Research On Constant Envelope And Quasi-constant Envelope Modulation & Demodulation Technology

Compared with other modulation techniques, the Constant Envelope and Quasi-constant Envelope Modulation&Demodulation technologies are insensitive to the non-linear characteristic of the power amplifier because of the constant envelope. Furthermore, when the phase is continuous, they could provide high power and bandwidth efficiency. Due to the low out-of-band radiation, the interfere between channels is also small. Therefore, similar to the OFDM technique, the Constant Envelope and Quasi-constant Envelope Modulation&Demodulation technologies are also hot research spots in resent years. They are widely used in the field of the Deep-Space Communications.This thesis focuses on the Constant Envelope Modulation such as the Phase-Shift Keying modulation and the Continuous Phase Modulation (CPM), and the Quasi-constant Envelope Modulation including IJF-OQPSK and FQPSK. Via the theoretical study and system simulation, we have accomplished the analysis of modulated wave envelope, phase properties, spectrum efficiency, power efficiency, and the implementation of Modulation&Demodulation System. And a number of key technologies of the CPM are studied. For MSK Modulation, we have proposed the optimal baseband filtering algorithms in order to improve the spectrum efficiency At the end of this thesis, a serially concatenated coded-modulation system with TCM (trellis coded modulation) code followed by a CPM is put forward and researched. Through the simulation evaluation, this proposal is proved to be highly power-efficient.