EGB342-Telecommunications and Signal Processing
Assignment 2A (20%)
Released: Friday, 30th August
Due: Sunday 22nd September, 11:59pm (Week 9)
Individual Assignment
Your previous FM radio design has been a great success, servicing the needs of the entire island.
Natalie was very pleased. Fraser island residents have additionally identified the need to be
able to communicate this important emergency information back to the mainland. A cable
was laid along the sea floor, providing a means for this communication to occur. After this
cable was laid a number of engineers performed final tests on the communications channel, and
found out that the assumption of an ideal channel is not true. Signals received at both ends are
attenuated and noisy. It is important that you implement appropriate receivers to overcome
this noise, so that vital information can be communicated to and from the mainland.
Figure 1: Cable Landing at Tuman Bay, Philippines. [Ref: www.wired.com]
The aim of this task is to gain an understanding of baseband modulation and matched filters
in digital communication. In particular, the detection of transmitted symbols at the receiver,
and the process of transmitter-receiver synchronisation. This consists of two parts. In Part 1,
you will modulate a given message using baseband signalling, to be transmitted to mainland.
You will implement and demonstrate the operation of matched filtering for symbol detection.
In Part 2, you will use a matched filter to synchronise the signal and detect a message with an
unknown synchronisation offset.
This is an individual task. All students must submit individual and original work. De-
tailed instructions on report format and submission guidelines are provided at the end of this
document. All solutions must be implemented in MATLAB unless instructed otherwise.
*Reminder* Read the entire document before attempting the questions
1
Work-space Preparation
Download the following files to be used in Assignment 2A from Blackboard and place them
into one working directory.
1. Matlab script EGB342 A2A Template.m
2. Matlab script GenerateAssignment2AData.m
3. Matlab protected script DataGen.p
Open GenerateAssignment2AData.m with MATLAB and read its instructions. Insert your
student number into the script and generate your signals for this assignment. [Note: Keep
EbN0 = 7 dB for now. You will change this in value in Part 2.7.]. The generated data will
be stored inside the file ‘A2AData.mat’. Contents of the A2AData.mat file will not be required
until Part 2.
Part 1 – Testing the performance of the cable
The aim in Part 1 of the assignment is to gain an understanding into the baseband modulation
and the use of matched filters to detect symbols in the presence of noise. The signal parameters
have been selected based on the data rate and the power requirements for the transmission.
Binary antipodal signalling will be used to transmit data. The following equation describes the
signal shape that has been selected for the initial testing of the cable.
S1(t) =
{
A(1− |t|/t0) V, |t| < t0
0 otherwise
(1)
where t0 = 500 ns and A = 2.5. Assume that the waveform S1(t) represents the binary digit
‘1’ and that binary digit ‘0’ is represented by waveform S0(t) = −S1(t).
1. Derive and plot the magnitude spectrum of the above pulse shape. (Hint: Use the
convolutional property of the Fourier Transform of a rectangular function to find the
magnitude spectrum of the above pulse.)
2. Calculate the average energy of the modulation schemes that utilises this pulse shape.
3. Draw a diagram to show the transmitted waveform for input bit sequence, [0, 1, 1, 0].
4. Create the signal waveforms S1 = S1(t) and S0 = S0(t), representing digit ‘1’ and digit
‘0’ respectively. Use 100 data points (NumPts) for each symbol, and plot these signals.
Both axes must have appropriate units and must be clearly labelled.
1.5 Find the average energy of the modulation scheme using the S1 and S0 generated above
and compare with the theoretical value calculated in Part 1.2. Comment on the observa-
tions.
1.6 Write a MATLAB code to modulate your name and ID number (e.g. ‘First Name Middle
Name Surname 1234567’) to be transmitted to the mainland using the above modulation
scheme. Consider this as your initial test message. Use the 7-bit ASCII table given at
the end of this document to convert text to binary data. [useful MATLAB functions:
double, de2bi, reshape.]
2
1.7 Plot the spectrum of the baseband modulated signal generated in Part 1.6, and find
the null-to-null bandwidth required to transmit the emergency text messages. Compare
this spectrum with the theoretical spectrum calculated in Part 1.1 and comment on the
observations. Comment of the bandwidth required to transmit speech signals (digital).
1.8 The given message signal need to be transmitted to two separate locations on mainland.
Location A and B are 15 km and 25 km away from the Fraser Island transmission station.
