ELEC 320, Fall 1998
Prof. Rich Kozick
Homework 20
Date Assigned: Friday, November 20, 1998
Date Due: Wednesday, December 2, 1998
Please answer the following question related to the fast
Fourier transform (FFT).
Refer to Lab 7
for notes on how to perform the FFT with MATLAB.

You are given a data file
sig1.dat
that can be downloaded from the Web version of this assignment at
http://www.eg.bucknell.edu/~kozick/elec32098/hw20.html
The file contains discretetime data that was obtained by
sampling a continuoustime signal at the rate of
300 samples per second.
The data can be loaded into MATLAB with
the command
load sig1.dat ascii
after which a variable named sig1 will be available.
(The MATLAB command whos gives you a listing of
all variables defined in the MATLAB workspace.)
Suppose it is known that either two or four distinct sine
waves are present in the data.

How many sine waves do you think are present in the data, two or four?

What are their frequencies, in hertz?
 Is there a difference in amplitude among the sine wave components?
If so, which frequency component(s) have the largest amplitude?
Explain your reasoning.
Thank you.