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This article presents a novel built-in test equipment (BITE) for phase measurements in millimeter-wave integrated circuits (ICs). The BITE targets 5G New Radio (NR) applications. It is able to measure the phase in good agreement with $\mathbf {S_{21}}$ measurements and has a relative rms phase error lower than 6° over the frequency band of interest. Aside from the relative phase, this BITE also addresses the absolute phase difference of all ICs on the same phased array. To the authors’ best knowledge, this is the first BITE and built-in self-test (BIST) to do so. The BITE is able to reduce the absolute phase discrepancy by a factor of 3. To reduce the measurement complexity, the BITE is implemented as a homodyne architecture to output a dc voltage relative to the phase of the channel. A built-in algorithm is used, mitigating the impairments normally associated with a homodyne receiver. This reduces the design complexity and hence the area overhead. The BITE occupies an area of 480 $\mathbf {\mu m} \times 135\,\,\mathbf {\mu m}$ , facilitating easy integration. [ABSTRACT FROM AUTHOR]

In this communication, a time-frequency joint method is proposed to evaluate the performance of ultrawideband (UWB) antennas for the radiation of high-power (HP) electromagnetic pulses. First, conventional antenna parameters, such as the efficiency, gain, and so on, are translated to UWB pulsed antennas from the energy perspective, so as to get several scalar antenna parameters, since energy in one pulse is finite. Thus, the power-spectrum weighted efficiency ($\eta _{e}$), directivity ($D_{e}$), and gain ($G_{e}$) are proposed. Then, several electromagnetic norms of the radiating pulse are selected to characterize the sensitive parameters of the equipment under test (EUT). Based on these, several other scalar antenna parameters are proposed, which are the effective potential gain ($G_{ep}$), pulse sharpening factor (PSF), and peaking impulse gain ($G_{PI}$). Thus, a set of time-domain scalar criteria are proposed to evaluate the performance of HP-UWB antennas. These criteria can be calculated with the frequency functions of conventional antenna parameters, which demonstrate the inherent properties of one antenna. Finally, the performance of two kinds of typical HP-UWB antennas, namely the impulse radiating antenna and the combined antenna, is measured and compared with the proposed method. It indicates that, with the proposed method, one can not only get the inherent properties of one antenna in the frequency domain but also quantitatively compare the performance of different antennas with a given exciting pulse in the time domain with the proposed scalar antenna parameters. [ABSTRACT FROM AUTHOR]

A technically easy way to reproduce lightning current pulses is to use a capacitive high-current impulse generator with a crowbar switch. For the crowbar switch, commonly spark-gaps are used which can withstand the mechanical and thermal stress due to the high current pulses. The spark-gap is triggered by an external high voltage trigger-device when the oscillating current attains the maximum. For extremely high currents, it is a common method to combine two of such generators to a tandem generator. In this case, it is necessary that the crowbar switches of both generators are triggered time-synchronized and decoupled by the use of an inductance. In order to avoid the triggering and the decoupling of the crowbar switches, we replaced the spark-gaps of both crowbar switches of our tandem generator by two diode-stacks, each consisting of 25 high-power diodes. After this modification, the tandem generator is able to reproduce even extremely high lightning currents as the 10/350 μs current pulse up to a level of more than 300 kA. The use of the diode-stacks also allows to combine the high-current generator with other current generators as a long duration current generator used for the experimental simulation of the continuing currents. Because no decoupling inductance is needed and the arc of the spark gap is avoided, the tandem generator is now able to test equipment with higher inductance and resistance compared to the generator with spark-gap based crowbar switch. [ABSTRACT FROM AUTHOR]

This article studies synchronization control of a novel devised treadmill-based testing apparatus for wheeled planetary rover roaming at low speed. To offer satisfactory tracking performance and to ameliorate internal conflicts amongst individual treadmills during rover-treadmill interaction, a decentralized synchronization control strategy integrating an adaptive friction compensation scheme is proposed. To overcome the nonlinear friction effect at low-velocity scenarios, the LuGre model based friction compensation scheme is constructed with a dual-observer structure that can handle parametric uncertainties without recourse to the high-resolution encoder-required parameter identification. With the proposed control design, asymptotic stability of the closed-loop system is guaranteed with the tracking error and synchronization error converging to zero in presence of parametric uncertainties. Experimental results demonstrate the effectiveness of the proposed control strategy, which significantly improves the tracking performance in comparison with the existing proportional differential (PD)-type controller and synchronization controller without friction compensation. [ABSTRACT FROM AUTHOR]

The pole drop test is the most widely applied off-line test for detecting shorted turns in the field winding of salient pole synchronous motors. It is a simple test where the voltage drop (or inductance) of the poles are compared to detect the presence of shorted turns. Although it does not require special test equipment, false indications due to sensitivity problems are common. In this letter, the voltage and inductance distribution between the poles are analyzed under shorted field turn conditions. Some practical insight for enhancing the sensitivity and reliability of the pole drop test are given based on the qualitative analysis and experimental testing on a 30 kVA synchronous motor with shorted field turns. It is shown that the sensitivity of the test is significantly higher when the test is performed with the rotor inserted, which is not reported elsewhere. It is also shown that the reliability of the test can be improved by observing the voltage or inductance in poles adjacent to the pole suspected with shorted turns. [ABSTRACT FROM AUTHOR]

