B]
Extracting timing information from the received signal
[C]
Pilot clock
[D]
All of the above
31
In coherent detection of signals,
[A]
The carrier is in synchronization with modulated carrier
[B]
Carrier of frequency and phase as same as transmitted carrier is generated
[C]
Local carrier is generated
[D]
All of the above
32
Impulse noise is caused due to
[A]
Power line load switching
[B]
Lightening strikes
[C]
Switching transients
[D]
All of the above
33
ISI may be removed by using
[A]
Polar NRZ
[B]
Differential coding
[C]
Manchester coding
[D]
None of the above
Answer: Differential coding
34
Overhead bits are
[A]
Encoded bits
[B]
Framing and synchronizing bits
[C]
Data due to noise
[D]
None of the above
Answer: Framing and synchronizing bits
35
The expected information contained in a message is called
[A]
Entropy
[B]
Coded signal
[C]
Efficiency
[D]
None of the above
36
The information I contained in a message with probability of occurrence is given by (k is constant)
[A]
I = k log21/P2
[B]
I = k log2P
[C]
I = k log21/P
[D]
I = k log21/2P
37
The memory less source refers to
[A]
Emitted message is independent of previous message
[B]
No previous information
[C]
No message storage
[D]
None of the above
Answer: Emitted message is independent of previous message
38
Entropy is
[A]
Average information per message
[B]
Information in a signal
[C]
Amplitude of signal
[D]
All of the above
Answer: Average information per message
39
The relation between entropy and mutual information is
[A]
I(X;Y) = H(X) – H(X/Y)
[B]
I(X;Y) = H(X/Y) – H(Y/X)
[C]
I(X;Y) = H(X) – H(Y)
[D]
I(X;Y) = H(Y) – H(X)
Answer: I(X;Y) = H(X) – H(X/Y)
40
The mutual information
[A]
Is symmetric
[B]
Always non negative
[C]
Both a and b are correct
[D]
None of the above
Answer: Both a and b are correct
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