Demonstrating Sampling Quality Using NI LabVIEW SignalExpress Software
PrintSignal to noise ratio online demonstration
Complete the following steps to learn more about Sampling Quality. You can re-create the demo and then try the additional exercise to learn more.
1. If you do not already have NI LabVIEW SignalExpress® installed on your PC, download and install the evaluation version from here.
2. Launch a new LabVIEW SignalExpress project by navigating to Start>>All programs>>National Instruments>>LabVIEW SignalExpress>>LabVIEW SignalExpress.
3. Complete the following steps to create an example shown in the online demonstration:
a. Create a sine wave by Selecting Add Step>>Create Signal. The settings should match the image below. After clicking the Close button, select the sine wave and drag it into the Data View.
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b. Create a noise wave by following the same process in step 1a, but select Noise Signal as the Signal Type.
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The Data View should now look like this:
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(*You can create new Data View windows by right-clicking on the Data View and selecting "Add Display")
c. Select Add Step>>Processing>>Arithmetic to add the sine wave and the noise signal together. Make sure that both the sine and noise signals appear on the Input tab of the step configuration page, and that the Add option is selected in the Operation control, as shown below:
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Drag the resulting signal to a new Data View. Your signal display window should now look like this:
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d. To make the resulting signal less impervious to noise, amplify the sine wave 10x. Double-click on the Create Signal step and change the sine wave's voltage to 10 Volts, then select Close. The resulting signal will look like this:
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4. From step 3d we can see that amplifying a signal before noise can distort it allows for more accurate signal acquisition.
5. As a challenge, increase and decrease the noise wave's and the sine wave's amplitudes to see different levels of "Signal to Noise Ratio."
Related Links:
NI Measurement Fundamentals: Sampling Quality
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