【正文】 圖410“Sound Input clear .VI”后版面 頻譜分析模塊頻譜分析VI圖標(biāo)如圖411所示 圖411 FFT Spectrum（MagPhase）.vi程序說(shuō)明：頻譜分析模塊，它的作用是對(duì)信號(hào)進(jìn)行頻譜分析。主要利用了FFT Spectrum 函數(shù)。其結(jié)果是返回一個(gè)幅值或相位值?！癋FT Spectrum（MagPhase）.vi”前版面如圖412所示圖412 FFT Spectrum（MagPhase）.vi前版面“FFT Spectrum（MagPhase）.vi”后版面如圖413所示：圖413“FFT Spectrum（MagPhase）.vi”后版面 數(shù)據(jù)測(cè)量和顯示模塊數(shù)據(jù)測(cè)量模塊和顯示所用到的vi如圖414所示圖414 數(shù)據(jù)測(cè)量和顯示模塊程序說(shuō)明：參數(shù)顯示模塊，它的作用是對(duì)信號(hào)的參數(shù)顯示出來(lái)。參數(shù)顯示是以數(shù)字的方式顯示?？紤]到聲卡本身采集質(zhì)量問(wèn)題。 虛擬示波器操作界面虛擬示波器前版面如圖51：圖51 虛擬示波器前版面前版面說(shuō)明：在該虛擬示波器前版面中，運(yùn)用3個(gè)波形顯示vi來(lái)分別顯示輸入信號(hào)的波形，相位，幅度，用數(shù)字控件來(lái)設(shè)置對(duì)聲音格式，采樣數(shù)和設(shè)備ID分別進(jìn)行設(shè)置，用數(shù)字顯示vi來(lái)對(duì)具體測(cè)量出來(lái)的數(shù)據(jù)進(jìn)行顯示，開(kāi)關(guān)控制程序的進(jìn)行。聲卡的采集應(yīng)該是連續(xù)的，所以，程序中運(yùn)用while循環(huán)，使程序能連續(xù)讀出聲卡信號(hào)，并且能夠連續(xù)的進(jìn)行數(shù)據(jù)測(cè)量和波形顯示。 虛擬示波器波形顯示聲音信號(hào)的顯示如圖53所示圖53 一般聲音信號(hào)的顯示為了清楚的顯示虛擬示波器的特性，我采用函數(shù)發(fā)生器產(chǎn)生單位信號(hào)，正弦信號(hào)，三角波信號(hào)，和方波信號(hào)?！敖Y(jié)論”以前的所有正文內(nèi)容都要編寫(xiě)在此行之前。對(duì)于現(xiàn)有計(jì)算機(jī)普及率不斷提高的高校實(shí)驗(yàn)室來(lái)說(shuō)，無(wú)疑具有很高的性能價(jià)格比，使實(shí)驗(yàn)教學(xué)的效果提高到一個(gè)新的層次。本文主要介紹了虛擬儀器的技術(shù)應(yīng)用到虛擬示波器的設(shè)計(jì)上，利用LabVIEW這一功能強(qiáng)大的虛擬儀器開(kāi)發(fā)工具，設(shè)計(jì)相關(guān)的虛擬儀器，實(shí)現(xiàn)相關(guān)的功能?；跀?shù)字濾波、快速傅立葉變換等常用信號(hào)分析與處理技術(shù)，以建造了數(shù)字濾波器、信號(hào)發(fā)生器等各種虛擬儀器。 參考文獻(xiàn)1 于潔,. 山東理工大學(xué)學(xué)報(bào)(自然科學(xué)版) 第19卷第2期. 2005年3月2 3 種蘭祥,張首軍,(自然科學(xué)版) .2002,32(6):629—632 4 ，2001.5 黃松嶺，6 龍華偉, 7 李瑋. 8 Gary W Gohson. LABVIEW Graphic Programming . GrawHill, 19989 陳敏,2001:501—503 10 種蘭祥,張首軍,(自然科學(xué)版) .2002 11 白云，高育鵬，12 :16—17 13 ，2005:P6725814LABVIEW Function Manual. USA：National Instruments 15 徐云峰,:46—47 附錄附錄A 英文原文July 2000 Edition, Part Number 370178A01Wele to the LabVIEW Tutorial. This interactive help file introduces you to basic LabVIEW concepts and guides you through several activities to familiarize you with graphical programming. What is LabVIEW?LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is a development environment based on graphical programming. LabVIEW uses terminology, icons, and ideas familiar to technicians, scientists, and engineers, and relies on graphical symbols rather than textual language to describe programming actions. LabVIEW is integrated fully for munication with hardware such as GPIB, VXI, RS232, RS485, and plugin data acquisition boards. LabVIEW also has builtin libraries for using software standards such as TCP/IP Networking and ActiveX.Virtual Instruments: The LabVIEW applications you create.The basic files you create with LabVIEW are called Virtual Instruments, or VIs. Each VI consists of two main parts—he front panel and the block diagram—and a third part—he icon and connector. Tools PaletteUse the Tools palette to modify the contents of the front panel and block diagram. Each icon on the Tools palette changes the behavior of the cursor in LabVIEW so you can perform positioning, operating, and editing tasks on your VIs.(1) Front Panel: The user interface to your virtual instrument.The front panel contains the user interface of your VI. The following image is an example of a front panel window.