A radar transceiver with two transmitters (TXs) and two receivers (RXs) is reported in 22 nm fully depleted silicon-on-insulator (FDSOI) CMOS. It includes a novel 200 MHz bandwidth 80 GHz phase-locked loop (PLL) based on a single-sideband (SSB) upconverter and an 11 GHz bandwidth phase-frequency detector to achieve >8 GHz locking range with record phase noise of −97, −103, and −113 dBc/Hz at 100 kHz, 1 MHz, and 10 MHz offset, respectively, and rms jitter < 40 fs. Stepped-frequency chirps with orthogonal frequency-division multiplexing (OFDM) modulation covering the 152–160 GHz range were demonstrated in a through-the-air loopback link along with a record settling time < 30 ns, limited by the test equipment. The RXs have an IIP3 of −8 dBm, SSB noise figure between 7.5 and 10 dB and a conversion gain of 15 dB, controllable from the LNA back gate over a range of 12 dB. The OP1 dB and $P_{\mathrm {SAT}}$ of the power amplifier (PA) in each TX are 5 and 9 dBm, respectively. The IQ amplitude mismatch and phase error of each RX are < 0.5 dB and 1°, respectively, while the $P_{\mathbf {out}}$ mismatch between the TXs is < 1 dB. The sensor consumes 1.13 W, with 300 mW by the PLL, 275 mW by the 160 GHz local oscillator (LO)-tree, 190 mW by each TX, and 87.5 mW by each RX. [ABSTRACT FROM AUTHOR]

In order to study the high-cycle and very-high-cycle fatigue (VHCF) performance of aero-engine blade materials under conditions close to their real service, an in situ fatigue performance testing apparatus for materials under coupling conditions of high-temperature and combined mechanical loads (HTCMFTA) has been developed. The main functions of the apparatus include: static loads loading, ultrasonic fatigue (up to 20 kHz) loading, high-temperature field (up to 1100 °C) building, and in situ monitoring. A series of tests on the compressor blade material Ti-6Al-4V alloy under coupling conditions of high temperature and combined mechanical loads were carried out with the apparatus. The results show that the apparatus can accurately simulate various mechanical loads and high-temperature fields to which the blade materials are subjected. The static and dynamic mechanical properties of Ti-6Al-4V alloy under high-temperature and combined mechanical loads were also revealed. The results show that there is a synergistic effect between tension and bending; as the pretension stress increases, the bending stiffness and bending-bearing capacity of Ti-6Al-4V alloy were enhanced. A coupling effect exists between temperature, tension, and bending. Under the combined loads, the bending stiffness of Ti-6Al-4V alloy slightly weakened with the increase of temperature, but the bending-bearing capacity increased significantly. This apparatus has important practical significance and scientific value for studying the high-cycle and VHCF performance of aero-engine blade materials and ensuring its service safety. [ABSTRACT FROM AUTHOR]

A testing apparatus, namely, touch sensation tester for fabrics (TST-F), was introduced to evaluate the touch properties of fabrics. This novel apparatus enables a simultaneous measurement of different mechanical properties of the sample with a combination of temporal and spatial resolution, enhancing the measuring accuracy and reliability of the time-dependent physical behavior of textile materials. The prototype of the TST-F and details of the measurement principle were exhibited, and nine indices relating to fabric’s deformation performance during wearing were extracted from measured force–displacement curve to characterize the mechanical properties relating to fabric’s touch sensory attributes. Stepwise regression was used to develop a series of prediction models for assessing human sensations toward bending stiffness, compression softness, and stretching tightness of fabrics by linking the measured indices to subjective assessments. Moreover, the prediction models were validated using a set of independent fabric samples. Results show that prediction values have good agreements with subjective grades as indicated by the coefficients of determination R2 higher than 0.887 and reasonably low mean square errors (MSEs). Also, the repeatability of the measured curves was confirmed by statistical analysis. Therefore, the TST-F provides an alternative to evaluate the touch properties of fabrics objectively. [ABSTRACT FROM AUTHOR]

Due to be launched in late 2021, the imaging X-ray polarimetry explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2–8-keV band, complemented with imaging, spectroscopy, and timing capabilities. At the heart of the focal plane, there are a set of three polarization-sensitive gas pixel detectors, each based on a custom-integrated circuit acting as a charge-collecting anode, with their readout electronics. We designed an integrated test equipment based on the VMEbus protocol to characterize the performance of such detectors, debug the IXPE readout electronics, and perform stable data acquisitions to study the whole system. The test campaign was conducted to validate the readout processor against the mission requirements in more demanding conditions than the worst case foreseen for in-orbit operations. The test showed that the device under test could sustain an event rate with a 5.9-keV source, nearly twice the worst case of 300 Hz at 3 keV, with a dead time down to 1.1 ms. Additionally, we performed various scans in the readout electronics parameter space to optimize its performance in observing celestial sources. The success of the test campaign proved the robustness and reliability of the system in these conditions, legitimating its adoption for the IXPE mission. [ABSTRACT FROM AUTHOR]

To investigate the high-altitude electromagnetic pulse (HEMP) immunity of electrical equipment in operation, a 10-kV transmission line (TL) experimental platform is built in this paper. The conducted transient electromagnetic disturbance (TED) could be injected to the electrical equipment of 10-kV TL with power on or power off. The TED is produced by the pulsed current injection (PCI) generator, whose rise time is less than 20 ns and full width at half maximum is in the range of 500 ∼ 550 ns on short-circuit state with 60 Ω resistor. On the other hand, the 10-kV TL is equivalently designed in cross section to make its characteristic impedance being 330 Ω to conform to the value of practical case. The voltages and currents applied on the tested equipment can be measured at nano-second level simultaneously, which are of great use to learn the effect mechanisms and compare the results under different working conditions. Some 10-kV pin-type porcelain insulators are tested under different conditions, which shows the capacity of the proposed platform to test immunity of 10-kV electrical equipment. [ABSTRACT FROM AUTHOR]

