UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

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Signals and Systems

Learning of Matlab

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

Supervisor: Adonis Bogris, Professor

UNIWA Profile · LinkedIn

Co-supervisor: Georgios Antoniou, Laboratory Teaching Staff

UNIWA Profile

Athens, April 2021

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Signals and Systems: MATLAB Task 1

This README provides an overview of the MATLAB laboratory assignment completed for the Signals and Systems course.

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Table of Contents

Section	Folder/File	Description
1	assign/	Assignment instructions and exercise description
1.1	assign/EXERCISE 1 - LEARNING OF MATLAB.pdf	Exercise instructions (English)
1.2	assign/ΑΣΚΗΣΗ 1 - ΕΚΜΑΘΗΣΗ ΤΟΥ MATLAB.pdf	Exercise instructions (Greek)
2	docs/	Documentation related to MATLAB learning exercises
2.1	docs/Learning-of-Matlab.pdf	MATLAB learning documentation (English)
2.2	docs/Εκμάθηση-του-Matlab.pdf	MATLAB learning documentation (Greek)
3	src/	MATLAB source code files
3.1	src/m.m	MATLAB script file
3.2	src/m1.m	MATLAB script file
3.3	src/m2.m	MATLAB script file
3.4	src/m3.m	MATLAB script file
3.5	src/m4.m	MATLAB script file
3.6	src/m5.m	MATLAB script file
4	README.md	Repository overview and usage instructions

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Project Overview

This assignment covers fundamental MATLAB operations, including:

• Vector manipulation
• Custom function creation
• Complex number analysis
• Mathematical visualization and plotting

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Exercise Summaries

1. Vector Operations

Objective: Create and manipulate vectors a and b.

Key Operations:

• Vector a defined in interval [0, 10] with step 0.1.
• Vector b defined as cos(x) for interval [0, 20] with step 0.2.
• Computations included:
  • Division (a / b)
  • Element-wise power (a.^4)
  • Inner product (a · b')

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2. Unit Conversion Function

Objective: Convert radians to degrees.

• Function name: gwnia(rad)
• Logic: Multiplies input by 180/π
• Verification:
  π/4 radians correctly converted to 45 degrees.

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3. Sinc Function Visualization

Objective: Plot the sinc function.

Function definition: sinc(x) = sin(πx) / (πx)

Implementation:

• Interval defined from -2 to 2.
• Plot formatted using:
  • plot
  • title
  • xlabel
  • ylabel

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4. Complex Number Analysis

Objective: Extract properties of a complex number.

• Function name: praxis(z)
• Outputs:
  • Phase (angle)
  • Magnitude (absolute value)
  • Real part
  • Imaginary part

Test cases included:

• i
• -i
• 1
• e^(3 + 4i)

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5. Multi-Plotting & Subplots

Objective: Compare two mathematical functions:

$$ f(x) = x e^{-x} $$

$$ y(x) = 2 \cos(x) $$

Features:

• Figure 1: Both functions plotted together with legend.
• Figure 2: Functions displayed in separate vertical subplots for clearer comparison.

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Technical Commands Used

Command	Description
linspace	Generates linearly spaced vectors
subplot	Creates multiple plots in one figure
angle, abs	Compute phase and magnitude of complex numbers
real, imag	Extract real and imaginary parts

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Summary

The laboratory assignment demonstrates proficiency in MATLAB basics, function creation, complex number manipulation, and data visualization techniques used in signals and systems analysis.

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Installation & Setup Guide

This guide explains how to install requirements and run the MATLAB exercises contained in this repository.

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1. Prerequisites

To run the project, you need:

• MATLAB installed on your system
  (Any recent version should work; recommended R2020 or newer)
• Basic familiarity with MATLAB scripts and workspace execution

Optional:

• Git (to clone the repository)

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2. Obtain the Project

Option A — Clone Repository (Recommended)

Open a terminal or command prompt and run:

git clone https://github.com/Signals-and-Systems-aka-Uniwa/Matlab.git

Option B — Download ZIP

1. Open the repository page in your browser.
2. Click Code → Download ZIP.
3. Extract the archive to a folder on your computer.

3. Open Project in MATLAB

1. Start MATLAB.
2. Click Home → Set Path → Add Folder or:
   • Use Set Current Folder in MATLAB.
3. Navigate to the repository folder.
4. Open the src/ directory.

Recommended folder:

Matlab/src/

4. Running the Scripts

Each exercise is implemented as MATLAB scripts. From MATLAB:

Method 1 — Double Click

Double-click any script:

m.m
m1.m
m2.m
m3.m
m4.m
m5.m

and press Run.

Method 2 — Command Window

Run scripts directly:

m
m1
m2
m3
m4
m5

5. Function Files Usage

Some scripts define or use custom functions such as:

• gwnia(rad) — radian to degree conversion
• praxis(z) — complex number analysis

Ensure:

• Function files are inside the same folder or
• Folder is added to MATLAB path.

6. Expected Outputs

Running scripts will generate:

• Console outputs
• Mathematical calculations
• Function plots
• Subplots comparing signals
• Complex number properties
• Plots appear automatically in MATLAB figure windows.

7. Common Issues & Fixes

Script Not Found

Ensure current folder is:

Matlab/src/

Function Undefined

Add folder to MATLAB path:

addpath(genpath(pwd))

Plot Not Showing

Make sure script execution finished without errors.