说明：  用LabVIEW编制一个完整应用软件，完成以下功能： 1、产生一个正弦波，叠加一个噪声信号，从界面上可以调整噪声和信号的幅度、频率等参数，此信号作为后续分析的信号源； 2、显示信号的时域波形，点击按钮可以显示信号的幅度谱、功率谱 3、图形上可以显示光标，具有峰值跟踪功能，同时将峰值频率、幅度显示在界面上。 4、点击按钮可以计算显示信号的失真度（THD）、信噪比（SNR）、各次谐波的频率和幅度；
(Preparation of a complete application using LabVIEW software, perform the following functions: 1, generates a sine wave, the superposition of a noise signal, the interface can be adjusted from the noise and the signal amplitude, frequency and other parameters, this signal as a follow-up analysis of the signal source 2. time-domain signal waveform display, click the button to display the signal amplitude spectrum, power spectrum 3, you can display a cursor on the graph, with a peak tracking, while the peak frequency, amplitude displayed on the screen. 4, click the button to display the calculated distortion (THD) signal to noise ratio (SNR), each harmonic frequency and amplitude )