On improving the algorithmic robustness of a low-power FIR filter

Voltage scaling is a promising approach to reduce the power consumption in signal processing circuits. However aggressive voltage scaling can introduce errors in the output signal, thus degrading the algorithmic performance of the circuit. We consider the specific case of the finite impulse response (FIR) filter, and identify two different sources of errors occurring due to voltage scaling: (a) errors introduced because of increased delay along the logic path and (b) errors caused by failures in the memory due to process variations. We design a FIR filter by using a simple feedback based approach to reduce the memory errors and a linear predictor structure for correcting the logic errors. The proposed filter is more robust to both logic and memory errors caused by voltage scaling. The results show a considerable improvement in the output Signal to Noise ratio (at least around 10 dB) for a probability of error (P_err) even as high as 0.5. We also utilize the proposed technique for an image filtering application and observe a considerable improvement in the visual quality of the output image along with an improvement of over 10 dB in the Peak Signal to Noise ratio for P_err as high as 0.5.