说明：  设计一个20Hz~20KHz范围内的频谱分析仪（用计算机声卡）； 要求： 1） 用计算机声卡实时采集语音信号，并实时显示时域波形信号； 2） 可以从计算机中读取语音信号文件，并能够实时显示时域波形信号； 3） 实现对信号进行幅度上的放大、缩小，存储等； 4） 实时显示信号的频谱，信号的频谱分辨率可以进行设置； 5） 采用常见的低通、高通、带通、带阻（50hz）滤波器对信号进行滤波，滤波器阶数可调，带宽可调，观察信号频谱的变化； 6） 对信号频谱进行非实时高分辨率分析； 7） 编制GUI用户界面。 8）掌握声卡模拟端输入的电压电路规格，并进行物理信号的测量；
(Design a spectrum analyzer (with computer sound card) in the range of 20Hz ~ 20kHz; requirement: 1) The computer sound card is used to collect the speech signal in real time and display the waveform signal in time domain; 2) It can read the voice signal file from the computer and display the waveform signal in time domain in real time; 3) Realize the amplification, reduction and storage of signal amplitude; 4) Display the spectrum of signal in real time, and the spectrum resolution of signal can be set; 5) The common low-pass, high-pass, band-pass and band stop (50 Hz) filters are used to filter the signal. The order of the filters is adjustable, the bandwidth is adjustable, and the change of the signal spectrum is observed; 6) Non real time high resolution analysis of signal spectrum; 7) Prepare GUI user interface. 8) Master the input voltage circuit specification of sound card analog terminal, and measure the physical signal;)