Saturday, January 3, 2009

Booms Bubbles and Busts in the Us Stock Market or Physical Principles of Wireless Communications

Booms, Bubbles and Busts in the Us Stock Market

Author: David L Western

Why did US stock markets experience such a huge bubble in the 1990s? Why did Greenspan 'allow' the bubble to occur? Why did investors appear to act irrationally and indulge in such vehement speculations? Why the euphoria?

This book examines the American stock market during one of its most intriguing periods. By turning his critical eye upon the rise of the stock market bubble during the 1990s boom years and its inevitable crash some years later, David L. Western has written a scholarly yet readable book. Providing historical background as well as solid statistical research, the book helps to explain the mysteries of the stock market in an authoritative manner.

Advanced undergraduate and postgraduate and postgraduate students will find this to be an enlightening read, whilst readers with an interest in how the biggest economy in the world got things badly wrong will find this to be a book that remains useful as a reference for many years to come.



See also: World Religions Cookbook or Catering Solutions

Physical Principles of Wireless Communications

Author: Victor L Granatstein

Wireless communications are based on the launching, propagation, and detection of electromagnetic waves emitted primarily at radio or microwave frequencies. Their history can be traced back to the mid-19th century when James Clerk Maxwell formulated the basic laws of electromagnetism and Heinrich Hertz demonstrated the propagation of radio waves across his laboratory. Recent engineering breakthroughs have led to wireless communication systems that have not only revolutionized modern lifestyles, but have also launched new industries. Based on the author's course in the physics of wireless communications, Physical Principles of Wireless Communications provides students with a solid foundation in modern wireless communication systems. It offers rigorous analyses of the devices and physical mechanisms that constitute the physical layers of these systems. Starting with a review of Maxwell's equations, the textbook details the operation of antennas and antenna arrays, teaching students how to perform the necessary design calculations. It also explores the propagation of electromagnetic waves, leading to important descriptions of mean path loss. The text also reviews the principles of probability theory, enabling students to calculate the margins that must be allowed to account for statistical variation in path loss. In addition, it covers the physics of Geostationary Earth Orbiting (GEO) satellites and Low Earth Orbiting (LEO) satellites so students may evaluate and make first-order designs of satellite communications (SATCOM) systems.



