On the suitability of DRFMs for in-service testing of complex systems for avionic applications

The paper deals with the problem of in-service testing of complex systems and apparatuses (in particular, radio frequency ones) for avionic applications. This is a fundamental step when maintenance and/or monitoring of the system or apparatus have to be carried out without stopping its standard operation condition. Traditional approaches usually work by measuring only the signals at the output of the final stage of the system or apparatus and trying to determine the eventual fault source. Unfortunately, they often fail when complex systems or apparatuses, characterized by several multiple and sequential stages, are taken into account; singling out the specific faulty component turns out to be impossible. Moreover, most of the considered approaches require to turn off or out-of-service the system or apparatus under test. To overcome the considered limitations, the authors suggest the insertion of digital radio frequency memories between each couple of successive stages. Thanks to the available computation power, it is possible to compensate the output of first block, thus making the successive one operating with its ideal input. This way, it should be possible to clearly and straightforwardly identify the defective stage of the chain.