Deck 7: Information Theory and Coding Techniques

Question 1

Coherent PSK and non coherent orthogonal FSK have a difference of_________   in PB.

A)1db
B)3db
C)4db
D)6db

Answer 1

4db

Question 2

Which is easier to implement and is preferred?

A)coherent system
B)non coherent system
C)coherent & non coherent system
D)none of the mentioned

Answer 2

non coherent system

Question 3

Which is the main system consideration?

A)probability of error
B)system complexity
C)random fading channel
D)all of the mentioned

Answer 3

all of the mentioned

Question 4

Self information should be

A)positive
B)negative
C)positive & negative
D)none of the mentioned

Question 5

The unit of average mutual information is

A)bits
B)bytes
C)bits per symbol
D)bytes per symbol

Question 6

When probability of error during transmission is 0.5, it indicates that

A)channel is very noisy
B)no information is received
C)channel is very noisy & no information is received
D)none of the mentioned

Question 7

The event with minimum probability has least number of bits.

Question 8

The method of converting a word to stream of bits is called as

A)binary coding
B)source coding
C)bit coding
D)cipher coding

Question 9

When the base of the logarithm is 2, then the unit of measure of information is

A)bits
B)bytes
C)nats
D)none of the mentioned

Question 10

When X and Y are statistically independent, then I (x,y) is

A)1
B)0
C)ln 2
D)cannot be determined

Question 11

The self information of random variable is

A)0
B)1
C)infinite
D)cannot be determined

Question 12

Entropy of a random variable is

A)0
B)1
C)infinite
D)cannot be determined

Question 13

Which is more efficient method?

A)encoding each symbol of a block
B)encoding block of symbols
C)encoding each symbol of a block & encoding block of symbols
D)none of the mentioned

Question 14

Lempel-Ziv algorithm is

A)variable to fixed length algorithm
B)fixed to variable length algorithm
C)fixed to fixed length algorithm
D)variable to variable length algorithm

Question 15

While recovering signal, which gets attenuated more?

A)low frequency component
B)high frequency component
C)low & high frequency component
D)none of the mentioned

Question 16

Mutual information should be

A)positive
B)negative
C)positive & negative
D)none of the mentioned

Question 17

ASCII code is a

A)fixed length code
B)variable length code
C)fixed & variable length code
D)none of the mentioned

Question 18

Which reduces the size of the data?

A)source coding
B)channel coding
C)source & channel coding
D)none of the mentioned

Question 19

In digital image coding which image must be smaller in size?

A)input image
B)output image
C)input & output image
D)none of the mentioned

Question 20

Which coding method uses entropy coding?

A)lossless coding
B)lossy coding
C)lossless & lossy coding
D)none of the mentioned

Question 21

Which achieves greater compression?

A)lossless coding
B)lossy coding
C)lossless & lossy coding
D)none of the mentioned

Question 22

Which are uniquely decodable codes?

A)fixed length codes
B)variable length codes
C)fixed & variable length codes
D)none of the mentioned

Question 23

A rate distortion function is a

A)concave function
B)convex function
C)increasing function
D)none of the mentioned

Question 24

Which of the following algorithms is the best approach for solving Huffman codes?

A)exhaustive search
B)greedy algorithm
C)brute force algorithm
D)divide and conquer algorithm

Question 25

How many printable characters does the ASCII character set consists of?

A)120
B)128
C)100
D)98

Question 26

Which bit is reserved as a parity bit in an ASCII set?

A)first
B)seventh
C)eighth
D)tenth

Question 27

How many bits are needed for standard encoding if the size of the character set is X?

A)log x
B)x+1
C)2x
D)x2

Question 28

The code length does not depend on the frequency of occurrence of characters.

Question 29

From the following given tree, what is the code word for the character 'a'?

A)011
B)010
C)100
D)101

Question 30

From the following given tree, what is the computed codeword for 'c'?

A)111
B)101
C)110
D)011

Question 31

What will be the cost of the code if character ci is at depth di and occurs at frequency fi?

A)cifi
B)?cifi
C)?fidi
D)fidi

Question 32

An optimal code will always be present in a full tree.

Question 33

The type of encoding where no character code is the prefix of another character code is called?

A)optimal encoding
B)prefix encoding
C)frequency encoding
D)trie encoding

Question 34

What is the running time of the Huffman encoding algorithm?

A)o(c)
B)o(log c)
C)o(c log c)
D)o( n log c)

Question 35

What is the running time of the Huffman algorithm, if its implementation of the priority queue is done using linked lists?

A)o(c)
B)o(log c)
C)o(c log c)
D)o(c2)

Question 36

Notch is a_________      

A)high pass filter
B)low pass filter
C)band stop filter
D)band pass filter

Question 37

Sin wave is_________      

A)aperiodic signal
B)periodic signal
C)random signal
D)deterministic signal

Question 38

What is the role of channel in communication system?

A)acts as a medium to send message signals from transmitter to receiver
B)converts one form of signal to other
C)allows mixing of signals
D)helps to extract original signal from incoming signal

Question 39

Sum of a periodic and aperiodic signal always be an aperiodic signal.

Question 40

Noise is added to a signal_________      

A)in the channel
B)at receiving antenna
C)at transmitting antenna
D)during regeneration of information

Question 41

Agreement between communication devices are called_________      

A)transmission medium
B)channel
C)protocol
D)modem

Question 42

What is the advantage of superheterodyning?

A)high selectivity and sensitivity
B)low bandwidth
C)low adjacent channel rejection
D)low fidelity

Question 43

Low frequency noise is_________      

A)flicker noise
B)shot noise
C)thermal noise
D)partition noise

Question 44

Relationship between amplitude and frequency is represented by_________      

A)time-domain plot
B)phase-domain plot
C)frequency-domain plot
D)amplitude-domain plot

Question 45

A function f(x) is even, when?

A)f(x) = -f(x)
B)f(x) = f(-x)
C)f(x) = -f(x)f(-x)
D)f(x) = f(x)f(-x)

Question 46

The minimum nyquist bandwidth needed for baseband transmission of Rs symbols per second is

A)rs
B)2rs
C)rs/2
D)rs2

Question 47

The capacity relationship is given by

A)c = w log2 ( 1+s/n )
B)c = 2w log2 ( 1+s/n )
C)c = w log2 ( 1-s/n )
D)c = w log10 ( 1+s/n )

Question 48

Which parameter is called as Shannon limit?

A)pb/n0
B)eb/n0
C)ebn0
D)none of the mentioned

Question 49

Entropy is the measure of

A)amount of information at the output
B)amount of information that can be transmitted
C)number of error bits from total number of bits
D)none of the mentioned

Question 50

Equivocation is the

A)conditional entropy
B)joint entropy
C)individual entropy
D)none of the mentioned