1、<p><b>　　中文1963字</b></p><p>　　Labview-based virtual function Signal Generator</p><p>　　V Marozas, R Jurkonis</p><p>　　1 Introduction</p><p>　　Since 198

2、6, the U.S. NI (National Instrument) companies to the concept of virtual instrumentation, along with computer technology and measurement technology, virtual instrument technology has also been developed rapidly. Virtual

3、instrument means: use of the existing PC, with a specially designed instrument hardware and proprietary software, the formation of the basic functions of both the ordinary instrument, there are usually no special equipme

4、nt features of the new instrument. Compared with th</p><p>　　2 virtual function signal generator structure and composition</p><p>　　2.1 Virtual Function Generator front panel</p><p>

5、;　　This virtual function signal generator mainly consists of a PCI bus, multi-function data acquisition card and appropriate software. Them installed on a PC running Windows95/98/2000/NT the machine, shall constitute a p

6、owerful function of signal generator. The design of the virtual function signal generator reference signal generator SG 1645 power functions, front panel shown in Figure 1.</p><p>　　Figure 1 virtual function

7、 signal generator front panel</p><p>　　The function generator's front panel function of the following components: instrument control button, the output frequency control window (including the frequency o

8、f display units), frequency fold into control, waveform selection, frequency tuning button, dc bias, square wave accounts for Air ratio adjustment, the output waveform amplitude control buttons. Frequency tuning range: 0

9、.1 ~ 1 Hz; DC bias: -10 ~ 10V; square wave duty cycle: 0 to 100%; output waveform range: 0 ~ 10V. Also increased the</p><p>　　2.2 Virtual Function Signal Generator hardware structure</p><p>　　Th

10、is virtual function signal generator hardware input and output data acquisition card and a certain configuration requirements of the PC, the data input and output depend on input data acquisition card, the definition of

11、output achieved. This design uses the PCI-1200 data acquisition card is a good cost-effective products, with the D / A conversion functions, can generate the digital signals into analog signals and digital-analog convert

12、er and high precision, but also has filtering capabilities</p><p><b>　　Figure 2</b></p><p>　　3 Virtual Function Signal Generator Design and Implementation</p><p>　　Some

13、use professional LabVIEW6i software virtual instrument graphical development tools. Virtual function signal generator output waveform mainly in software production and the output signal frequency display. Changes in the

14、frequency of the output waveform is a concrete realization of data acquisition waveform data written to the buffer among the buffers by setting the update frequency (to change the internal clock frequency) to achieve the

15、 output data frequency. The process is mainly in the us</p><p>　　Digital waveform generator module 3.1</p><p>　　Waveform generated virtual function signal generator module is the core of the sof

16、tware. The module can be realized using sine, square, sawtooth, triangle and other waveforms. Sine wave generation principle is by calling the sin (x) function to implement. In this design, the design of each component s

17、ine wave cycle from 1000, using similar language in the For loop C as x assignment, so that the implementation of a For loop, you can generate a cycle of sine wave generating the data needed, and th</p><p>&

18、lt;b>　　Figure 3</b></p><p>　　Change of 3.2 unit of frequency control module</p><p>　　When the output frequency dynamic range is large, with a single spin button control, due to a small

19、rotation angle, you will have a greater change in the frequency, to the frequency of accurate Shezhi brought greater Kunnan, and frequency by using a knob Times by combining the output frequency can greatly improve the c

20、ontrol accuracy. In order to improve control accuracy of the output frequency, which in this design, by using the unit of frequency change control module, the output control accura</p><p><b>　　Figure 4

21、</b></p><p>　　4 Total Results:</p><p>　　As a Labview graphical programming software development and testing system is a powerful, convenient and efficient programming tools. Similarity bet

22、ween the good, open, exclusive, making the test development cycle is short, low cost and high quality. Labview-based virtual machine interaction with the function signal generator is good, easy to operate and so on, to a

23、 wide range of applications and in scientific research, production and other fields.</p><p>　　1 Pan H Z, et al. LabVIEW-based virtual Function Signal Generator[J] . Control Enginerring Practice,</p>&

24、lt;p>　　2. Evans P D, Brown D. Simulation of brushless DC drives[c] ． IEE Proceedings B, Electric Power Applications，137(5) : 299-308．</p><p>　　3. René Spée, Alan K. Wallace and Joel Davis. Model

25、ing of brushless dc drive systems with pulse-width modulated excitation[J], Mathematical and Computer Modelling, Volume 11, 1988, Pages 1166-1171.</p><p>　　4. Jawad Faiz, M. R. Azizian and M. Aboulghasemian-

