Presence Of Electromagnetic Interference Research Articles

Theoretical aspects and numerical modelling of the GPR method to analyse its possibilities for the detection of leakages in urban water supply networks

Geophysical methods, especially selected electrical and electromagnetic ones, have been used for many years for the non-invasive detection of leakages from water supply networks. In this paper, the author focuses on theoretical aspects and numerical simulations to analyse the possibilities and limitations of the application of the selected electromagnetic method, i.e., the ground-penetrating radar (GPR) method for the aforementioned purpose. Various measurement techniques are used in the GPR method but in the paper the author refers to the most commonly used technique known as short-offset reflection profiling (SORP). As demonstrated in the paper, the detection of water leakages into a homogeneous and isotropic geological medium using the GPR method is a simple matter. However, the detection of leakages occurring in heterogeneous ground subjected to strong anthropopression and with the presence of electromagnetic interference becomes a difficult task, and interpretation may be difficult or even impossible. An important issue analysed in the paper was the phenomenon of the scattering of electromagnetic waves on underground anthropogenic objects, which very often occurs in urbanised areas. The results of the numerical modelling carried out for various scenarios of water leakages into typical ground allowed the possibilities and limitations of using the GPR method for the detection of leakages from water supply networks to be determined.

Innovative measurement and noise reduction of voltage coupling in shielded cables for enhanced signal integrity

The reliable transmission of electrical signals through shielded cables in the presence of electromagnetic interference (EMI) remains a critical challenge for signal integrity. This paper presents a novel and comprehensive approach for measuring and reducing voltage coupling in shielded cables connected to a shielded room from a waveguide. Additionally, we introduce an innovative active EMI filter to effectively mitigate common-mode (CM) and differential-mode (DM) noises, thereby enhancing the overall signal quality. To address the issue of voltage coupling, an open circuit method with a transmission line is considered for the measurement of output voltage at the end of the shielded cable. In order to assess the impact of EMI on transmitted signals, we utilize a state-of-the-art noise separator that enables precise differentiation and characterization of CM and DM noise components. This analysis provides valuable insights into the overall noise profile, guiding the subsequent steps toward noise reduction. An active EMI filter was designed to effectively attenuate the unwanted noise. The filter intelligently targets and mitigates both CM and DM noises, resulting in improved signal integrity. The experimental setup encompasses a shielded room, shielded cables, a waveguide, and the equipment. The obtained output voltage from the shielded cable is 495 V. It is given as an input to the equipment (Cuk converter). The noises are generated when the input voltage is given; the noises are separated by using a noise separator. CM noise obtained at the output of an active noise separator is 118.8 dBµV. DM noise obtained at the output of a differential mode noise separator is 115.8 dBµV. With the active EMI filter, we achieve remarkable reductions in CM and DM noise levels. After adding a filter to the circuit, the noises are reduced below the limit line according to the International Special Committee on Radio Interference standard; the CM noise is 44.8 dBµV and the DM noise is 47.8 dBµV.

An Electromagnetic Interference Immune PAM-4 Transceiver System

This article presents the design of a pulse amplitude modulation (PAM-4) transceiver that supports high-speed wireline communication in the presence of electromagnetic interference (EMI). The proposed PAM-4 transceiver uses an input level shifter (ILS) and a modified electrostatic discharge (ESD)-protection circuit to reduce the effects of EMI at the transmitter. In order to overcome the effects of EMI at the receiver, the front end is designed with an enhanced input common-mode range. The transverse electromagnetic (TEM) cell method, as provided in the IEC 62132-2 standard, is followed to experimentally verify the radiated EMI-immunity of the proposed PAM-4 transceiver system over its traditional counterpart. For proof of concept, the proposed EMI-immune PAM-4 transceiver and the traditional PAM-4 transceiver circuits are implemented using the 130-nm BiCMOS process. The proposed transceiver operates at a data rate of 6.5 Gbps while maintaining an eye-opening of 70 mV for each bit in the presence of EMI, meeting the requirement of the IEEE 802.3 bs standard. The proposed PAM-4 transceiver withstands a wide range of EMI frequencies that span from 150 kHz to 2 GHz with an EMI power of 0–20 dBm.

