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Explore the world of electrical communications systems covering technology successes, trends, Shannon’s Theorem, noise limitations, and more. Learn about block diagrams, wireless evolution, and course logistics in this comprehensive study.
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Electrical Communications SystemsECE.09.433Spring 2019 Lecture 1aJanuary 22, 2019 Shreekanth Mandayam ECE Department Rowan University http://users.rowan.edu/~shreek/spring19/ecomms/
Plan • Why are we studying ECOMMS? • Technology successes, Trends and Decisions • What is a communications system? • Objectives • Block diagram • What limits our ability to communicate? • Fundamental limits - Shannon’s Theorem • Wireless communications evolution • What are we studying in this course? • Course logistics
Communications: Where are we? ??? 1975 2019 www.apple.com (what the consumer sees……………………………)
Communications: Where are we? ? 1950 2019 www.samsung.com (what the consumer sees……………………………)
Info Sink Info Source Comm System What is a communications system? • Communications Systems: Systems designed to transmit and receive information
Info Source m(t) message from source n(t) noise Receiver Rx Transmitter Tx Channel received message to sink s(t) transmitted signal r(t) received signal Block Diagram Info Sink
What limits our ability to communicate? • NOISE!!!!! • Noise: an unwanted, random fluctuation in the signal • Without the effects of noise, a message with infinitesimally small power could be transmitted over infinitely large distances • ALL advances in communications technology are advances to combat the effects of noise
Fundamental Limit: Shannon’s Theorem (1948,1949) • Theoretical limit for error-free transmission in a communications system in the presence of noise • Source Data Rate: R [bits/sec] • Channel Capacity: C = B log2(1 + S/N) [bits/sec] • R < C: No Error!!!
Mars Orbiter (Odyssey/Mars Global Surveyer) 12k – 3.5k bps DSN Antenna (on Earth) X-Band 128 kbps Mars Rover (Spirit/Opportunity)
Hardware dependent Hardware INdependent ECOMMS: What are we studying? Electrical Communications Systems • Communications protocols • Measures of information and noise • Capacities for information transmission • Design of communications systems • Measures of performance • Communications circuits
Receiver Rx Transmitter Tx Channel m(t) s(t) r(t) ECOMMS: Topics Noise Wire/wireless Antennas/ Coupling Demodulation circuits and systems DSP Antennas/ Coupling Modulation circuits and systems DSP Analog/digital Protocols Fundamental limits
ECOMMS: Course Logistics http://users.rowan.edu/~shreek/spring19/ecomms/ No Lab Today!!!!