Convolution Encoding and Decoding

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Example for convolution encoder state diagram is
Tree diagram
Trellis diagram
Tree & Trellis diagram
None of the mentioned
Explanation:
Tree diagram and trellis diagram are both examples for convolution encoding state diagram.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The method used for representing convolution encoder are
Connection pictorial
State diagram
Tree diagram
All of the mentioned
Explanation:
Several methods are used for representing convolution encoder such as connection pictorial, connection vector or polynomials, state diagram, tree diagram and trellis diagram.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
How many number of transitions can be made at each bit time?
One
Two
Three
Half
Explanation:
An a consequence of shifting-in-one bit at a time there are only two possible transitions that the register can make at each bit time.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
The measure of the amount of redundancy is given by
Code size
Code weight
Code rate
Minimum distance
Explanation:
The rate of the code gives the measure of the amount of redundancy. The rate is given by the ratio of number of data bits that form an input to a block encoder to the total number of bits.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Finite state machines have
Past memories also
Only present and future memories
Only future memories
Only present memories
Explanation:
A convolution encoder belongs to a class of device called as finite state machines which are those machines that have a memory of past signals.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
In trellis diagram, the number of nodes ______ at successive branching.
Increases by 1
Doubles
Triples
None of the mentioned
Explanation:
As per the algorithm, in the trellis diagram at successive branching the number of nodes doubles.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The number of k bit shift over which a single information bit influences the encoder output is given by
Code rate
Constraint length
Code length
Code weight
Explanation:
The constraint length represents the number of k bit shifts over which a single information bit influences the encoder output.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
In maximum likelihood detector the error probability is
Maximum
Minimum
Zero
None of the mentioned
Explanation:
The maximum likelihood detector is an optimal detector which minimizes the error probability.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Periodic truncation is done by
Appending zero to end of the input data sequence
Appending zero to the beginning of the input data sequence
Appending one’s to end of the data sequence
Appending one’s to beginning of the data sequence
Explanation:
Convolution code are forced into a block structure by periodic truncation which is done by appending zero to the end of the input data sequence, for the purpose of clearing or flushing the encoding shift register of the data bits.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
In maximum likelihood decoding technique, the likelihood function compares the
Joint probabilities
Individual probabilities
Conditional probabilities
None of the mentioned
Explanation:
If all input messages are equally likely a decoder that achieves the minimum probability of error is that which compares the conditional probabilities also called the likelihood function.