Effects of realistic reradiation models in digital reconfigurable intelligent surfaces

Reconfigurable intelligent surfaces (RISs) are a promising technology for wireless communication applications, but their performance is often optimized using simplified electromagnetic reradiation models. In this study, we explore the impact on the RIS performance of more realistic assumptions, including the (possibly imperfect) quantization of the reflection coefficients, sub-wavelength inter-element spacing, near-field location, and presence of electromagnetic interference. We find that design constraints can cause an RIS to reradiate power in unwanted directions. Therefore, it is important to optimize an RIS by considering the entire reradiation pattern. Overall, our study indicates that a 2-bit digitally controllable RIS with a nearly constant reflection amplitude and RIS elements with a size and inter-element spacing between (1/8)th and (1/4)th of the signal wavelength may offer a reasonable tradeoff between performance, complexity, and cost.

Оценка функционирования беспроводных систем обнаружения пожаров на промышленных объектах

Introduction. Wireless fire detection systems are the most effective means of protecting industrial facilities. However, a comprehensive assessment of their work is needed. The variety of wireless systems with different functions and parameters determines the need for scientifically based methods for assessing the functioning of these systems at industrial facilities. The objective of the study. Evaluation of the effectiveness of wireless fire detection systems at industrial facilities. Experimental studies on the stable operation of a wireless fire detection system at industrial facilities. Methods. Analysis of wireless fire detection systems at industrial facilities. Evaluation of the reliability of wireless fire detection systems at industrial facilities based on mathematical models and experiments. Investigation of possible results of verification of the detection of wireless fire detection systems at industrial facilities. Results and discussion. As a result of the study, factors affecting the efficiency of wireless fire detection systems at industrial facilities were identified. Experimental studies were carried out on the stable operation of wireless fire detection systems at industrial facilities, which showed that the presence of electromagnetic interference at the surveyed substation has little effect on the functioning of wireless fire detection systems while providing the required (third) the degree of rigidity of the equipment to the effects of electromagnetic interference at a radio signal frequency of 434 MHz from the fire detector to the control panel. Conclusions. A comprehensive assessment of the operation of a wireless fire detection system in industrial facilities is an important aspect of safety. In order for the system to be able to effectively provide security, it is necessary to conduct a comprehensive assessment of their work, taking into account the many factors that affect their work and work. The introduction of a wireless fire detection system into the decision support model for fire safety will allow for more rapid and objectively respond to the threat of fire and eliminate the spread of fire in a timely manner. Keywords: wireless fire detection systems; fire protection; industrial facility; reliability; response time; electromagnetic interference.

Downlink URLLC System Over Spatially Correlated RIS Channels and Electromagnetic Interference

This letter explores a reconfigurable intelligent surfaces (RISs) assisted multi-user ultra-reliable low-latency communication (URLLC) system in presence of electromagnetic interference (EMI). The spatial correlation among the channels corresponding to the RIS meta-atoms is considered. For downlink communication, source selects a user out of arbitrary <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> users through random or absolute channel power based (CPB) scheduling schemes. We derive the closed form expressions for outage probability, block error rate (BLER), capacity and system goodput for both the scheduling schemes under the assumption of imperfect channel state information (CSI). Moreover, asymptotic expression for outage probability is also derived. The correctness of the derived expressions is verified through Monte-Carlo simulations.

FoReCo: A Forecast-Based Recovery Mechanism for Real-Time Remote Control of Robotic Manipulators

Wireless communications represent a game changer for future manufacturing plants, enabling flexible production chains, as machinery and other components not to be restricted to a location by the rigid wired connections on the factory floor. However, the presence of electromagnetic interference in the wireless spectrum may result in packet loss and delay, making it a challenging environment to meet the extreme reliability requirements of industrial applications. In such conditions, achieving real-time remote control, either from the Edge or Cloud, becomes complex. In this paper, we investigate a forecast-based recovery mechanism for real-time remote control of robotic manipulators (FoReCo) that uses Machine Learning (ML) to infer lost commands caused by interference in the wireless channel. FoReCo is evaluated through both simulation and experimentation in interference prone IEEE 802.11 wireless links, and using a commercial research robot that performs pick-and-place tasks. Results show that upon interference FoReCo reduces the trajectory error by more than a 34.35% in both simulation, and experimentation. We also show that FoReCo is sufficiently lightweight to be deployed in existing hardware.

