傅里叶变换 复杂信号描述为一组正弦信号的叠加 Fundamental frequency +0.5× 2×fundamental +0.33× 3×fundamenta1 N +0.25× 4 x fundamental +0.5× 5×fundamental傅里叶变换 11 复杂信号描述为一组正弦信号的叠加