1. As stated on the Homework 17 assignment, please experiment with the Fourier series demonstrations at
   http://spectrum.ece.jhu.edu/wjr/
   

   In particular, try the "Listen to Fourier Series" and the "Fourier Series Approximation" demos. Please answer the following questions.

   • Which frequencies are contained in "white noise"? What does filtered noise sound like?
   • Did you notice anything interesting while experimenting with the Fourier Series Approximation demo?

2. Please review the analysis of a square wave that is filtered by an RC circuit that we discussed in class. Run the MATLAB program sqrfilt.m. Based on what you know about the Fourier series coefficients for a triange wave from Homework 16, does it make sense that the filter output is triangular? Please explain, using the Fourier series of the square wave and the frequency response of the RC circuit.

3. Please read Sections 4.3 and 4.4 on the Fourier transform.

4. Please study Example 4.7 in the text on pages 166-167. Do your best to write down all of the steps required to show that the Fourier transform of a rectangular pulse is a "sinc" function. This is one of the most important Fourier transform pairs to understand -- it arises in many applications.

Thank you.