This article investigates the risk to declare compliant a faulty equipment under test during a radiated susceptibility test performed in a reverberation chamber (RC) working imperfectly, i.e., in the lowest frequency range when the chamber is undermoded. The results obtained from an extensive measurement campaign are compared, using the same worst-case approach, to a probabilistic model proposed recently for well-stirred RCs. Below the frequency when the RC can be assumed to be well-stirred, the variance (or the standard deviation) of the electromagnetic field (or of the induced power on the equipment) may strongly differ from the ideal case, depending on the effect of the stirring process and of the modal density. If the variance is low, the test is, as expected, quite meaningless and it makes sense to avoid this corresponding frequency range. However, more surprisingly, if the variance is higher than the one observed in ideal conditions, the risk is paradoxically reduced for weakly susceptible equipment (but increased for highly susceptible ones). Indeed, this higher variance makes the appearance of a strong amplitude of the disturbance for a given stirring configuration more probable. This article is considered as an incremental step in the understanding of the RC behavior from the point of view of radiated susceptibility testing, particularly when the RC is undermoded, a frequency range generally used to perform this kind of tests. [ABSTRACT FROM AUTHOR]

In this article, we propose and implement a novel technique to locate electromagnetic interference (EMI) sources using the concept of time-reversal (TR) cavity. We show in an intuitive manner that reflections from the surfaces of a cavity can emulate an infinite number of sensors in the TR method. In order to locate EMI sources, the equipment under test (EUT) is placed in a rectangular metallic cavity, of suitable dimensions according to the considered frequency band and the EUT size, equipped with a simple monopole or dipole antenna. We demonstrate that by using only one sensor, we are able to locate EMI sources by taking advantage of the focusing properties of a TR cavity. The entropy criterion is applied to obtain the focusing time slice in which the maximum electric field determines the location of the EMI source. Both 2- and 3-D numerical simulation schemes are deployed to demonstrate the ability of the proposed technique. The validity of numerical simulations is tested against frequency-domain measurements. Compared with the conventional EMI tests in anechoic chambers and scanning methods, the proposed technique represents a simpler and cost-effective test method requiring only one sensor (a monopole or dipole antenna). [ABSTRACT FROM AUTHOR]

Very high frequency (VHF)-line impedance stabilization network (VHF-LISN), which is defined as the termination device for mains cable of equipment under test to specify the input impedance of each line at the mains power supply outlet, can improve correlation between test sites that perform radiated emission measurement. Balanced and unbalanced types of VHF-LISN are currently under proposal with International Special Committee on Radio Interference (CISPR) as a device for prescribing the terminating condition of the power supply cable. Simulation analysis with common mode (CM)/differential mode (DM) signal sources was performed to investigate the emission characteristics with the two types of termination devices under several measurement arrangements that used two-wire and three-wire mains cables. Furthermore, to confirm the validity of the simulation analysis, measurement of a versatile comb-generator-operated by ac mains was performed under the same test arrangement and two types of termination devices. Quasi CM/DM signal from an ac-operated comb generator was injected back into the mains cable of the same comb generator. This article explains how we ascertained the radiated emission characteristics with each termination device, and provides guidance for their appropriate usage. [ABSTRACT FROM AUTHOR]

This article presents a packaged SiGe BiCMOS reflectometer for 0.01–26-GHz two-port vector network analyzers (VNAs). The reflectometer chip is composed of a resistive bridge coupler and two wideband heterodyne receivers for coherent magnitude and phase detection. In addition, a high-linearity receiver channel is designed to accommodate ~20 dBm of RF input power to the reflectometer. External sources are used to provide stimulus over the entire bandwidth, and a high-linearity shunt 50- $\Omega $ switch is placed at the input of each reflectometer chip to provide a matched condition for better measurement accuracy. The measured dynamic range (DR) of the heterodyne receiver is 129±3 dB at 0.01–26 GHz at an IF resolution bandwidth (RBW) of 10 Hz. The reflectometer chip is packaged on a low-cost printed circuit board (PCB) and connectorized for repeatable measurements. Several passive and active device-under-test (DUTs), such as filters and amplifiers, are measured in single- and dual-port complex $S$ -parameter setup at 0.01–26 GHz. The single-chip reflectometer results in excellent agreement with commercially available test equipment and with minimal magnitude and phase difference. Several definitions (mean deviation and error vector) are used to quantify the measurement accuracy. A measured $S_{21}$ of −80 dB is obtained using high-rejection filters. An in-depth DR analysis of possible limiting factors in the measurement setup is also presented. This article shows that silicon-based highly integrated reflectometers can be used in low-cost VNAs with excellent DR and accuracy. [ABSTRACT FROM AUTHOR]

Proximal-field sensing is introduced as an integrated sensing scheme for the in situ characterization of far-field radiation properties of integrated radiators, and the proximal-field radiation sensors (PFRSs) are proposed as the tools to enable this capability. These sensors are integrated on the same dielectric substrate as the transmitting antennas and extract the existing information in the excited substrate modes and use it to predict the far-field radiation properties in real time based on in situ field measurements in the close proximity of the transmitting antennas, without any need to use additional test equipment, remove the antenna from its operating environment, or interrupt its operation in a wireless system. The functionality of this sensing scheme is verified on both PCB and IC platforms through the implementation of two proof-of-concept prototypes, and different aspects of the electromagnetic and electronic design of the PFRS integration with integrated radiators are investigated. [ABSTRACT FROM AUTHOR]

