Probabilistic Compensation for Digital Filters Using Pervasive Noise-Induced Operator Errors

It is well known that scaled CMOS technologies are increasingly susceptible to induced soft errors and environmental noise. Probabilistic checksum-based error detection and compensation has been proposed in the past for scaled DSP circuits for which a certain level of inaccuracy can be tolerated as long as system-level quality-of-service (QoS) metrics are satisfied. Although the technique has been shown to be effective in improving the SNR of digital filters, it can only handle errors that occur in the system states. However, the transient-error rate of combinational logic is increasing with technology scaling. Therefore, handling errors in the arithmetic logic circuitry of DSP systems is also essential. This is a significantly more difficult task due to the fact that a single error at the output of an adder or multiplier can propagate to more than one system state causing multiple states to be erroneous. In this paper, a unified scheme that can address probabilistic compensation for errors both in the system states and in the embedded adders and multipliers of DSP filters is developed. It is shown that by careful checksum code design, significant SNR improvements (up to 13 dB) can be obtained for linear filters in the presence of soft errors.