How is Zero-Span Implemented When Using the NI PXI-5661/5660?Primary Software: Driver Software>>NI-RFSAPrimary Software Version: 1.5 Primary Software Fixed Version: N/A Secondary Software: Driver Software>>NI-RFSA Hardware: Modular Instruments>>RF Measurement Devices, Modular Instruments>>RF Measurement Devices>>PXI-5660, Modular Instruments>>RF Measurement Devices>>PXI-5661
Problem: I understand that zero-span, a common feature of RF Signal Analyzers, allows users to view an incoming signal with a power versus time display instead of power versus frequency. How is it implemented when using NI PXI-5661/5660 RF Signal Analyzers? Solution: Both RF Signal Analyzers use a High Speed Digitizer to acquire IQ data. In order to plot power versus time, convert this IQ data into complex pairs (I + jQ), then convert the complex data to magnitude data via a Cartesian to Polar coordinate conversion (i.e. sqrt(I^2+Q^2)). Finally, apply a dBm calculation to turn the magnitude into power dBm. If using the NI PXI-5660, please see Developer Zone Example: Zero Span Measurement with 5660. If using the NI PXI-5661, there are shipping examples for both LabVIEW and LabWindows CVI. Launch the NI Example Finder in either development environment by selecting Help » Find Examples from the menu bar. Browse by task to the following folder: Hardware Input and Output » Modular Instruments » NI-RFSA (RF Signal Analyzer) » IQ Acquisition. LabVIEW: RFSA Power vs Time (Zero-Span).vi LabWindows/CVI: PowerVsTime(Zero-Span).prj Related Links: Developer Zone Example: Zero Span Measurement with 5660 Attachments:
Report Date: 10/06/2008 Last Updated: 05/29/2009 Document ID: 4Q57C5D2 |
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