【正文】 ation and procedures for the implementation of efficiency. The main function: DAQmx Read, Digital IIR Filter, Waveform Graphs, Write To Measurement File, Read To Measurement File, and other major function. Customizing the Waveform Graph The waveform graph indicator displays the two signals. To indicate which plot is the scaled signal and which is the simulated signal, you customize the plots. Complete the following steps to customize the appearance of an indicator on the front panel. 1. Move the cursor over the top of the plot legend on the waveform graph. Notice that while there are two plots on the graph, the plot legend displays only one plot. 2. When a doubleheaded arrow appears, shown in Figure 111, click and drag the border of the plot legend until the second plot name appears. Figure 111. Expanding a Plot Legend 3. Rightclick the waveform graph and select Properties from the shortcut menu to display the Graph Properties dialog box. 4. On the Plots tab, select Sawtooth from the pulldown menu. Click the Line Color color box to display the color picker. Select a new line color. 5. Select Sawtooth (Scaled) from the pulldown menu. 6. Place a checkmark in the Don’t use waveform names for plot names checkbox. 7. In the Name text box, delete the current label and change the name of this plot to Scaled Sawtooth. 8. Click the OK button to apply the current configuration and close the Graph Properties dialog box. Notice how the plot color on the front panel changes. 9. Experiment with other properties of the graph by using the Graph Properties dialog box. For example, try disabling the autoscale feature located on the Scales tab. 10. Click the Cancel button to avoid applying the changes you made while experimenting. If you want to keep the changes you made, click the OK button. 11. Save and close this VI. Saving Data when Prompted by a User Complete the following steps to build a VI that logs data to a file when the user clicks a button on the front panel. 1. On the block diagram, doubleclick the Write LabVIEW Measurement File Express VI to access the Configure Write LabVIEW Measurement File dialog box. 2. Change the file name to Selected in the File name text box to save the data to a different file. 3. Close the Configure Write LabVIEW Measurement File dialog box. 4. Rightclick the Signal input of the Write LabVIEW Measurement File Express VI. Select Insert Input/Output from the shortcut menu to insert the Comment input. 5. Rightclick the Comment input of the Write LabVIEW Measurement File Express VI. Select Select Input/Output187。 ~ 177。 12 accuracy。s multipurpose data acquisitioncardPXI6670E, its main functions are as follows: 64way singleended / 32way differential analog input。 177。 eight digital I/ 24 counter /timer. Functional equipment In this case virtual digital oscilloscope with realtime data acquisition, spectralanalysis and window treatment and filtering capabilities. In the virtual digital oscilloscope main panel on data collection and analysis of the spectrum, and window processing, filtering and other function keys, according to the corresponding button we can enter into the appropriate subpanel. Software Design and Implementation Virtual digital oscilloscope software design based on the use of Clanguage programming environment LabWindows / CVI. LabWindows / CVI support numerical type, Boolean, and the string of text, and other data types, but the biggest advantage is through dialog forms of interactive operations generate standard C code. In addition LabWindows / CVI provides a very rich debug tools, including singlestep, breakpoints, variable view, monitor window, and so on, these features make the adjustment process has bee more vulnerable. The main function modules Virtual digital oscilloscope mainly by the software control signals the pletion of the acquisition and display processing, data collection in the main panel to plete the following features: Setting up access, set up sampling frequency, set up a manner that waveform, data collection in the main panel to plete the following Features: Acquisition of realtime signal and the signal on its own spectrum analysis, see lines, and other functions, and window panels dealing with the acquisition of realtime signal and the signal to increase processing windows (including windows Haiming, Hamming window, Buiakean smoothing windows and window, etc.).Filtering in handling panel includes the following features: the acquisition of realtime signal and the signal on its own filtering treatment (including singlestep filtering, multistep filtering method and tradit ional methods, etc.) The source files generated when the control panel to plete the set, you can have a function of the code of procedure. Specific methods for: to have pleted the panel as a response to the current state of the [Code] menu, select [Generate] in the [All Code], in the popup dialog function selected in the main panel and withdraw from the function , And the user interface will be able to produce documents relative to the framework of the code function. Add the code generated automatically step on the corresponding control is a function of the framework, to make certain controls to plete the function, we must add code to control the controls. One main () function is the entrance procedures, it is the function of initialization procedures, loading the user and display panels, such as to plete other functions required to add code. Following the code for data acquisition functions, data acquisition process by calling the callback function button SHOU external acquisition. Software development environment: virtual digital oscilloscope software design based on the use of Clanguage programming environment LabWindows / CVI. LabWindows / CVI