信号的抽样及抽样定理 加深理解连续时间信号的离散化过程中的数学概念和物理概念，掌握时域抽样定理的基本内容，观察取样信号的频谱混叠现象；-Signal sampling and sampling theorem to deepen understanding of the discrete-time signal continuous process of mathematical concepts and physical concepts, time domain sampling the