True software instrument set to revolutionize RF test: Page 2 of 4

August 15, 2012 //By Jean-Pierre Joosting
Moore’s law has been a driving force in electronics since the first integrated circuit. However, test and measurement has not benefitted to the same degree — largely dominated by vendor-specific test boxes and modules. Software-based instruments exist today but such instruments are still designed with a view to the vendor-specific test paradigm and remain programmable in a limited sense. Four key factors define the effect of Moore’s law: smaller size, faster operation, lower power consumption and higher integration with increased functionality. This process is illustrated by the evolution of the first wireless handset through to today’s smartphones.
first true software instrument, the NI PXIe-5644R vector signal transceiver (VST). Not only does this instrument bring Moore’s law to the test world but it can be customized down to firmware. Engineers can ‘touch the pins’ through code.

The instrument features a software-centric architecture and represents a new era in which engineers and scientists can use LabVIEW to tailor open, field-programmable gate array (FPGA)-based hardware for their specific needs.

The vector signal transceiver is a new class of instrumentation that combines a vector signal generator (VSG) and vector signal analyzer (VSA) with FPGA-based real-time signal processing and control into a single PXI modular instrument. A user-programmable FPGA allows custom algorithms to be implemented directly into the hardware design of the instrument. This software-designed approach allows a VST to have the flexibility of a software-defined-radio (SDR) architecture with RF instrument class performance. Figure 1 illustrates the difference between traditional approaches to RF instrumentation and a software-designed approach with a VST.

Figure 1: Software-designed approach of a VST versus traditional approaches. Click image to enlarge.

Ideal for testing the latest wireless and cellular standards such as 802.11ac and LTE, the VST features up to 6.0 GHz frequency coverage and 80 MHz instantaneous RF bandwidth, more than 10 times faster measurements than comparable solutions, and can easily be expanded to support multiple input, multiple output (MIMO) configurations or parallel testing in a single PXI chassis. Further, engineers can transform the vector signal transceiver into a different instrument or enhance its existing functionality using LabVIEW system design software.


Testing 802.11ac

VSTs offer both the fast measurement speed and small form factor of a production test box combined with the flexibility and high-performance expectation of instrument-grade box instruments. The transmit, receive, baseband I/Q, and digital inputs and outputs all share a common user-programmable FPGA, which reduces complexity, boosts measurement speed and increases flexibility in how the instrument is used. This gives the VST the ability

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