For the safe operation of high-temperature superconducting (HTS) Maglev vehicles, the liquid nitrogen (LN2) level in the onboard cryostat should be monitored in real-time during the whole running process. The previous method of LN2 level detection was proposed by using resistance sensors or liquid volume meters as the testing equipment to estimate the liquid level. However, the fluctuation of LN2 level causes great disturbance for the liquid level detection, which leads to unsteady detection and loss of valid data. In this paper, an effective method for LN2 level detection under dynamic conditions is proposed. First, the static evaporation of LN2 in rectangular and circular containers are measured by PT100 platinum resistances. And then, a self-developed simple hardware is designed for onboard cryostats, further improving the HTS maglev vehicle performance. Furthermore, the state estimation theory, which uses particle filter algorithm, is employed to eliminate the interference caused by fluctuation of the LN2 level. The real-time measurement results illustrate that the proposed dynamic liquid nitrogen level detection is able to meet the requirements of the LN2 level detection with high precision. [ABSTRACT FROM AUTHOR]

The magnetic flux leakage (MFL) type pipeline inspection gauge (PIG) is commonly used to detect defects on the underground pipelines as one of the nondestructive testing instruments. Although it is effective for the inter-city scale large size pipeline, it is hard to detect defects for the small size pipeline installed inside the city. So, it is necessary to adopt self-driving robot system to drive PIG module because the small gas pressure inside a small size pipeline is not enough to push PIG module. Even though it is enough to pass in straight line, when this module passes through bent pipe or welded pipe joint, the magnetic force between pipe and inspection module is increased sharply so that the PIG module could be stuck eventually. This paper proposed a new design structure of MFL system to decrease stuck forces on the pipe wall. All structural parameters for MFL sensors based on the magnetic field theory were designed to minimize the magnetic force and maximize the detection sensitivity of defect signals. The performance of the proposed system was verified by simulation results using 3-D finite-element method and experimental measured ones. [ABSTRACT FROM AUTHOR]

A ball screw is a typical mechanical part that experiences wear-out and is widely used in computer numerical control machine tools to control the movement of processing targets and spindles. These types of parts need frequent checks so that they are replaced before excessive wear occurs. Until now, there was no simple way to measure directly the state of wear quantitatively. An indirect approach is logging the signals (vibration, temperature, and preload change) during the operation of mechanical parts. This information can be used to construct a wear model for estimating its remaining lifetime. For embedding sensors into mechanical devices, wireless sensors bring advantages in that they may be installed freely without constraints from data or power cables. However, wireless transmission is subjected to interference. To make wireless sensors that can be used practically within an industrial environment, we propose a wireless sensor system that: 1) emphasizes low-power and low cost in hardware design; 2) logs the signals during the operation of a mechanical part that could experience wear; and 3) guarantees that all the logged data can be wirelessly delivered to the data server. To our knowledge, this is the first wireless sensor system for measurement of mechanical operation signals that guarantees complete data delivery and correctness. We designed, implemented, and evaluated this system in real environments. This ensures that the design is practical. We envision that a miniature version of our design could be embedded in the ball screw shaft and gearbox reducer for logging signals to enable the building of a wear model to estimate the part's lifetime. [ABSTRACT FROM PUBLISHER]

A novel method for monitoring parameters of absorbing coatings, which are widely used for stealth technology, is described in this paper. The offered method of measurements is based on the use of slow-wave structures (SWSs), which electrodynamic parameters strongly depend on the electromagnetic properties of the absorbing coatings. The main advantages of the SWS-based measurements are in the possibility to concentrate electromagnetic field in a volume with linear dimensions much smaller the wavelength in free space and to split electric and magnetic fields, providing practically independent monitoring of dielectric and magnetic properties of the coatings. Resonant frequencies and $Q$ -factor of a SWS section placed in parallel to a monitored coating can be used as primary measuring parameters. Analysis of the dispersion equation derived for a SWS-based sensitive element in the presence of a coating allows creating algorithms for converting measured electrodynamic parameters into the reading of the coatings' electromagnetic properties. It is shown also that the use of coupled SWSs leads to the increase in the informative parameters' number and to the significant increase in sensitivity. [ABSTRACT FROM AUTHOR]

In this paper, an approach for high dynamic torque control of an industrial engine test bed is proposed. The main goal is to develop a control concept that is capable of periodic reference tracking at high control bandwidth while at the same time sufficiently rejecting disturbances coming from external excitations. For that reason, model predictive control (MPC) is utilized which offers two major benefits as compared to classical controllers. On the one hand, its capability to explicitly consider constraints can be applied to limitations of the actuating variable on the test bed. On the other hand, it can also be used to increase control bandwidth by anticipating future reference trajectories. For MPC, an accurate test bed model is of vital importance. Therefore, a system model is developed and validated using measurements obtained from the engine test bed. Moreover, a robustifying approach is proposed based on an extended system model to overcome hardly observable, weakly damped engine block suspension dynamics which are difficult to model. The proposed control concept is discussed and validated through simulations as well as through experimental results. [ABSTRACT FROM PUBLISHER]

A design is suggested for testing equipment of antennas operating in short millimeter waveband (SMW, f = 60...300 GHz). Testing is based on amplitude and phase measurements over a plane in the near field of the antenna under test. Design solutions are offered for critical subsystems, including the mechanical scanner, the radio-measurement subsystem and the automatic control subsystem. The approach should allow near-field testing of SMW antennas to achieve high accuracies comparable to those of similar testing of centimeter waveband antennas. [ABSTRACT FROM AUTHOR]

