Spectrogram Using RFSA and the Advanced Signal Processing Toolkit.

This example codes shows you how to calculate a spectrogram using RFSA driver and the Advanced Signal Processing Toolkit.

Use the spectrogram to visualize RF signals that change their frequency content over time. The spectrogram is a intensity graph (3D information) that contains time, frequency and amplitude data of a signal.

 

The example is a simple Producer-Consumer event structure with two main sections: first one is the normal spectrum display shown on Figure 1. Use the settings on the left to change center frequency, span, RBW and other settings.

[+] Enlarge ImageFigure 1: Spectrum display of and FM signal.

 

The second section is the spectrogram tab. Use the settings on the left to modify the different variables for the spectrogram: span, acquisition time and window type. Figure 2 displays the spectrogram of an FM signal. Notice how the power changes frequency as time.

[+] Enlarge ImageFigure 2: Spectrogram of an FM signal. Notice that the power varies over time, this is the message of the FM signal.

 

To generate this same spectrogram, you can use the Modulation Toolkit shipped example called "MT RFSG Generate FM.vi" with the settings that Figure 3 shows.

[+] Enlarge Image

Figure 3: Example from Modulation Toolkit to generate an FM signal.

 

The example is supported on LabVIEW 8.5 and over using Spectral Measurements Toolkit and Advance Signal Processing Toolkit. Since the example uses NI-RFSA driver, RF devices supported under this driver should work.

Requirements

Filename: rfsa_spectrogram_smt.zip

Software Requirements

Application Software: LabVIEW Professional Development System 8.5
Toolkits and Add-Ons: LabVIEW Advanced Signal Processing Toolset 7.5, Spectral Measurements Toolkit 2.5
Language(s): LabVIEW

Hardware Requirements

Hardware Group: RF
Hardware Model: PXI-5661
Driver: NI-RFSA 2.1

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