Structural DMR: A Technique for Implementation of Soft Error Tolerant FIR Filters

In this brief, an efficient technique for implementation of soft-error-tolerant finite impulse response (FIR) filters is presented. The proposed technique uses two implementations of the basic filter with different structures operating in parallel. A soft error occurring in either filter causes the outputs of the filters to differ, or mismatch, for at least one sample. The filters are specifically designed so that, when a soft error occurs, they produce distinct error patterns at the filter output. An error detection circuit monitors the basic filter outputs and identifies any mismatches. An error correction circuit determines which filter is in error based on the mismatch pattern and selects the error-free filter result as the output of the overall error-protected system. This technique is referred to as structural dual modular redundancy (DMR) since it enhances traditional DMR to provide error correction, as well as error detection, by means of filter modules with different structures. The proposed technique has been implemented and evaluated. The system achieves a soft error correction rate of close to 100% for isolated single soft errors and has a logic complexity significantly less than that of conventional triple modular redundancy.