EEEE4120: Digital Signal Processing
Course Assignment 2 - Real-time Filtering of Audio
Department of Electrical and Electronic Engineering
1. Introduction
As part of the Digital Signal Processing Module (EEEE4120), students are required to complete two coursework assignments - each assignment will account for 30% of the module assessment. The projects outlined in these documents are based on real-world problems - students will have ample time to study different solutions to the problems, design and write the code for these solutions, implement and document the results, and write a report on all these aspects.
This course assignment is a personal task - it requires students to collaborate only during the experimental part, but not to work together in the preparation of the written report.
1.1 Background
In the modern environment, signals are typically recorded through analog sensors (such as microphones, magnetic pickups, sensors, etc.), then amplified, and converted into digital signals. This enables the signals to be stored and replicated on media that do not deteriorate after use. However, in all the aforementioned electronic processing stages, the signals are prone to being affected by noise, including when they are transmitted between these states.
The content and source of this noise are unknown. Engineers usually only have access to the output waveform. for operation. In engineering practice, real-time processing of signals (here referring to sounds) is a common practice, and knowing how to properly filter while not losing the original signal is a useful skill.
Under normal circumstances, engineers are not only responsible for the development of the process, but also for clearly and concisely communicating problems, solutions, designs and results. This is equally important - for this course assignment, it will be presented in the form. of a report document.
1.2 Objective
This project aims to design, implement and test digital filters to remove the noise in the waveform. of.wav audio segments and restore the original signal as much as possible. In this course assignment, students will process signals using MATLAB, design and test filters, and then implement the filter in a real-time environment using the STM32 microcontroller in the laboratory sessions (weeks 8 and 11).
The learning outcomes of Course Assignment 2 are as follows:
• An introduction to filter design, covering both post-processing and real-time applications.
• Introduce the application and testing of digital filtering in a real-time hardware environment.
• Understand the design issues involved in real-time filtering of signals (i.e., the trade-off between improvement of signal-to-noise ratio and delay and/or CPU load).
Students will have the opportunity to design, test and apply digital filters and other signal processing techniques. By the end of the course, students should have a deeper understanding of these techniques.
1.3 Deliverables
KeyBased on the application of signal processing technology, students will complete the following tasks: (a) a brief report (see Section 3.4), (b) a Matlab script. (filter design and offline testing), and (c) a main.c script. (real-time implementation).
When submitting, students must provide all the written Matlab code (including input parameters) they used to obtain the results. The code should be organized in a separate .m file, and this file must not have any compilation errors. If students used the signalAnalyzer or other graphical user interface programs, they should list all the input parameters used in the report. Students should also submit the .c files (only the main.c file) for the filtering functions used to generate the results for STM32.
The reports and Matlab files should be completed independently by each individual. The .c files used for programming STM32 can be the same among each group allocated to each experimental bench.
The submission of course assignments will be strictly conducted online through the Moodle page of the Digital Signal Processing course (https://moodle.nottingham.ac.uk).
Students should submit their written reports only in the .pdf format, and there is no need to submit the data files used for the reports.