BroadR-Reach® is a point-to-point Ethernet Physical Layer (PHY) standard, which is used in automo... more BroadR-Reach® is a point-to-point Ethernet Physical Layer (PHY) standard, which is used in automotive applications. This technology allows full-duplex communication between two devices over a single, Unshielded Twisted-wire Pair (UTP) cable. Here, alien crosstalk in a 6 UTP bundle is investigated for meeting electromagnetic compatibility requirements. Alien crosstalk refers to crosstalk to the BroadR-Reach® communication channel from an unrelated signal wire. Alien Near-End and Far-End Crosstalk in two different UTPs with and without an inline Circular Plastic Connector (CPC) are compared to standard limits. An inline connector in the middle of a 15 m 6 UTP cable bundle, with a 25 cm untwisted region, fails the Power Sum Alien Near-End Crosstalk (PSANEXT) standard limit by 4 dB at 100 MHz, while the same bundle without the connector passes the standard by a margin of 8 dB at 100 MHz.
Switching of logic gates in integrated circuits is responsible for significant power supply noise... more Switching of logic gates in integrated circuits is responsible for significant power supply noise on the chip and on the printed circuit board (PCB). Predicting power supply noise can be critical for analyzing the proper operation of high-speed devices. A vectorless method was developed to predict the statistical distribution of dynamic currents drawn by an IC and was used to predict the statistical characteristics of power supply noise on the PCB. Simulations and measurements of noise on the PCB power delivery network demonstrate the approach can determine the average and standard deviation of the power supply voltage within 20%, which is more than sufficient for predicting the statistical impact of switching noise on circuit performance
Skills in hardware-software co-design are quickly becoming critical to product development in hig... more Skills in hardware-software co-design are quickly becoming critical to product development in hightechnology computer industries. Systems-on-silicon typically include a considerable amount of software as well as custom hardware and are increasingly difficult to develop using traditional techniques. To satisfy a growing demand in industry, students in electrical engineering, computer engineering, and computer science should be introduced to concepts of hardware-software co-design at the undergraduate level. This paper examines a new laboratory at the University of Missouri-Rolla in which students in Electrical and Computer Engineering are exposed to modern system design concepts through the use of hardware-software co-simulation. Key tools used in the course including a hardware prototype consisting of an 8051 microcontroller and a field programmable gate array, and a VHDL model of the prototype are discussed.
New methods, based on Tikhonov regularization, were developed to infer the magnitude and phase of... more New methods, based on Tikhonov regularization, were developed to infer the magnitude and phase of pericardial potentials directly. These methods were tested in an adult-male torso model using measured human epicardial potentials. With 1% noise added to body-surface potentials, regularization with an optimal parameter at each frequency from 1 to 100 Hz gave an average relative error ͑RE͒ in inferred spectral magnitudes of 0.44. Regularization with the composite-residualsmoothing-operator ͑CRESO͒ parameter increased the RE slightly to 0.47. With 10% additive noise, 10 mm overestimation of heart radius, and a 10 mm error in heart position, the average CRESO parameter from 1 to 100 Hz gave an average RE of 0.71. Performance was frequency dependent. The smallest REs occurred at low frequencies. With 1% noise, optimal regularization gave average REs of 0.20, 0.40, and 0.53 in the 1-15, 15-46, and 46-100 Hz bands, respectively. Direct inference of spectral magnitudes was more accurate than Fourier transformation of inferred time-domain waveforms. Results suggest that when heart size and location are not known, minimum REs in spectral estimates are found using an overestimated heart size and a regularization parameter which is the average value over the frequency band of interest.
