13739844
Frage 1
Frage
... is a measure of uncertainty
Antworten
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Encoding
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Entropy
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Information
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Redundancy
Frage 2
Frage
{1,2,3,4,5,6} is the sample space of ...
Antworten
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one coin toss
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one dice roll
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sum of two dice
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removing a card from the standard deck
Frage 3
Frage
A redundancy of a code S = ...
Antworten
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1 - Iavr/Imax
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Iavr/Imax
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1 + Iavr/Imax
-
Imax/Iavr
Frage 4
Frage
An average length of codewords qavr = ...
Antworten
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∑ (pi * qi)
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∑ (pi / qi)
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∑ pi
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∑ qi
Frage 5
Frage
An efficiency of a code E = ...
Antworten
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Iavr/Imax
-
Imax/Iavr
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Iavr/100
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Imax - Iavr
Frage 6
Frage
ASCII code is a
Antworten
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Variable length code
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Fixed length code
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Error-correction code
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None of the given
Frage 7
Frage
By the Bayes' rule for conditional entropy H(Y|X) \= ...
Antworten
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H(X|Y) - H(X) + H(Y)
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[P(B|A)][P(A)] /P(B)
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H(X|Y) - H(X)
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H(X|Y)+ H(Y)
Frage 8
Frage
By the Bayes' theorem ...
Antworten
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P(B|A) = P(A and B)/P(A)
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P(A|B) = [P(B|A)][P(A)] /P(B)
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P(B|A) = P(A and B)*P(A)
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P(A|B) = [P(B|A)][P(A)] * P(B)
Frage 9
Frage
21. By the Chain rule H(X,Y) \= H(Y|X) + ...
Antworten
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H(X)
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H(Y)
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H(Y|X)
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H(X|Y)
Frage 10
Frage
By the Hartley's formula the amount of information I = ...
Antworten
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I = n*log m
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I = m*n
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I = log (m/n)
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I = log (m*n)
Frage 11
Frage
By the Hartley's formula the entropy H = ...
Antworten
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H \= - ∑(pi * log pi)
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H \= - ∑ (log pi)
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H \= log m
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H \= - ∑ (pi / log pi)
Frage 12
Frage
By the property of joint entropy H(X,Y) <= ...
Antworten
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H(X)
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H(Y)
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H(X) + H(Y)
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None of the given
Frage 13
Frage
By the property of joint entropy H(X,Y) ...
Antworten
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H(X,Y) >= H(X) and H(X,Y) <= H(Y)
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H(X,Y) <= H(X) and H(X,Y) >= H(Y)
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H(X,Y) >= H(X) and H(X,Y) >= H(Y)
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H(X,Y) >= H(X) + H(Y)
Frage 14
Frage
By the Shannon's formula the amount of information I = ...
Antworten
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H \= - n * ∑( pi * log pi)
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H \= - n * ∑ (log pi)
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H \= - n * ∑ pi
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H \= - n * ∑ (pi / log pi)
Frage 15
Frage
By the Shannon's formula the entropy H = ...
Antworten
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H \= - ∑( pi * log pi)
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H \= - ∑ (log pi)
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H \= - ∑ pi
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H \= - ∑ (pi / log pi)
Frage 16
Frage
Calculate the code rate for Hamming (15,11) code
Antworten
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1
-
0,733
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0,571
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0,839
Frage 17
Frage
Calculate the code rate for Hamming (31,26) code
Antworten
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1
-
0,839
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0,733
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0,571
Frage 18
Frage
Choose the formula to determine the number N of possible messages with length n if the message source alphabet consists of m characters, each of which can be an element of the message
Antworten
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N = mn
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N = nm
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N = m*n
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N = log m
Frage 19
Frage
Code is optimal when ...
Antworten
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qavr = H
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qavr ≠H
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qavr <H
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qavr >H
Frage 20
Frage
Code rate R (k information bits and n total bits) is defined as
Antworten
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k = n/R
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R = k * n
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n = R * k
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R = k/n
Frage 21
Frage
Conditional entropy H(Y|X) lies between
Antworten
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- H(Y) and 0
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0 and H(Y)
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- H(Y) and H(Y)
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0 and 1
Frage 22
Frage
Conditional probability P(B|A) = ...
Antworten
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P(A and B)/P(A)
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[P(B|A)][P(A)] /P(B)
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P(A and B)*P(A)
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[P(B|A)][P(A)] * P(B)
Frage 23
Frage
Find the information amount of a symbol from the language with total number of symbols n = 18.
Antworten
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I = log218
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I = log182
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I = 18 * log218
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I = 18 * log182
Frage 24
Frage
For a Hamming (15, 11) code, 15 is the total number of bits and 11 is the number of ...
Antworten
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redundant bits
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data bits
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parity bits
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none of the given
Frage 25
Frage
Which of the following symbols will get the shortest codeword after Shannon-Fano coding if probabilities are p(a) = 0.05, p(b) = 0.6, p(c) = 0.2 and p(d) = 0.15?
