本文通过matlab分析信号在不同采样频率和变换点数的FFT下的频谱图，研究采样频率和变换点数对信号FFT的影响。同时还讨论了信号在不同频带噪声背景下的采样频率和变换点数的选择。-In this paper, matlab sampling frequency of the signal at different points in the FFT and transform under the frequency spectrum, change the sampling frequency and FFT of the signal points. Also discussed the noise signal in the context of different frequency bands and transform points sampling frequency selection.