Little research has been performed to study how intentional electromagnetic signals may couple in... more Little research has been performed to study how intentional electromagnetic signals may couple into recording devices. An electromagnetic susceptibility study was performed on an analog tape recorder, a digital video camera, a wired computer microphone, and a wireless microphone system to electromagnetic interference. Devices were subjected to electromagnetic stimulations in the frequency range of 1-990 MHz and field strengths up to 4.9 V/m. Carrier and message frequencies of the stimulation signals were swept, and the impacts of device orientation and antenna polarization were explored. Message signals coupled into all devices only when amplitude modulated signals were used as stimulation signals. Test conditions that produced maximum sensitivity were highly specific to each device. Only narrow carrier frequency ranges could be used for most devices to couple messages into recordings. A basic detection technique using cross-correlation demonstrated the need for messages to be as long as possible to maximize message detection and minimize detection error. Analysis suggests that detectable signals could be coupled to these recording devices under realistic ambient conditions.
In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model us... more In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to the incident excitation properties such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions, the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems.
In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model us... more In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The simplified surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to properties of the incident excitation waveform, such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems. INDEX TERMS Electromagnetic coupling, characteristic mode analysis (CMA), electromagnetic interference, current measurement, unmanned aerial vehicles (UAVs).
Globalization of micro-chip fabrication has opened a new avenue of cyber-crime. It is now possibl... more Globalization of micro-chip fabrication has opened a new avenue of cyber-crime. It is now possible to insert hardware Trojans directly into the chip during the manufacturing process. These hardware Trojans are capable of destroying a chip, reducing performance or even capturing sensitive data. This paper presents a modification to a recently presented method of Trojan defense known as RECORD: Randomized Encoding of COmbinational Logic for Resistance to Data Leakage. RECORD aims to prevent data leakage through a randomized encoding and split manufacturing scheme. Its weakness, however, it that it is only applicable to combinational circuits. Sequential RECORD proposes a method to extend RECORD concepts to sequential designs. Experimental work with Sequential RECORD on a Data Encryption Standard circuit show that it is effective with the cost of a 3.75x area overhead, 4.5x power overhead and only a 3% decrease in performance.
The radiated emissions from a partially shielded cable mounted 5 cm above a metal plane have been... more The radiated emissions from a partially shielded cable mounted 5 cm above a metal plane have been found to be dominated by the emissions from the 5 cm vertical conductor segments, which connect the cable shield and the signal wires to the metal plane at various locations. An equivalent circuit model has been developed for predicting radiated emissions from the cable. As part of an extension from the developed model, an additional wire is included and pulled back in the test setup. The methodology of modeling is applied to this new setup by adding an additional transmission line for the wire against the metal plane, and by including the mutual inductance between the transmission lines, which accounts for the locations of the transmission lines. The predicted radiated emissions match the full-wave simulated radiated emissions, further validating the modelling technique that was previously developed. This modelling procedure can be used to determine if a system meets a given radiated emission specification before any actual testing is done. If the radiation is predicted to be excessive then design changes, such as additional filtering, can be modelled before the cabling is built to determine if the changes will allow the system to meet the radiated emissions specification before testing begins.
IEEE Transactions on Electromagnetic Compatibility, Aug 1, 2016
Coupling between closely spaced wideband analog radio frequency integrated circuits can cause deg... more Coupling between closely spaced wideband analog radio frequency integrated circuits can cause degradation in device performance. Methods for reducing the coupling between packages were tested, with a strong focus on maintaining manufacturability and minimizing any increase in coupling between structures within the package. Methods include the application of magnetic absorbing material or resistive sheets to the package surface and the inclusion of conductive vias in the package walls. Package modifications were tested from 5-40 GHz through both full-wave simulation and physical measurement. The best tradeoff in performance and manufacturability below 20 GHz was found using 250-Ω/sq. resistive sheets connected to the return plane with vias in the package corners, while above 20 GHz, the best tradeoff was found by covering the package with magnetic absorbing materials. The magnetic absorbing material can be embedded directly in the package polymer itself, allowing easy manufacture.
