6. Fundamental Theory of Constant Envelope Multiplexing for Spread-Spectrum Signals

This chapter offers an in-depth discussion of the basic theory of constant envelope multiplexing (CEM) for satellite navigation signals. It mathematically models the constant envelope multiplexing process of general satellite navigation signals and gives mathematical and geometric descriptions of the constant envelope on the basis of the baseband complex envelope concept. Further, the concepts of the phase mapping table, constellation diagrams, and multiplexing efficiency are given. Then, starting from the intermodulation component structure and the phase mapping table, this chapter explores the design equations and analysis methods of general constant envelope multiplexing technology of these two seemingly disparate constant envelope multiplexing design concepts. Finally, by using the concept of the baseband signal to unify the conclusions of the two viewpoints, three equivalent representations of a constant envelope multiplexing scheme are discussed. We believe that with this elaborate text structure, this chapter will give the reader a global overview of CEM highlighting connections and differences between the assorted techniques.