Lesson_20 - EEL 3135 Dr. Fred J. Taylor, Professor Lesson...

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EEL 3135 Dr. Fred J. Taylor, Professor Lesson #2 Signal Representation Introduction Signal processing refers to the art and science of creating, modifying, manipulating, extracting, and displaying information and attributes from signals. Since the dawn of time, man has been the quintessential signal processor. Signal processing was performed by the most powerful signal processing engine ever developed, the 25 Watt human brain, which commits about 10 Watts to information processing (comparable to an Intel mobile Pentium III processor). As humans evolved, other elements were added to man’s signal processing environment and repertoire, such as information coding in terms of intelligent speech and the written word. In time, communication links expanded from local, to global, to galactic. It was the introduction of electronics, however, that enabled the modern information revolution. The earliest, analog electronics, gave rise to such innovations as the plain old telephone system (POTS), radio, television, radar/sonar and a host of other inventions that have revolutionized man’s life. With the introduction of digital technologies over a half century ago, man has witness an explosion of innovations that have facilitated the conversion of many of the analog solutions to system having a high digital content. In other instances, digital technology has enabled solutions that previously never existed. Included in this list include digital entertainment systems, digital controllers, digital cameras, digital mobile telephony, and so forth. In some cases, digital technology has been a disruptive technology , giving rise to products that where impossible to envision prior to the technologies existence. An example of this is the now ubiquitous personal digital computer. Origins of Modern Signal Processing The foundations of modern signal processing were laid in the middle of the 20 th Century. To some the master mason was Claude Shannon, and others, Harry Nyquist. Both can be credited with formulating a sampling theorem that described how a continuous signal could be represented by a set of periodic samples. The representation was found to be so perfect that the original signal could be reconstructed from a sparse set of discretely distributed samples. The work of Shannon and Nyquist provided both the key and the motivation to convert signals from their natural continuous- time form into a domain characterized by sample values which, today, and digital words. Since then analog and digital technologies have increasingly been fused together to define a technical area called digital signal processing (DSP). During the 1950s, and into the 1960s, digital computers began to make their initial appearance on the technology scene. These early computing machines were considered to be far too costly to be used in the mundane role of signal analysis or as a laboratory support tool by lowly engineers. In 1965, Cooley and Tukey introduced an algorithm that is now known as the
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This note was uploaded on 08/21/2010 for the course EEL 3135 taught by Professor ? during the Spring '08 term at University of Florida.

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Lesson_20 - EEL 3135 Dr. Fred J. Taylor, Professor Lesson...

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