IEEE Transactions on Very Large Scale Integration Systems, Oct 1, 2018
Globalization of microchip fabrication opens the possibility for an attacker to insert hardware T... more Globalization of microchip fabrication opens the possibility for an attacker to insert hardware Trojans into a chip during the manufacturing process. While most defensive methods focus on detection or prevention, a recent method, called Randomized Encoding of Combinational Logic for Resistance to Data Leakage (RECORD), uses data randomization to prevent hardware Trojans from leaking meaningful information even when the entire design is known to the attacker. Both RECORD and its sequential variant require significant area and power overhead. In this paper, a Time-Division Multiplexed version of the RECORD design process is proposed which reduces area overhead by 63% and power by 56%. This time-division multiplexing (TDM) concept is further refined to allow commercial off the shelf (COTS) products and IP cores to be safely operated from a separate chip. These new methods tradeoff latency (5.3× for TDM and 3.9× for COTS) and energy use to accomplish area and power savings and achieve greater security than the original RECORD process.
IEEE Transactions on Biomedical Engineering, Aug 1, 2004
Direct inference of heart-surface from bodysurface potentials has been the goal of most recent wo... more Direct inference of heart-surface from bodysurface potentials has been the goal of most recent work on electrocardiographic inverse solutions. We developed and tested indirect methods for inferring heart-surface potentials based on estimation of regularized multipole sources. Regularization was done using Tikhonov, constrainedleast-squares, and multipole-truncation techniques. These multipole-equivalent methods (MEM) were compared to the conventional mixed boundary-value method (BVM) in a realistic torso model with up to 20% noise added to bodysurface potentials and ± 1 cm error in heart position and size. Optimal regularization was used for all inverse solutions. The relative error of inferred heart-surface potentials of the MEM was significantly less (p < 0.05) than that of the BVM using zero-order Tikhonov regularization in 10 of the 12 cases tested. These improvements occurred with a fourth-degree (24 coefficients) or smaller multipole moment. From these multipole coefficients, heart-surface potentials can be found at an unlimited number of heart-surface locations. Our indirect methods for estimating heart-surface potentials based on multipole inference appear to offer significant improvement over the conventional direct approach.
IEEE Transactions on Electromagnetic Compatibility, Aug 1, 2015
ABSTRACT A small amount of jitter can quickly eat up timing budgets and create timing issues. Pre... more ABSTRACT A small amount of jitter can quickly eat up timing budgets and create timing issues. Precise characterization of deterministic and crosstalk-induced jitter can help isolate and solve issues within high-speed links. Characterizing deterministic and crosstalk-induced jitter is challenging, however, because many types of jitter work together to create the overall jitter profile. Methods are presented in this paper to characterize the deterministic and crosstalk-induced jitter from measurements of total jitter. An improved tail-fit deconvolution method is proposed for characterizing the impact of deterministic jitter in the presence of random jitter. The contribution of random jitter to total jitter is found first, and then that contribution is accounted for to find deterministic jitter. A Wiener filter deconvolution method is also presented for extracting the characteristics of crosstalk-induced jitter from measurements of total jitter made when the crosstalk sources were and were not present. The Wiener filter allows for accurate deconvolution of the measured histograms for total jitter even in the presence of the measurement noise. The proposed techniques are shown to work well both in simulations and in measurements of a high-speed link.
Knowledge of high-frequency currents in the chip and chip-package are necessary for EMI analysis ... more Knowledge of high-frequency currents in the chip and chip-package are necessary for EMI analysis and prediction, though measurement of these currents may be difficult to obtain in many cases. One possibility is to estimate currents from nearfield scan data. In this paper, measurements were made of the magnetic field over a simple circuit and a chip package. The current flowing in the circuit and the chip lead frame was estimated from the compensated near-field data and compared with measurements made directly on the pins. Estimation was performed both with and without structural information of the lead frame. The susceptibility of estimated currents to measurement errors was analyzed. Results show this technique can be a powerful tool for analyzing high frequency chip currents.
