辅导英文MATLAB、讲解MATLAB编程、辅导MATLAB AI

Welcome to the internship program of the Brisbane-based Australian Space Agency (BASA).

You will be working with, and learning from, the engineering team in charge of this historic first

mission to Mars. The agency is always looking for capable engineers, and has instructed the

team to assess your competence in this multifaceted field. The team has provided opportunities

for you to demonstrate your knowledge, skills and abilities, as individuals. You will also be

demonstrating your ability to work as effective team members. This is the first of three tasks

aimed at preparing you to contribute to the critical engineering work needed for the operation,

monitoring and safety of the MARS-242 astronauts and their spaceship. Figure 1 shows

something you can aspire to!

Figure 1: ‘To Mars!’

1

BASA Headquarters: Preparation

The engineering team at BASA wishes to investigate the interference affecting the speech received

by the spaceship. Communication disruptions often occur as periodic patterns and this

formed the rationale for our engineers to consider periodic noise.

Follow these steps for preparation:

i Read through the entire document before attempting the tasks.

ii Open GenerateDataAssignment1A.m in your MATLAB working directory. This file generates

the data you will need for this assignment. Carefully read all of the comments

and instructions in the file. Enter your student numbers into the appropriate variables

and then run the script. This script only needs to be executed once. The generated data

will be stored in the file Data1A at the current working directory. GenerateDataAssignment1A.m

file can be closed once Data1A has been generated.

iii Write down your group’s test signal parameters for s1(t), s2(t) and s3(t) - displayed on

the command window when you run the GenerateDataAssignment1A.m file.

iv Open preparation.m and mission.m, carefully reading the comments and instructions.

You will be writing MATLAB code in these files to perform the required tasks. Always

make sure that the data file Data1A.mat and your MATLAB code are in the same working

directory. Data generated in Step (ii) will be loaded by the existing code upon execution

of this script. Variables A, B and C are required in all sections of this assignment. The

variable noiseSound will be used in Section A3.

v The parentheses at the end of each question refer to the particular criteria which are

relevant for that part. These criteria, which will be used for marking can be found on

the CRA sheet. Your Criteria 1 mark comes from the theoretical understanding that you

demonstrate in the report, your Criteria 2 mark will come from your code implementation,

and your Criteria 3 mark comes from the presentation of your report and your group

reflection.

vi As a guide, a report with all sections complete should be between 20 and 30 pages,

including figures and code.

vii Ensure that all work (including process description, code used and plots) are

included within the report. An example report showing how this should be

presented is available on Blackboard.

2

Test Signal Definitions

A single period of the periodic functions s1(t), s2(t) and s3(t) are defined below,

Section A1 (BASA Headquarters: Problem Solving)

A1.1 Substitute your group’s variables (A, B and C) into the corresponding signals, and graph

two periods (0 to 10 seconds) of each signal by hand. These should be presented as

separate figures with key elements of each signal labeled (such as amplitude and gradient

changes, axes, units etc. where applicable). Ensure scanned material is easily readable.

(Criteria: 1)

Parts A1.2 to A1.9 can be presented as either handwritten or using typeset equations.

A1.2 Determine the trigonometric and complex exponential Fourier series of s1(t) from first

principles i.e. Using the integral definitions. Do not convert from one form to the other.

Show all working. (Criteria: 1a)

A1.3 Explain how the trigonometric and exponential coefficients change for the signal s(t) =

s1(t) + 2. Describe in words, do not show mathematically. (Criteria: 1c)

A1.4 Expand the signal s2(t) into the Fourier series of your choosing (trigonometric or complex)

from first principles, then convert to the other form. Show all working. (Criteria: 1a)

A1.5 Clearly explain your choice of Fourier series for first principle expansion of s2(t).

A1.6 Calculate the coefficients a0, an and bn for n ≤ 3, and the cn coefficients for −3 ≤ n ≤ 3

for s2(t). Show all working. (Criteria: 1b)

A1.7 Derive the Fourier series of s3(t) from first principles (trigonometric or complex), then

convert to the other form. Show all working. (Criteria: 1a)

A1.8 Clearly explain your choice of Fourier series for first principle expansion of s3(t).

A1.9 Calculate the coefficients a0, an and bn for n ≤ 3, and the cn coefficients for −3 ≤ n ≤ 3

for s3(t). Show all working. (Criteria: 1b)

A1.10 Classify each of the the test signals as either even, odd or neither? Justify your answer

using the mathematical definitions. (Criteria: 1c)

3

Section A2 (BASA Headquarters: Training Exercise)

This section should be implemented in MATLAB - preparation.m. Be sure to include relevant

figures and code snippets when presenting your results in your report. Discuss what you are

doing, and most importantly why.

