说明：  对于参数估计问题,克拉美罗界(简称CRB)为任何无偏估计量的方差确定了一个下限. 即不可能求得方差小于下限的无偏估计量,并为比较无偏估计量的性能提供了一个标准. 本程序对CLRB（克拉美罗下界）进行了描述，预留了参数。 希望能对同志们提供帮助。
(For the parameter estimation problem, Cramer-Rao bound (referred to as CRB) for any unbiased estimator of variance to determine a lower limit that can not be obtained is less than the minimum variance unbiased estimator and unbiased estimator for comparing the performance of provides a standard procedure for this CLRB (Cramer-Rao lower bound) for a description of the reserved parameters. Hoping to help comrades.)