Cable loss is 4 dB/km. Assuming single sided noise power spectral density to be N0 =
10−13 W/Hz, calculate signal-to-noise ratio (SNR) at the destinations. SNR can be
calculated using the following expression -
SNRdB =
(
Eb
N0
)
dB
+ 10 log10(2)− 10 log10(NumPts) (2)
where Eb
N0
is the energy-per-bit to noise-density ratio, and NumPts is the number of
samples per symbol.
1.9 Generate and plot these noisy signals received at locations A and B and comment on
your results. Note that if the total cable loss is L, the signal power at the receiver can be
calculated using -
PRx =
PTx
L
or PRx(dBW ) = PTx(dBW )− L(dB)
where PTx and PRx are transmitted and received power respectively.
1.10 Illustrate and describe the block diagram for the detection of antipodal binary data us-
ing the matched filter implementation. Your diagram can be hand drawn, or computer
generated. How can the transmitted symbol be determined based on the matched filter
output? Why is it important to know the starting location of the first symbol?
This diagram must be done by you, and not cut-and-pasted.
1.11 Create and plot the impulse response hopt(t) of the optimum receiver filter matched to
detect symbol S1. Describe how you can detect both S1 and S0 using the single matched
filter matched to S1.
1.12 Filter the clean and noisy messages generated in Part 1.4 using the filter() command
and the impulse response of the matched filter, hopt(t), to find the filtered signals.
1.13 Plot and compare the three filtered messages. Comment on the similarities and differences
of the matched filter output for the clean and noisy input signals.
1.14 Decode the output and display the received text messages. Estimate the number of bit
errors and the bit-error probability in each case. Comment on the output for the clean
and noisy received signals. [Useful MATLAB functions: char, bi2de, reshape.]
1.15 Compare the bandwidth of the given pulse shape with that of standard pulse shapes
(Rectangular, Nyquist, Raised Cosine) and comment on the observations. [Hint: Refer
to Nyquist criterion for zero inter symbol interference.]
3
Part 2 – Decoding emergency messages at the receiver
You are now ready to tackle the main task. You are required to detect a message, based on a
noisy received signal which is provided to you.
Upon receiving a signal, the receiver does not know where the transmitted symbol sequence
begins, thus a preamble is inserted prior to the symbol sequence. The preamble can be regarded
as a specific long symbol of shape and duration known to both the transmitter and receiver.
Once the receiver detects this preamble, it then knows that the unknown transmitted sequence
will follow.
An optimum receiver filter, matched to the known preamble, can be used to detect the
preamble in a similar manner to detecting the particular symbol that follows the preamble.
Each student has been given a different preamble based on their student number. The preamble
and its corresponding time vector are stored in variables preamble and t preamble respectively.
Variables called ‘rx’ and ‘t signal’ would also be loaded into your workspace upon loading
A2AData.mat. These are the noise-corrupted message and its corresponding time domain vec-
tor, respectively.
Check that you still have these in your workspace, and reload A2AData.mat if necessary.
A 7-bit ASCII character is represented in binary, using the bit symbols S1 and S0. The
symbol definitions are the same as in Part 1. The transmitted ASCII can be any of the 94
printable characters. A preamble has been inserted prior to the 7 bits for synchronisation. The
data has gone through an Additive White Gaussian Noise (AWGN) channel with a random
delay.
The received signal has the following structure, and is corrupted by noise:
Random Delay
Preamble
(1000)
7-bit symbols
(variable length)
Trailing Space
(variable length)
2.1 Find the impulse response hpre(t) of the optimum receiver filter to detect your preamble.
Plot your preamble and hpre(t).
2.2 Identify, and state, the start of the message symbol stream using the matched filter for the
preamble hpre(t). Remove the preamble and random delay from the start of the received
signal to leave only the message. These tasks are to be performed using MATLAB. Plot
the signal representing the noisy message sequence.
2.3 Design the impulse response(s) needed for the matched filter. Filter the received signal
rx using the filter() command. Plot the output.
4
2.4 Implement a function (MF receiver) for the matched filter receiver. The function header
is to conform to the following syntax.
[recovered data] = MF receiver(noisy message, NumPts, h opt)
The (MF receiver) function should perform the following operations.
(a) Pass the noisy received signal through the matched filter and record the output.
(b) Sample the output of the matched filter every symbol period. Keep in mind that
each symbol is NumPts data points long.
