Exploring design diversity redundancy to improve resilience in mixed-signal systems
Abstract Redundancy is the most popular technique to add fault tolerance at system level to electronic systems. Redundancy with hardware and software diversity of digital computers is currently employed in safety critical applications, as, for example, in spacecrafts and commercial aircrafts, to increase the reliability of such systems. This work presents a study of the design diversity redundancy technique in the context of mixed-signal systems, identifying the advantages and associated costs of applying this technique to subsystems with both analog and digital parts. The discussion is based on three case studies: two data acquisition systems and a low-pass filter, all of them prototyped in mixed-signal programmable platforms. In these systems, different combinations regarding the number of modules (double or triple modular redundancy) and specific issues related to the applied diversity modes are considered. Based on the results of fault injection campaigns by hardware emulation and one neutron irradiation test, the achieved reliability level of each studied system is discussed, as well as the tradeoffs of applying design diversity redundancy to mixed-signal systems.