Electrical Communications Systems ECE.09.433 Introduction Dr. Shreek Mandayam Electrical & Computer Engineering Rowan University

Plan Why are we studying ECOMMS? What is a communications system? 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……………………………)

What is a communications system? Communications Systems: Systems designed to transmit and receive information Info Source Sink Comm System

Block Diagram m(t) message from source n(t) noise Transmitter Tx s(t) Info Source n(t) noise Transmitter Tx s(t) transmitted signal Receiver Rx received message to sink Channel r(t) received signal 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)

ECOMMS: What are we studying? Electrical Communications Systems Measures of information and noise Capacities for information transmission Design of communications systems Measures of performance Communications circuits Communications protocols Hardware INdependent dependent

ECOMMS: Topics Receiver Rx Transmitter Tx s(t) Channel r(t) m(t) Noise Wire/wireless Antennas/ Coupling Antennas/ Coupling Demodulation circuits and systems DSP Modulation circuits and systems DSP Analog/digital Protocols Fundamental limits

ECOMMS: Details

Textbook and Resources Leon W. Couch II, Digital and Analog Communication Systems, 8th Edition, Pearson, 2013.   Professor Couch's Companion Website for the Textbook: http://www.couch.ece.ufl.edu/ Communications Toolbox https://www.mathworks.com/help/comm/index.html

Summary