An FPGA-based solution for testing legacy video displays

The theme for Autotestcon 2010 is “45 Years of Support Innovation - Moving Forward at the Speed of Light." This theme is particularly relevant for military ATE systems because it highlights the dichotomy of striving to maintain state-of-the-art testing capabilities, while at the same time needing to support legacy technologies that may be decades old - indeed, as old as Autotestcon itself. The need to support discrete transistor-based electronics, TTL, CMOS and other technologies developed in the 1960's and 1970's, using test systems built around custom ASIC's, high performance FPGA's and logic levels whose peak-to-peak amplitudes were once considered “noise”, presents unique challenges. Systems deployed in the last century used CRT monitors to display information to a technician or operator. These monitors were based on analog video transmission standards such RS170, NTSC (National Television Standards Council), PAL (Phase Alternating Line) and other similar standards. Today, with the widespread use of DVI and HDMI digital video, it is rare to find CRT monitors in commercial use. But they are still widely used in older deployed systems. This paper is a case study based on the requirement for a PXI-based instrument that can generate simple color bar signals in NTSC and PAL formats to support the Mini-Samson/Katlanit Remote Controlled Weapon Station. By integrating an off-the-shelf PXI FPGA card, with an intellectual property (IP) core available in the public domain and a handful of commercially available support components, a cost effective solution was developed which supports the generation of both analog and digital video signals for testing CRT and LCD monitors. The flexibility of this approach allowed the extension of the original requirement for generating color bar patterns to include more complex test patterns.