Triple modular redundancy

Abstract

In computing, triple modular redundancy (TMR) is a fault tolerant form of N-modular redundancy, in which three systems perform a process and that result is processed by a voting system to produce a single output. If any one of the three systems fails, the other two systems can correct and mask the fault. If the voter fails then the complete system will fail. However, in a good TMR system the voter is much more reliable than the other TMR components. Alternatively, if there is another stage of TMR logic following the current one (for example, in systems such as the Saturn Launch Vehicle Digital Computer), then three voters are used - one for each copy of the next stage of logic.