y trial and error. With the evolution of mobile networks, the requirement for frequency synchronization broadened to include phase synchronization. The challenges faced by designers of equipment and networks for frequency distribution are also present in phase, but with an additional set of challenges that come on top. An additional factor is that recent international standards from the ITU Telecommunication Stand- ardization Sector (ITU-T) specify tighter performance requirements for the transfer of phase. Com- bined with the increasing criticality of accurate phase synchronization to the future mobile network (due to the forecasted far-higher numbers of radio stations resulting in increased overlapping broad- cast footprints), and the use of time/phase in several emerging applications, it has never been more important to ensure that quality and performance are robustly designed in at every stage of the life cycle. Many other industry sectors are now looking at the need to include time as a core element of their architecture; for example, factory automation, audio/video systems, financial networks utilizing ma- chine trading, and SO on. Although the accuracy requirements will vary between applications, sev- eral application-specific implementation challenges will arise. Core to all of these applications is an understanding of the dynamics of time/phase transfer. Under- standing these principles, the challenges involved, and the effects that cause problems is vital. Most importantly, if you are a designer, understanding how to mitigate against problems that impede reli- able time/phase delivery is critical. Once you develop this knowledge for one application, you will be able to use these skills to design synchronization networks that meet the specific needs of any application that requires time/phase. As you can see from looking at the table of contents of this book, there are many dimensions and areas of knowledge involved in developing a broad and deep understanding of all aspects of syn- chronization. If deep