Effects of the 3^rd Harmonic Component on False Negatives in a Time Diverse Triple Modular Redundant System Under Reverberation Conditions

Abstract

In this paper, time diversity is used as an EM resilience technique in a Triple Modular Redundant (TMR) communication channel that is subjected to a multi-harmonic electromagnetic disturbance under reverberation conditions. The study shows that time diversity proves to be quite an effective measure in order to incorporate fault tolerance in the system. However, when compared to the single frequency case for which time diversity eliminates all potential false negatives, the multi-harmonic disturbance tends to have a slight percentage of false negatives, especially at high field strengths. Together with reverberation simulation results, a theoretical explanation is also presented that explains this phenomenon of multi-harmonic Electromagnetic Interference (EMI) induced false negatives.

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

“…In [16] the effects of a multi-harmonic EM disturbance on FNs were analyzed for a time diverse system. A 3 rd harmonic component was added to the fundamental frequency as the homo-polar nature of 3 rd harmonic is most likely to disrupt the optimal performance of time diversity for 2oo3 TMR system.…”

“…The result shown in Fig. 6 has also been converted in terms of SIR and comes from [16] where time diversity was applied in a multi-harmonic reverberation environment. The addition of the 3 rd harmonic indeed leads to appearance of FNs at low SIRs which were eliminated for the single frequency case.…”

“…In addition, this paper aims to study the effectiveness of time-diversity against multi-harmonic disturbances in light of new EMI condition monitoring definitions which help to understand the underlying phenomenon from a system's perspective [14]. In [16] an analysis was carried out for the same system to study the phenomenon behind the occurrence of dangerous failures which remain undetected, the so called false negatives. In this paper, a model-based simulation The remainder of the paper is organized as follows.…”

Safety and Availability Considerations in a Triple Modular Redundant Time Diverse System with Over- Voltage Detection

“…EM-diversity can be achieved in several ways, e.g. time diversity [2,3,4], frequency diversity [5], spatial diversity [6], etc. This EM-diverse behavior allows the redundant channels to be influenced differently when exposed to Elec-troMagnetic Disturbances (EMD).…”

“…Time diversity in conjunction with majority voting for a Triple Modular Redundant (TMR) system has been studied in detail for various environments. Time diversity as an EM-resilience measure has been studied for plane wave environments in [3] and for reflecting environments in [2,4]. The results show a marked improvement in terms of parameters such as Bit Error Rate (BER) and percentage of false negatives (CFN according to EM condition monitoring definitions introduced in [8]).…”