Integrated circuits (ICs) sometimes fail when their power supply is disrupted by external noise, ... more Integrated circuits (ICs) sometimes fail when their power supply is disrupted by external noise, like an electrical fast transient (EFT). Soft failures in these cases are often caused by timing errors in the IC, for example when delays through logic become too large to meet internal timing constraints. Methods are needed to predict when these failures will occur. A closedform expression is proposed in this paper to predict the change in propagation delay through logic as a result of an EFT on the IC power supply. The expression uses process parameters that can be found from SPICE models of FETs within the IC or through external measurements of the IC when SPICE models are unavailable. The model is used to predict the frequency of a CMOS ring oscillator manufactured in 0.5 um technology. Predicted results closely match those found through measurements with a maximum relative error of approximately 1%.
IEEE Transactions on Electromagnetic Compatibility, Jun 1, 2014
Eliminating crosstalk problems in a complex system requires methods that quickly predict where pr... more Eliminating crosstalk problems in a complex system requires methods that quickly predict where problems may occur and that give intuitive feedback on how best to solve these problems. Solutions for the maximum crosstalk are often used for this purpose. Limit lines for maximum crosstalk in the frequency domain are available in the literature when signal lines are electrically small and weak coupling is assumed; however, little research has been performed for the case where signal lines are electrically large. This paper provides derivations for maximum crosstalk in the frequency domain when signal lines are electrically large and weak coupling applies. The coupling mechanisms are represented by distributed voltage and current sources. These sources result from aggressor circuit voltages and currents as well as mutual terms in the transmission line per-unit-length parameters. The maximum crosstalk expressions for the victim loads are represented by piecewise expressions dependent on the total electrical length of the aggressor circuit and the electrical length of the coupling region. Measurements and simulations are presented, which show the maximum crosstalk estimates can predict the maximum envelope of crosstalk within a few dB.
2023 Joint Asia-Pacific International Symposium on Electromagnetic Compatibility and International Conference on ElectroMagnetic Interference & Compatibility (APEMC/INCEMIC)
BroadR-Reach® is a point-to-point Ethernet Physical Layer (PHY) standard, which is used in automo... more BroadR-Reach® is a point-to-point Ethernet Physical Layer (PHY) standard, which is used in automotive applications. This technology allows full-duplex communication between two devices over a single, Unshielded Twisted-wire Pair (UTP) cable. Here, alien crosstalk in a 6 UTP bundle is investigated for meeting electromagnetic compatibility requirements. Alien crosstalk refers to crosstalk to the BroadR-Reach® communication channel from an unrelated signal wire. Alien Near-End and Far-End Crosstalk in two different UTPs with and without an inline Circular Plastic Connector (CPC) are compared to standard limits. An inline connector in the middle of a 15 m 6 UTP cable bundle, with a 25 cm untwisted region, fails the Power Sum Alien Near-End Crosstalk (PSANEXT) standard limit by 4 dB at 100 MHz, while the same bundle without the connector passes the standard by a margin of 8 dB at 100 MHz.
Switching of logic gates in integrated circuits is responsible for significant power supply noise... more Switching of logic gates in integrated circuits is responsible for significant power supply noise on the chip and on the printed circuit board (PCB). Predicting power supply noise can be critical for analyzing the proper operation of high-speed devices. A vectorless method was developed to predict the statistical distribution of dynamic currents drawn by an IC and was used to predict the statistical characteristics of power supply noise on the PCB. Simulations and measurements of noise on the PCB power delivery network demonstrate the approach can determine the average and standard deviation of the power supply voltage within 20%, which is more than sufficient for predicting the statistical impact of switching noise on circuit performance
Skills in hardware-software co-design are quickly becoming critical to product development in hig... more Skills in hardware-software co-design are quickly becoming critical to product development in hightechnology computer industries. Systems-on-silicon typically include a considerable amount of software as well as custom hardware and are increasingly difficult to develop using traditional techniques. To satisfy a growing demand in industry, students in electrical engineering, computer engineering, and computer science should be introduced to concepts of hardware-software co-design at the undergraduate level. This paper examines a new laboratory at the University of Missouri-Rolla in which students in Electrical and Computer Engineering are exposed to modern system design concepts through the use of hardware-software co-simulation. Key tools used in the course including a hardware prototype consisting of an 8051 microcontroller and a field programmable gate array, and a VHDL model of the prototype are discussed.
