Tech: Lasers/RF-CDMA


Introduction to Laser Physics is a compilation of material developed over the years while teaching a number of informal classes on laser theory to undergrads, technicians, and engineers. The primary goal in this effort was to make the mechanisms behind lasing accessible to as wide an audience as possible, ranging from those with no prior exposure to the subject of Quantum Physics, to those with some grasp of the subject.

To that end, a concerted effort has been made to defang the math in the initial sections of each chapter as much as possible, postponing the more rigorous material to the latter sections and appendices for completeness. In an attempt to achieve this “user friendly” goal, a range of basic models and analogous examples are developed, including an initial look at the laser as a “Carnot engine”, as well as the classical ball-and-spring model for atoms and molecules. These examples are then refined using Quantum models in order to explain aspects of lasing that cannot be understood using classical physics alone. Hopefully most readers will find this more “user friendly” approach helpful, allowing each individual to explore the various aspects of lasers to a depth that suits their needs and background.


Spread Spectrum CDMA by Steve Lee offers a comprehensive overview of 2G and 3G cellular implementations of Code Division Multiple Access (IS-95 and IS-2000). Beginning with a basic description of the typical wireless link (e.g. RF propagation, link budget analysis, digital modulation, etc.), the text then progresses the reader through an understanding of how CDMA works (e.g. the use of Pseudo-Random Noise codes and orthogonal Walsh Codes, Direct Sequence Spreading gain, recovering energy previously lost via multipath reflections, etc.), and the significant advantages CDMA offers in a multi-user environment over existing 2G/3G wireless technologies. To provide something of a “real world” application of CDMA in action, the text also offers a basic “day-in-the-life” overview of a generic CDMA cell phone operating on a typical wireless network.

This book is highly recommended for technicians and engineers with a basic background in wireless technologies, and who are looking to expand that knowledge to understand how Direct Sequence Spread Spectrum CDMA works, and the advantages it offers in improving the capacity of a wireless system in a multi-user environment.