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This paper introduces a design and implementation of a base station, capable of positioning sensor nodes using an optical scheme. The base station consists of a pulse laser module, optical detectors and beam splitter, which are mounted on a rotation-stage, and a Time to Digital Converter (TDC). The optical pulse signal transmitted to the sensor node with a Corner Cube Retro-reflector (CCR) is reflected to the base station, and the Time of Flight (ToF) data can be obtained from the two detectors. With the angle and flight time data, the position of the sensor node can be calculated. The performance of the system is evaluated by using a commercial CCR. The sensor nodes are placed at different angles from the base station and scanned using the laser. We analyze the node position error caused by the rotation and propose error compensation methods, namely the outlier sample exception and decreasing the confidence factor steadily using the recursive least square (RLS) methods. Based on the commercial CCR results, the MEMS CCR is also tested to demonstrate the compatibility between the base station and the proposed methods. The result shows that the localization performance of the system can be enhanced with the proposed compensation method using the MEMS CCR.

This paper describes an optical interference suppression scheme that allows flash light detection and ranging (LiDAR) imagers to run safely and reliably in uncontrolled environments where multiple LiDARs are expected to operate concurrently. The issue of optical interference is a potential show-stopper for the adoption of flash LiDAR as a technology of choice in multi-user application fields such as automotive sensing and autonomous vehicle navigation. The relatively large emission angle and field of view of flash LiDAR imagers make them especially vulnerable to optical interference. This work illustrates how a time-correlated single-photon counting LiDAR can control the timing of its laser emission to reduce its statistical correlation to other modulated or pulsed light sources. This method is based on a variable random delay applied to the laser pulse generated by LiDAR and to the internal circuitry measuring the time-of-flight. The statistical properties of the pseudorandom sequence of delays determines the effectiveness of LiDAR resilience against unintentional and intentional optical interference. For basic multi-camera operation, a linear feedback shift register (LFSR) was used as a random delay generator, and the performance of the interference suppression was evaluated as a function of sequence length and integration time. Direct interference from an identical LiDAR emitter pointed at the same object was reduced up to 50 dB. Changing integration time between 10 ms and 100 ms showed a marginal impact on the performance of the suppression (less than 3 dB deviation). LiDAR signal integrity was characterized during suppression, obtaining a maximum relative deviation of the measured time-of-flight of 0.1%, and a maximum deviation of measurements spread (full-width half-maximum) of 3%. The LiDAR signal presented an expected worst-case reduction in intensity of 25%.

The upgrade of the ATLAS muon spectrometer for the high-luminosity LHC requires new trigger and readout electronics for various elements of the detector. We present the design of a time-to-digital converter (TDC) ASIC prototype for the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and power dissipation characteristics meet the design specifications, with a timing bin variation of ± 40 ps for all 48 TDC slices and a power dissipation of about 6.5 mW per slice. [ABSTRACT FROM AUTHOR]

This study was carried out to find a method to control tyrosine decarboxylase activity (TDC) of a strain of Enterococcus faecium capable of producing high levels of tyramine. To select a TDC inhibitor, enzyme assay was first performed using purified TDC enzyme and 0.1% of TDC inhibiting chemicals. When 0.23% of nicotinic acid was added, tyramine content (363 ug/mL) was lower than that of the control group (873 ug/mL). At the same time, bacterial growth was decreased 1 log cycle from 8.62 to 7.56 log CFU/mL. TDC expression level in E. faecium was measured by using RT-qPCR. Lower expression level (below 0.7) was observed after the addition of 0.23% nicotinic acid (in vitro). When cheonggukjang was manufactured with addition of nicotinic acid, tyramine contents were decreased from 698.67 to 117.27 mg/kg when the concentration of nicotinic acid added was increased from 0.10 to 0.30%. These results suggest that nicotinic acid could be used as an agent (TDC inhibitor) to reduce tyramine content in cheonggukjang. [ABSTRACT FROM AUTHOR]