(c) Determine the sequence of binary ‘1’ and binary ‘0’ (recovered data) estimated
from the sampled matched filter output.
2.5 Pass the received signal, rx, through the MF receiver and decode the output and display
the text message.
2.6 Can you decode the message correctly? This message was created assuming an Eb/N0 of 7
dB. Describe two methods that you can employ to reduce the bit errors at the destination.
2.7 Record the received messages when the Eb/N0 = 0 dB and Eb/N0 = 10 dB respectively and
comment on the observations. You can do this by running the GenerateAssignmen2AData.m
file with different EbN0 [Change the Eb/N0 value on line 25] values and generating a new
A2AData.mat file for each Eb/N0.
Important: Answers to all the questions should be clearly recorded in the report. If you
submit only a MATLAB code without a report you will get a fail grade.
5
ASCII Table
010 0000
32 space
010 0001
33 !
010 0010
34 ”
010 0011
35 #
010 0100
36 $
010 0101
37 %
010 0110
38 &
010 0111
39 ’
010 1000
40 (
010 1001
41 )
010 1010
42 *
010 1011
43 +
010 1100
44 ,
010 1101
45 -
010 1110
46 .
010 1111
47 /
011 0000
48 0
011 0001
49 1
011 0010
50 2
011 0011
51 3
011 0100
52 4
011 0101
53 5
011 0110
54 6
011 0111
55 7
011 1000
56 8
011 1001
57 9
011 1010
58 :
011 1011
59 ;
011 1100
60 ¡
011 1101
61 =
011 1110
62 ¿
011 1111
63 ?
100 0000
64 @
100 0001
65 A
100 0010
66 B
100 0011
67 C
100 0100
68 D
100 0101
69 E
100 0110
70 F
100 0111
71 G
100 1000
72 H
100 1001
73 I
100 1010
74 J
100 1011
75 K
100 1100
76 L
100 1101
77 M
100 1110
78 N
100 1111
79 O
101 0000
80 P
101 0001
81 Q
101 0010
82 R
101 0011
83 S
101 0100
84 T
101 0101
85 U
101 0110
86 V
101 0111
87 W
101 1000
88 X
101 1001
89 Y
101 1010
90 Z
101 1011
91 [
101 1100
92 \
101 1101
93 ]
101 1110
94 ˆ
101 1111
95
110 0000
96 ‘
110 0001
97 a
110 0010
98 b
110 0011
99 c
110 0100
100 d
110 0101
101 e
110 0110
102 f
110 0111
103 g
110 1000
104 h
110 1001
105 i
110 1010
106 j
110 1011
107 k
110 1100
108 l
110 1101
109 m
110 1110
110 n
110 1111
111 o
111 0000
112 p
111 0001
113 q
111 0010
114 r
111 0011
115 s
111 0100
116 t
111 0101
117 u
111 0110
118 v
111 0111
119 w
111 1000
120 x
111 1001
121 y
111 1010
122 z
111 1011
123 {
111 1100
124 —
111 1101
125 }
111 1110
126 ˜
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Reflection (Mandatory)
A reflection is to be written and appended to the end of your report. Include a short discussion
(150 to 200 words) that addresses problems encountered, and things that you would have done
differently. Identify what concepts this assignment has reinforced, and areas where you can
improve. This section is mandatory and the assignment is regarded as incomplete if absent.
Academic Integrity Declaration (Mandatory)
Each student must complete the ‘Academic Integrity Declaration’ online form using the pro-
vided link on Blackboard. Marks will be withheld if this is not completed, or if the
declaration is not agreed to.
Interview (Mandatory if requested)
Interviews will take place (at the discretion of the teaching team) to assess the conceptual
understanding. This will be a casual discussion. These interviews are compulsory and grades
are withheld until they are completed. Marks may be deducted for poor demonstration of
content/assignment knowledge. These interviews will only be for selected individuals, and you
will be notified if you need to take part in an interview.
Presentation Standards
This assignment includes elements of written and coding assessment. You are expected to work
individually. Each student is expected to generate and submit one assignment report and one
set of MATLAB code. Marks are based on how easily and effectively ideas are articulated to
the reader.
The teaching team has put together some things to consider -
The Report Component
An outstanding report demonstrates knowledge and understanding of the subject area. It
communicates ideas clearly and logically with a combination of visual, mathematical and code
assets. It demonstrates insight about the underlying concepts and their implications within
telecommunications and signal analysis. Verbose responses, or correct information not articu-
lated clearly, will attract deductions.
