Trellis Coded Modulation

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Trellis coded modulation uses
Non binary method
Uses redundant bits
No expansion of bandwidth
All of the mentioned
Explanation:
Trellis coded modulation is a achieves error performance improvements without expansion of bandwidth. It uses redundant non binary modulation in combination with finite state machines.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Adding improvement to the signal subset choice by starting with the densest possible lattice for the space is called as
Optimum signal constellation boundaries
Higher density lattice structures
Trellis coded modulation
None of the mentioned
Explanation:
Higher density lattice structures are formed by adding improvement to the signal subset choice by starting with the densest possible lattice for the space.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
In TCM channel capacity can be increased.
True
False
Explanation:
In trellis coded modulation increase in channel capacity is achieved by signal set expansion.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
In TCM the signals are decoded using
Soft decision decoders
Hard decision decoders
Soft & Hard decision decoders
None of the mentioned
Explanation:
In trellis coded modulation the noisy received signals are decoded using soft decision decoders.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which determines the error performance in TCM?
Reduced distance
Free distance
Bandwidth
None of the mentioned
Explanation:
Free distance which is the minimum distance between members of set of allowed code sequences determines the error performance.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
In finite state machines, output is predicted using
Past output
Present input
Past output & Present input
None of the mentioned
Explanation:
In finite state machines, the set of possible future outputs are predicted using present input and past output.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The TCM decoder uses
Minimum likelihood detector
Maximum likelihood detector
Does not use redundant bits
None of the mentioned
Explanation:
The task of convolutional decoder is to estimate the path that the message had traversed through the encoding trellis using maximum likelihood detector.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Choosing a closely packed signal subset from any regular lattice or array of candidate points is called as
Optimum signal constellation boundaries
Higher density lattice structures
Trellis coded modulation
None of the mentioned
Explanation:
Optimum signal constellation boundaries are obtained by choosing closely packed signal subset from any regular lattice or array of candidate points.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Trellis coded modulation scheme
Has memory
Is memory-less
Needs more bandwidth
None of the mentioned
Explanation:
Trellis coded modulation scheme has memory ( a finite state machine) such as the convolutional code.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Transmission bandwidth depends on
Rate of signalling
Density of signal points
Reduced distance
None of the mentioned
Explanation:
Transmission bandwidth of non orthogonal signalling depends on rate of signalling and not on density of signal points in the constellation.