A systematic study, both experimentally and analytically, is conducted to evaluate the feasibility of using appropriate shock table tests to mimic the drop impact environment for components and systems adopted in portable electronics. Firstly, experiments are carried out to observe the dynamic characteristics of typical portable electronic systems and components under drop impact. Then a series of shock table tests with different constraint conditions are designed to mimic the real-life impact state. By comparing the typical results from shock table tests and those from drop tests, the correlation of shock table test parameters and drop tests conditions is investigated. The results reveal that the conventional fully constrained shock table test cannot mimic the real-life drop impact conditions, while an appropriate shock table test method should allow the sample to rotate freely. Theoretical analysis is developed to explain the mechanics of the impact scenarios. It is found that due to Hertz contact spring effect and the rotational acceleration during the impact, the acceleration of the centroid sample is significantly different to that of the table. In addition, acceleration estimated by traditional force-divided-by-mass method may underestimate the real acceleration of components inside the products. [ABSTRACT FROM AUTHOR]

In this paper, the design and implementation of a high-performance, real-time power quality (PQ)-measuring instrument based on a digital signal processor is discussed. The system is realized according to the latest standards about PQ monitoring, and it can be reconfigured for future developments of the standards. The instrument is particularly implemented to operate in stand-alone mode, and it is interfaced with a hardware module that adopts Transmission Control Protocol/Internet Protocol to exchange information and data. The main advantage of the realized device is the possibility to perform a comprehensive PQ monitoring that adopts a single low-cost instrument. Finally, this paper reports some preliminary experimental results of the accuracy characterization of an implemented prototype of the proposed instrument. [ABSTRACT FROM AUTHOR]

A traditional constant voltage conductivity test method was used to measure how the conductivity of highly insulating low-density polyethylene (LDPE) polymer films depends on applied electric field, repeated and prolonged electric field exposure, and sample temperature. The strength of the applied voltage was varied to determine the electric field dependence. At low electric field, the resistivity was measured from cryogenic temperatures to well above the glass transition temperature. Comparisons were made with a variety of models of the conduction mechanisms common in insulators, including transient polarization and diffusion and steady-state thermally activated hopping conductivity and variable range hopping conductivity, to determine which mechanisms were active for LDPE and to provide a better picture of its electrical behavior. [ABSTRACT FROM AUTHOR]

Phase noise testing for TV tuners is time consuming and expensive because of the large number of TV channels. This paper presents a hierarchical simulation method for a complex single-chip TV tuner. Based on the simulation results, an effective and economic test method is proposed to save the test application time. This method determines the most effective channels and frequencies to test so that the number of phase noise measurements is reduced. Experimental results on commercial chips show that our proposed method reduces the test time by a factor of ten without test escapes. [ABSTRACT FROM AUTHOR]

The rapid growth of digital video broadcasting by terrestrial transmission (DVB-T) has created the need for new measurement methods, as well as new test equipment that is capable of providing reliable and repeatable results. Some problems are, in fact, being experienced with power measurements, particularly with those involving the integration of the input signal power spectrum over a certain frequency interval. Trying to give a proper answer to the cited need, a digital signal processing method, which has already been proposed in the literature and specialized for power measurements in spread spectrum systems, is optimized here to be operative in the presence of DVB-T signals as well. Suitable stages, in simulation and emulation environments, are designed and applied to optimally regulate key parameters of the method, thus making it assure negligible bias and high repeatability in most operative conditions. The results of a number of experiments on actual DVB-T signals also give evidence of the method's efficacy with respect to competitive measurement solutions. [ABSTRACT FROM AUTHOR]

As complex very-large-scale integration circuit testing using external automatic test equipment is becoming increasingly expensive, built-in self-test (BIST) is an alternative technique that can significantly reduce the cost of testing. On the other hand, artificial immune systems have been considered as one of the most promising nature-inspired techniques used for novelty detection systems. One of the main features of such systems is self-nonself discrimination, which enables the body to distinguish any foreign cell from the body's own cell. In this paper, based on the principles of self-nonself discrimination, an immune-based output response analyzer for BIST is presented. Using the proposed scheme, the evaluation of the circuit under test (CUT) is performed by a set of immune-based detectors that are capable of detecting faulty output responses. Since the number of detectors is proportional to the hardware overhead consumed by the scheme, it is also presented as an optimization algorithm to reduce the number of detectors. Using the reduced set of immune-based detectors, zero aliasing is achieved, and, in addition, the evaluation of the CUT is performed during the test. The experimental results show the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Vector ordering is an essential task in testing very large scale integration systems because it affects this process from two perspectives: 1) power consumption and 2) correlation among test data. The former feature is crucial and, if not properly controlled, may result in permanent failure of the device under test (DUT). The latter feature is also important because correlation is captured by coding schemes to efficiently compress test data and ease memory requirements of automatic test equipment (ATE) while reducing volume and lowering test application time. Vector ordering, however, is NP-complete. This paper presents an evaluation of different heuristic techniques for vector ordering using the 1985 and 1989 IEEE International Symposium on Circuits and Systems (ISCAS85 and ISCAS89, respectively) benchmark circuits in terms of run time and solution quality. For this application, it is shown that the best heuristic technique is not the one based on the famous Christofides or Lin-Kernighan criteria but on the multifragment technique. It has been shown that the selection of an appropriate heuristic can lead to an increase in the compression ratio of up to 178% and a reduction in the power consumption during test of up to 46%. [ABSTRACT FROM AUTHOR]

