中文说明：
信号频谱分析，观测已知方波信号、正弦波信号的频谱 分析频率为4KHz、8KHz的占空比为50 的方波信号、正弦波信号的频谱。记录所得频谱图。 观测实时模拟信号（语音）的频谱 用音频设备采集一段语音，将语音存为.wav格式。对wav文件作分段傅里叶变换分析。语音是分音节的，应把它分段分析，而且实际运用中的数字信号处理的FFT的点数是有限的，一般只能达到千点。用傅里叶反变换IFFT，从频域恢复信号。画出频谱图和语音波形图。
English Description：
Signal spectrum analysis, observation of known square wave signal, sine wave signal spectrum _ analysis frequency of 4 KHZ, 8 of duty ratio of 50 KHZ square wave signal, sine wave signal spectrum.Record the spectrum diagram._ observation of the frequency spectrum of real-time analog signal (voice) _ with audio equipment acquisition section of voice, the voice for. Wav format.Segmenting the wav files for Fourier analysis.Voice is syllabify, should put its piecewise analysis, and practical application of digital signal processing of FFT points is limited, normally only reached thousands of points.By inverse discrete Fourier transform (IFFT), and to recover from a frequency domain signals.Voice waveform and spectrum diagram plotted on a graph.