EEET2465 – Assignment 2
EEET2465 – Communication Engineering 1: Assignment 2
– Assignments should be submitted to Canvas using the eReport Submission link
before 11:59 pm on the Friday of week 8.
– A deduction of 10 marks per day late will apply to late submissions (inclusive of
weekends and public holidays).
– Reports MUST be submitted in either Word format (.doc or .docx) or portable
document format (.pdf). Due to compatibility issues reports in other formats
including (but not limited to) Open Office format (.odt) and Mac OS format (.pages)
will not be accepted!
– You MUST submit your MATLAB script file (.m file) along with your report to Canvas.
MATLAB code that has been screenshot or copied and pasted into a document will
not be accepted!
– The assignment is an individual task and is worth 15% of the overall course grade.
The assignment should be presented as follows:
Page 1: Cover Page (example):
RMIT University
School of Engineering
EEET2465 – Communication Engineering 1
Assignment #2
Lecturer: ………….
Student Name: …….. Student Number: ………
Submission Due Date: …….
Page 2 onwards:
– Answers to the questions with appropriate predictions, calculations, MATLAB graphs
and discussions.
– References: Any sources used to find out more information. I.e. textbooks, journal/
conference papers, websites, etc. must be in IEEE style format.
– Appendix: MATLAB code and other results and calculations.
The assignment will be assessed on the depth of conceptual understanding shown for each
task. It’s important not only to present correct results/graphs/code but also to be able to
analyse and discuss what your results are showing and how they link in with the concepts
behind digital communications.
wflee
Rectangle
Assignment 1: Digital Communications
This assignment is going to examine how to design a quantising system to quantise a signal
and encode that signal using QAM/PSK. You will be required to demonstrate you can design
the parameters required for this encoder system as well as decode the output at the end.
Problem – Part A:
A MATLAB script file and protected function (myQuantiser()) have been provided to
you that contain the base-code for this task. The protected function (myQuantiser())
takes in the following inputs: your original signal and the codebook containing all the
quantised voltage levels in a monotonically increasing array, i.e.:
output = myQuantiser(sig, codebook);
You will need to modify the script to:
1. You have been given the continuous-time signal:
𝑥(𝑡) = 𝐴1 cos (2𝜋𝑓1𝑡 −
𝜋
6
) + 𝐴2cos(2𝜋𝑓2𝑡 +
𝜋
4
)
The following parameters (based on the 6
th
number in your student number) will be used:
Table I: Specifications for your signal and 4-bit quantiser
6
th
Student
Number
A1 A2 f1 f2 Dynamic range
1 0.6 0.4 500 1000 1 V
2 1 0.5 400 1100 1.5 V
3 0.2 0.3 500 1200 0.5 V
4 1.6 0.4 600 900 2 V
5 1.7 0.7 1000 900 2.5 V
6 1.1 0.5 500 1500 1.5 V
7 2 1 1000 1500 3 V
8 2.2 1.5 200 1000 3.5 V
9 1.5 1.1 100 500 2.5 V
0 2 2 300 600 4 V
For example, if your student number was 3210987 your 6
th
number would be 8, so you
would need to use the signal:
𝑥(𝑡) = 2.2 cos (400𝜋𝑡 −
𝜋
6
) + 1.5cos(2000𝜋𝑡 +
𝜋
4
)
wflee
Text Box
2:
Determine the sampling rate of this signal if it’s to be sampled at exactly the Nyquist
rate. Record this value in your documentation. Fill in the value of this in the first
blank part of the MATLAB script.
2. Now design a 4-bit quantiser for this system (initially on paper). The maximum
dynamic range of this quantiser is also in the last column of Table I (maximum
possible amplitude of incoming signal).
Make sure you change the values in the MATLAB script to the parameters you have
designed, these include the number of bits, total number of quantisation levels,
dynamic range of quantiser, voltage spacing between levels and codebook of
quantised levels.
