In the body of the dissertation , different performance indexes are defined and analyzed based on the analysis of different types of fwl errors in digital controller , and different fwl digital controller design and realization problems are considered and solved . the major contributions of this dissertation are as follows : considering the fwl errors of controller coefficients , define and analyze the closed - loop transfer function sensitivity measure with respect to the controller coefficients , obtain the optimal controller realizations via minimizing the transfer function sensitivity measure 本論文首先對數字系統,特別是數字控制器設計與實現中的有限字長問題和非脆弱控制器設計的背景、歷史發展情況等作了簡單介紹,然后通過分析數字控制器中不同來源的有限字長誤差,定義不同的性能指標,較系統地分析并討論不同的有限字長數字控制器設計和實現問題。