# Review of an Alternate Signals and Systems Textbook

This is a review of Fundamentals of Signals & Systems by M. J. Roberts as an alternative to the current textbook, Signals & Systems by Oppenheim and Willsky, for ECE 301.

## Chapter 1: Introduction

In this chapter, signals and systems are defined. My four biggest impressions after reading this chapter were:

1) The author uses examples which are much better explained than those that the current textbook offers.

2) This textbook is much easier to understand. The current textbook is a little bit dense, and it sometimes takes a few times of reading through a section to figure out what it's going on about, but this one was much clearer.

3) Important words/words that are currently being defined are listed in BOLD. That makes it a lot easier to pick out the important terms (and is possibly one of the reasons I find it easier to understand).

4) I really only have one complaint with this book so far. Sometimes it feels like the author has gotten distracted by his own example and the writing rambles on a slight tangent for a while, before coming back to the topic that he was originally discussing. This is slightly distracting.

Another interesting note from the first chapter is that the author says that he will present MATLAB examples throughout the book. That could be really helpful/useful, if he uses good examples

## Chapter 2: Mathematical Description of Continuous-Time Signals

In this chapter, various types of continuous-time signals and functions that will be used throughout the book are defined. Some are simple definitions, such as sine or complex exponential. However, for the unit step and impulse functions, the author goes into a lot of detail. A lot more of the math behind these was explained, which I liked. However, I'm not sure that it's totally necessary.

One interesting thing that comes out in this chapter is that the author has a tendancy to represent frequency as 2πf as opposed to ω

Finally, the author continues to offer excellent examples, and rambles much less in this chapter. However, this chapter might be a little more in depth than is really necessary for ECE301.

## Chapter 3: Mathematical Description of Discrete-Time Signals

This chapter is very much the same as Chapter two, except that it discusses DT signals. This author, for the most part, does a much better job of describing the two types of signals than the current textbook by Oppenheim & Willsky.

## Chapter 4: Properties of Continuous-Time Systems

The beginning of this chapter contains a very thorough (and quite good) definition of systems, then follows with several detailed examples of how to model systems mathematically. The rest of the chapter is devoted to definitions of the properties of systems, along with detailed examples.

In my opinion, this author does a much better job of defining the properties of systems than the current book. The definitions are clear and concise, and are accompanied by examples. However, in some cases, the examples are mathematical, and possibly more complex than necessary to clarify the definition. In a few cases (especially those in which a very mathematical example is embeded in the text of the chapter, not broken off into an example box) the examples distracted from the main text, as I worked through the math.

## Chapter 5: Discrete-Time System Properties

This chapter is a little disappointing, as it essentially says "look at chapter 4," but it does contain a few excellent examples.

## Chapter 6: Time-Domain Analysis of Continuous-Time Systems

The chapter begins with a discussion of the unit impulse response, along with some quite good examples, then quickly moves on to the convolution integral. A detailed derivation of the convolution integral follows, along with some convolution properties. One of the properties is derived, but the rest are simply presented in table form, and it would be nice to see the rest of the derivations. Following this is a section on using the convolution integral with interconnected systems, then a section on system responses. The chapter ends with an excellent little section on block diagrams for differential equations.

As has been the case throughout the beginning of the book, this chapter contains many excellent examples scattered throughout.

## Chapter 7: Time-Domain Analysis of Discrete-Time Systems

This section follows exactly the same format as chapter 6, and builds on the derivations seen there. An interesting note is that several of the examples in this section involve Matlab, which is quite interesting.

After Chapter 7, the book moves on to frequency domain discussions of signals. Unfortunately, the author has chosen to use $\mathfrak f = 2\pi\omega$ rather than simply using $\omega$. This is really distracting, and unless ECE301 professors were to switch to this method of dealing with the frequency domain (I don't suggest it...), the rest of the book would be more confusing than helpful.