Typical test methods for characterizing the single event upset performance of an analog to digital converter (ADC) have involved holding the input at static values. As a result, output error signatures are seen for only a few input voltage and output codes. A test method using an input beat frequency and output code error detection allows an ADC to be characterized with a dynamic input at a high frequency. With this method, the impact of an ion strike can be seen over the full code range of the output. The error signatures from this testing can provide clues to which area of the ADC is sensitive to an ion strike. [ABSTRACT FROM AUTHOR]

In this paper, a reduced-pin-count-testing technique is presented to control the IEEE-1500 wrapper through the IEEE-1149.1 TAP for scan delay test. By using only the IEEE- 1149.1 TAP control pins as test-access pins and by embedding an on-chip test clock generator, low-cost automated test equipment (ATE) can be efficiently utilized to reduce testing costs. Experiments show the effectiveness of our technique in utilizing the ATE channels and scan delay testing. [ABSTRACT FROM AUTHOR]

Open defects have been intentionally designed in a set of interconnect metal lines. In order to improve the controllability and the observability of the experimental design, a simple bus structure with a scan register followed by a hold register is used to manage the set of interconnect lines. The strength of the open defects has been varied within a realistic range of resistances ranging from a full (complete) open to a weak (low resistance) open by means of broken metal lines and transmission gates, respectively. Experiments performed with an automatic test equipment show the influence of coupling capacitances with adjacent lines on the electrical behavior of the defective line. Furthermore, experimental evidence of the history effect on the delay caused by resistive opens is investigated. Validation of the measured results by means of theoretical as well as simulation analysis is presented. Finally, some recommendations to generate Stuck-at, IDDQ, and delay test are discussed in order to improve the detectability of such defects. [ABSTRACT FROM AUTHOR]

Traditional testing of analog-to-digital converters (ADCs) with automatic test equipment is time-consuming and expensive, and a built-in self-test (BIST) can be one solution to this problem. Most of the proposed BIST routines require a well-known test stimulus which is much more linear than the device under test. A stimulus error identification and removal (SEIR) method that does not require a high-linearity stimulus has been proposed recently, and it is evident that reliable test results could be achieved with a stimulus linearity lower than the required measurement accuracy. This paper presents a simple and easy-to-implement calculation algorithm for use with the stimulus-identification method, particularly for BIST purposes. Simulations demonstrate that the integral-nonlinearity measuring accuracy of the SEIR method with the new calculation algorithm is 1 least significant bit for 14-b ADCs, even though the linearity of the test stimulus is only 7 b. The SEIR method and the new simpler calculation algorithm can reduce the hardware resources required for ADC BIST [ABSTRACT FROM AUTHOR]

Electrical utilities have adapted insulator leakage distances to a wide range of contamination environments. This has led to development of guidelines for unified specific creepage distance, for example in IEC 60815. Under freezing conditions, a number of factors change. The surface conductivity of ice is much lower than that of water, but there is the countervailing possibility of accumulating a significant amount of ice. One of the crossover points between applications occurs when a very light layer of hoar frost or freezing fog, simulated in a "cold fog" test, fully wets a pre- contaminated insulator. The leakage distance requirements for these conditions are compared with those suggested for conventional clean-fog requirements. The possibility of treating fog accretion as a form of non-soluble deposit density is explored. [ABSTRACT FROM AUTHOR]

To be able to determine, verify and monitor the ice- and snow performance of different insulation solutions, laboratory test methods and an on-site, on-line web based surveillance system are needed. The method for determining the ice performance in laboratory conditions, Ice Progressive Stress (IPS) method, is described in this paper. Further it is described how to use the results of this type of test to estimate statistically the performance of complete overhead line equipped by different insulators. To verify the laboratory ice- and snow test method, to get an idea about the type and number of ice and snow events actually occurring in service and to get more information about ice and snow phenomena in real life an on-site on-line web based surveillance system was designed and built. This sophisticated system, including the automatic image analysis and used statistical tools is described in this paper. Besides the description of the laboratory test method and the surveillance system, service experience, pictures and interesting results obtained so far are also presented. [ABSTRACT FROM AUTHOR]

A method is introduced for testing insulators under icing conditions. The method is based on and developed from those described in the standard of IEC60-1, IEC 60507 and IEEE Task Force on Insulator Icing Test Methods, which give instructions to test insulators under pollution. Then, the paper explores the effects of various factors, including ice thickness, pollution severity on the surface of insulators before ice accretion, atmospheric pressure, and shed profiles, on the flashover performance of short samples of two different types of silicone rubber (SIR) composite long rod insulators intended for ultra high voltage (UHV) ac transmission lines. The experiments were carried out in the multi-function artificial climate chamber in the High Voltage and Insulation Technological Laboratory of Chongqing University, China. The experimental results reveal the regularity of the effects of ice thickness, pollution severity and atmospheric pressure on the average flashover voltage of two types of composite insulators. Those can provide reference for the outdoor insulation design for UHV ac transmission lines. [ABSTRACT FROM AUTHOR]

This work presents a novel procedure to characterize damage using an array of ultrasonic measurements in a generalized model-based inversion scheme, which integrates the complete information recorded from the measurements. In the past, we proposed some idealized non-destructive evaluation test methods with emphasis on the numerical results, but it is necessary to develop the techniques in greater detail in order to apply the techniques to real conditions. Our detection principle is based on the measurement and inversion of frequency-domain data combined with a reduced set of output parameters. The approach is developed and tested for the case of an aluminum specimen with a synthetic array of point contact ultrasonic transmitters and receivers. The first part of this two-part paper is focused on numerical synthesis of the experimental measurements using the boundary element method for a general ultrasonic propagation model. This part also deals with the deconvolution by comparing the data measured from the damaged and undamaged specimens. The deconvolution technique allows us to calibrate the data by taking into account the uncertainties due to mechanical properties, input signal, and other coherent noise. The second part of the paper presents the inversion of the measurements to obtain the parameters and ultimately. to predict the position and size of the real defect. [ABSTRACT FROM AUTHOR]

