Communication Engineering Set 9

Computer Science Engineering (CSE)

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This set of Communication Engineering Multiple Choice Questions & Answers (MCQs) focuses on Communication Engineering Set 9

Q1 | Coherent PSK and non coherent orthogonal FSK have a difference of               in PB.
  • 1db
  • 3db
  • 4db
  • 6db
Answer: 4db
Explaination:
the difference of pb is approximately 4db for the best ( coherent psk ) and the worst (non coherent orthogonal fsk).
Q2 | Which is easier to implement and is preferred?
  • coherent system
  • non coherent system
  • coherent & non coherent system
  • none of the mentioned
Answer: non coherent system
Explaination:
a non coherent system is desirable because there may be difficulty is establishing and maintaining a coherent reference.
Q3 | Which is the main system consideration?
  • probability of error
  • system complexity
  • random fading channel
  • all of the mentioned
Answer: all of the mentioned
Explaination:
the major system considerations are error probability, complexity and random fading channel. considering all this non coherent system is more desirable than coherent.
Q4 | Self information should be
  • positive
  • negative
  • positive & negative
  • none of the mentioned
Answer: positive
Explaination:
self information is always non negative.
Q5 | The unit of average mutual information is
  • bits
  • bytes
  • bits per symbol
  • bytes per symbol
Answer: bits
Explaination:
the unit of average mutual information is bits.
Q6 | When probability of error during transmission is 0.5, it indicates that
  • channel is very noisy
  • no information is received
  • channel is very noisy & no information is received
  • none of the mentioned
Answer: channel is very noisy & no information is received
Explaination:
when probability of error during transmission is 0.5 then the channel is very noisy and thus no information is received.
Q7 | The event with minimum probability has least number of bits.
  • true
  • false
Answer: false
Explaination:
in binary huffman coding the event with maximum probability has least number of bits.
Q8 | The method of converting a word to stream of bits is called as
  • binary coding
  • source coding
  • bit coding
  • cipher coding
Answer: source coding
Explaination:
source coding is the method of converting a word to stream of bits that is 0’s and 1’s.
Q9 | When the base of the logarithm is 2, then the unit of measure of information is
  • bits
  • bytes
  • nats
  • none of the mentioned
Answer: bits
Explaination:
when the base of the logarithm is 2 then the unit of measure of information is bits.
Q10 | When X and Y are statistically independent, then I (x,y) is
  • 1
  • 0
  • ln 2
  • cannot be determined
Answer: 0
Explaination:
when x and y are statistically independent the measure of information i (x,y) is 0.
Q11 | The self information of random variable is
  • 0
  • 1
  • infinite
  • cannot be determined
Answer: infinite
Explaination:
the self information of a random variable is infinity.
Q12 | Entropy of a random variable is
  • 0
  • 1
  • infinite
  • cannot be determined
Answer: infinite
Explaination:
entropy of a random variable is also infinity.
Q13 | Which is more efficient method?
  • encoding each symbol of a block
  • encoding block of symbols
  • encoding each symbol of a block & encoding block of symbols
  • none of the mentioned
Answer: encoding block of symbols
Explaination:
encoding block of symbols is more efficient than encoding each symbol of a block.
Q14 | Lempel-Ziv algorithm is
  • variable to fixed length algorithm
  • fixed to variable length algorithm
  • fixed to fixed length algorithm
  • variable to variable length algorithm
Answer: variable to fixed length algorithm
Explaination:
lempel-ziv algorithm is a variable to fixed length algorithm.
Q15 | While recovering signal, which gets attenuated more?
  • low frequency component
  • high frequency component
  • low & high frequency component
  • none of the mentioned
Answer: high frequency component
Explaination:
high frequency components are attenuated more when compared to low frequency components while recovering the signals.
Q16 | Mutual information should be
  • positive
  • negative
  • positive & negative
  • none of the mentioned
Answer: positive & negative
Explaination:
mutual information can also be negative.
Q17 | ASCII code is a
  • fixed length code
  • variable length code
  • fixed & variable length code
  • none of the mentioned
Answer: fixed length code
Explaination:
ascii code is a fixed length code. it has a fixed length of 7 bits.
Q18 | Which reduces the size of the data?
  • source coding
  • channel coding
  • source & channel coding
  • none of the mentioned
Answer: source coding
Explaination:
source coding reduces the size of the data and channel coding increases the size of the data.
Q19 | In digital image coding which image must be smaller in size?
  • input image
  • output image
  • input & output image
  • none of the mentioned
Answer: output image
Explaination:
in digital image coding, output image must be smaller than the input image.
Q20 | Which coding method uses entropy coding?
  • lossless coding
  • lossy coding
  • lossless & lossy coding
  • none of the mentioned
Answer: lossy coding
Explaination:
lossy source coding uses entropy coding.
Q21 | Which achieves greater compression?
  • lossless coding
  • lossy coding
  • lossless & lossy coding
  • none of the mentioned
Answer: lossy coding
Explaination:
lossy coding achieves greater compression where as lossless coding achieves only moderate compression.
Q22 | Which are uniquely decodable codes?
  • fixed length codes
  • variable length codes
  • fixed & variable length codes
  • none of the mentioned
Answer: fixed length codes
Explaination:
fixed length codes are uniquely decodable codes where as variable length codes may or may not be uniquely decodable.
Q23 | A rate distortion function is a
  • concave function
  • convex function
  • increasing function
  • none of the mentioned
Answer: convex function
Explaination:
a rate distortion function is a monotone decreasing function and also a convex function.
Q24 | Which of the following algorithms is the best approach for solving Huffman codes?
  • exhaustive search
  • greedy algorithm
  • brute force algorithm
  • divide and conquer algorithm
Answer: greedy algorithm
Explaination:
greedy algorithm is the best approach for solving the huffman codes problem since it greedily searches for an optimal solution.
Q25 | How many printable characters does the ASCII character set consists of?
  • 120
  • 128
  • 100
  • 98
Answer: 100
Explaination:
out of 128 characters in an ascii set, roughly, only 100 characters are printable while the rest are non-printable.
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