HOLTER ECG MONITORING AS METHOD FOR ASSESSING INTERACTION OF IMPLANTED PACEMAKER AND SOURCE OF ELECTROMAGNETIC INTERFERENCE

The aim of the study was to assess the interaction of the cardiostimulation system of the patient and the source of electromagnetic interference (EMI) during the patient’s work by Holter monitoring of ECG. Finally, to analyze ECG recording and evaluate possible pacemaker (PCM) program responses to the presence of EMI. The observation was performed in the selected patient with the single-chamber conventional pacemaker during practicing of a profession in an industrial environment with a real risk of interaction with the defined source of interference. The heart rhythm was monitored with a standard Holter monitor and the measurement was repeated during three work shifts. The PCM was revised before each measurement and at the same time the programming was adjusted for monitoring purposes. The ECG record was back-analyzed and the device response to the presence of EMI was evaluated. No program response to the presence of an interfering electromagnetic field (EMF) was observed from the ECG recording analysis. This program response would manifest to abnormalities in the ECG curve (asynchronous pacing, pacing inhibition, competitive pacing). There were no events in the PCM memory indicating the effect of the EMI.

An EMI-Immune PAM-4 Transmitter With Input Level Shifter in 130-nm BiCMOS Technology

This work presents a design of an electromagnetic interference (EMI)-immune pulse amplitude modulation-4 (PAM-4) transmitter. The traditional PAM-4 transmitters are prone to failing in the presence of EMI, which is experimentally verified. The proposed PAM-4 shows superior performance over the traditional PAM-4 transmitter, in the presence of EMI, by using an Input Level Shifter (ILS). ILS minimises the effect of EMI on a PAM-4 signal by reducing the input commonmode level of the transmitter and renders it compatible with the previous logic state. The proposed PAM-4 transmitter is fabricated in 130-nm BiCMOS technology with a chip area of 580mum×915 mum. EMI-immunity measurements are aligned with the IEC 62132-2 standard by using a transverse electromagnetic (TEM) cell for radiated EMI-immunity. In the presence of a wide range of EMIs, the proposed PAM-4 transmitter operates at a data rate of 6.5 Gbps and maintains the minimum required eye-opening of 70mV as per the standard IEEE 802.2bs. The proposed EMI-immune transmitter can withstand EMI powers of 0-16dBm in frequencies ranging from 1MHz to 1.5 GHz.

Bearing diagnostics under strong electromagnetic interference based on Integrated Spectral Coherence

Rolling element bearing fault diagnostics has been a topic of intensive research in recent decades, as they are critical components of rotating machinery and therefore their failure may result in sudden breakdown of machines and industrial installations. The early and accurate detection of incipient faults on bearings can reduce the production cost by allowing maintenance engineers to schedule a replacement at the most convenient time. Envelope Analysis is a widespread powerful method in bearing diagnostics, often used along with Fast Kurtogram. However, the presence of ElectroMagnetic Interference (EMI) and generally speaking of impulsive and non gaussian noise, increases the complexity of bearing fault diagnosis and may lead to rather poor diagnostic performance. EMI is often present in mechanisms and machines, where motors are controlled by Variable-Frequency Drives (VFD) and can present a vibration signature similar to that of bearing faults. Therefore, the main aim of this paper is the proposal of advanced signal processing techniques, which can detect bearing faults under the presence of strong ElectroMagnetic Interference or other impulsive noise (where state of the art methods fail). Two novel diagnostic methodologies are proposed based on the Cyclic Spectral Coherence (CSCoh). The integration of the CSCoh, over the full spectral frequency axis or over a specific spectral frequency band, results respectively in the Enhanced Envelope Spectrum or in the Improved Envelope Spectrum. The two novel diagnostic methodologies allow for the automatic selection and integration of the optimal bands on the CSCoh under heavy impulsive noise, such as EMI, resulting in a spectrum with enhanced characteristic bearing fault frequencies, without any human intervention required besides the knowledge of the characteristic fault frequency which is under investigation. The methods are applied on vibration data, captured on an epicyclic gearbox with seeded bearing faults, operating under the influence of strong EMI. The methods are tested and evaluated on different fault cases and achieve improved performance compared to state of the art diagnostic methodologies.

