Research And Realization Of Constant Envelope Modulation And Demodulation Technology

The signal generated by constant envelope modulation technology has constant envelope, which has good performance on fully using satellite resource, when the high-power amplifier is working on the non-linear amplify state. As these reasons, constant envelope modulation technology has employed in many satellite communication applications.Firstly, this thesis starts from constant envelope modulation, which has studied very familiar now. Basing on observing the changing of signal's phase, we divide the constant envelope modulation into discontinuous phase modulation and continuous phase modulation, then we compare them in the satellite channel which is band-limited and non-linear. Then, we conclude that CPM is more efficient and equal to working in the amplifier's non-linear area, so we take CPM as the main object to research.Secondly, we take further research on the demodulation algorithm of CPM. Aim at the complexity of demodulation which is brought by CPM signal with memory, we introduce Laurent decompose to change the expression of CPM, then, we designed the optimal and sub-optimal receiver for CPM, between them, the sub-optimal receiver can reduce the complexity of demodulation for CPM.Thirdly, considering that high-level modulation takes more advantage to high-rate data transmission, and now the modulation level of CPM is not so high mostly, we designed a 8PSK modulation which owns continuous phase called CP8PSK-1REC.And, we designed the CP8PSK-1REC receiver based in Laurent decompose, after then, analyze and compare the symbol error rate characteristic of CP8PSK-1REC and 8PSK when they're working on the non-linear amplify state.Finally ,and at last we realize the CP8PSK-1REC modulation signal through FPGA.