(2) Block Diagram: The graphical code of your virtual instrument.The block diagram contains the graphical code for your VI. The following image is an example of a block diagram window.In this block diagram, the values passed from the front panel knob controls are added every 500 milliseconds. The results are displayed on the waveform graph when the user presses the Boolean button on the front panel to stop the VI.Figure 1Figure 2(3) Icon and Connector: The key to modular design. The icon and connector of a VI are located in the upperright corner of the front panel and block diagram window. The icon is what you see on the block diagram when you use a VI as a subVI.Use the connector to set up the input and output terminals of the VI so you can use it as a subVI in another VI.The LabVIEW Environment: A brief overview of the LabVIEW programming model. The basic LabVIEW environment elements are the menus at the top of the front panel and block diagram windows, the toolbar, and the freefloating palettes, which you can place anywhere on the screen. Controls PaletteYou build a front panel by placing controls and indicators from the Controls palette. Each palette icon represents a subpalette, which contains controls you place on the front control is a front panel object that the user manipulates to interact with the VI. Simple examples of controls are buttons, slides, dials, and text boxes. An indicator is a front panel object that displays data to the user. Examples of indicators are graphs, thermometers, and gauges. When you place a control or indicator on the front panel, a corresponding terminal is placed on the block diagram. Functions PaletteYou build the block diagram using the terminals from the front panel controls and indicators and the VIs, functions, and structures from the Functions palette. Each palette icon represents a subpalette, which contains VIs and functions you place on the block diagram. The structures, functions, and VIscollectively known as nodeson the Functions palette provide the functionality of your VI. As you add nodes to the block diagram, you wire them to each other and to the terminals from the front panel objects using the Wiring tool, found on the Tools palette. A plete block diagram appears similar to a flowchart.Dataflow: The Basic Concept Behind LabVIEW: An overview of LabVIEW39。s allinone Waveform data type. Front Panel(1) Open a new front panel by selecting Filenew VI, pressing Ctrln, or pressing the New VI button on the LabVIEW dialog box.(2) Add the following items to the front panel:a. Digital Control, available from the Controlsnumeric palette. Label it Amplitude.b. Digital Control, available from the Controlsnumeric palette. Label it Frequency.c. Digital Control, available from the Controlsnumeric palette. Label it Square Duty Cycle (%).d. Enum control, available from the Controlsring amp。什么是LabVIEW? LabVIEW (實(shí)驗(yàn)室虛擬儀器工程學(xué)工作室)是基于圖形編程的開(kāi)發(fā)環(huán)境的。 LabVIEW與硬件充分的交互通信，例如GPIB， VXI， RS232, RS485，和插入式數(shù)據(jù)收集模板。虛擬儀器：你所創(chuàng)建的LabVIEW應(yīng)用您所創(chuàng)建的LabVIEW的基本文件叫虛擬儀器