Résumé But de l’étude L’objectif de cette étude était de comparer les profils attentionnels et exécutifs d’enfants porteurs de trouble du déficit de l’attention/hyperactivité (TDA/H) en l’absence et en présence de deux troubles habituellement associés au TDA/H : la dyslexie développementale (DD) et le trouble développemental de la coordination (TDC). Patients et méthode Cent soixante et un enfants âgés en moyenne de 8,9 ans diagnostiqués avec un TDA/H par une équipe pluridisciplinaire ont été répartis en quatre groupes : TDA/H isolé ( n = 61), TDA/H et DD associés ( n = 36), TDA/H et TDC associés ( n = 27), et TDA/H avec à la fois DD et TDC associés ( n = 37). Le Test d’Évaluation de l’Attention chez l’Enfant (TEA-Ch) a été administré à tous les enfants pour une évaluation détaillée des fonctions attentionnelles et exécutives. Résultats Les résultats des comparaisons entre les quatre groupes mettent en évidence des différences significatives sur plusieurs variables : attention sélective visuelle, attention auditive, attention divisée, capacités d’inhibition et attention soutenue. Conclusion Ce travail met en évidence des différences de fonctionnement attentionnel et exécutif chez des enfants TDA/H en fonction de la présence ou non de DD et/ou de TDC associé. Les implications cliniques qui en découlent sont à considérer et sont susceptibles d’éclairer la pratique des professionnels, notamment aux niveaux diagnostique et thérapeutique. Background Children with attention-deficit hyperactivity disorder (ADHD) manifest deficits in attentional and executive domains. Yet, although ADHD is often associated with other neurodevelopmental syndromes such as developmental dyslexia (DD) and developmental coordination disorder (DCD), very few studies exploring the impact of these associated disorders on cognitive abilities of children with ADHD are available. Whether and how these comorbid disorders may influence attentional and executive abilities among ADHD patients remained to be explored. Aim of the study The goal of the current study was to compare the attentional and executive profiles of ADHD children with and without one or two often-associated comorbid neurodevelopmental disorders: DD, and DCD. Participants and method One hundred and sixty-one children (mean age: 8.9 years) were classified into four groups: children with ADHD in isolation ( n = 61), children with ADHD and associated DD ( n = 36), children with ADHD and associated DCD ( n = 27), and children with the three associated disorders (ADHD-DCD-DD, n = 37). For assessing attentional and executive skills, we used the Test of Everyday Attention for Children (TEA-Ch). Results We observed differences between the groups among the majority of attentional and executive measures: selective visual attention, auditive attention, divided attention, inhibition, and sustained attention. Conclusion These results show that children with ADHD manifest different cognitive performances depending on the presence of associated DD and/or DCD. Most of attentional executive domains are negatively impacted by DD and/or DCD. These findings concur with the current theoretical point of view whereby neurodevelopmental disorders partially share etiological and clinical factors. Our results also matter in the way professionals can understand how neurodevelopmental disorders influence each other, and how specific therapeutic projects could be built taking into consideration often-associated disorders in ADHD. [ABSTRACT FROM AUTHOR]

In view of the numerous clock domain crossings found in modern systems-on-chip and multicore architectures precise metastability characterization is a fundamental task. We propose a conceptually novel approach for the experimental assessment of upset rate over resolution time that is usually employed to extract the relevant characteristics. Our method is based on connecting a time-to-digital converter to the output of the flip flop under test, rather than using a phase shifted clock, as conventionally done. We present the details of an FPGA implementation of our approach and show its feasibility through an experimental evaluation, whose results favorably match those obtained by the conventional method. The benefits of the novel scheme are the ability to perform a calibration for the delay steps, a speed-up of the measurement process, and the availability of a more comprehensive and ordered measurement data set. Especially the latter can be of crucial importance when (even multiple) glitches or oscillation are suspected to result from metastability, or when the temporal distribution of upsets matters (bursts of upsets, e.g.). [ABSTRACT FROM AUTHOR]

A four-channel nanosecond time-resolved avalanche-photodiode (APD) detector system is developed at Beijing Synchrotron Radiation. It uses a single module for signal processing and readout. This integrated system provides better reliability and flexibility for custom improvement. The detector system consists of three parts: (i) four APD sensors, (ii) four fast preamplifiers and (iii) a time-digital-converter (TDC) readout electronics. The C30703FH silicon APD chips fabricated by Excelitas are used as the sensors of the detectors. It has an effective light-sensitive area of 10 × 10 mm 2 and an absorption layer thickness of 110 μ m. A fast preamplifier with a gain of 59 dB and bandwidth of 2 GHz is designed to readout of the weak signal from the C30703FH APD. The TDC is realized by a Spartan-6 field-programmable-gate-array (FPGA) with multiphase method in a resolution of 1ns. The arrival time of all scattering events between two start triggers can be recorded by the TDC. The detector has been used for nuclear resonant scattering study at both Advanced Photon Source and also at Beijing Synchrotron Radiation Facility. For the X-ray energy of 14.4 keV, the time resolution, the full width of half maximum (FWHM) of the detector (APD sensor + fast amplifier) is 0.86 ns, and the whole detector system (APD sensors + fast amplifiers + TDC readout electronics) achieves a time resolution of 1.4 ns. [ABSTRACT FROM AUTHOR]