Antworten
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c
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a
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d
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b
Frage 26
Frage
Which of the following is not a correct statement about a probability.
Antworten
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It must have a value between 0 and 1
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It is the collection of several experiments
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A value near 0 means that the event is not likely to occur/happens
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It can be reported as a decimal or a fraction
Frage 27
Frage
Which of the following is a part the channel coding?
Antworten
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Huffman code
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Hamming code
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Shannon-Fano code
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RLE code
Frage 28
Frage
For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...
Antworten
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redundant bits
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data bits
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parity bits
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none of the given
Frage 29
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For Hamming distance d<sub>min</sub> and s errors in the received word, the condition to be able to correct the errors is
Antworten
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dmin>= s+1
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dmin>= 2s+1
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dmin>= 2s+2
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dmin>= s+2
Frage 30
Frage
Hamming distance can easily be found with ...
Antworten
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XNOR operation
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XOR operation
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OR operation
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AND operation
Frage 31
Frage
In a throw of coin what is the probability of getting head.
Antworten
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1
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1/2
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2
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0
Frage 32
Frage
Specify the formula to calculate numbers of k and n bits to create the Hamming code
Antworten
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(n, k) = (2r - 1, 2r - 1 - r)
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(n, k) = (2r, 2r - 1 - r)
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(n, k) = (2r - 1, 2r - r)
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(n, k) = (2r - 1, 2r - 1 + r)
Frage 33
Frage
In a throw of coin what is the probability of getting tails.
Antworten
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1
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1/2
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2
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0
Frage 34
Frage
Specify the formula to find the amount of information if events have different probabilities.
Antworten
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Hartley's formula
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Shannon's formula
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Fano's formula
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Bayes' formula
Frage 35
Frage
Specify the formula to find the amount of information if events have the same probabilities.
Antworten
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Shannon's formula
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Hartley's formula
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Fano's formula
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Bayes' formula
Frage 36
Frage
Specify the most effective type of code when an alphabet consists of 2 symbols with probabilities p(x1) = 0,05 and p(x2) = 0,95.
Antworten
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ASCII code
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Shannon-Fano's code
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Shannon-Fano's code by blocks
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Hartley's code
Frage 37
Frage
In digital communication system, smaller the code rate, ... are the redundant bits.
Antworten
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a. less
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b. equal
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c. more
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d. unpredictable
Frage 38
Frage
Specify the right formula if dmin is Hamming distance, s - number of correctable errors and r - number of detectable errors.
Antworten
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dmin>= s+r+1
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dmin>= 2s+r+1
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dmin>= s+2r+1
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dmin>= s+r+2
Frage 39
Frage
Specify two types of error control algorithms
Antworten
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block and linear
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linear and nonlinear
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block and convolution
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none of the given
Frage 40
Frage
Noise affects ...
Antworten
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information source
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receiver
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channel
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transmitter
Frage 41
Frage
The basic idea behind Shannon-Fano coding is to
Antworten
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compress data by using more bits to encode more frequently occuring characters
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compress data by using fewer bits to encode more frequently occuring characters
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compress data by using fewer bits to encode fewer frequently occuring characters
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expand data by using fewer bits to encode more frequently occuring characters
Frage 42
Frage
Probability of occurrence of an event lies between
Antworten
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-1 and 0
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0 and 1
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-1 and 1
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exactly 1
Frage 43
Frage
The Hamming distance between "client" and "server" is
Antworten
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0
-
1
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6
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impossible to detect
Frage 44
Frage
The Hamming distance between "make" and "made" is
Antworten
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4
-
3
-
1
-
impossible to detect
Frage 45
Frage
The Hamming distance between "push" and "pull" is
Antworten
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0
-
4
-
2
-
impossible to detect
Frage 46
Frage
Probability of second event in situation if first event has been occurred is classified as
Antworten
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conditional probability
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joint entropy
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conditional entropy
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none of the given
Frage 47
Frage
The Hamming distance between "starting" and "finishing" is
Antworten
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4
-
3
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impossible to detect
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5
Frage 48
Frage
The Hamming distance between 001111 and 010011 is
Antworten
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1
-
2
-
3
-
4
Frage 49
Frage
Shannon-Fano and Huffman codes are an encoding algorithms used for
Antworten
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lossy data compression
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lossless data compression
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error correction
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error detection
Frage 50
Frage
The Hamming distance between 010111 and 010011 is
Antworten
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2
-
3
-
1
-
4
Frage 51
Frage
The Hamming distance between 011111 and 010011 is
Antworten
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1
-
3
-
2
-
4
Frage 52
Frage
Specify parts of the receiver side
Antworten
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Source encoder, channel encoder, digital modulator
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Source decoder, channel decoder, digital demodulator
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Source decoder, channel encoder, digital modulator
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Source encoder, channel decoder, digital modulator
Frage 53
Frage
The Hamming distance between 101001 and 010011 is
Antworten
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1
-
2
-
4
-
3
Frage 54
Frage
The Hamming distance between two strings with equal length is ...
