An explicit expression to compute the h norm of the discrete - time symmetric system is established using the bounded real lemma . one explicit solution of stabilizing output feedback gains is obtained for the output feedback stabilization problem . ah explicit expression for h norm and the sub - optimal output feedback controllers have been obtained for the h control problem 证明边界实引理在离散对称系统时有单位矩阵解，利用这一性质给出一个计算h ~范数的格11浙江大学博士学位论文式，并给出对称输出反馈可稳定问题的一个明显解和h ”控制次优输出反馈控制器。
