Introduction

Signals and systems is one of the toughest classes you’ll take as an engineering student. But struggling to figure out this material doesn’t necessarily mean you need to sprout early-onset gray hairs and resign yourself to frown lines in your college years. And you definitely don’t want to give up on engineering over this stuff because becoming an engineer is, in my opinion, one of the best career choices you can make. See, you’re no dummy!

This book can help you make sense of the fundamental concepts of signals and systems that may be giving you some static — or even frying your brain. Even better, you can apply the tips and tricks I provide in this book to the courses you’ll take down the line — and right into the real world of computer and electrical engineering!

About This Book

Like all other For Dummies books, Signals & Systems For Dummies isn’t a tutorial. It’s a reference book that you can use as you need it. You don’t need to read each chapter cover to cover (but you may find all the material utterly mesmerizing). You can jump right to the topics or concepts that are giving you trouble, get the help you need, and be on your way with helpful insight to real-world examples of electrical concepts that may be tough to imagine in your textbook of equations.

Conventions Used in This Book

I use the following conventions throughout the text to make things consistent and easy to follow:

New terms appear in italic and are closely followed by an easy-to-understand definition. Variables also appear in italic.

Bold highlights keywords in bulleted lists and the action parts of numbered steps.

Lowercase variables indicate signals that change with time, and uppercase variables indicate signals that are constant. For example, v(t) and i(t) denote voltage and current signals that change with time. If, however, V and I are capitalized, these signals don’t vary in time.

What You’re Not to Read

Although I’m sure you want to read every word of this book, I realize you have other reading material to get through. When you’re short on time and need to just get through the basics, you can skip the sidebars (the shaded boxes sprinkled throughout the book) and paragraphs flagged with a Technical Stuff icon.

Foolish Assumptions

I know you’re a unique kind of brilliant and have one-of-a-kind skills and attributes, but as I wrote this book, I had to make some assumptions about my readers. Here’s what I assume about you:

You’re currently taking an introductory signals and systems course as part of your computer or electrical engineering major, and you need help with certain concepts and techniques. Or you’re planning to take a signals and systems course next semester, and you want to prepare by checking out some supplementary material.

You have a solid handle on algebra and calculus.

You’ve taken an introductory physics class, which exposed you to the concepts of voltage, current, and power in circuits.

You’re familiar with linear differential equations with constant coefficients.

How This Book Is Organized

The study of signals and systems integrates a handful of specific topics from your math and physics courses, and it introduces new techniques to design and manage electrical systems. To help you grasp the core concepts of this electrifying field (sorry, I couldn’t resist) in manageable bites, I’ve split the book into several parts, each consisting of chapters on related topics. Chapters are laid out in an alternation of continuous- and discrete-time topics, starting with the time domain, moving to the frequency domain, and then covering the s- and z-domains.

Additional content, including case studies, is available online at www.dummies.com/extras/signalsandsystems.

Part I: Getting Started with Signals and Systems

This part gives you the signals and systems lingo and an overview of the basic concepts and techniques necessary for tackling your signals and systems course. If you’re already familiar with the fundamentals of how signals and systems operate in the continuous- and discrete-time domains, you can use this part as a refresher.

Part II: Exploring the Time Domain

The focus of these chapters narrows to more closely examine the time domain of signals and systems. In Chapter 7, I introduce differential and difference equation system models, which are used to represent electronic circuits, the audio equalizer on your MP3 music player, filters that separate signals from one another, hybrid systems composed of electrical and mechanical components, and more. I also describe signal and system classifications and properties in these chapters.

Part III: Picking Up the Frequency Domain

The chapters in this part drill down on the frequency domain and the world of system design, particularly wireless systems. Bridging the gap between the continuous- and discrete-time worlds is sampling theory, which is covered in Chapter 10.

Part IV: Entering the s- and z-Domains

This part gets tougher because you’re dealing with the s- and z-domains — a third domain system that engineers use to view the world. Poles and zeros rule here. Signal processing and control systems designers are fond of the s- and z-domains because, for starters, they reduce the mathematics of passing a signal through a system to rather simple algebraic manipulation. From the poles and zeros, you can easily discern system stability and the impact they have on the frequency domain. Great stuff.

Part V: The Part of Tens

Here, get hip to more than ten common mistakes people make when solving problems for signals and systems. Also find a list of ten properties you never want to forget. You may want to print these lists and keep ’em within view.

Icons Used in This Book

To make this book easier to read and simpler to use, I include some icons to help you find key information.

Anytime you see this icon, you know the information that follows is so important that it’s worth recalling after you close this book — even if you don’t remember anything else you read.

This icon appears next to information that’s interesting but not essential. Don’t be afraid to skip these paragraphs.

This bull’s-eye points out advice that can save you time when managing signals and systems.

This icon tries to prevent you from making fatal mistakes in your analysis.

This icon flags worked-through examples in the content so you can find the most practical stuff fast if you’re especially pressed for time.

Where to Go from Here

This book isn’t a novel — although it just may be as intriguing as one. You can start at the beginning and read through to the end, or you can jump in at any chapter to get the information you need on a specific topic. If you need help with calculus and other math basics before dishing out the heartier fare of signals and systems, then pick through Chapter 2 for a quick review. If you just can’t wait another second to find out how the Fourier transform works with different types of signals, then by all means flip to Chapters 9 and 11 right away.

If you’re not sure where to start, or you don’t know enough about signals and systems yet to even wonder about specific topics, no problem — that’s exactly what this book is for. I recommend starting with the chapters in Part I and moving forward from there if you really are a newbie. Then, keep on reading; you’ll be charged up with nitty-gritty details of signals and systems in no time.