本文提出设计公式(1)和(2)。它们给一般工程上应用提供了有用的设计依据。这些公式的提出,是以M法(振荡指标法)为基础的,并利用了Z变换直接求解的方法对公式进行了校验,其结果和表Ⅰ所列数值相近。本文最后提出了新的含有M的评价函数J_1=intgral from n=0 Me~2(t)dt,并举了一个用J_1的极小值来作为最优设计的例题。这对于实际系统的应用是十分有价值的。 This paper presents design formulas (1) and (2). They provide a useful design basis for general engineering applications. The formulation of these formulas is based on the M method (Oscillatory Index method), and the formula is directly verified by the Z-transform method. The results are similar to those in Table I. In the end of this paper, a new evaluation function with M is proposed, which is J_1 = intgral from n = 0 Me ~ 2 (t) dt. An example is given by using the minimum of J_1 as the optimal design. This is very valuable for the practical application of the system.