Remember that you are writing to inform.
Mathematical working shows a logical procedure (or justification) for the final solutions i.e. All
non-trivial steps are included. It can be typed or handwritten but must be legible and easily
followed.
Code snippets used in-text should only contain relevant lines of code and should rarely have
more than five lines in a snippet.
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Present the report so that it can be understood without reference to the assignment brief. Any
figures or code referenced within the code should be no more than one page turn away. Avoid
the use of “see appendix” and “refer to .m file”. Document flow and coherence is to be priori-
tised. Reports that are difficult to navigate are marked poorly in this criteria.
Write the report assuming that the reader only knows concepts from 1st year
engineering and does not have access to your .m file/s.
Include a title page that states the unit name, unit code, assignment number, your name and
student number. Do not include a table of contents, list of figures, nor a list of
tables. Convert the report to the PDF file format before submission. This ensures document
typesetting is preserved across different computers running different operating systems.
The Code Component
The submitted code needs to be executable (in MATLAB R2016b or later) and without run-
time error. If an error is encountered at execution, your assignment will only be marked until
the error. No error correction will be made to make your code ‘run’. Coding for this assignment
should remain within one (provided) file (unless otherwise explicitly instructed). Only include
a separate .m file if absolutely necessary.
Code should be fully commented to describe intent. Comments should contain enough informa-
tion to understand the process without referring to the report. Quality comments encapsulate
your understanding of the topic.
* You may use the code provided in the weekly tutorials to check your solutions, however you
are expected to generate your own code for your assignment. Submitting supplied .p code as
your own work constitutes academic misconduct and will be considered a run-time error. *
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Submission Checklist
Submission deadline is on the Sunday 22nd September 2019, 11:59 pm. This will be a
hard deadline and late submission penalties will apply. As per QUT policy, late assignments
receive 0 marks.
 The report, in PDF format, submitted to Turnitin via the Blackboard link
 A .zip file, submitted directly to QUT Blackboard via the provided link, that contains -
• EGB342 A2A Template.m with your name and ID
• A2AData.mat [Generated for Eb/N0 = 7dB]
• Functions that are written as a result of explicit assignment instruction
• Any other MATLAB scripts you have developed
 Submissions have been re-downloaded from submission portals and run as-is to confirm
successful upload.
 Online Academic Integrity Declaration from is completed.
Submission FAQ
⇒ You do not need to assign your submission with a special name. Blackboard assigns
unique IDs to all submissions. The submission link is accessible through:
EGB342 19se2 → Assessment → Assignment 2A → Assignment 2A: Submis-
sion.
⇒ You may submit as many times as you like before the deadline. New submissions overwrite
old submissions. Only the latest submission is recorded and marked. Upload in-progress
versions so there is something to mark if your final submission is late.
⇒ All documents can be reviewed after submission and thus it is your responsibility to verify
that the uploaded documents are not corrupt. Corrupt files are treated as incomplete
assignments.
⇒ Be aware that the electronic time stamp is placed only after all files have uploaded.
Blackboard may experience high traffic or your connection may fail unexpectedly. Begin
your final upload at least an hour before the deadline.
Hardship
If you experience a hardship which affects your ability to complete, or contribute to, this
assignment, please contact the teaching team as soon as it occurs.
QUT also offers counselling services if required.
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EGB342 Assignment 2A: Individual
Criteria
Standards
7+ 7 6 5 4 3 2/1
CR1 - 50% weighting
Theoretical understanding
Key Milestones
- Baseband modulation
- Noise and attenuation
- Signal detection using
Matched Filters
- Spectral Analysis
- Symbol Synchronisation
Demonstrates understanding of
the mathematical concepts
underpinning this assignment
beyond the expected ‘7’ level.
Explanations and justifications
are unambiguous, accurate and
logical. Graphical and
mathematical tools are used
masterfully to convey
knowledge of all topics. Uses
appropriate terminology.
Has no conceptual errors, but
one minor technical/numerical
error may exist. Discusses all
required concepts and shows
evidence of further research.
Demonstrates in-depth
understanding of the
fundamental concepts in this
assignment. Explanations and
justifications are generally
clear, accurate and logical.
Graphical and mathematical
tools are used fittingly to
convey knowledge of all topics.