New methods, based on Tikhonov regularization, were developed to infer the magnitude and phase of... more New methods, based on Tikhonov regularization, were developed to infer the magnitude and phase of pericardial potentials directly. These methods were tested in an adult-male torso model using measured human epicardial potentials. With 1% noise added to body-surface potentials, regularization with an optimal parameter at each frequency from 1 to 100 Hz gave an average relative error ͑RE͒ in inferred spectral magnitudes of 0.44. Regularization with the composite-residualsmoothing-operator ͑CRESO͒ parameter increased the RE slightly to 0.47. With 10% additive noise, 10 mm overestimation of heart radius, and a 10 mm error in heart position, the average CRESO parameter from 1 to 100 Hz gave an average RE of 0.71. Performance was frequency dependent. The smallest REs occurred at low frequencies. With 1% noise, optimal regularization gave average REs of 0.20, 0.40, and 0.53 in the 1-15, 15-46, and 46-100 Hz bands, respectively. Direct inference of spectral magnitudes was more accurate than Fourier transformation of inferred time-domain waveforms. Results suggest that when heart size and location are not known, minimum REs in spectral estimates are found using an overestimated heart size and a regularization parameter which is the average value over the frequency band of interest.
Little research has been performed to study how intentional electromagnetic signals may couple in... more Little research has been performed to study how intentional electromagnetic signals may couple into recording devices. An electromagnetic susceptibility study was performed on an analog tape recorder, a digital video camera, a wired computer microphone, and a wireless microphone system to electromagnetic interference. Devices were subjected to electromagnetic stimulations in the frequency range of 1-990 MHz and field strengths up to 4.9 V/m. Carrier and message frequencies of the stimulation signals were swept, and the impacts of device orientation and antenna polarization were explored. Message signals coupled into all devices only when amplitude modulated signals were used as stimulation signals. Test conditions that produced maximum sensitivity were highly specific to each device. Only narrow carrier frequency ranges could be used for most devices to couple messages into recordings. A basic detection technique using cross-correlation demonstrated the need for messages to be as long as possible to maximize message detection and minimize detection error. Analysis suggests that detectable signals could be coupled to these recording devices under realistic ambient conditions.
In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model us... more In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to the incident excitation properties such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions, the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems.
In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model us... more In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The simplified surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to properties of the incident excitation waveform, such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and under which RF excitation conditions the coupled current is maximized. We verified these predictions using direct experimental measurement of the coupled currents. The presented simulations and measurements show the usefulness of CMA for studying electromagnetic coupling to practical systems. INDEX TERMS Electromagnetic coupling, characteristic mode analysis (CMA), electromagnetic interference, current measurement, unmanned aerial vehicles (UAVs).
Globalization of micro-chip fabrication has opened a new avenue of cyber-crime. It is now possibl... more Globalization of micro-chip fabrication has opened a new avenue of cyber-crime. It is now possible to insert hardware Trojans directly into the chip during the manufacturing process. These hardware Trojans are capable of destroying a chip, reducing performance or even capturing sensitive data. This paper presents a modification to a recently presented method of Trojan defense known as RECORD: Randomized Encoding of COmbinational Logic for Resistance to Data Leakage. RECORD aims to prevent data leakage through a randomized encoding and split manufacturing scheme. Its weakness, however, it that it is only applicable to combinational circuits. Sequential RECORD proposes a method to extend RECORD concepts to sequential designs. Experimental work with Sequential RECORD on a Data Encryption Standard circuit show that it is effective with the cost of a 3.75x area overhead, 4.5x power overhead and only a 3% decrease in performance.
