Concurrent error detection and fault-tolerance in linear analog circuits using continuous checksums

The problem of concurrent error detection and fault tolerance is studied. These checksums of time-varying functions are possible because the function of a linear analog circuit can be represented mathematically by a set of matrices to which checksum codes can be applied. For the purpose of error detection, it is assumed that a fault can cause the value of a passive circuit component to deviate from its normal value, result in a line short or open, or change the operating characteristics of the active components (operational amplifiers). If the specifying parameters of a linear analog circuit change due to a fault and the failed circuit behaves as a linear system, then error correction is performed by compensating for the changed parameter values. Otherwise, partical correction is possible. Error detection and correction are performed by a small amount of hardware added to the linear analog circuit. The hardware overhead is virtually constant irrespective of the circuit size, and the sensitivity of the error detection circuit to failures can be easily calibrated.<
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