Fault-tolerant implementation of direct FIR filters protected using residue codes

The design of fault-secure and fault-tolerant versions of digital finite input response (FIR) filters implemented in direct form is studied. The fault-secure versions proposed are protected using residue codes mod A (A is an odd integer) and guarantee the 100% error coverage for all single line faults, should some elementary design rules be respected. The fault-tolerant versions rely on duplication of fault-secure versions. The synthesis results suggest that the hardware overhead needed could be also as low as for their transposed versions counterparts proposed recently: for all fault-secure filters with 16-bit operands and protected using the residue code mod 3 it is about 3%. For fault-tolerant versions with 16-bit operands, the hardware overhead ranges only from about 105 to 117.5%, which is significantly less than over 200% for triplication.