## EE 451

Homework Assignment 12
Due Dec. 1, 1999

1. Problem 10.1.

2. Problem 10.2.

3. Problem 10.7.

4. Problem 10.8.

5. A signal is sampled with a sampling frequency of 10 kHz. It is obvious that there is a predominant signal at one frequency, but you suspect there may be other frequencies with smaller amplitudes present. You want to verify this for any frequency which has an amplitude of at least 1% of the main frequency, and is separated from the main frequency by at least 10 Hz.

1. What windows can you use to see if you are correct?

2. Chose one window from (a). What length DFT do you need to use to see if you are correct?

3. Download the file signal.mat. Load this signal into MATLAB using the command load signal.mat. (If you cannot load the binary file signal.mat, try the ASCII file signal.dat. You will have to use the command load signal.dat to load it.) You will have a signal called x. Use the MATLAB fft function to determine the dominate frequency, and to determine if any other frequencies are present. If other frequencies are present, what are they?

Bill Rison, <rison@ee.nmt.edu >