Rich Kozick
Spring, 1997

EE 329: Laboratory 8
FIR Filter Design with the Window Method

You will be given samples of an audio file that is corrupted by interference. Your assignment is to:
  1. Analyze the audio file, and specify requirements on the frequency response of an FIR digital filter that will remove the interference. Your filter should remove the interference as much as possible, but also preserve as much of the original signal as possible. (These requirements are conflicting, so you will need to decide on a compromise.)
  2. Design FIR digital filters to remove the interference. Use two approaches to design your digital filters: Which design achieves better results?

Download the data file and load it into Matlab using either of the following methods:

You can listen to the audio file in Matlab with the command sound(x). If you would like to here the original, uncorrupted music, it can be loaded into Matlab with the command:
xgood = auread('/home/pleiades/ACM/snd/');

Matlab has built-in functions for generating many of the common window functions. For a listing of the available window commands, type help signal and look at the "Windows" section.

Lab Report: Please submit a brief report describing your design procedure and your results by Friday, April 11. Also, I will ask each of you to demonstrate the effectiveness of your filter to the class. As we talk about other types of digital filters, feel free to try them out on this particular signal processing problem.

Thank you.