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. 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: () = 1 cos (21 − 6 ) + 2cos⁡(22 + 4 ) The following parameters (based on the 6th 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 6th number would be 8, so you would need to use the signal: () = 2.2 cos (400 − 6 ) + 1.5cos⁡(2000 + 4 ) 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.