本論文主要是根據 DMSK (Duobinary Minimum Shift Keying) 調變 系統的編碼架構,來設計一種新的 ŕ-bit" 相差解調 (Differential De- modulation). 傳統 DMSK 的相差解調在傳送器 (transmitter) 的設計上, 包括一相差產碼器 (precoder);然而近代發現,任何的 CPM (Continuous Phase Modulation) 皆可分解成一線性編碼器或無記憶性調變之組合,而 此線性編碼器本身即具備有相差產碼之功能.而本論文所研究之 DMSK 相 差解調,即在研究設計上無須外加相差產碼之可行性. 研究發現,一種新的 1-bit 相差解調方法,不但可省去外加相差產碼 器,而模擬結果顯示其傳統相差解調方法在性能上幾乎相同.

This project is to design a new ŕ-bit" differential demodulation which is mainly based on the encoding structure of DMSK modulation sys- tem. In the design of the transmitter of traditional DMSK differential demodulation, a precoder is included. According to recently research, we find that any type of CPM can be decomposed to the combination of "continuous phase encoder"(CPE) and "memoryless modulator"(MM), in which the CPE has the same function as a precoder. This project is to research the reliability of the design of DMSK differential demodulation without precoder. In this project we find that precoder is not necessary in this new 1-bit differential demodulation, and the simulation result also shows that the performance of the approach of this project and traditional approach are almost the same.