摘要: The lifting technique is now a well recognized tool for H1 design and analysis of sampled-data systems. However, the efficiency of the method depends on the structure of the problem. The structure of the H1 sensitivity problem is analyzed in this paper. And the constraints on the H1-optimization problem and on the design parameters in lifting design are also discussed. Under such constraints the resulting performance from the design is generally low. Therefore, the lifting technique can not be recommended as a synthesis tool for the sampled-data systems. An example is also given in the paper.