26、Azami. Simulation and analysis of brushless DC motor drives using hysteresis, ramp comparison and predictive current control techniques[J], Simulation Practice and Theory, Volume 3, Issue 6, 15 January 1996, Pages 347-36

27、3.</p><p>　　5. J. Figueroa, C. Brocart, J. Cros and P. Viarouge. Simplified simulation methods for polyphase brushless DC motors[J]. Mathematics and Computers in Simulation, Volume 63, Issues 3-5, 17 Novembe

28、r 2003, Pages 209-224.</p><p>　　6. J. Shao, D. Nolan, and T. Hopkins. A Novel Direct Back EMF Detection for Sensodess Brushless DC (BLDC) Motor Drives[C]. Applied Power Electronic Conference (APEC 2002), 200

29、2: 33-38.</p><p>　　7. Doo-Hee Jung and In-Joong Ha. Low Cost Sensorless Control of Brushless DC Motors Using a Frequency Independent Phase Shifter [J]．IEEE Transactions on power electronic, 2000, 15: 744-752

30、.</p><p>　　8. Kuang-Yao Cheng and Ying -Yu Tzou. Design of a Sensorless Commutation IC for BLDC Motors [J]．IEEE Transactions On power electronic, 2003, 18: 1365-1375.</p><p>　　基于Labview的虛擬函數(shù)信號發(fā)生

31、器的設(shè)計</p><p>　　V Marozas, R Jurkonis</p><p><b>　　1前 言</b></p><p>　　自從1986年美國NI(National Instrument)公司提出虛擬儀器的概念以來,隨著計算機(jī)技術(shù)和測量技術(shù)的發(fā)展,虛擬儀器技術(shù)也得到很快的發(fā)展。虛擬儀器是指:利用現(xiàn)有的PC機(jī)，加上特殊設(shè)計的儀

32、器硬件和專用軟件,形成既有普通儀器的基本功能,又有一般儀器所沒有的特殊功能的新型儀器。與傳統(tǒng)的儀器相比其特點(diǎn)主要有:具有更好的測量精度和可重復(fù)性;測量速度快;系統(tǒng)組建時間短;由用戶定義儀器功能;可擴(kuò)展性強(qiáng);技術(shù)更新快等。虛擬儀器以軟件為核心,其軟件又以美國NI公司的Labview虛擬儀器軟件開發(fā)平臺最為常用。Labview是一種圖形化的編程語言,主要用來開發(fā)數(shù)據(jù)采集，儀器控制及數(shù)據(jù)處理分析等軟件,功能強(qiáng)大。目前,該開發(fā)軟件在國際測試、測

33、控行業(yè)比較流行,在國內(nèi)的測控領(lǐng)域也得到廣泛應(yīng)用。函數(shù)信號發(fā)生器是在科學(xué)研究和工程設(shè)計中廣泛應(yīng)用的一種通用儀器。下面結(jié)合一個虛擬函數(shù)信號發(fā)生器設(shè)計開發(fā)具體介紹基于圖形化編程語言Labview的虛擬儀器編程方法與實現(xiàn)技術(shù)。</p><p>　　2虛擬函數(shù)信號發(fā)生器的結(jié)構(gòu)與組成</p><p>　　2.1虛擬函數(shù)信號發(fā)生器的前面板</p><p>　　本虛擬函數(shù)信號發(fā)生器

34、主要由一塊PCI總線的多功能數(shù)據(jù)采集卡和相應(yīng)的軟件組成。將它們安裝在一臺運(yùn)行Windows95/98/2000/NT 的PC機(jī)上，即構(gòu)成一臺功能強(qiáng)大的函數(shù)信號發(fā)生器。本虛擬函數(shù)信號發(fā)生器的設(shè)計參考了SG 1645功率函數(shù)信號發(fā)生器，前面板如圖1所示。</p><p>　　本函數(shù)信號發(fā)生器的前面板主要由以下幾個部分構(gòu)成：儀器控制按鈕，輸出頻率控制窗口（包括頻率顯示單位），頻率倍成控制，波形選擇，頻率微調(diào)按鈕，直流偏

35、置，方波占空比調(diào)節(jié)，輸出波形幅度控制按鈕。頻率微調(diào)范圍：0.1～1 Hz；直流偏置：-10～10V；方波占空比：0～100%；輸出波形幅度：0～10V。此外還增加了許多修飾性的元件如面板上的壓控輸入、記數(shù)輸入、同步輸出、電壓輸出等。使用這些修飾性的元件的目的是為了增加儀器的美觀性，并盡量與真實儀器的使用界面相一致</p><p>　　2.2虛擬函數(shù)信號發(fā)生器的硬件構(gòu)成</p><p>　　