Table of Contents:
Figure Legends     xiii
List of Tables     xvii
Preface     xix
Acknowledgments     xxi
About the Author     xxiii
An Introduction to Modern Wireless Communications     1
A Brief History of Wireless Communications     1
Faraday, Maxwell, and Hertz: The Discovery of Electromagnetic Waves     2
Guglielmo Marconi, Inventor of Wireless Communications     5
Developments in the Vacuum Electronics Era (1906 to 1947)     10
The Modern Era in Wireless Communications (1947 to the Present)     11
Basic Concepts     13
Information Capacity of a Communication Channel     13
Antenna Fundamentals     14
The Basic Layout of a Wireless Communications System     15
Decibels and Link Budgets     17
Characteristics of Some Modern Communication Systems     19
Mobile Communication Systems and Cell Phones     19
Wireless Local Area Networks (WLANs) of Computers     27
SATCOM Systems     27
The Plan of This Book     29
Noise in Wireless Communications     33
Fundamental Noise Concepts     33
Radiation Resistance and Antenna Efficiency     33
NyquistNoise Theorem, Antenna Temperature, and Receiver Noise     35
Equivalent Circuit of Antenna and Receiver for Calculating Noise     38
Contributions to Antenna Temperature     40
Cosmic Noise     40
Atmospheric Noise     42
Big Bang Noise (Cosmic Microwave Background Radiation)     44
Noise Attenuation     47
Noise in Specific Systems     48
Noise in Pagers     48
Noise in Cell Phones     49
Noise in Millimeter Wave SATCOM     49
Antennas     53
A Brief Review of Electromagnetism     53
Maxwell's Equations and Boundary Conditions     53
The Vector Potential, A, and the Inhomogeneous Helmholtz Equation     57
Radiation from a Hertzian Dipole     58
Solution of the Inhomogeneous Helmholtz Equation in the Vector Potential A     58
Near Fields and Far Fields of a Hertzian Dipole     61
Basic Antenna Parameters     63
Directive Gain, D([phi], [theta] Directivity, D; and Gain, G     65
Radiation Resistance of a Hertzian Dipole Antenna     66
Electrically Short Dipole Antenna (Length [double less-than sign lambda])     67
Receiving Antennas, Polarization, and Aperture Antennas      70
Universal Relationship between Gain and Effective Area     70
The Friis Transmission Formula     74
Polarization Mismatch     74
A Brief Treatment of Aperture Antennas     76
Thin-Wire Dipole Antennas     80
General Analysis of Thin-Wire Dipole Antennas     82
The Half-Wave Dipole     84
Antenna Arrays     89
Omnidirectional Radiation Pattern in the Horizontal Plane with Vertical Focusing     89
Arrays of Half-Wave Dipoles     89
Co-linear Arrays     90
Co-linear Arrays with Equal Incremental Phase Advance     92
Elevation Control with a Phased Co-linear Antenna Array     94
Antennas Displaced in the Horizontal Plane     96
Radiation Pattern of Two Horizontally Displaced Dipoles     97
Broadside Arrays     99
Endfire Arrays     99
Smart Antenna Arrays     102
Image Antennas     103
The Principle of Images     103
Quarter-Wave Monopole above a Conducting Plane     103
Antennas for Handheld Cell Phones     105
Half-Wave Dipoles and Reflectors     105
Rectangular Microstrip Patch Antennas     110
The TM[subscript 10] Microstrip Patch Cavity     110
Duality in Maxwell's Equations and Radiation from a Slot     112
Radiation from the Edges of a Microstrip Cavity     113
Array of Microstrip Patch Antennas     118
Radio Frequency (RF) Wave Propagation     121
Some Simple Models of Path Loss in RF Wave Propagation     122
Free-Space Propagation     122
Laws of Reflection and Refraction at a Planar Boundary     123
Effect of Surface Roughness     126
Plane Earth Propagation Model     127
Diffraction over Single and Multiple Obstructions     130
Diffraction by a Single Knife Edge     130
Deygout Method of Approximately Treating Multiple Diffracting Edges     135
The Causebrook Correction to the Deygout Method     137
Wave Propagation in an Urban Environment     139
The Delisle-Egli Empirical Expression for Path Loss     139
The Flat-Edge Model for Path Loss from the Base Station to the Final Street     141
The Ikegami Model of Excess Path Loss in the Final Street     143
The Walfisch-Bertoni Analysis of the Parametric Dependence of Path Loss     144
Statistical Considerations in Designing Cell Phone Systems and Wireless Local Area Networks (WLANs)     151
A Brief Review of Statistical Analysis     151
Random Variables     151
Random Processes     153
Shadowing     153
The Lognormal Probability Distribution Function     154
The Complementary Cumulative Normal Distribution Function (Q Function)     154
Calculating Margin and Probability of Call Completion     155
Probability of Call Completion Averaged over a Cell     157
Additional Signal Loss from Propagating into Buildings     159
Shadowing Cross-Correlation     161
Slow and Fast Fading     163
Slow Fading     163
Rayleigh Fading     164
Margin to Allow for Both Shadowing and Rayleigh Fading     166
Bit Error Rates in Digital Communications     167
Ricean Fading     170
Doppler Broadening     171
Wireless Local Area Networks (WLANs)     173
Propagation Losses inside Buildings     173
Standards for WLANs     176
Sharing WLAN Resources     177
Tropospheric and Ionospheric Effects in Long-Range Communications     181
Extending the Range Using Tropospheric Refraction     181
Limit on Line-of-Sight Communications     181
Bouguer's Law for Refraction by Tropospheric Layers     183
Increase in Range Due to Tropospheric Refraction     185
Long-Range Communications by Ionospheric Reflection     187
The Ionospheric Plasma     187
Radio Frequency Wave Interaction with Plasma     189
Sample Calculations of Maximum Usable Frequency and Maximum Range in a Communications System Based on Ionospheric Reflection     192
Propagation through the Ionosphere     194
Time Delay of a Wave Passing through the Ionosphere     194
Dispersion of a Wave Passing through the Ionosphere     195
Faraday Rotation of the Direction of Polarization in the Ionosphere     196
SATCOM     205
Satellite Fundamentals     205
Geosynchronous Orbit (GSO)     205
Example of a GSO SATCOM System     207
SATCOM Signal Attenuation     208
Attenuation Due to Atmospheric Gases     208
Attenuation Due to Rain     209
The Rain Rate Used in SATCOM System Design     212
Design of SATCOM Systems     214
Noise Calculations for SATCOM     214
Designing a GSO SATCOM System for Wideband Transmission     219
Global Positioning Systems (GPSs) and General Relativity     221
Low Earth Orbit (LEO) Communication Satellites     222
The Iridium LEO SATCOM System     223
Path Loss in LEO SATCOM     223
Doppler Shift in LEO SATCOM     227
Glossary     231
English Alphabet     231
Greek Alphabet     236
Table of Physical Constants     239
Del Operators in Cartesian and Spherical Coordinates     241
Differential Line, Area, and Volume in Cartesian and Spherical Coordinates     243
Index     245

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