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Television Technology Demystified > Digital Television - Pg. 67

Digital Television 5 In the 1970s, digital technology in television appeared timidly, almost through the back door, as an already mature technology widely used in different areas of telecommunications and in the computer industry. In fact, one could say that it was an old technology since it is possible to trace the first mention of something resembling a digital approach to the works of the famous English scientist and philosopher Roger Bacon, who lived in the thirteenth century. Six centuries later, English mathematician Charles Babbage developed the necessary mathematical apparatus for this technology, and in 1937 another Englishman, an engineer this time, Alec Reeves, submitted the first patent describing a possible application of PCM (pulse code modulation) in the transmission of speech. Nevertheless, several decades of development of electronic devices and circuitry would have to pass before Reeves's ideas could be implemented. 5.1 What Is a Digital Signal? What is the meaning of digital? What is a digital signal? What is the difference