36、本虛擬函數(shù)信號發(fā)生器的輸入輸出的硬件部分為一數(shù)據(jù)采集卡和具有一定配置要求的PC機(jī)，數(shù)據(jù)的輸入輸出靠對數(shù)據(jù)采集卡輸出輸入口的定義來實現(xiàn)。本設(shè)計采用的PCI-1200數(shù)據(jù)采集卡是一塊性價比較好的產(chǎn)品，具備數(shù)/模轉(zhuǎn)換的功能，能將產(chǎn)生的數(shù)字信號轉(zhuǎn)換成模擬信號且數(shù)模轉(zhuǎn)換精度高，而且還具備濾波功能，從而使輸出波形光滑。它支持單極和雙極性模擬信號輸入，信號輸入范圍分別為-5～+5V和0～10V。提供16路單端/8路差動模擬輸入通道、2路獨(dú)立的DA輸出

37、通道、24線的TTL型數(shù)字I/O、3個16位的定時計數(shù)器等多種功能。硬件接口部分用于數(shù)據(jù)輸入或輸出時的通道設(shè)置。硬件接口部分程序框圖如圖2所示：</p><p>　　3虛擬函數(shù)信號發(fā)生器的軟件設(shè)計與實現(xiàn)</p><p>　　軟件部分采用專業(yè)的LabVIEW6i圖形化虛擬儀器開發(fā)工具。虛擬函數(shù)信號發(fā)生器主要由軟件完成輸出波形信號的產(chǎn)生和輸出信號頻率的顯示。輸出波形頻率的變化的具體實現(xiàn)是將波形

38、數(shù)據(jù)寫入數(shù)據(jù)采集卡的緩沖區(qū)當(dāng)中，通過設(shè)置緩沖區(qū)的更新頻率（改變內(nèi)部的時鐘頻率）來實現(xiàn)輸出數(shù)據(jù)頻率的變化。該過程主要運(yùn)用了Labview中的數(shù)據(jù)采集子模塊中的AO START 功能模塊。從實現(xiàn)功能的角度來說，本次設(shè)計的虛擬函數(shù)信號發(fā)生器的功能結(jié)構(gòu)主要包括兩大功能模塊：波形產(chǎn)生模塊（FG模塊）和頻率單位變化控制（DISPLAY）模塊。波形產(chǎn)生模塊又調(diào)用FGEN模塊。FGEN模塊為數(shù)字波形產(chǎn)生模塊。</p><p>　

39、　3.1數(shù)字波形產(chǎn)生模塊</p><p>　　波形產(chǎn)生模塊是虛擬函數(shù)信號發(fā)生器軟件的核心。利用該模塊可實現(xiàn)正弦波、方波、鋸齒波、三角波等波形。正弦波的產(chǎn)生原理是通過調(diào)用sin(x)函數(shù)來實現(xiàn)。在本次設(shè)計，設(shè)計每一正弦波周期由1000點(diǎn)組成，利用類似C語言中的For循環(huán)為x 賦值，這樣執(zhí)行一次For循環(huán)，便可以產(chǎn)生生成一個周期正弦波所需的數(shù)據(jù)，然后利用While 循環(huán)，使程序反復(fù)執(zhí)行，就可以連續(xù)輸出正弦波形。方波、

40、鋸齒波、三角波的產(chǎn)生原理與正弦波產(chǎn)生原理相近,都是通過數(shù)學(xué)運(yùn)算來實現(xiàn)代表波形的數(shù)字序列。與模擬信號相比，利用軟件的方法產(chǎn)生的波形數(shù)字序列雖然存在著一定的誤差，但只要一個周期內(nèi)選的點(diǎn)數(shù)足夠的多，就可以使誤差降到最低，對結(jié)果的影響最小。利用軟件產(chǎn)生波形的一個最大的優(yōu)點(diǎn)是使儀器的成本大大降低，而且使儀器小型化，智能化。波形產(chǎn)生模塊的前面板如圖3所示，波形產(chǎn)生模塊的程序框圖如圖3所示。</p><p>　　3.2 頻率單

41、位變化控制模塊</p><p>　　當(dāng)輸出頻率動態(tài)范圍較大時，用單個旋轉(zhuǎn)按鈕控制時，由于旋轉(zhuǎn)一個很小的角度就會產(chǎn)生較大的頻率變動，給頻率的準(zhǔn)確設(shè)置帶來了較大困難，通過使用一個旋鈕和頻率倍乘相結(jié)合，可大大提高頻率的輸出控制精度。為了提高頻率的輸出控制精度，在本次的設(shè)計當(dāng)中，通過使用頻率單位變化控制模塊，使輸出控制精度可達(dá)到0.001Hz。該模塊的前面板如圖5所示，該模塊的程序框圖如圖 4所示。</p>