The Department of Defense's (DoD) NxTest initiative was driven by goals to reduce the total cost of ownership of DoD automatic test systems (ATS), cut development time to field new or upgraded ATS, provide greater flexibility to the warfighter through Joint Services interoperable ATS, reduce the logistics footprint and improve the quality of test. To achieve these goals, emphasis is placed upon the use of COTS equipment wherever possible, within a common and shared technical framework. Thus, synthetic test instruments promise to meet the goals outlined by NxTest.

Concurrently, obsolescence is another hurdle facing the military test systems. The length of time required to decide on and purchase test equipment for a military system may take several years. By the time the decision is made, initial system design decisions can become impractical at the time of implementation. In addition, the need to upgrade or replace existing systems is pacing at a much faster rate.

“NxTest and the development of synthetic instrumentation” by Marvin Rozner, vice president of business development at Aeroflex Systems Division explores the state of the art of COTS synthetic instrumentation for meeting NxTest requirements with an analysis of the rationale, limitations and alternatives for specifying new and upgrade class NxTest instantiations based upon traditional instrument specifications. The author states that the realization of synthetic instrumentation promises to take the test industry to the next level of performance and value.

With demands on reliability of COTS components rising, suppliers like Mini-Circuits are incorporating rigorous new design guidelines and reliability inspection verifications to ensure such components will last more than the lifetime of the end products. To enable designers to decide on incorporating COTS components into their military or other high-reliability applications, the manufacturer has instituted a thorough design and quality assurance program. The details are given in the paper titled “Commercial off the shelf MMIC components have high reliability” by Radha Krishna Setty, Kelvin Kiew and Harvey Kaylie of Mini-Circuits. In short, according to the article, the following actions have been incorporated into the suppliers manufacturing processes and qualifications:

• 5000 hours extended high temperature operating life (HTOL) tests instead of the industry standard 1000 hours.

• Continuous CSAM tests for delamination of plastic encapsulated parts.

• S-parameter inspection tests for every wafer lot, with acceptance by comparing against performance of previous lots and specification limits.

• Junction temperature measurements performed on each manufactured wafer.

Thus, to save time and money in high-quality component procurement, the authors conclude that designers of military products should closely review the quality of COTS produced by quality-conscious manufacturers.

The final paper in this supplement extols the virtues of solid-state relays (SSR) for military satellite applications. Satellite and launch vehicle applications traditionally use electromechanical relay (EMR) technology in many of the control systems of the satellite. EMR relays contain inherent reliability issues and may not perform correctly under severe environmental conditions such as the vibration profile during launch. Clearly, a more desirable solution is required. Recent generations of radiation-hardened MOSFET technology packaged and configured as an SSR have enabled designers to implement increasingly complex electronic control schemes. Furthermore, packaging multiple rad-hard MOSFET devices into a single package reduces the amount of interconnection, parasitic inductance and capacitance, and increases the reliability of the system.

In the article titled “Rad-hard SSRs offer alternative to EMRs in satellite applications” by International Rectifier's Alan Tasker and Michael Toland, the authors show that satellite systems require rad-hard devices that can withstand the rigors of space environment. EMRs designed into such systems require special care and additional circuitry to withstand shock and vibration, thereby adding space and weight and affecting reliability of the end system. This article presents a new generation of rad-hard SSRs that offer a cost-effective alternative with high reliability to electromechanical relays for defense satellite applications.