Investigation of the viscoelastic effect on optical-fiber sensing and its solution for 3D-printed sensor packages.

Viscoelasticity is an effect seen in a wide range of materials, and it affects the reliability of static measurements made using fiber Bragg grating (FBG)-based sensors, because the target structure, the adhesive used, or the fiber itself could be viscoelastic. The effect of viscoelasticity on FBG-based sensing has been comprehensively researched through theoretical analysis and simulation using a finite-element approach, and a further data processing method to reconstruct the graphical data has been developed. An integrated sensor package comprising an FBG-based sensor in a polymer host and manufactured by using three-dimensional (3D) printing was investigated and examined through tensile testing to validate the approach. The application of the 3D-printed FBG-based sensor package, coupled with the data process method, has been explored to monitor the height of a railway pantograph, a critical measurement requirement to monitor elongation, employing a method that can be used in the presence of electromagnetic interference. The results show that the effect of viscoelasticity can be effectively eliminated, and the graphical system response allows results that are sufficiently precise for field use to be generated.

Safety concerns of Piezoelectric Units in Implantable Cardioverter Defibrillator

Evidence-based research appears to conflict on the potential risk of electromagnetic interference (EMI) between piezoelectric units (Pzs) and implantable cardioverters and defibrillators (ICDs). The purpose of this study was to observe whether the EMI produced by Pzs is hazardous for ICDs. A cross-sectional study of 6 Pzs was conducted invitro for EMI using an ICD system. To simulate the human body's electrical resistance, electrographic recordings were made of the ICD and lead that were immersed in a bath of saline solution. The variables investigated were the presence of EMI, the distance between the ICD and the Pz, and signal intensity, damage, and type of damage to the ICD and lead. Each series of tests was repeated 3 times, beginning with a 15-second baseline recording (control), until all recording conditions had been covered. Each Pz was recorded under the following conditions: less than 2cm from the tip of the ICD lead; less than 2cm from the ICD; less than 2cm from the lead body and coils; and 15cm from the lead or the ICD (R4). In the positive control (direct contact between the lead or the ICD with the Pz switched on), the ICD detected electrical activity as false heart activity. However, after covering all test conditions, no EMI was produced by the Pzs. No EMI or permanent changes in the functioning of the ICD were detected invitro.

A photodetector for the diagnostics of turbulent gas flows and flames by the method of absorption spectroscopy with diode lasers

A photodetector device that is intended for absorption measurements at a level of 10–2–10–3 under the conditions of large intensity fluctuations of probing radiation, nonstationary broadband illumination of the photodetector, and in the presence of electromagnetic interference is described. Using a differential measurement circuit, an absorption signal is formed in the analog manner and amplified to a level of ~1 V directly near the photodetector. During periodic wavelength scanning, the influence of the broadband illumination and vibrations is compensated at the beginning of each scan. This compensation is preserved during a current scan and renewed in each subsequent scan due to the use of sample-and-hold amplifiers. The device can be used in the diagnostics of turbulent gas flows and flames.

Ensuring a stable wireless communication in cyber-physical systems with moving objects

The data transmission process in cyber-physical system (CFS) with wireless communication channels between cyber-physical objects (CFO) is studied in the article. In the presence of obstacles (mechanical and electromagnetic),zero direct visibility or exceeding the allowable distance between CFO (Wi-Fi communication modules of unmanned vehicles – UMV – and/or mobile devices) that need to share data, it is necessary to take measures to restore broken communication line or to stabilization of the data transmission rate.The method for regularly radio situation overriding in CFS coverage area is proposed. The stability of wireless communication is achieved by changing energy and frequency characteristics of the communication line between CFO, as well as through the use of intermediate CFO as the signal transmitters. An algorithm for performing the specified settings depending on the model of used cyber-physical components, the distance between CFO and the delay of time interval is described. The full-scale experiment in the field using real hardware and software and with the presence of electromagnetic interference has been recreated to verify the algorithm. It is shown that for certain set of initial parameters, reducing a Wi-Fi module maximum power by 50 % improves the quality of communication in almost 8 times.Assessment of changes in the data transmission rate depending on the number of retransmissions is conducted. The stability performances of data transmission rate up to 90 %are improved by transition of communication line to another frequency range with less interference and introduction of signal retransmission function using intermediate CFO.The direction of future research is dependent on trends in the market of construction materials for UMV and computer components with built-in Wi-Fi communication modules.

