在本論文中提出一個簡單的分集計畫(diversity scheme)，探討其在相加性白高斯雜訊通道(AWGN channel)環境的效能。在傳送端，包含非線性區塊的編碼器和M陣列相移鍵(MPSK)的調變器兩部分。這裡考慮頻譜效益保留、頻譜效益擴展和頻譜效益縮短的情況。在接收端，使用最大可能性(ML)同調偵測的分析來逐字接收分集信號。按照碼價值計算(CMF)作為聯合邊界的辦法，使用碼搜尋程序可搜尋好的分集碼，並且拿它們與錯誤更正碼作比較。分集系統使用尋得的短碼展現出好的性能增益而且有小的處理延遲。最後，探討分集編碼系統的相位同步誤差(imperfect phase synchronization )之效能影響。 A simple diversity scheme  which operates on an AWGN channel is proposed in this thesis. The transmitter consists of a nonlinear block encoder and MPSK modulator. Bandwidth-preserving, bandwidth-expanding and bandwidth-reducing signaling formats are considered. The performance analysis with maximum-likelihood (ML) coherent receiver is presented to detect the received diversity signal codeword by codeword. According to the union bound as the code merit figure (CMF), useful short diversity codes are searched based on the code search procedure and compared with error control codes. It is concluded that diversity systems using the found short-blocklength codes not only exhibit good performance gain but also little procession delay. The effect of imperfect phase synchronization to the proposed diversity coding systems is also taken into account in this thesis.