Most modern instruments include one or more FPGAs (field programmable gate arrays) in their circuitry. Almost all discrete logic is consolidated there, and increasingly vendors are turning to FPGAs to implement DSP (digital signal processing) functions rather than deploying ASICs (application specific integrated circuits) or dedicated DSP chips.
Module vendors in VXI, PXI, and AXIe often deploy FPGAs to perform the interface function to their respective backplanes, in addition to the specific instrument functions of the module. Since modular systems attain much of their speed advantage by avoiding ASCII communication found in traditional instruments, the FPGA creates a memory map interface that, along with the software driver, defines the automation interface of the instrument. Eliminating the processor found on traditional instruments places the FPGA front and center in defining the operation of the module, but often at hardware speeds.
But there is a trend afoot that may be as disruptive as modular instrumentation itself: Giving users the ability to directly customize the FPGA. While the automated test metaphor since the 1970s has been fixed-definition hardware instruments controlled through flexible programming, this recent trend now allows users to program the hardware definition of the instrument itself. That’s Flexibility with a capital F. Maybe all caps, in fact.
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