Resilience of Time Diversity Against Multiharmonic Electromagnetic Disturbances Under Reverberation Conditions: An Overview of Fault Mechanisms

Abstract

In this paper, time diversity is used as an electromagnetic resilience technique in a Triple Modular Redundant (TMR) communication channel that is subjected to a multiharmonic electromagnetic disturbance under semi-reverberant environments. The study is carried out in light of new Elec-troMagnetic Interference (EMI) condition monitoring definitions which provide a better insight into the actual state of the system. An explanation of the different fault mechanisms based on the new definitions is provided for a time diverse TMR system with a two-out-of-three majority voter and is compared with the previously used EMI condition monitoring definitions. The new definitions provide a better understanding on how to interpret the results of an EMI detector or an EMI corrector by keeping in consideration the safety and availability aspects of system.

Decision Algorithm Based on the Modified Bellman Equation to Deal With EMI-Induced Errors in Hamming-Based Communications

“…This paper relies on an in-house developed simulation framework that combines the paper of Hill [21], Magdowski et al [22], and Vanhee et al [23]. Different studies, as performed by [24], [25], use and extensively describe this framework. This section will shortly recapitulate this framework, which performs a Monte-Carlo simulation of single or multifrequency continuous wave disturbances, which are incident to a device-under-test (DUT), in this case a Printed Circuit Board (PCB).…”

“…Figure 4 shows the response of the number of faults as a function of the SIR for a reverberation wave of f EMI = 500 MHz and f BIT = 350 MHz. The algorithm for computation of SIR is explained in [25]. To calculate these probabilities, a large number of codewords are sent through the simulation framework, and the Hamming code is applied to the received codewords.…”

Symbol Diversity as a Means to Make PAM-4 Modulation More Resilient in Harsh Electromagnetic Environments

“…Similarly, in [16] it was shown that the 3 rd harmonic component of f Bit was responsible for the first occurring CFNs. Furthermore, in [17], it was shown that the time diverse TMR setup leads to increasing number of CFNs at low SIR values. As this algorithm won't be affected by the 3 rd harmonic homopolar component, this technique is likely to perform better in a multi-harmonic reverberation environment.…”

“…electromagnetically diverse redundant channels in order to cope with the systematic and common cause effects of EMI. Some of the ways of realizing this diversity is either by varying the bit delays of the transmitted bit stream (time diversity) [3], [17], or the data rate (frequency diversity) [4], or the spatial orientation of traces (spatial diversity) [5].…”

“…The novelty of the symbol diversity technique lies in the manner in which this electromagnetically diverse behaviour is realized in a TMR communication channel. Instead of varying the bit delays like it is done with the time diversity technique in [17], the encoding of the PAM-4 symbols is varied across the redundant channels. This symbol diversity ensures that as the EMI induced couple voltages increase, the symbols don't follow the EMI trajectory and therefore don't transform into other valid symbols, leading to undetected failures.…”