ECE714/814 Fall 2009 Test #2 Study Guide
The second exam will be given in class on Wednesday, December 2. It will be given closed book and
closed notes. The exam will emphasize visualization and basic understanding rather than memorizing
equations or performing computations. However, a little computing (adding, subtracting, multiplying,
dividing) will be necessary. You are welcome to bring a simple calculator (but not a laptop computer),
although I will try to choose numbers that can be manipulated without one (e.g. 10/2 = ?).
The following items are intended to help you in preparing for the exam. This should give a good idea of
what to emphasize, although it is not guaranteed to be absolutely inclusive (since I haven’t made the
test up yet). Also, I can’t guarantee to ask about all of these things, given that the exam is only 50
minutes in duration.
Chapters 1-5 (and Assignment #1-5). Material Covered in the First Test
Look over the study guide for the first test and the corresponding assignments (and the test as well). It
would be a shame to lose points on a question on the second test, which you already lost points on
during the first test!
Chapter 6 (and Assignment #6 and #7). IIR Filters (and the Z-Transform)
This chapter first introduced the Z-Transform and its basic properties when applied to the
representation of the properties of LTI systems. The chapter then used the Z-Transform to discuss the
properties of, and the design of, Infinite Impulse Response (IIR) filters.
1. You should be completely comfortable with the 4 basic representations of a discrete time LTI
system: H(z) (such as eq. 6-25 in the text), H(w) (such as eq. 6-26 or 6-28 in the text), the time
domain sampled data equation (such as eq. 6-21 in the text), and the block diagram
representation (such as figure 6-18 in the text). Given one representation with a specific filter
order and specific coefficient values, you should be able to generate any of the other
representations of the same LTI system. In other words, I might give you a block diagram and
ask you to write down the corresponding H(z) or the sampled data equation, or I might give you
H(z) and ask you to write down the corresponding H(w) or to draw the block diagram, etc.
2. I can’t ask you on a test to factor an H(z) to determine the positions of the poles and zeros.
However, I could show you a plot with a small number of poles and zeros at specific locations in
the z-plane and ask you to build an H(z) transfer function to match.
3. I can’t ask you to design any IIR filters on the test, but you should be familiar with the basic ideas
of the four methods discussed in the text, in class and the assignment: “impulse invariance”,
“bilinear transform”, “standard shapes” (Butterworth, Chebyshev, Elliptic), and “optimal
frequency response” . For example, I might have a list of some general filter characteristics (e.g.
“builds h(n) from the h(t) of a continuous time filter”, “directly maps poles and zeros of a
desirable H(s)to create a similar H(z)”, “creates maximally flat frequency response”, and so
forth) and ask you to match each item in that list to a filter design type.