The utilization of handheld, radio frequency (RF) equipment (spectrum analyzers and signal generators) for both classroom demonstrations and for student exercises conducted in the field is discussed. Demonstrations employ real-world, wireless systems to illustrate undergraduate concepts, such as channel access, modulation methods, and transmission bandwidth. The equipment has also been used to illustrate antenna concepts, such as gain, beamwidth, and polarization. Finally, the portability and robustness of the equipment has enabled students to collect field data for the purpose of characterizing both large- and small-scale propagation effects in a variety of environments. [ABSTRACT FROM AUTHOR]

This paper presents how it is possible to characterize a current probe in terms of its transfer impedance inside a reverberation chamber. The probe catches a floating wire placed inside the working volume of the chamber. The current on the wire is calculated from the knowledge of the total measured average field along the wire in the working volume. The current is calculated by representing the field in terms of a summation of random plane waves, where a finite-difference time-domain (FDTD) code is used to compute the current induced by each plane wave along the wire caught by the probe under test. Results for the current distribution along the wire are reported for several frequencies. Finally, the transfer impedance of commercial probes is recovered from the knowledge of the current and compared to the values given by the manufacturers and by an external laboratory. [ABSTRACT FROM AUTHOR]

Classically, the statistical model of the maximum field inside a reverberation chamber (RC) is derived from the field magnitude model that is only known for the overmoded RC. We pro- pose in this paper to model the maximum field by the generalized extreme value (GEV) distribution, as an application of the Fisher-Tippett theorem that formulates the asymptotic distributions of sample maximum. As the knowledge of the parent distribution (field magnitude) is not required, the GEV distribution is suitable for both overmoded and undermoded regimes (few modes excited). A Monte Carlo simulation illustrates the use of the GEV distribution for the overmoded RC. Modal FEM analysis of the RC extends the application to the undermoded regime. Special attention is brought to the issue of GEV parameter estimation: The so-called L-moments technique is advantageously employed to estimate the parameters from the small data sample. Dispersion of the estimated parameters is approximated and reduced by averaging uncorrelated values obtained from a narrow frequency band. [ABSTRACT FROM AUTHOR]

The position of the transmit antenna is analyzed and evaluated according to the measurement data in our developed reverberation chamber. Nine calibrations are measured carefully. The key parameters such as field uniformity, quality factor, the average normalized electric field, and the receive antenna calibration factor are analyzed in detail. It is indicated that the position of the transmit antenna has insignificant influence on the test repeatability of calibrations. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the design parameters for efficient stirring in reverberation chambers. We have measured the efficiency of the stirrer in terms of the lowest possible frequency for which it gives a certain number of uncorrelated samples. Rotating stirrers, when rotated about their axes, generate cylindrical volumes. The impact of a change of the stirrer diameter is approximately cubic compared with the change of the stirrer height. The efficiency of stirrers that are translated is proportional to the stepping increment and to the square root of the area of projection of the stirrer on a plane orthogonal to the direction of translation. [ABSTRACT FROM AUTHOR]

We review the difficulties linked to the modal approach when modeling a reverberation chamber by the finite element method (FEM). The numerical challenge is due to the large-scale problem involved by the overdimensioned cavity. Moreover, the field singularity on the stirrer has to be captured by the FEM. First, the following issues are discussed: existence of null-frequency solutions, convergence rate for h and p adaption, and formulation type in E or H field. The modal analysis is then compared to the classical harmonic one. Focus is put on the field singularity at the source point. [ABSTRACT FROM AUTHOR]

Abstract-The increasing complexity of system-on-chip (SOC) integrated circuits has spurred the development of versatile automatic test equipment (ATE) that can simultaneously drive different channels at different data rates. Examples of such ATEs include the Agilent 93000 series tester based on port scalability and the test processor-per-pin architecture and the Tiger system from Teradyne. The number of tester channels with high data rates may be constrained in practice, however, due to ATE resource limitations, the power rating of the SOC, and scan frequency limits for the embedded cores. Therefore, we formulate the following optimization problem: Given two available data rates for the tester channels, an SOC-level test access mechanism (TAM) width W, an upper limit V (V < W) on the number of channels that can transport test data at the higher data rate, determine an SOC TAM architecture that minimizes the testing time. We present an efficient heuristic algorithm for TAM optimization that exploits port scalability of ATEs to reduce SOC testing time and test cost. We present experimental results for the ITC '02 SOC test benchmarks and investigate the impact of dual-speed TAM architectures on power consumption during testing for one of these benchmarks. [ABSTRACT FROM AUTHOR]

To explore the impact of temperature on the post-irradiation response of ICs, we characterized the temperature response of transistors, SRAMs, and a custom mixed-signal ASIC. Devices were irradiated at room temperature and electrically characterized post irradiation as a function of temperature. Devices exhibit significantly more parametric degradation when characterized at elevated temperatures. In addition to parametric degradation, it is demonstrated that post-irradiation elevated temperature characterization can also induce functional failures at significantly lower total dose levels than at room temperature. As a result, to ensure system functionality, it is essential that devices be characterized over the full system temperature range pre- and post-irradiation. Recommendations for incorporating temperature testing into a hardness assurance test method (i.e., Method 1019) are suggested. Methods for minimizing the detrimental effects of elevated temperature anneals on hardness assurance testing are also discussed. [ABSTRACT FROM AUTHOR]

