Digital Communications

Structured Sequence

Question 1
Marks : +2 | -2
Pass Ratio : 100%
In a real time communication system addition of redundant bits leads to
More bandwidth requirement
Faster rate of transmission
More bandwidth requirement & Faster rate of transmission
None of the mentioned
Explanation:
In a real time communication system the addition of redundant bits dictates a faster transmission rate and which means more bandwidth.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The probability of message error is written as
Block error
Word error
Block & Word error
None of the mentioned
Explanation:
We can write the probability of message error also called as block error or word error.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
In Gaussian channel demodulator ______ decision is made.
Hard
Soft
Hard & Soft
None of the mentioned
Explanation:
In Gaussian channel demodulator consists of continuous alphabet or quantized approximation thus soft decision is made.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
In binary symmetric channel, in the demodulator _____ decision is made.
Hard
Soft
Hard & Soft
None of the mentioned
Explanation:
In binary symmetric channel the demodulator consists of only two discrete elements. Thus it makes hard or firm decision.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Structured sequences are
Block codes
Convolutional codes
Turbo codes
All of the mentioned
Explanation:
Structured sequences are those which add structured redundancy to the source code. Examples are turbo codes, block codes, and convolutional codes.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
If the parity bit takes value one then the summation of code-word gives
Even result
Odd result
Even & Odd result
None of the mentioned
Explanation:
The parity bit takes on the value of one or zero to ensure that the summation of all the bits in the code-word yields even or odd result.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The summation operation is performed using _____ logical operation.
EX-OR
AND
OR
EX-NOR
Explanation:
The summation operation is performed using modulo 2 arithmetic or exclusive OR operation.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Which decoders are less complex?
Soft decision decoder
Hard decision decoder
Hard & Soft decision decoder
None of the mentioned
Explanation:
The design of a soft decision decoder is more complex than the design of hard decision decoder.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
The ratio of redundant bits to data bits is called as
Code rate
Redundancy rate
Symbol rate
Transmission rate
Explanation:
The ratio of redundant bits to data bits is called as redundancy of the code and the ratio of data bits to total bits is called as code rate.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Coding gain is defined as
Reduction in Eb/N0
Increase in Eb/N0
Same as Eb/N0
None of the mentioned
Explanation:
For a given bit error probability coding gain can be defined as reduction in Eb/N0 that can be realized through the use of code.