Optimised Spectral Kurtosis for bearing diagnostics under electromagnetic interference

The selection of the optimal demodulation frequency band is a significant step in bearing fault diagnosis because it determines whether the fault information can be extracted from the demodulated signal via envelope analysis. Two well-known methods for selecting the demodulation band are the Fast Kurtogram, based on the kurtosis of the filtered time signal, and the Protrugram, which uses the kurtosis of the envelope (amplitude) spectrum. Although these two methods have been successfully applied in many cases, the authors have observed that they may fail in specific environments, such as in the presence of electromagnetic interference (EMI) or other impulsive masking signals.In this paper, a simple spectral kurtosis-based approach is proposed for selecting the best demodulation band to extract bearing fault-related impulsive content from vibration signals contaminated with strong EMI. The method is applied to vibration signals obtained from a planetary gearbox test rig with planet bearings seeded with inner and outer race faults. Results from the Fast Kurtogram and Protrugram methods are also included for comparison. The proposed approach is found to exhibit superior diagnostic performance in the presence of intense EMI.Another contribution of the paper is to introduce and explain the issue of EMI to the condition monitoring community. The paper outlines the characteristics of EMI arising from widely-used variable frequency drives, and these characteristics are used to simulate an EMI-contaminated vibration signal to further test the performance of the proposed approach. Although EMI has been acknowledged as a serious problem in many industrial cases, there have been very few studies showing its adverse effects on machine diagnostics. It is important for analysts to be able to identify EMI in measured vibration signals, lest it interfere with the analysis undertaken.

Hot carrier effect on the bipolar transistors’ response to electromagnetic interference

Damage of bipolar transistors (BJTs) during the mission could affect their response to electromagnetic interference (EMI) and change the Integrated Circuit (IC)’s electromagnetic susceptibility (EMS). This work investigated the effect of hot carrier stress on BJT’s response to EMI. The experimental results demonstrate that the base current increases under EMI and the amplitude enlarges after hot carrier stress. The variation of EMI induced collector current shift after hot carrier stress depends on the base supply resistance Rt. When Rt=0, IC shift in presence of EMI is not affected by hot carrier stress whereas in the case of Rt≠0, the EMI induced IC increment reduces or even reverses in variation direction. When the base terminal is biased by a current source, the voltage across the emitter-base junction drops more significantly after hot carrier stress.

IPad2(R) use in patients with implantable cardioverter defibrillators causes electromagnetic interference: the EMIT Study.

BackgroundOver 140 million iPads® have been sold worldwide. The iPad2®, with magnets embedded in its frame and Smart Cover and 3G cellular data capability, can potentially cause electromagnetic interference in implantable cardioverter defibrillators. This can lead to potentially life‐threatening situations in patients. The goal of this study was to determine whether the iPad2® can cause electromagnetic interference in patients with implantable cardioverter defibrillators.Methods and ResultsTwenty‐seven patients with implantable cardioverter defibrillators were studied. The iPad2® was held at reading distance and placed directly over the device with cellular data capability activated and deactivated. The manufacturers/models of devices and the patients' body mass index were noted. The presence of electromagnetic interference was detected by using a programmer supplied by each manufacturer. Magnet mode with suspension of anti‐tachycardia therapy was triggered in 9 (33%) patients. All occurred when the iPad2® was placed directly over the device. The cellular data status did not cause interference and no noise or oversensing was noted. There was no significant difference between the mean body mass index of the groups with or without interference.ConclusionsThe iPad2® can trigger magnet mode in implantable cardioverter defibrillators when laid directly over the device. This is potentially dangerous if patients should develop life‐threatening arrhythmias at the same time. As new electronic products that use magnets are produced, the potential risk to patients with implantable defibrillators needs to be addressed.

