The importance of testing complex electronics
The increasing functionality of modern electronics systems is being achieved through more complex integrated circuits, dense surface mount assemblies and increasingly through the use of multiple complex ICs interconnected to form multi-chip modules, all of which have progressively increased the cost of testing and its share of production cost, so that test costs are dominant today. Initiatives taken in Europe by leading corporations and recently adopted as IEEE standards for logic circuit testability, are now enabling electronic access for in-circuit testing and diagnostics at IC and board and MCM level, thereby improving quality and throughput in the manufacture of electronics. various proprietary solutions are also being introduced very effectively for analogue circuits, and for specialised computing and telecommunications systems, some using expert systems to aid diagnostics and improving the quality and throughput of testing. The solutions are most cost-effectively introduced at the design stage when maximum impact can be achieved on subsequent life-cycle costs.
Chip Carrier Based Systems and their Testability
Testing has become one of the dominant costs in the process of bringing a product from initial conception to the market place. Because of this, it is now imperative that the impact of any technology change on the test process is considered at an early stage. In this light, the increasing trend towards the use of surface‐mounting techniques in the fabrication of electronic systems is examined, with particular emphasis on the consequences on product testing during design validation, manufacture and repair. The aim is to highlight areas in which new attitudes and replacements for traditional solutions will be needed if surface‐mounting techniques are to be as cost‐effective as possible.
Bone changes in tuberous sclerosis mimicking metastases.
Sclerotic and lytic bone changes of tuberous sclerosis (TS) can mimic bone metastases. We report a case of bone metastases from bronchogenic carcinoma in a patient with TS bone changes. Bone scintigraphy and magnetic resonance imaging are useful in distinguishing the TS bone lesions from bone metastases.