The radiated emissions from a partially shielded cable mounted 5 cm above a metal plane have been... more The radiated emissions from a partially shielded cable mounted 5 cm above a metal plane have been found to be dominated by the emissions from the 5 cm vertical conductor segments, which connect the cable shield and the signal wires to the metal plane at various locations. An equivalent circuit model has been developed for predicting radiated emissions from the cable. As part of an extension from the developed model, an additional wire is included and pulled back in the test setup. The methodology of modeling is applied to this new setup by adding an additional transmission line for the wire against the metal plane, and by including the mutual inductance between the transmission lines, which accounts for the locations of the transmission lines. The predicted radiated emissions match the full-wave simulated radiated emissions, further validating the modelling technique that was previously developed. This modelling procedure can be used to determine if a system meets a given radiated emission specification before any actual testing is done. If the radiation is predicted to be excessive then design changes, such as additional filtering, can be modelled before the cabling is built to determine if the changes will allow the system to meet the radiated emissions specification before testing begins.
IEEE Transactions on Electromagnetic Compatibility, Aug 1, 2016
Coupling between closely spaced wideband analog radio frequency integrated circuits can cause deg... more Coupling between closely spaced wideband analog radio frequency integrated circuits can cause degradation in device performance. Methods for reducing the coupling between packages were tested, with a strong focus on maintaining manufacturability and minimizing any increase in coupling between structures within the package. Methods include the application of magnetic absorbing material or resistive sheets to the package surface and the inclusion of conductive vias in the package walls. Package modifications were tested from 5-40 GHz through both full-wave simulation and physical measurement. The best tradeoff in performance and manufacturability below 20 GHz was found using 250-Ω/sq. resistive sheets connected to the return plane with vias in the package corners, while above 20 GHz, the best tradeoff was found by covering the package with magnetic absorbing materials. The magnetic absorbing material can be embedded directly in the package polymer itself, allowing easy manufacture.
IEEE Transactions on Very Large Scale Integration Systems, Oct 1, 2018
Globalization of microchip fabrication opens the possibility for an attacker to insert hardware T... more Globalization of microchip fabrication opens the possibility for an attacker to insert hardware Trojans into a chip during the manufacturing process. While most defensive methods focus on detection or prevention, a recent method, called Randomized Encoding of Combinational Logic for Resistance to Data Leakage (RECORD), uses data randomization to prevent hardware Trojans from leaking meaningful information even when the entire design is known to the attacker. Both RECORD and its sequential variant require significant area and power overhead. In this paper, a Time-Division Multiplexed version of the RECORD design process is proposed which reduces area overhead by 63% and power by 56%. This time-division multiplexing (TDM) concept is further refined to allow commercial off the shelf (COTS) products and IP cores to be safely operated from a separate chip. These new methods tradeoff latency (5.3× for TDM and 3.9× for COTS) and energy use to accomplish area and power savings and achieve greater security than the original RECORD process.
IEEE Transactions on Biomedical Engineering, Aug 1, 2004
Direct inference of heart-surface from bodysurface potentials has been the goal of most recent wo... more Direct inference of heart-surface from bodysurface potentials has been the goal of most recent work on electrocardiographic inverse solutions. We developed and tested indirect methods for inferring heart-surface potentials based on estimation of regularized multipole sources. Regularization was done using Tikhonov, constrainedleast-squares, and multipole-truncation techniques. These multipole-equivalent methods (MEM) were compared to the conventional mixed boundary-value method (BVM) in a realistic torso model with up to 20% noise added to bodysurface potentials and ± 1 cm error in heart position and size. Optimal regularization was used for all inverse solutions. The relative error of inferred heart-surface potentials of the MEM was significantly less (p < 0.05) than that of the BVM using zero-order Tikhonov regularization in 10 of the 12 cases tested. These improvements occurred with a fourth-degree (24 coefficients) or smaller multipole moment. From these multipole coefficients, heart-surface potentials can be found at an unlimited number of heart-surface locations. Our indirect methods for estimating heart-surface potentials based on multipole inference appear to offer significant improvement over the conventional direct approach.
