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Convert IQ data to I & Q data

Overview

The aim of this example is to allow IQ data which has been stored for playback, to be split into I & Q constituents, to allow analysis.

 

Description

This example is intended to be used with a TDMS file which includes stored IQ data. The VST Streaming Sample Project (comes with NI LabVIEW Instrument Design Libraries for Vector Signal Transceivers) stores IQ data to a DMA FIFO, which can then be transferred to a TDMS file on the host, using TDMS Record for VST. As the data file created from this VI is intended for playback (TDMS Playback for VST), not for analysis, the data is stored as joined IQ data, as opposed to the individual I & Q components, to make a smaller, more efficient TDMS file.

I have created this example to split out the I & Q constituents, allowing analysis to be completed on the data.

I created the code looking at the Sample Project for NI PXIe-5646R, using version 15 of LabVIEW, the NI LabVIEW Instrument Design Libraries for Vector Signal Transceivers and RFSA & RFSG.

 

Code used for Record and Playback - Streaming Host Example for the NI PXIe-5644R/45R/46R
https://decibel.ni.com/content/docs/DOC-30516

 

Requirements
1. LabVIEW 2015
2. A TDMS data file including IQ data, acquired from VST Streaming (NI 5646R)

 

Steps to Implement or Execute Code
1. Acquire RF signal data; Use TDMS record for VST to save the data to a TDMS file on the host.
2. Open “IQ to I and Q conversion” project.
3. In “File Path (IQ)” enter the file path to the data stored in step 1.
4. In “File Path (I & Q)”, enter the new file path to store TDMS file, containing separated I & Q data.
5. Run the VI

 

Additional Information or References

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Amy K
Applications Engineer
National Instruments UK & Ireland