Signal Processing Analysis

Inline Analysis and Signal Processing

Make decisions faster with inline analysis and signal Processing in NI LabVIEW.

Time domain analysis is beneficial when observing data such as temperature. However, some applications require analyzing the frequency components of signals. This allows you to see which frequencies make up a sound signal, similar to an audio equalizer or the vibration frequencies of a motor while running. Use this module to identify and filter out frequencies in NI LabVIEW software.

Step-by-Step Procedure

Download the Step-by-Step Procedure PDF

Before starting this procedure, you need to complete the exercise and use the solution in the Taking a Measurement module. You can also create a numeric control to simulate the data acquisition input.

Note: This exercise works best when a variable frequency sine wave generator is connected to the ai0 terminals of your device.

Right-click the block diagram, select Express»Signal Analysis»Filter, and left-click to place the Filter Express VI to the right of the DAQ Assistant
1. Select Lowpass for Filtering Type
2. Enter 500 for the Cutoff Frequency (Hz)
3. Increase the Order of the filter to 5
4. Select OK to apply the configuration
Wire the Data output terminal of the DAQ Assistant to the Signal input terminal of the Filter Express VI
Wire the Error Out output terminal of the DAQ Assistant to the Error In input terminal of the Filter Express VI
Right-click the block diagram, select Express»Signal Analysis»Spectral Measurements, and left-click to place the Spectral Measurements Express VI to the right of the Filter Express VI
1. Select Power Spectrum for Selected Measurement
2. Select Linear for the Result
3. Select OK to apply the configuration
Wire the Filtered Signals output terminal of the Filter Express VI to the Signals input terminal of the Spectral Measurements Express VI
Wire the Error Out output terminal of the Filter Express VI to the Error In input terminal of the Spectral Measurements Express VI
Create graphical indicators for the filtered time and frequency spectrum signals
1. Delete the existing graph indicator
2. Right-click the Filtered Signals output wire of the Filter Express VI and select Create»Graph Indicator
3. Right-click the Power Spectrum output terminal of the Spectral Measurements Express VI and select Create»Graph Indicator
Unwire the input to the Unbundle by Name function and then wire the Error Out output terminal of the Spectral Measurements Express VI
1. Ensure Status is selected to be unbundled
Run the VI to visualize the results
1. Vary the frequency of the sine wave input to see when the filter begins to attenuate the input signal

You can convert your DAQ Assistant Express VIs into low-level NI-DAQmx functions by right-clicking the DAQ Assistant and selecting Generate NI-DAQmx Code. The low-level NI-DAQmx API exposes more functionality and customization options for programming.

Cumulative Exercise and Project: LabVIEW and DAQ

Assess your working knowledge of building a complete system by acquiring, processing, and displaying data with LabVIEW and a DAQ device. This exercise is recommended after you complete all of the modules for LabVIEW Basic Concepts and LabVIEW Basic Tasks. Additionally, test your skills be taking the Cumulative LabVIEW and DAQ Exam.

Start the Project

Begin the Exam

1. LabVIEW Environment

2. Graphical Programming

3. Programming Tools

4. Debugging and Handling Errors

5. Data Types and Structures

6. Signal Processing Analysis

7. Integrating Text-Based Programming

8. Execution Structures

9. Help with LabVIEW

1. Connect to Hardware

2. Acquire and Generate Data

3. Analyze Data

4. Present and Log Data

Step-by-Step Procedure

Cumulative Exercise and Project: LabVIEW and DAQ

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Signal Processing Analysis

Step-by-Step Procedure

Cumulative Exercise and Project: LabVIEW and DAQ

What Do You Want to Learn Next?

I have a question…

I want to order…

Tell me more about NI…

I want to see my stuff…

It's not what we make, it's what we make possible.

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