Overview
Module 1 presents the topics required to understand the key concepts of digital communications. It goes over the concepts from a prerequisite course in signal analysis, such as filtering, bandwidth, or power spectral density. It then introduces the important concept of intersymbol interference and its roots in a bandlimited channel. It also includes a brief introduction to random processes, focusing on the gaussian model of the noise. Finally, it touches on the formatting of numerical data.
Videos
Signals, filtering and bandwidth
Spectral density and random signals
- ESD vs. PSD
- Random processes
- Wise sense stationary (WSS) random process
- WSS example and counter example
- Power Spectral Density example
- Additive White Gaussian Noise (AWGN)
Formatting and modulation
Course notes
Objectives
Signals, filtering and bandwidth
- review concepts from the prerequisite course "Signal analysis"
- know various bandwidth definitions
Spectral density and random signals
- appreciate the difference between ESD and PSD
- be able to manipulate autocorrelation functions
- understand wide sense stationarity and ergodicity
- appreciate random process concepts regarding noise and data
- understand the concept of additive white Gaussian noise (AWGN) and its filtered (colored) version
Formatting and modulation
- appreciate analog-to-digital conversion concepts
- appreciate uses of line codes
- understand PCM (pulse coded modulation) and PAM (pulse amplitude modulation)
- understand the trading off of spectral efficiency, performance and complexity (cost)
- understand the source of pulse dispersion and intersymbol interference (ISI)
Reading
Sklar textbook
- section 1.2 Classification of Signals
- section 1.6 Signal Transmission through Linear Systems
- section 1.7 Bandwidth of Digital Data
- section 1.3 Spectral Density
- section 1.4 Autocorrelation
- section 1.5 Random Signals
- section 2.4 Formatting Analog Information
- section 2.5 Sources of Corruption
- section 2.6 Pulse Code Modulation