A2.1 Generate and plot a periodic signal based on s2(t) named s2 hinf 1

.

The signal is to span 5 cycles (periods) and have a total of 500 sample points (i.e. 100

points per period).

A2.2 Compute the trigonometric coefficients of s2(t), numerically using MATLAB. Do not use

the trapz or syms functions.

A2.3 Create a 4x500 matrix called s2 matrix. The first row represents the DC component

of s2(t). Each remaining row contains a single harmonic component of the signal for

n ∈ {0, 1, 2, 3}

A2.4 Now create a vector s2 approx which contains an approximation of the signal s2(t). You

can use s2 matrix to do this.

A2.5 In the same figure as s2 hinf, and using different colours, also plot the following Fourier

series approximations using the trigonometric coefficients:

Hint: this can be implemented in a for loop

• An approximation of s2(t) using the DC component and the fundamental frequency,

• An approximation of s2(t) using the DC component, the fundamental frequency and

the second harmonic,

• An approximation of s2(t) using the DC component, the fundamental frequency and

the second and third harmonics. Note that the fundamental, second harmonic and

third harmonic correspond to n = 1, 2, 3 respectively.

Label the axes appropriately and include a legend. Ensure the signal and all approximations

can be easily seen in the report. Use different line styles if necessary. (Criteria: 1b,

2a)

A2.6 For s3(t), repeat the steps of A2.1 to A2.5 using exponential coefficients, and a 7x500

matrix. Maintain naming conventions i.e. s3 hinf, s3 matrix and s3 approx. (Criteria:

1b, 2a)

A2.7 What can be said about the approximations when the number of harmonics used increases?

Are the previous approximations sufficient to represent these signals? Why or

why not? What are the practical benefits and drawbacks of using 3 harmonics as opposed

to more or fewer? Hint: Consider what it would be like to do by hand. (Criteria: 1c)

1hinf refers to infinite harmonics i.e. the ideal signal

4

MATLAB variables that should be included in your workspace for section A2

(preparation.m),

t - Time vector

T - Period

n trig - Number of harmonics for Trigonometric Fourier Series

a0, an, bn - Trigonometric Fourier series coefficient vectors

s2 hinf - s2(t) ideal time series representation

s2 matrix - s2(t) harmonic component matrix

s2 approx - s2(t) signal approximation

n comp - Number of harmonics for Complex Fourier Series

c0, cn - Complex Fourier series coefficient vectors

s3 hinf - s3(t) ideal time series representation

s3 matrix - s3(t) harmonic component matrix

s3 approx - s3(t) signal approximation

5

Section A3 (Mars Mission: De-noising Speech)

This section should be implemented in MATLAB - mission.m. Be sure to include relevant

figures and code snippets when presenting your results in your report. Senior analysts from

the engineering team have determined that the received speech has been corrupted by an

additive noise process. This model is illustrated in Figure 2.

Figure 2: Model of additive noise

Your primary objective in this task is to identify the noise signal and de-noise the speech

(remove the noise). The speech is provided in the variable noiseSound. Original speech was

recorded at a rate of 44100 samples per second for 20 seconds. Follow the instructions below

to help you complete your task.

A3.1 One of the test signals that you have used above is the sample waveform of your periodic

noise, which you will need to identify. Explain how you identified your noise waveform -

consider things such as the period, offset and shape. (Criteria: 1c, 2a)

A3.2 Generate your noise waveform. Save this to the variable additive noise. It is to contain

the same number of periods as the noise waveform in the corrupted speech signal.

Make sure that an appropriate time domain vector, t, was generated for this waveform.

(Criteria: 2a)

A3.3 Use MATLAB to evaluate the coefficients of your noise signal of either the Complex

Fourier Series; c0 and cn for −10 ≤ n ≤ 10, or the Trigonometric Fourier Series; a0, an

and bn for 0 ≤ n ≤ 10. (Criteria: 2b)

A3.4 Write code to generate the Fourier series approximation (FS1), using the time vector t

of your periodic noise. (Criteria: 2b)

A3.5 Using FS1, recover the corrupted speech by reversing the additive process illustrated in

Figure 2. Store the de-noised result in the variable dnSnd. (Criteria: 2a)

A3.6 Plot and listen to the recovered speech signal. Comment on visual changes as compared

with the noisy speech signal, along with an explanation of what has happened. Include a

transcription of the message, you just listened to, in your report. (Criteria: 1c, 2b)

6

MATLAB variables that should be included in your workspace for section A3

(mission.m),

t - Time vector

T - Period

additive noise - Your noise waveform

c0, cn - Complex Fourier series coefficient vectors, OR, a0, an, bn - Trig Fourier series

coefficient vectors

FS1 - Fourier series approximation vector

dnSnd - De-noised resulting wave

Section A4 (Reflection) (Criteria: 3d)

A two paragraph reflection is to be written and appended at the end of your report. In the first

paragraph, discuss the effects that changes in noise amplitude and frequency have on the message

signal transmitted to the spaceship i.e. summarize the conceptual understanding you have

demonstrated in this assignment. The second paragraph should be a discussion/professional

reflection that covers any lessons learned from doing this assignment, and things that you would

have done differently. Each paragraph should not exceed 250 words. Marks for this are included

as part of the criteria available on Blackboard.

