A Text for EE501
Michael P. Fitz The Ohio State University firstname.lastname@example.org Fall 2001
2 Note to Students. This text is an evolving entity. Please help make an OSU education more valuable by providing me feedback on this work. Small things like catching typos or big things like highlighting sections that are not clear are both important. My goal in teaching communications (and in authoring this text) is to provide students with 1. the required theory, 2. an insight into the required tradeoﬀs between spectral eﬃciency, performance, and complexity that are required for a communication system design, 3. demonstration of the utility and applicability of the theory in the homework problems and projects, 4. a logical progression in thinking about communication theory. Consequently this textbook will be more mathematical than most and does not discuss a host of examples of communication systems. Matlab is used extensively to illustrate the concepts of communication theory as it is a great visualization tool. To me the beauty of communication theory is the logical ﬂow of ideas. I have tried to capture this progression in this text. This book is written for the modern communications curriculum. Most modern communications curriculum at the undergraduate level have a networking course hence no coverage is given for networking. For communications majors it is expected that this course will be followed by a course in digital communications (EE702). The course objectives for EE501 that can be taught from this text are (along with their ABET criteria) 1. Students learn the bandpass representation for carrier modulated signals. (Criterion 3(a)) 2. Students engage in engineering design of communications system components. (Criteria 3(c),(k)) 3. Students learn to analyze the performance, spectral eﬃciency and complexity of the various options for transmitting analog message signals. (Criteria 3(e),(k)) 4. Students learn to characterize noise in communication systems. (Criterion 3(a)) Prerequisites to this course are random variables (Math530 or STAT427) and a signal and systems course (EE351-2). Many of my professional colleagues have made the suggestion that analog modulation concepts should be removed from the modern undergraduate curriculum. Comments such as ”We do not teach about vacuum tubes so why should we teach about analog modulations?” are frequently heard. I heartily disagree with this opinion but not because I have a fondness for analog modulation but because analog modulation concepts are so important in modern communication systems. The theory and notation for signals and noise learned in this class will be a solid foundation for further explorations into modern communication systems. For example in the testing of modern communication systems and subsystems analog modulation and demodulation concepts are used extensively. In fact most of my good problems for the analog communication chapters have come as a result of my work in experimental wireless communications even though my research work has always been focused on digital communication systems! Another example of the utility of analog communications is that I am unaware of a synthesized signal generator that does not have an option to produce amplitude modulated (AM) and frequency modulated (FM) test signals. While modern communication engineers do not often design analog communication systems, the theory is still a useful tool. Consequently EE501 focuses on analog communications and noise but using a modern perspective that will provide students the tools to ﬂourish in their careers. Finally thanks go to the many people who commented on previous versions of these notes. Peter Doerschuk (PD) and Urbashi Mitra (UM) have contributed homework problems. c 2001 - Michael P. Fitz - The Ohio State University
1 Signals and Systems Review 1.1 Signal Classiﬁcation . . . . . . . . . . . . . . . . . . . . . . . 1.1.1 Energy versus Power...