The glaucous gull ( Larus hyperboreus ) is an arctic top predator and scavenger exposed to high levels of mixtures of organohalogenated contaminants (OHCs) of which many interfere with the thyroid hormone (TH) system. In the present study, we applied statistical modeling to investigate the potential combined influence of the mixture of chlorinated, brominated and perfluorinated organic compounds in plasma of glaucous gulls on their plasma TH concentrations. In females, there were significant negative associations between several organochlorinated compounds (OCs) and free thyroxin (FT4) and triiodothyronine (FT3), indicating additive negative effects on FT4 and FT3. However, in these females there was also a significant positive association between perfluorooctane sulfonate (PFOS) and FT3. The inverse associations between several OCs and FT3 and the contrasting positive association between PFOS and FT3, indicate that these two groups of OHCs may have dissimilar and antagonistic effects on FT3 in female glaucous gulls. In males, there were no associations between any of the OHCs and the THs. That OHCs affect THs in a complex manner involving both additive and antagonistic effects add to the challenge of interpreting the overall functional effect of thyroid disruptive chemicals in wildlife. However, experimental studies are needed to confirm or disprove such effects. [ABSTRACT FROM AUTHOR]

Purpose The study aims to compare the accuracy of washout and perfusion CT techniques in diagnosis of adrenal tumors. Patients and methods A prospective study included 38 patients with incidentally detected adrenal masses on conventional abdominal CT studies performed for unrelated reasons were subjected to full medical history, physical examinations, serum creatinine assessment, dynamic perfusion CT using 64 MDCT scanner with Absolute washout (APW), Relative washout (RPW) assessment and CT perfusion parameters calculation [perfusion, Peak enhancement intensity (PEI), Time to peak (TTP) & Blood volume (BV)]. Time density curves (TDCs) for all adrenal masses were done. The gold standard was either follow up or histopathological examination after fine needle biopsy or surgical resection. Results Washout CT differentiated between adenomas and non-adenomas using APW (≥55%) with sensitivity 73.3%, specificity 90% and accuracy 82.8%, and using RPW (≥36%) with sensitivity 53.3%, specificity 85% and accuracy 81.8%. Perfusion CT differentiated between adenomas and nonadenomas using BV (≥15 ml/100 g) with sensitivity 80%, specificity 75% and accuracy 77.1%. TDC curves of adenomas show slow-rise platform pattern. Conclusion Perfusion CT can distinguish between adrenal adenomas and non-adenomas using the BV, however washout CT was more accurate than perfusion CT in characterization of adrenal masses using the APW and RPW. [ABSTRACT FROM AUTHOR]

On account of the intensive interaction between the prefractionator and main distillation column involved, achieving tight product purity control with a small set of temperature measurements represents a considerably challenging issue in the derivation of temperature inferential control systems for dividing-wall distillation columns (DWDCs). Although double temperature difference control (DTDC) scheme appears more effective than temperature control and temperature difference control schemes, the former should not always be considered as the best control decision under the premise of maximally three temperature measurements in each control loop. Instead of a symmetrical temperature control (STC) structure as the DTDC scheme, an asymmetrical temperature control (ATC) structure with each control loop involving a different number of temperature measurements can be derived and lead to not only a simplified control structure but also improved control system performance. In the current work, such possibility is highlighted with reference to a frequently studied benzene–toluene– o -xylene DWDC system. With the perfect maintenance of the four controlled product compositions on their specifications, the three kinds of controlled variables, i.e., temperature, temperature difference, and double temperature difference, are assessed with reference to all kinds of feed composition disturbances and the one with the minimum averaged variability is screened out for each control loop. In combination with the interaction analysis, three ATC schemes are finally derived. Closed-loop evaluations of these ATC schemes are carried out through in-depth comparison with the DTDC scheme and the former ones all show comparable transient responses and improved steady-state behaviors in comparison with the latter. Although the three ATC schemes result in relatively great steady-state discrepancies in the intermediate product purity, the drawback can be suppressed completely with the addition of two temperature measurements in the intermediate control loop. These findings demonstrate the feasibility and potential of adopting the ATC schemes for the tight inferential control of the DWDC. [ABSTRACT FROM AUTHOR]

