EE 311
Assignment 05
February 17, 2016
Due: Never
1. A low pass filter has 70db attenuation in the stop band. How many bits are needed in the A/D converter?
2. When you watch a movie you often see the wheel of vehicles moving backwards even though the
vehicle is moving forward. Explain this phenomenon in terms of aliasing. What is being sampled and how
is it aliased?
3. A sinusoid at 400 Hz is sampled at 5000 Hz. If the sinusoid is down sampled by a factor of 10 by
removing 9 samples out of each set of 10, the frequency of the down sampled sinusoid will be 100 Hz.
Explain.
4. The unit step response of a difference equation is given by
y (nT ) xstep  {0.4, 1.0, 1.18, 1.09, 0.991, 0.97, 0.987, 1.003, 1.005, 1.00, 1.00, 1.00,...}
From looking at the step response alone, what can you conclude about the frequency response of this
difference equation?