Antworten
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the number of positions at which the corresponding symbols are different
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the number of positions at which the corresponding symbols are equal
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the number of identical symbols in the first string
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the number of identical symbols in the second string
Frage 55
Frage
Specify parts of the transmitter side
Antworten
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Source decoder, channel decoder, digital demodulator
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Source encoder, channel encoder, digital modulator
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Source decoder, channel encoder, digital modulator
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Source encoder, channel decoder, digital modulator
Frage 56
Frage
The number of digits by which any two binary sequences differ is called the ...
Antworten
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Hamming weight
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Hamming distance
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Hamming code
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Hamming length
Frage 57
Frage
Specify the case when entropy is maximum
Antworten
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p1=0,5 and p2=0,5
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p1=1 and p2=0
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p1=0 and p2=1
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p1=0,9 and p2=0,1
Frage 58
Frage
The prefix code is also known as ...
Antworten
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block code
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uniquely decodable code
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convolutional code
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parity bit
Frage 59
Frage
In a throw of dice what is the probability of getting number greater than 5.
Antworten
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a. 1/3
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b. 1/6
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c. 1/5
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d. 1
Frage 60
Frage
The string was encoded with Hamming (15,11) code using the transformation matrix. Specify numbers of positions of the parity bits.
Antworten
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12,13,14,15
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1,2,3,4
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1,2,4,8
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2,3,4,5
Frage 61
Frage
78. For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...
Antworten
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a. redundant bits
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b. data bits
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c. parity bits
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d. none of the given
Frage 62
Frage
The string was encoded with Hamming (31,26) code using the transformation matrix. Specify numbers of positions of the parity bits.
Antworten
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27,28,29,30,31
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1,2,3,4,5
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1,2,4,8,16
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2,3,4,5,6
Frage 63
Frage
79. For a Hamming (7, 4) code, 7 is the total number of bits and 4 is the number of ...
Antworten
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a. redundant bits
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b. data bits
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c. parity bits
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d. none of the given
Frage 64
Frage
When data is compressed, the goal is to reduce
Antworten
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noise
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redundancy
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channel capacity
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none of the given
Frage 65
Frage
When the base of the logarithm is 10, then the unit of measure of information is
Antworten
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bytes
-
dits
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nits
-
bits
Frage 66
Frage
43. Code has dmin = 3. How many errors can be detected by this code?
Antworten
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1
-
3
-
2
-
4
Frage 67
Frage
When the base of the logarithm is 2, then the unit of measure of information is
Antworten
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bytes
-
bits
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nits
-
dits
Frage 68
Frage
When the base of the logarithm is e, then the unit of measure of information is
Antworten
-
bytes
-
nits
-
dits
-
bits
Frage 69
Frage
Which block or device does the data compression?
Antworten
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Channel encoder
-
Source encoder
-
Modulator
-
None of the given
Frage 70
Frage
Which letter will get the shortest codeword after Huffman coding of the word "abracadabra"?
Antworten
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c
-
r
-
d
-
a
Frage 71
Frage
Which of the following codes has the highest code rate?
Antworten
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code rate is constant for all of the Hamming codes
-
Hamming (31,26)
-
Hamming (15,11)
-
Hamming (7,4)
Frage 72
Frage
Which of the following codes has the highest redundancy?
Antworten
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redundancy is constant for all of the Hamming codes
-
Hamming (7,4)
-
Hamming (15,11)
-
Hamming (31,26)
Frage 73
Frage
Which of the following codes is non-uniform?
Antworten
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Shannon-Fano
-
ASCII
-
Hamming
-
None of the given
Frage 74
Frage
Which of the following codes is prefix?
Antworten
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0, 111, 11
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0, 111, 10
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0, 101, 10
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00, 10, 101
Frage 75
Frage
Which of the following codes is prefix?
Antworten
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0, 01, 11
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0, 10, 11
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0, 10, 1
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0, 01, 001
Frage 76
Frage
Which of the following codes is uniform?
Antworten
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ASCII
-
Shannon-Fano
-
Huffman
-
None of the given
Frage 77
Frage
Which of the following codes is uniform?
Antworten
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10,011,11,001,010
-
0,10,110,1110,1111
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10,01,0001,100,1010
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100,110,001,000,010
Frage 78
Frage
Which of the following indicate(s) an error in a received combination?
Antworten
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Parity bits
-
Error syndrome
-
Data bits
-
None of the given
Frage 79
Frage
The string was encoded with Hamming (7,4) code using the transformation matrix. Specify numbers of positions of the parity bits.
Antworten
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a. 5,6,7
-
a. 1,2,3
-
a. 1,2,4
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a. 2,3,4
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