This paper proposes a digital-to-time converter (DTC)-assisted fractional-N wide-bandwidth all-digital phase-locked loop (ADPLL) with a fine-resolution time-to-digital converter (TDC). The TDC employs a two-channel time-interleaved time-domain register with an implicit adder/subtractor realizing an error-feedback topology. Such an error-feedback unit of a first-order $\Delta \Sigma $ -TDC can be cascaded as a multi-stage noise shaping configuration to achieve higher-order noise-shaping and, thereby, low in-band phase noise (PN) of the ADPLL. A digitally controlled oscillator with a transformer and a pair of cross-coupled NMOS amplifiers exploits magnetic and capacitive coupling to achieve nearly an octave frequency coverage, i.e., 1.73–3.38 GHz (after a $\div $ 2 division). Fabricated in 40-nm CMOS, the ADPLL achieves better than −110-dBc/Hz in-band PN and occupies an active area of 0.5 mm2. With a 50-MHz reference clock, a 2-GHz output RF clock, and a loop bandwidth of 800 kHz, this prototype achieves 420-fs $_{{\mathrm{rms}}}$ jitter, integrated from 1-kHz to 30-MHz offset, while drawing 10.7 mW. [ABSTRACT FROM AUTHOR]

We have been developing superconducting time-of-flight mass spectrometry systems that utilize superconducting strip particle detectors and single-flux-quantum (SFQ) time-to-digital converters (TDCs). We previously demonstrated a 24-bit SFQ TDC with a 3 × 24-bit first-in first-out (FIFO) buffer using the AIST Nb standard process (STP2) with a time resolution of 100 ps. In this study, we improved the SFQ TDC by using a current recycling technique. The technique enables us to increase the FIFO buffer capacity without increasing the total supply current, and the result is an improvement of ion count rates. We designed and demonstrated the SFQ TDC with a 12 × 24-bit FIFO buffer, whose total supply current was reduced by 71% with the current recycling technique. [ABSTRACT FROM PUBLISHER]

Background. Developmental coordination disorder (DCD) is a motor skills disorder that can have negative lifelong psychosocial impacts if not diagnosed. Occupational therapists have a role in facilitating a diagnosis for children with DCD through assessment. Purpose. The purpose of this study was to determine the level of understanding of current DCD guidelines for assessment and diagnosis among occupational therapists working in paediatric settings in British Columbia, Canada. Method. An online survey was e-mailed to occupational therapists who consented to be contacted for research purposes; 169 paediatric therapists responded. Data were reported using percentage, mean, and standard deviation of responses for each answer. Findings. Although many occupational therapists are aware of DCD and the diagnostic criteria, most are unaware of current guidelines for assessment and diagnosis. Many are using cutoff scores inconsistent with current recommendations and thus may not be facilitating a diagnosis when one may be appropriate. Implications. Occupational therapists may benefit from targeted education regarding DCD assessment and diagnosis. [ABSTRACT FROM AUTHOR]

This paper presents a power- and area-efficient 16-way time-interleaved (TI) analog-to-digital converter (ADC) achieving 24-GS/s conversion speed and 6-bit resolution in 28-nm CMOS. A voltage-time hybrid pipeline technique exploiting the comparator input-voltage-output-time dependency is reported to enhance the throughput of successive-approximation-register (SAR) ADCs. A reference-buffer-free capacitive digital-to-analog (CDAC) converter is utilized to mitigate the crosstalk problem in TI-ADCs. Timing mismatches between individual sub-ADCs are estimated with a reference-ADC dithering technique and corrected by digitally controlled delay lines (DCDL). The techniques collectively enabled a very compact design, obviating any input buffer or hierarchical sampling structures. The ADC core consumes 23 mW and occupies an area of 0.03 mm2. A signal-to-noise plus distortion ratio (SNDR) of 35 dB and a spurious-free dynamic range (SFDR) of 54 dB were measured for a 40-MHz input. For a Nyquist input, the prototype measured an SNDR of 29 dB and an SFDR of 41 dB with all timing mismatch spurs suppressed below −50 dBc after skew calibration. [ABSTRACT FROM AUTHOR]

• A new operation mode of time-to-digital converters to separate the detection of the minimum distance and the depth of field in time-of-flight measurements. • The mode achieves a long detection range with high resolution in a small pixel area. • The mode reduces the power consumption of the readout integrated circuit. A novel time-to-digital converter (TDC) operation mode, called double-frame-multiplexing (DFM), is proposed for time-of-flight (TOF) measurements. It is based on the separate detection of the minimum distance and depth of the measured targets, which reduces the power consumption of in-pixel TDCs and expands the maximum detection distance under high resolution. A 64 × 64 direct TOF image sensor chip is fabricated in a 0.18 μm CMOS process. Driven by a 125 MHz multi-phase clock and a 50 MHz data readout clock, the chip achieves a maximum frame rate of 20 kframe/s, a maximum detection distance of 750 m (5 μs), and a maximum depth of field of 3 m (20 ns) with a temporal resolution of 1 ns. The DFM mode reduces the average power consumption to 60 mW without consideration of SPADs. The worst-case measured differential nonlinearity is −0.61/+0.69 least significant bit (LSB) and the maximum integral nonlinearity is −1.06/+0.66 LSB. [ABSTRACT FROM AUTHOR]