The interior permanent-magnet (IPM) machine is used in many industrial drives. In order to analyze performance and to design efficient and fast controllers, accurate knowledge of machine parameters such as d- and q-axes inductances is essential. Although there are a number of methods available to calculate these inductances, none of them is considered standard. Accuracy levels of all these methods are also not consistent, and some of the measurement methods require complicated arrangements. Among these test methods, the ac standstill test and a newly developed test method that uses vector current control technique are ideal for a laboratory environment. In this paper, these two methods are compared by applying them to a prototype IPM machine. The paper analyzes the test results of the methods and their differences in detail with the help of finite-element analysis. [ABSTRACT FROM AUTHOR]

An accurate yield evaluation is essential in selecting redundancy allocation and testing strategies for memories. Yield evaluation can resolve the many issues revolving around cost-effective built-in self-test (BIST) and automatic test equipment (ATE)-based solutions for a higher test transparency. In this paper, two yield-calculation methodologies for SRAM arrays are proposed. General yield expressions for VLSI chips are initially presented. The regular and repetitive structure of an SRAM array is exploited, and substantial yield improvements can be achieved by the introduction of redundancy. Two repair yield-evaluation methods for one-dimensional redundant memory arrays are introduced and compared for ATE application. The first method is based on the sum of the probabilities of all repairable fault patterns; the second method is based on Markov modeling. Using industrial data, it is shown that these methods are applicable to ATE usage under different conditions of defect rate in the possible defects. Different features of the proposed methods are discussed. [ABSTRACT FROM AUTHOR]

This paper presents an innovative test procedure for the prediction of the shielding effectiveness of small sample materials, consisting of a dielectric substrate coated with thin conducting film, in a wide frequency range up to 8 GHz. The proposed technique overcomes the limitations of the ASTM D4935 test method concerning the upper operating frequency and the required minimum specimen dimensions. A new high-order equivalent circuit model of the test fixture is developed. A correction factor is applied to the measured insertion loss to eliminate both the resonance peak below cutoff appearing in the high-frequency range and the low-frequency errors due to the weak capacitive coupling between the flanges of the coaxial cell. The accurate prediction of the shielding effectiveness of the test material against a plane wave is then derived from the insertion loss measurements. [ABSTRACT FROM AUTHOR]

This paper describes the most important factors influencing the aluminum electrolyte capacitor showing, in particular, the effect of temperature on the lifetime of this device. The automation of the measurement system, with the oven interfaced with a PC, was also completed to control all the involved parameters. [ABSTRACT FROM AUTHOR]

Methods to test the practical performance of the Philips Gemini PET/CT system during clinical imaging are described and results presented. The test methods used were based on the NEMA standards and those suggested by a task group of the Commission of European Communities (EEC). These were performed using the EEC emission phantom, and phantoms provided by Philips. Scans were acquired using the routine clinical protocols. Images were reconstructed using a 3D row action maximum likelihood algorithm (RAMLA). Attenuation correction (AC) was applied using CT data (CTAC) and Cs-137 source transmission scans (CsAC). Images can be acquired with the PET and CT gantries closed or open. Results of tests on the gantry alignment show that the static offsets varied by a maximum of 4.5 mm when the system was first installed, but as the floor has settled these variations have decreased to a maximum of 2.5 mm. The mean negative nonuniformity was -4.8 ± 1.1% and -5.3 ± 1.1% for CsAC and CTAC respectively and the mean positive nonuniformity was 4.7 ± 1.4% and 5.5 ± 1.6%. Scatter fraction measurements were made in the EEC body phantom. The reconstructed scatter fractions were 0.18 and 0.16 with and without out-of-field-of-view activity respectively (±OFOVA) for both CsAC and CTAC images. The sinogram-derived (NEMA NU 2-1994) scatter fraction was 0.44 and 0.43 ± OFOVA. At the centre of the field of view (FOV) the transverse spatial resolution (SR) was 5.0 mm in air (5.0 mm in water) and the axial SR was 6.0 mm (6.8 mm). 10 cm away from the centre the transverse radial SR was 5.4 mm (5.3 mm), the transverse tangential SR was 5.2 mm (5.4 mm) and the axial SR was 6.6 mm (7.2 mm). The recovery coefficients demonstrate the partial volume effect. The AC accuracy was similar in water (both 0.2 ± 0.1%) and Teflon [10.9 ± 1.9% (CTAC) and 10.0 ± 2.0% (CsAC)], for both types of AC, but very different in air [14.3 ± 2.2% (CTAC) and 31.3 ± 1.5% (CsAC)]. If the transmission maps were not segmented prior to AC these gave much higher and very different residual AC errors. The peak noise equivalent count rate was 45.2 kcps at 184 MBq and 25.2 kcps at 127 MBq ± OFOVA. The system sensitivity to true and scattered counts was 34.1 kcps/(kBq/cm³) and to true counts was 19.4 kcps/kBq/cm³). [ABSTRACT FROM AUTHOR]

The characteristic nondestructive single-event latchup (SEL) phenomena, "local" and "pseudo" SELs, were identified in complex digital Large Scale Integrations (LSIs) by using a photo-emission microscope. Usually, SELs are detected as an abrupt increase of power supply current. However, it was experimentally demonstrated that the simple method could not give sufficient information to determine if it is a destructive or a non-destructive phenomenon. If the observed SELs can be confirmed as a nondestructive phenomenon with a certain confidence level, a simple circumvention technique can be effectively employed and the chance to utilize attractive commercial devices will be greatly enhanced. The SEL test method to identify this type of LSI was discussed and a new procedure was proposed. [ABSTRACT FROM AUTHOR]