Acquisition of Nonadjacent RF Frequency Bands

• NI LabVIEW
• NI Spectral Measurements Toolset
• NI RF Signal Analyzer (PXI-5660)
• NI High-Speed Digital I/O

Many RF applications center around sweeping a frequency range and then making measurements on all or part of this frequency range. However, there are many applications particularly in defense and surveillance where the measurement devices need to "hop" around the frequency range capturing bands randomly. This application uses the PXI-5660 RF signal analyzer, which consists of two hardware products, the PXI-5660 RF downconverter, and the PXI-5620 IF digitizer. The PXI-5600 RF downconverter contains onboard memory that you can program with a list of center frequencies to tune to. It is then possible to use software triggering based on conditions in a LabVIEW application; or hardware triggering using one of the lines on the PXI backplane to move through this scan list very rapidly. The PXI-5620 digitizer has a mode of operation called multirecord acquisition, where at the end of each acquisition, the PXI-5620 digitizer can place a trigger on the backplane and trigger the PXI-5600 downconverter to tune to the next frequency. The PXI-5600 downconverter would then place a trigger on a different line to start the digitizer. This is essentially HW handshaking between the downconverter and digitizer. Furthermore, you can use PXI digital I/O and analog I/O products to receive trigger signals from external devices and use this along with the hardware triggering capabilities of the PXI backplane to build a highly flexible and completely tunable RF test system.
Related Links:
Multi Span Analysis Application for Spans Greater than 20 MHz
PXI-5660 RF Signal Analyzer Interactive Tutorial

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