S. Mandayam/ECE Dept./Rowan University Digital Communications / Fall 2002 Shreekanth Mandayam ECE Department Rowan University Lecture 2 September 16, 2002

S. Mandayam/ECE Dept./Rowan University Plan ECOMMS Review QUIZ Baseband Data Transmission Digital Signaling Orthogonal representation Vector Representation Binary and Multilevel Signals Baud Rate, Bit Rate and Bandwidth

S. Mandayam/ECE Dept./Rowan University Digital Communications Transceiver Anti- aliasing Filter SamplingQuantization Data Encryption Encoder Source Encoder Error Control Encoder Channel/ Line Encoder Modulator MUX Audio Amp Source Decoder Data Encryption Decoder Error Control Decoder Equalization / Decision Circuits Demod- ulator DEMUX Reconstruction/ DAC ADC CODEC MODEM Analog o/p Multiple access channel Analog i/p

S. Mandayam/ECE Dept./Rowan University Vector Representation of a 3-bit Binary Signal s(t) T T 0 =3T t 5V p 1 (t) t 5V t p 2 (t) t 5V p 3 (t) 0 T 2T 3T p(t) T t 5V 11 s 22 33 Digital signal Bit shape pulse Orthogonal set Signal vector

S. Mandayam/ECE Dept./Rowan University Multilevel Signaling Binary Source l-bit DAC Binary signal D symbols/second = R bits/second L=2 l Multilevel Signal D symbols/second = R/l R bits/second

S. Mandayam/ECE Dept./Rowan University Summary