若采样周期为，求采样后的离散时间信号；又设A/D变换的量化步长为 ，求量化后的数字信号，并绘出曲线。-If the sampling cycle is, evaluates to the sampled discrete-time signal　Suppose the quantization step size for the A/D conversion, seeking the digital signal after the quantization, and plotted curve.