Laboratory 2: Simple Digital Filtering with Matlab

  1. Please finish Lab 1, if you haven't already.

  2. Please download the Matlab program digmus.m, which reads in a file with digitized music. You will also need to download the file and save it in the same directory as digmus.m. You will have an opportunity to apply various digital filters to the music and listen to the results.

    If x[n] represents the digital music signal and y[n] is the output from the digital filter, implement the following filters in MATLAB and apply them to the music:

    Can you identify each filter as low-pass or high-pass? Does this agree with your understanding of the associated difference equation?

    Digital filters are widely used in modern systems. Digital filters are nothing more than discrete-time systems that are described by difference equations! Digital filters are often executed on DSP chips that are specially designed to execute multiply-and-add operations very fast.


  1. Original music:
  2. Result of filter 1 with N = 5:
  3. Result of filter 2 with a = 0.9:
  4. Result of filter 3:

You can listen to each file from a web browser, or you can download each file into your filespace and read it into Matlab with the commands:

y1 = auread(''); sound(y1);

Thank you.