Guided Probabilistic Checksums for Error Control in Low-Power Digital Filters
Guided Probabilistic Checksums for Error Control in Low-Power Digital Filters
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用于低功耗数字滤波器中错误控制的引导概率校验和
DOI：
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发表时间：
2008
影响因子：
3.7
通讯作者：
A. Chatterjee
中科院分区：
文献类型：
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作者：
Muhammad Mudassar Nisar;A. Chatterjee
在许多 DSP 应用（图像和语音处理）中，可以容忍几个 dB 的 SNR 损失，而不会对应用级性能产生明显影响。对于此类应用中的功率优化，可以使用电压超标度 (VOS) 在关键电路路径延迟或略低于关键电路路径延迟的情况下操作算术电路，同时由于计算中产生的周期性误差而导致可容忍的 SNR 损失。在本文中，低成本校验和代码用于检测和补偿线性数字滤波器中由于电压超标度引起的间歇性错误。在传统的编码理论中，错误诊断是一个关键问题，并且会产生大量的计算和延迟成本。在所提出的方法中，低精度影子锁存器用于识别由于电压超标引起的可能的错误源，以避免错误诊断。这允许使用距离 2 校验和代码进行精确的错误补偿，该校验和代码通常仅适用于错误检测，但不适用于纠正。通过将误差值的负值均匀地分布在可能的错误状态上，可以实现非常精确的补偿。这称为引导概率补偿，因为当错误在不止一种状态下同时发生时，补偿并不准确。反馈控制器用于动态电压超标度 (DVOS)，同时将系统中的错误率保持在可接受的范围内。结果表明，低成本的精确误差补偿可以显着节省功耗，同时将系统性能 (SNR) 的降低降至最低。
In many DSP applications (image and voice processing), several dBs of SNR loss can be tolerated without noticeable impact on application level performance. For power optimization in such applications, voltage overscaling (VOS) can be used to operate the arithmetic circuitry at or marginally below the critical circuit path delay while incurring tolerable SNR loss due to the resulting periodic errors in computation. In this paper, low cost checksum codes are used for detection and compensation of intermittent errors due to voltage overscaling in linear digital filters. In traditional coding theory, diagnosis of errors is a key problem and incurs significant computation and latency cost. In the proposed approach, low-precision shadow latches are used to identify likely sources of errors due to voltage overscaling to avoid error diagnosis. This allows accurate error compensation with distance-2 checksum codes that are normally good only for error detection but not for correction. Very precise compensation is achieved by distributing the negative of the error value evenly across only the likely erroneous states. This is called guided probabilistic compensation, as compensation is not exact when errors occur simultaneously in more than one state. A feedback controller is used for dynamic voltage overscaling (DVOS) while keeping the error rate in the system within an acceptable range. It is shown that the low cost accurate error compensation allows significant power savings with minimal degradation in system performance (SNR).