Uses appropriate terminology.
Has no conceptual errors, but
one minor technical/numerical
error may exist. Discusses all
required concepts.
Demonstrates strong
understanding of the
fundamental concepts in this
assignment. Explanations and
justifications are generally
accurate and logical.
Graphical and mathematical
tools are used satisfactorily to
convey knowledge of all
topics. Uses appropriate
terminology.
Has no conceptual errors, but
minor technical/numerical
errors exist. Discusses all
required concepts.
Demonstrates sound
understanding of the
fundamental concepts in this
assignment. Explanations and
justifications are generally
accurate and logical. Graphical
and mathematical tools are
used satisfactorily to convey
knowledge of most topics.
Uses appropriate key
terminology.
One minor conceptual error
and no more than two
technical/numerical errors may
exist. Discusses all key
concepts.
Demonstrates rudimentary
understanding of the
fundamental concepts in this
assignment. Explanations
and justifications are
generally accurate and logical
but are sometimes unclear.
Graphical and mathematical
tools are used adequately to
convey knowledge of most
topics. Uses appropriate key
terminology.
Only minor conceptual,
technical or numerical errors
exist. Discusses most key
concepts.
Conceptual
understanding is
not demonstrated
explicitly
OR
Major conceptual
error
OR
Discussion does
not demonstrate
understanding of
the expected ‘4’
level.
Incorrect
interpretation/s
of underlying
concepts i.e.
Multiple major
conceptual
errors. Does
not recognise
basic errors
when discussing
generated
diagrams.
CR2 - 20% weighting
Effective written
communication
Key Milestones
- Informative
- Easy to read
- Clearly explained core
ideas
- Reflection demonstrates
intended learning
outcomes
Professional format, insightful,
core technical ideas are clearly,
accurately and succinctly
conveyed. The report is very
easy to read, and has been
written to inform. Only
relevant code included in
snippets. Figures demonstrate
intended point excellently.
Referencing is present, and has
been done correctly (IEEE).
Reflection shows all learning
outcomes were reached.
Professional format, core
technical ideas are clearly and
accurately conveyed. The
report is easy to read, and has
been written to inform.
Mostly relevant code included
in snippets. Figures
demonstrate intended point
very well. Reflection shows all
learning outcomes were
reached.
Professional format, technical
ideas are clearly conveyed,
one minor inaccuracy. The
report is informative and easy
to read. Mostly relevant code
included in snippets. Figures
demonstrate intended point
well. Reflection shows most
learning outcomes were
reached.
Report format is adequate but
missing some coherence in its
structure. The report is difficult
to read in one or two sections.
Consistently irrelevant code
included in snippets. Figures
demonstrate intended point
satisfactorily. Reflection shows
some learning outcomes were
reached.
Report format is missing
several critical explanations.
The report is difficult to read
in several parts. Large
amounts of irrelevant code
included. Figures
demonstrate intended points
adequately. Little evidence
of reflective thinking.
Report formatting
was attempted.
Contains little, or
vague, discussion
and lacks
cohesion. Largely a
code and figure
dump. No
evidence of
reflective thinking.
The report has
little or no
structure. No
evidence of
reflective
thinking.
CR3 - 30% weighting
Application using Coding
Key Milestones – For a 7 in this criteria, all milestones must be satisfactorily reached; For a 6, most must be satisfactorily reached, and so on.
• Correct individual-question outputs as per solution-script options
Code appears to give correct outputs if widely-varying solutions are possible
• Code is optimised (i.e. makes use of vectorisation where appropriate)
• Comments are effectively used to describe the code
• No runtime errors
• Uses functions that are within the scope of the assignment
• Code achieves desired output/s on completion
Large sections of code incomplete
OR
Multiple runtime errors
For moderation of overall marks: At the discretion of the teaching team, your group may be selected to attend an interview if the teaching team require clarification about how the group arrived at their solutions, or how individuals
contributed to the overall solution. If selected, you will be notified and given details of the location and time of the interview.
Oral interview Demonstrated knowledge is consistent with submitted report and code. No moderation of marks. Demonstrates knowledge
noticeably below the
standard of the submitted
report and code. Individual
marks may be moderated
down up to 20%.
Demonstrates knowledge significantly
below the standard of the submitted
report and code OR Does not attend
interview. Individual marks may be
moderated down up to 100%.
1