IEEE Transactions on Electromagnetic Compatibility, Aug 1, 2015
ABSTRACT A small amount of jitter can quickly eat up timing budgets and create timing issues. Pre... more ABSTRACT A small amount of jitter can quickly eat up timing budgets and create timing issues. Precise characterization of deterministic and crosstalk-induced jitter can help isolate and solve issues within high-speed links. Characterizing deterministic and crosstalk-induced jitter is challenging, however, because many types of jitter work together to create the overall jitter profile. Methods are presented in this paper to characterize the deterministic and crosstalk-induced jitter from measurements of total jitter. An improved tail-fit deconvolution method is proposed for characterizing the impact of deterministic jitter in the presence of random jitter. The contribution of random jitter to total jitter is found first, and then that contribution is accounted for to find deterministic jitter. A Wiener filter deconvolution method is also presented for extracting the characteristics of crosstalk-induced jitter from measurements of total jitter made when the crosstalk sources were and were not present. The Wiener filter allows for accurate deconvolution of the measured histograms for total jitter even in the presence of the measurement noise. The proposed techniques are shown to work well both in simulations and in measurements of a high-speed link.
Knowledge of high-frequency currents in the chip and chip-package are necessary for EMI analysis ... more Knowledge of high-frequency currents in the chip and chip-package are necessary for EMI analysis and prediction, though measurement of these currents may be difficult to obtain in many cases. One possibility is to estimate currents from nearfield scan data. In this paper, measurements were made of the magnetic field over a simple circuit and a chip package. The current flowing in the circuit and the chip lead frame was estimated from the compensated near-field data and compared with measurements made directly on the pins. Estimation was performed both with and without structural information of the lead frame. The susceptibility of estimated currents to measurement errors was analyzed. Results show this technique can be a powerful tool for analyzing high frequency chip currents.
Integrated circuits (ICs) sometimes fail when their power supply is disrupted by external noise, ... more Integrated circuits (ICs) sometimes fail when their power supply is disrupted by external noise, like an electrical fast transient (EFT). Soft failures in these cases are often caused by timing errors in the IC, for example when delays through logic become too large to meet internal timing constraints. Methods are needed to predict when these failures will occur. A closedform expression is proposed in this paper to predict the change in propagation delay through logic as a result of an EFT on the IC power supply. The expression uses process parameters that can be found from SPICE models of FETs within the IC or through external measurements of the IC when SPICE models are unavailable. The model is used to predict the frequency of a CMOS ring oscillator manufactured in 0.5 um technology. Predicted results closely match those found through measurements with a maximum relative error of approximately 1%.
IEEE Transactions on Electromagnetic Compatibility, Jun 1, 2014
Eliminating crosstalk problems in a complex system requires methods that quickly predict where pr... more Eliminating crosstalk problems in a complex system requires methods that quickly predict where problems may occur and that give intuitive feedback on how best to solve these problems. Solutions for the maximum crosstalk are often used for this purpose. Limit lines for maximum crosstalk in the frequency domain are available in the literature when signal lines are electrically small and weak coupling is assumed; however, little research has been performed for the case where signal lines are electrically large. This paper provides derivations for maximum crosstalk in the frequency domain when signal lines are electrically large and weak coupling applies. The coupling mechanisms are represented by distributed voltage and current sources. These sources result from aggressor circuit voltages and currents as well as mutual terms in the transmission line per-unit-length parameters. The maximum crosstalk expressions for the victim loads are represented by piecewise expressions dependent on the total electrical length of the aggressor circuit and the electrical length of the coupling region. Measurements and simulations are presented, which show the maximum crosstalk estimates can predict the maximum envelope of crosstalk within a few dB.
2023 Joint Asia-Pacific International Symposium on Electromagnetic Compatibility and International Conference on ElectroMagnetic Interference & Compatibility (APEMC/INCEMIC)
Uploads
Papers by Daryl Beetner