Academic Integrity Declaration and Group Contribution

The provided Academic Integrity Declaration and contribution online form must be completed

and submitted along with the assignment. Each student from the group will need to complete

their own form. Marks may be moderated depending on contributions. Assignments with

incomplete or missing declarations will not be marked. Familiarise yourself with the university’s

policy regarding plagiarism and collusion. See the file “Academic Honesty Slides.pdf ” posted

with this assignment for some useful details.

If academic misconduct is discovered, the suspected student/s will be given an opportunity to

explain the similarities to the teaching team. If no response if received within 1 business day

of first contact, the matter will be escalated to the faculty, which may affect the release date

of final marks for the subject. Please take this seriously. Do not share your code or report

with other students, or use other students code or reports.

Hardship and Personal Matters

If you experience a significant personal event that interferes with your ability to complete this

task, contact the teaching team as soon as possible. The team may be able to suggest optimal

courses of action. The team can not approve extensions - Extension applications must be

submitted through the faculty, with supporting documentation.

7

Report and Code Presentation

This assignment includes elements of writing and coding. This is a group assessment item and

you are expected to generate and submit:

• One assignment report, “The Report”,

• One set of MATLAB code, “The Code” (including at least ‘preparation.m’ and ‘mission.m’),

and

• One Data1A.mat file.

The attached Criteria Reference Assessment (CRA) sheet has the outlines of the marking

standards of this assignment.

The teaching team has put together some pointers for you to consider:

The Report (Criteria: 3)

An outstanding report demonstrates clear knowledge and understanding of the subject through

a combination of visual, mathematical and coding elements. Correct information that is not

articulated clearly will attract deductions. Remember that you are writing to inform.

• Present the report so it can be understood without reference to the assignment brief.

• Figures or code referenced should be no more than 1 page turn away.

• You should only include code that is relevant to the question.

• Avoid the use of “see appendix” and “refer to .m file”.

• Full working is required in mathematics-based sections.

• Ensure legibility in any handwritten working.

• Include a title page that states the unit name, unit code, group number, and your names

and student ID numbers.

• Do not include a table of contents, list of figures, nor a list of tables.

As a guide, a report with all sections complete should be between 20 and 30 pages, including

figures and code.

The MATLAB Code (Criteria: 2)

Working MATLAB code is expected to be submitted, alongside your report to Blackboard.

The code needs to be executable (in *.m) and without run-time errors. No error correction

will be made to make your code “run.”

Code should be fully commented to describe intent. 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 not be awarded any marks.

Code for this assignment will be marked with the assistance of an automated marking system.

Ensure that you follow given instructions carefully, including naming conventions. Your code

submitted will also be checked for academic misconduct.

8

Interview

Group interviews will take place (at the discretion of the teaching team) to ensure demonstrated

understanding and skills required for this assignment, by the group, and the individual members.

You may be selected and contacted to attend an interview if the teaching team requires

clarification about how you arrived at your solutions. Interviews 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 understanding of content or assignment knowledge.

Consult the CRA sheet for the guidelines of what is expected.

Submission Protocol

Assignments are to be submitted in soft-copy through QUT Blackboard in three parts

• A completed academic integrity and group contribution online form. This form is to be

completed individually by every student.

• The report. Only ONE group member is required to submit the report to the Turnitin

link. Coordinate within your group who this will be.

• Your data and code files. Include everything here that your code needs to run. You may

submit as either a single zip file, or attach your required files individually.

Some further points:

• Submission deadline is on Thursday the 30th of August, at 11:59pm.

• This will be a hard deadline, and late submission will not be accepted. As per QUT policy,

late assignments receive 0 marks, unless you have applied for and received approval for

extension, as per the university policy.

• You do not need to assign your submission with a special name.

• You will need to be registered to a group before you can submit your assignment.

• You may submit as many times as you like before the deadline. New submissions overwrite

old submissions. Therefore, only the latest submission will be marked.

• All documents can be reviewed after submission, and thus it is your responsibility to

verify the uploaded documents.

• Be aware that the electronic time stamp is placed only after all files have been uploaded

successfully.

reflections.

EGB242 Assignment 1A: Group 2018