A Systematic Electromagnetic-Circuit Method for EMI Analysis of Coupled Interconnects on Dispersive Dielectrics

This paper presents a systematic electromagnetic-circuit method for efficient simulation of coupled interconnects on dispersive dielectrics in the presence of electromagnetic interference. The dispersive substrate of coupled interconnects is characterized by the multiterm Debye or Lorentz formula. According to the differential equations derived from the equivalent circuit modeling of dispersive media, the full-wave finite-difference time-domain algorithm is utilized to capture accurate field in a dispersive substrate. The effects of incident field, under the quasi-TEM assumption, are then represented by the distributed sources along transmission lines. An efficient algorithm based on the waveform relaxation with transverse partitioning (WR-TP) is employed for fast simulation of coupled transmission lines. A simple and clear derivation of the relaxation sources in WR-TP is described and the compact results are given. The impact of dispersive dielectrics on the incident field, and thus to the transient response of interconnects, is investigated by comparison with conventional techniques. Several numerical examples are given to illustrate the accuracy and efficiency of the proposed method.

Electromagnetic Susceptibility Analysis on a Digital Pulse Width Modulator for SMPSs

In this paper, a digital pulse width modulator (DPWM) is analyzed from the point of view of susceptibility to radio-frequency interference (RFI). The chosen DPWM architecture is based on the hybrid delay-line/counter scheme commonly used in the digital control of switched-mode power supplies (SMPSs). This paper focuses on the DPWM performance degradation in the presence of electromagnetic interference (EMI), and for this purpose a DPWM with time resolution down to 350 ps has been designed and manufactured in a standard 0.35- mum complementary metal-oxide semiconductor technology. Measurements and analytical analyses are presented for both EMI effects on the internal generated clock signal and on the PWM duty-cycle precision. The immunity degradation mechanisms are investigated by means of an analytical approach, demonstrating that the PWM susceptibility is more strictly related to its functional design rather than to the implemented topology. The effects of clock and duty-cycle jitter induced by RFIs are finally verified using a simulation model on a digitally controlled buck converter, highlighting the importance of such issue on steady-state performances of SMPSs.

Quantum Efficiency and Quantum Yield of an HgCdTe Infrared Sensor Array

ABSTRACTWe measure the quantum efficiency and quantum yield of an H2RG HgCdTe near-infrared sensor array. Using a blackbody, narrowband filters, and a pinhole camera to provide a calibrated irradiance on the HgCdTe sensor, we determine a 2 σ lower limit of 85% for the quantum efficiency averaged over the array and over three observed wavelengths, 3.38, 3.9, and 4.5 μm. The peak quantum efficiency occurs near the center of the sensor and is unity within measurement uncertainty (5%). By substituting a calibrated PbSe diode for the H2RG sensor, we verify the methods and equipment at the three wavelengths, 3.38, 3.9, and 4.5 μm. Accurate measurement of the quantum efficiency requires a well-calibrated system gain, the determination of which is complicated by interpixel capacitance, which correlates noise between adjacent pixels. If unaccounted for, the correlation induced by interpixel capacitance would cause the system gain and hence the quantum efficiency to be overestimated by ∼20%. We accurately measure the interpixel capacitance using the autocorrelation method of Brown, Schubnell, and Tarlé and by a method described in this paper that uses post-readout binning. The two methods yield consistent results, but the binning method is more robust than the autocorrelation method in the presence of electromagnetic interference. The interpixel capacitance we measure for the H2RG-S010 sensor is similar to that of another epoxy-backfilled H2RG sensor tested recently by Brown, Schubnell, and Tarlé. Using the same PbSe diode to calibrate the quantum efficiency of the 5.5-μm-cutoff H2RG sensor from 0.7 μm to 6.0 μm, and correcting for the interpixel capacitance, we derive implausible quantum efficiencies greater than unity between 1.4 μm and 2.4 μm that we cannot explain. The apparent system gain, measured at many monochromatic wavelengths with the usual variance-versus-mean photon-transfer analysis of flat-field images, is a function of wavelength for wavelengths less than 2 μm, which we interpret as evidence for quantum yield larger than unity, i.e., more than one electron being produced by each photon detected by the sensor. We derive the effects of Fano noise and quantum yield on the photon-transfer curve.