Random / Numericals

Question 1

The information rate R for given average information H= 2.0 for analog signal band limited to B Hz is

a. 8 B bits/sec
b. 4 B bits/sec
c. 2 B bits/sec
d. 16 B bits/sec

Answer 1

4 B bits/sec

Question 2

The memory less source refers to

a. No previous information
b. No message storage
c. Emitted message is independent of previous message
d. None of the above

Answer 2

Emitted message is independent of previous message

Question 3

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 3

I(X;Y) = H(X) – H(X/Y)

Question 4

The information I contained in a message with probability of occurrence is given by (k is constant)

a. I = k log21/P
b. I = k log2P
c. I = k log21/2P
d. I = k log21/P2

Answer 4

I = k log21/P

Question 5

Alternate Mark Inversion (AMI) is also known as

a. Pseudo ternary coding
b. Manchester coding
c. Polar NRZ format
d. None of the above

Answer 5

Pseudo ternary coding

Question 6

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

Answer 6

Information bits

Question 7

The capacity of Gaussian channel is

a. C = 2B(1+S/N) bits/s
b. C = B2(1+S/N) bits/s
c. C = B(1+S/N) bits/s
d. C = B(1+S/N)2 bits/s

Answer 7

(c) C = B(1+S/N) bits/s

Question 8

For M equally likely messages, the average amount of information H is

a. H = log10M
b. H = log2M
c. H = log10M2
d. H = 2log10M

Answer 8

H = log2M

Question 9

The attenuation level in bounded power spectral density is

a) 35
b) 50
c) 35 & 50
d) none of the mentioned

Answer 9

35 & 50

Question 10

Granular noise occurs when

a. Step size is too small
b. Step size is too large
c. There is interference from the adjacent channel
d. Bandwidth is too large

Answer 10

Step size is too large

Question 11

The crest factor of a waveform is given as –

a. 2Peak value/ rms value
b. rms value / Peak value
c. Peak value/ rms value
d. Peak value/ 2rms value

Answer 11

Peak value/ rms value

Question 12

The number of voice channels that can be accommodated for transmission in T1 carrier system is

a. 24
b. 32
c. 56
d. 64

Answer 12

24

Question 13

The maximum data transmission rate in T1 carrier system is

a. 2.6 megabits per second
b. 1000 megabits per second
c. 1.544 megabits per second
d. 5.6 megabits per second

Answer 13

1.544 megabits per second

Question 14

For a binary symmetric channel, the random bits are given as

a. Logic 1 given by probability P and logic 0 by (1-P)
b. Logic 1 given by probability 1-P and logic 0 by P
c. Logic 1 given by probability P2 and logic 0 by 1-P
d. Logic 1 given by probability P and logic 0 by (1-P)2

Answer 14

(a) Logic 1 given by probability P and logic 0 by (1-P)

Question 15

Code rate r, k information bits and n as total bits, is defined as

a. r = k/n
b. k = n/r
c. r = k * n
d. n = r * k

Answer 15

r = k/n

Question 16

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

Answer 16

B ≤ tl

Question 17

The minimum distance for unextended Golay code is

a. 8
b. 9
c. 7
d. 6

Answer 17

7

Question 18

The Golay code (23,12) is a codeword of length 23 which may correct

a. 2 errors
b. 3 errors
c. 5 errors
d. 8 errors

Answer 18

3 errors

Question 19

The Golay code (23,12) is a codeword of length 23 which may correct

a. 2 errors
b. 3 errors
c. 5 errors
d. 8 errors

Answer 19

3 errors