设计一M阶自适应回波抵消器，已u(n)作为系统输入，d(n)作为系统期望响应，其中d(n)中混有u(n)的回声，信号以8kHz采样，现要求回波抵消器可以消除16ms之内的回声,The design of a M-order adaptive echo cancellation, and have u (n) as the system input, d (n) as a system to respond to the expectations, in which d (n) in a mixt