3. Run the code to see it outputs the correct graphs for this design
4. Now repeat this with a sampling rate of twice the Nyquist rate.
Discussion Points:
– Show the mathematical workings of your quantiser design. Explain how you
determined the correct sampling rate and show what output you expect.
– Show the graphs of both the Nyquist rate sampling and 2 x Nyquist rate sampling
and describe the advantages of oversampling.
Problem – Part B:
In this task you’ll be required to explain the modulation process of a 4-QAM modulation
system.
This task does not require a MATLAB script
A 4-QAM modulation scheme with the constellation diagram shown in Figure 1 is used to
encode the binary sequence d(n):
1 0 1 1 0 0 0 1 0 1 1 0
Figure 1: Constellation diagram of 4-QAM modulation scheme
For this sequence, being passed into the system shown in Figure 2, show the following:
Figure 2: A 4-QAM system
1. What would be the output from the 1-bit serial to parallel converter? Show this
in your documentation.
2. Now show and explain with reference to the constellation diagram what the
outputs from the Two (2) digital to analogue converters (DACS) would be
(generating the Im and Qm data).
3. Show how these DAC outputs now modulate the two quadrature carriers and
then combine to produce the 4 different phases given in the constellation
diagram.
Assessment Guide For Communication Engineering 1 Assignments
0-49 Fail
NN
50-59 Pass
PA
60-69 Credit
CR
70-79 Distinction
DI
80-100 High Distinc’n
HD
Results (e.g. MATLAB
figures/output) (30%)
No results presented or
there are fundamental
flaws in the student’s
understanding of the
task and/or MATLAB
code resulting in
meaningless results.
Some results are
correct but many of the
graphs contain errors
resulting from poor
understanding of the
task and/or MATLAB
syntax errors.
Results are mostly
correct.
There may be a couple
of graphs that contain
minor errors and/or
section contains
superfluous or irrelevant
results.
Results presented are
correct.
Minimum required
results presented to
successfully answer
assignment questions.
All results presented in
the report are correct
and well presented.
Student may also have
included extra (relevant)
results to help explain
advanced concepts
relating to the project.
Discussion and
analysis (50%)
No relevant analysis
has been presented in
report.
Student was unable to
make links to theoretical
concepts related to the
topic and may have
included irrelevant facts
to explain results.
Analysis presented in
the report was
superficial and only very
basic links were made
to the theoretical
concepts related to the
topic. Overall student
appears to lack in-depth
understanding.
A reasonable analysis
of the results has been
presented, but it may
lack some depth.
Links have been made
to theoretical concepts
relating to the topic, but
may lack essential
details.
A good analysis of
results has been
presented with only
minor details missing.
Student was able to
make links to theoretical
concepts relating to the
topic to explain results.
Student has presented
an in-depth analysis of
their results and has
made links to advanced
theoretical concepts
relating to the topic to
explain results.
Referencing and
citations (10%)
Poor referencing style
or no references used.
Material may be copied
without citing sources
appropriately.
References were
inappropriate and/or
lacked relevancy (e.g.
Wikipedia or opinion
pieces used).
Citations may be
missing.
References are mostly
appropriate and show
some variation in type.
A good attempt has
been made at using the
IEEE reference format
with only minor errors.
References used are all
appropriate and show
good variation in type.
IEEE referencing format
used correctly with very
few errors.
Has used a wide range
of appropriate
references.
IEEE referencing format
used flawlessly.
Layout (10%) No structure or
structure is highly
disorganised.
Poor use of grammar,
and punctuation. Poor
layout and difficult to
read.
Structure is sufficient to
present the content.
Ideas often presented in
a disorganised manner.
Grammar and spelling
just acceptable.
Content is generally
organised logically with
only some sections
needing more attention.
Few errors in spelling
and grammar, report
easy to navigate.
Structure is sound
throughout and follows
a logical order.
No errors in spelling
and grammar, report
clearly organised.
Outstanding
presentation of material
which supports all
requirements.
Outstanding and
professional use of
language.