All electromagnetic compatibility (EMC) problems can be traced back to integrated circuit (IC). Thus, the research on electromagnetic compatibility of integrated circuit is the main topic of this book. Among all research methods on EMC, measurement of immunity and emission of IC is the basic method. This book talks about how to do the EMC measurement of IC using standard methods and improved methods. After research the behavior of IC under the pressure of interference, the book presents the basics and concepts of hardware methods to improve the immunity of IC. An interference detection method to improve the immunity of IC is also presented in the book. Beside the hardware method, defensive software methods can also be used to improve the immunity of IC. Compared to hardware methods, the software method is economical. Combined of interference detection method, defensive software methods are very effective.