NI creates a new instrument class at NI Week 2012
I traveled to Austin, deep in the heart of Texas, to see the introduction personally. Let’s start with the hardware. Included in a VST are four instruments: a VSG (Vector Signal Generator), a VSA (Vector Signal Analyzer), a Digital I/O port, and a flexible programmable FPGA. The product sports a 6 GHz frequency range with 80 MHz instantaneous bandwidth. Requiring only 60 watts of power, it snuggles into just 3 slots of PXI Express. OK- so not everything is big in Texas!
NI showed benchmarks that showed the product competing favorably with top of the line box instruments for RF parametric performance. I’m not going to get into a battle of spec wars because so much is so dependent on instrument set-up, especially when it comes to EVM measurements. I will leave it to users to determine whether the stated specifications of any specific instrument are sufficient for their application. Theoretical performance is no longer a box vs. module thing, as I believe vendors can bring their top of the line performance to whichever form factor they choose.
But the other implications of platform choice are real. Readers of “Outside the Box” blog know very well the speed advantages of modular architectures explained here and here. National Instruments demonstrated their new VST performing 802.11ac EVM measurements at many times the speed of a comparable box system. Indeed, Doug Johnson of Qualcomm Atheros testified to the speed Qualcomm has attained using the product in an 802.11ac application. He reported that the VST performed measurements 20 times faster than their previous PXI RF equipment, which was itself 10 times faster than the original box instrumentation it replaced.
Now let’s turn to the software. NI calls this a “software-designed instrument.” That is, the firmware is user programmable. The magic behind this is LabVIEW FPGA. Users can use LabVIEW to develop customer-specific and lightning fast instrument firmware that runs at hardware speed on the internal FPGA. For example, these might be special instrument control operations, device control, sophisticated triggering, or DSP functions. Dr. Jim Truchard, CEO of NI, observed that this brings another benefit: customers can define FPGA code that creates for them a competitive advantage that they don’t have to share with their competitors.
But that doesn’t mean everyone is on their own. You can get a full functioning VST starting at $45,000. You can then choose to add functionality through template or sample applications. NI expects an ecosystem of partners to develop FPGA apps for the VST, expanding the offering. It will be very interesting to watch to see how robust of an ecosystem is formed around partner IP.
Now back to the hardware. Take a look at the 24-pin Digital I/O port on the face. Each pin can be defined by the user, and is controlled by the user-definable FPGA. This allows a user to control and monitor some pins to place the DUT (Device Under Test) into a specific state. Though not currently fast enough for some of the Digital RF applications, other control like power amp control is feasible today. Keep an eye on this feature, as it could be a wild card.
There's a certain irony that the VST is in some ways an integrated box: an integrated combination of a VSA, a VSG, Digital I/O and FPGA. So, what are the modular advantages? NI will point out that there is huge firmware/software modularity within each unit due to its software-designed instrument architecture. Fair enough. But here is the cool thing: You can put up to five VSTs in a standard PXI 18 slot chassis- and all of them can be phase synchronous. So it is hardware modular at the per channel level. And this is also where the capabilities of PXI shine. One of the NI demos was a 2x2 MIMO Channel Emulator. Two VSTs are used, and the virtual channel characteristics were programmed by LabVIEW FPGA into the instrument firmware. By exploiting the peer-to-peer capabilities of PXI Express, the multi-path interference characteristics can also be programmed. NI had sample programs, one of a pedestrian walking and one of a moving vehicle, each dynamically changing the channel characteristics.
Think about this. NI has developed a fading and channel emulator within the FPGAs inside the VST. They can combine them in any arbitrary multipath combination by using the peer-to-peer communication inherent in PXI Express. This is coupled with precision RF front ends, both transmitters and receivers. I've said before, MIMO is short for Modular Instruments Match Opportunity. This multi-channel application is a great example of that.
There’s a lot more that has been introduced by NI and others here at NI Week. But lets go back to the headlines. NI promised to redefine instrumentation. But by delivering the world’s first software-defined RF instrument, what they actually did is allow you to redefine instrumentation.
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