Briefing a New Approach to Improve the EMI Immunity of DSP Systems

摘要

Hereafter, we present an approach dealing to improve the reliability of digital signal processing (DSP) systems operating in real noisy (electromagnetic interference - EMI) environments. The approach is based on the coupling of two techniques: the "DSP-oriented signal integrity improvement" technique deals to increase the signal-to-noise ratio (SNR) and is essentially a modification of the classic Recovery Blocks Scheme. The second technique, named "SW-based fault handling" aims to detect in real-time data- and control-flow faults throughout modifications of the processor C-code. When compared to conventional approaches using Fast Fourier Transform (FFT) and Hamming Code, the primary benefit of such an approach is to improve system reliability by means of a considerably low complexity, reasonably low performance degradation and, when implemented in hardware, with reduced area overhead. Aiming to illustrate the proposed approach, we present a case study for a speech recognition system, which was partially implemented in a PC microcomputer and in a COTS microcontroller. This system was tested under a home-tailored EMI environment according to the International Standard Normative IEC 61.000-4-29. The obtained results indicate that the proposed approach can effectively improve the reliability of DSP systems operating in real noise (EMI) environments.