At its annual NIWeek conference, National Instruments knocked the socks off of the wireless test engineers, the press, and the competition with PXIe-5644R vector signal transceiver (VST). The PXIe-5644R combines a vector signal generator, a vector signal analyzer, a programmable FPGA, and a flexible digital I/O port all in a three-slot PXIe module. It’s the latest in NI’s virtual instrumentation quest, where “the software is the instrument.”

The software in this case is NI’s well-known and amazingly flexible LabVIEW graphical data flow programming language, which can be used to build test systems and smaller virtual instruments on a PC or laptop. With the VST, LabVIEW is used to program the FPGA. This development introduces the software-defined instrumentation (SDI) concept where users can customize and enhance the basic instrument, making conventional fixed-function benchtop instruments less desirable for some applications.

The PXIe-5644R boasts a frequency range of 85 MHz to 6 GHz with a real-time bandwidth up to 80 MHz. The analog-to-digital and digital-to-analog chips have 16-bit resolution. The digital I/O has 24 lines that are programmable and useable up to 250 Mbits/s. The user can implement I²C, SPI, or any other I/O protocol to match up with the device under test (DUT) as needed.

The FPGA is a Xilinx Virtex-6 LX195T. It is fully user programmable with LabVIEW FPGA software, so users can create any special instrumentation function needed but not included in the instrument’s basic repertoire. You can’t do that with a traditional single-function rack-and-stack instrument.

NI has been building up to this product. The company has offered vector signal generators and vector signal analyzers in PXI format for years. It also developed the idea of programming an FPGA with LabVIEW a few years back. Its reconfigurable input/output (RIO) modules are programmed with LabVIEW as well. This has led to the combination of all these technologies in to the VST.

And by making the FPGA user programmable, SDI comes alive. This is a fundamental change in the architecture and function of a test instrument. Users can design the specific instrument or test function to fit the project. The FPGA programming software is fully open source.

The VST is designed to tackle the challenging test needs of new 802.11ac Wi-Fi and Long-Term Evolution (LTE) chips and products. With many features and combinations of capabilities, products like smart phones take hours to test. But the VST can accelerate test times by a factor of 10 or more depending on the tests. Multiple VSTs can be combined in a chassis to test multiple-input multiple-output (MIMO) functionality in wireless devices. Qualcomm Atheros used an early version of the VST to test its new 802.11ac products. With its flexibility and programmable pin control capability, it made the testing faster and more specific.

The PXIe-5644R probably won’t make traditional benchtop instruments obsolete, but it will probably dominate some applications, specifically automated and production testing. Not only will it greatly speed testing, it also will significantly reduce test costs. Compare the VST’s basic $45,000 price to the $100,000 cost of a traditional set of instruments with the same functionality and you can see the benefit. It will be interesting to see what the competition does. In the meantime, NI has its hands full trying to educate its customers about the features and benefits of the VST and SDI. Will this technique migrate down to lower frequency, lower speed products? We shall see.

National Instruments