PXI in optical test
Richard A. Quinnell, Contributing Technical Editor -- Test & Measurement World, 6/1/2005
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| Bit-error-rate testing is one of the many functions for optical communications test available on the PXI platform. Courtesy of PXIT. |
Q: A quick search of the Internet did not reveal many companies involved in PXI-based optical test. Is this a small market, or is there some other reason why there appears to be limited activity?
A: This is a very small market just now, although there is a much larger untapped market out there. The real challenge facing us by using the PXI platform is the need to change people's mindsets. Convincing customers to use PC-based test instruments as opposed to large mainframes with knobs and dials on them is harder than you would think. It is mostly about breaking down the mental barriers. R&D customers still prefer the knobs, although manufacturing customers now prefer the PC control-card instruments
Q: What are the needs of optical testing that PXI is addressing?
A: PXI is addressing the needs of manufacturing test for components in the optical communications industry. PXIT, in particular, is meeting DC test needs of the optical component market with our current source, power meters, and spectrometer and LIV (light current versus voltage) testing for LEDs and VCSELs (vertical cavity surface emitting lasers). Our transmission test products include data-generation capability, bit-error-rate testing, and eye-diagram tests.
Q: What kinds of test setups do the PXI instruments replace?
A: For the present range of transmission test instruments, companies were previously using rack-and-stack instruments from manufacturers such as Agilent, Tektronix, and Anritsu.
Q: Why choose PXI as the basis for your optical test products, as opposed to VME or other frameworks?
A: PXIT already had a range of products in the PXI form factor, such as optical and electrical switches, current sources, and power meters, so it was the natural step to use the PXI platform for our optical test product range.
Q: What, if any, characteristics of PXI make it particularly useful in optical test?
A: Two of PXI's extremely useful attributes are its form factor and its scalability. The issue of size speaks for itself. The scalability of PXI opens the possibility for customers to scale their production and test capacity without significantly increasing costs or space demands. An additional benefit of PXI is that it uses PC-based technology. This makes it extremely user friendly in ATE environments. You do not need fully qualified engineers to man test stations in order to control the testing and interpret the results. Using PC technology allows less-skilled (and less-expensive) personnel to perform the task.
Q: What limitations exist in using PXI as the basis for optical test?
A: We have not been limited at all by using PXI. The size of the board does introduce some design challenges, however.
Q: What else do you see as the challenges that the PXI architecture must face in the future?
A: PXI could use more standardization. We develop high-end products with stringent performance requirements that typically compete with high-end benchtop instruments selling above $50k. In order to ensure the required performance of our instruments in the field, we must test them with a wide sample of chassis and power supplies from various PXI vendors.
Accommodating the variations among suppliers imposed additional constraints on the design of our instruments. In other words, there is wide performance variation among supplies and chassis offered from different vendors. What would help is some standardization, such as two levels of performance specifications like commercial and industrial or low-cost and high-performance grade to meet the requirements of various applications.
