傅里叶原理是“信号与系统”课程重要的教学内容,是信号分析与系统分析的基础理论,傅里叶分析将时间变量变换成频率变量,揭示了信号内在的频率特性以及信号时间特性与其频率特性之间的密切关系,从而导出了信号的频谱、带宽以及滤波、 Fourier theory is an important teaching content in the Course of Signal and System. It is the basic theory of signal analysis and system analysis. Fourier analysis transforms time variables into frequency variables, revealing the inherent frequency characteristics of signal and signal time Characteristics and its frequency characteristics of the close relationship between the derived signal spectrum, bandwidth and filtering,