Data Communication Theory & Coding

Data Communication Theory & Coding

http://eent3.lsbu.ac.uk/staff/baoyb/dctc

1

Ya Bao

2

Website:http://eent3.lsbu.ac.uk/staff/baoyb/dctchttp://www.lsbu.ac.uk/bb/

Methods of Teaching and Learning : Lectures, Tutorials and WorkshopsAssessment of the Module :2-hour written examination -- 70% Laboratory report -- 30% Lecturer: Ya Bao and J G ZhangLab tutor: Ya Bao and Vincent Siyau.Ya Bao

Text Books

3

Ya Bao

Ya Bao

4

Chapter 1. Introduction

5

Ya Bao

table_01_01a

table_01_01a1.1 Historical Background

6

Ya Bao

1.2 The Block Diagram of a Communication Systems

7

Ya Bao

1.3 Channel Characteristics

8

Types of transmission channels

• Electromagnetic wave propagation channels (wireless)• Guided electromagnetic wave

channels (wired)• Optical links

Ya Bao

1.4 System analysis techniques

9

a.Time-domain and frequency-domain analysesSignal frequency and signal bandwidth, Fourier Analysis

b.Modulation and communication theoriesChanging some parameter of a carrier wave in accordance with the message signal.

c. Detection theoryd. Probability theory

Ya Bao

Ya Bao

10

1.5 The Electromagnetic Spectrum1. Electromagnetic Waves and Energy Velocity: speed at which the energy

travels through Frequency: the number of oscillations or

cycles per second (hertz, abbreviated Hz) of the waveform

Wavelength: the distance between peaks of the oscillations of the energy wave

frequencyvelocitywavelength

Ya Bao 11

Wavelength can also be measured as the distance between the negative peaks, zero points.

Ya Bao 12

speed of light: The propagation velocity is less in any medium

other than vacuum In wire, it is anywhere from 60% to 85% of c a common type of cable used for cable TV has a

propagation factor of 75% of c. Example 1What is the wavelength in vacuum for a frequency of

1 million hertz?Example 2What is the frequency when the measured

wavelength is 6 m?

smc /103 8

Ya Bao 13

1.6 THE ELECTROMAGNETIC SPECTRUM

Ya Bao 14

Frequency Range Designations---------------------------------------------------

30 Hz‑----300 Hz ELF 0.3 kHz‑--3 kHz VF3 kHz-----‑30 kHz VLF 30 kHz‑---300 kHz LF 0.3 MHz‑-3 MHzMF3 MHz‑----30 MHz HF 30 MHz---300 MHz VHF 0.3 GHz‑--3 GHz UHF 3 GHz‑----30 GHz SHF 30 GHz‑---300 GHz EHF 0.3 THz‑---3 THz Infrared light3 THz‑------30 THz Infrared light30 THz‑----300 THz Infrared light0.3 PHz‑---3 PHz Visible light3 PHz‑-----30 PHz Ultraviolet light30 PHz‑----300 PHz X‑rays0.3 EHz‑---3 EHz Gamma rays3 EHz‑------30 EHz Cosmic rays

1 kilohertz (kHz)= 103 Hz, 1 megahertz (MHz)= 1*106 Hz 1 gigahertz (GHz)= 1*109 Hz,

1012 : terahertz (THz); 1015 : petahertz (PHz); 1018 : exahertz (EHz);