In this paper, we present a high accuracy laser range finder and velocimeter using ultra-fast time-to-digital converter (TDC). The system operation is based on the measuring the round-trip time of a narrow laser pulse. A low-dark current high-speed PIN photodiode is used to detect the triggered laser beam and to produce start signal. The pulsed laser diode generates 45W optical power at 30ns duration time and 905nm wavelength. A high-responsivity avalanche photodiode (APD) detects the reflected beam from the target. An optical head including beam splitter, lenses and optical filters is also designed and implemented. The signal conditioner of the system includes pre- and post-amplifiers, comparator, opto-isolators and monostable. By using a 3MV/W reach-through structure avalanche photodiode and a wideband pre-amplifier, the pre-amplifier output reaches 15.9mV, resulting from the minimum detectable optical power. The APD temperature and as a result its responsivity is controlled by a thermoelectric controller unit. The start and stop signals from PIN and APD are led to the time-to-digital converter to count the round-trip time of the laser beam. The system is tested by a retro-reflector as a target for 30-1200m distances. The resolutions of the distance and velocity measurement are limited to 18.75mm and 1.2m/s, respectively. In the worst condition, the minimum reflected optical power is limited to about 5.3nW in 1.2km distance.

El objetivo de este estudio fue determinar la estructura de la Función Ejecutiva (FE) desde el dominio conductual derivado de las subescalas de padres y maestros del BrRiefEF (Behavior Rating Inventory of Executive Function) en adolescentes infractores con Trastorno Disocial de la Conducta (TDC) y un grupo control (no-TDC) del valle del Aburrá. La muestra fue de 128 adolescentes: 56 infractores con TDC y 72 no infractores no-TDC. Se realizó un análisis factorial con las puntuaciones de las subescalas del BrRiefEF. Se observó una estructura factorial de las conductas de la FE con un único factor en ambos grupos. A este factor se le denominó Sistema de Supervisión Conductual (SSC). El BrRiefEF evalúa un Sistema de Supervisión Conductual (SSC) que diferencia significativamente ambos grupos.

This paper presents a prototype of a 16-channel Time-to-Digital Converter (TDC) based on the coarse-fine architecture for a small animal Position Emission Tomography (PET) system, which achieves both a large measurement range and high precision. The coarse time stamp is provided by two 12-bit counters, and the duplication of hardware is intended to avoid metastability when the hit signal edge is close to the edge of the counter clock. The fine time stamp is realized with a tunable delay line, which is adjusted by a 32-stage Delay-Locked Loop (DLL) and provides submultiples of the counter clock period. The device has been designed and fabricated in a 180 nm CMOS process. With a 200 MHz system clock, the full-scale measurement range is 20. 48 μ s and the fine bin size is 156 ps. The test results show that the differential nonlinearity (DNL) is between −0.2 to ＋0.2 LSB, and the and integral nonlinearity (INL) is within the range of −0.5 to 0.2 LSB for all 16 channels. The one-shot time precision is better than 60 ps RMS. Power consumption of each channel is less than 8 mW. [ABSTRACT FROM AUTHOR]

A high-resolution time-to-digital converter (TDC) implemented with field programmable gate array (FPGA) based on delay wrapping and averaging is presented. The fundamental idea is to pass a single clock through a series of delay elements to generate multiple reference clocks with different phases for input time quantization. Due to periodicity, those phases will be equivalently wrapped within one reference clock period to achieve the required fine resolution. In practice, a hybrid delay matrix is created to significantly reduce the required number of delay cells. Multiple TDC cores are constructed for parallel measurements and then exquisite routing control and averaging are applied to smooth out the large quantization errors caused by the inhomogeneity of the TDC delay lines for both linearity and single-shot precision enhancement. To reduce the impact of temperature sensitivity, a cancellation circuit is created to substantially reduce the offset and confine the output difference within 2 LSB for the same input interval over the full operation temperature range of FPGA. With such a fine resolution of 2.5 ps, the integral nonlinearity is measured to be from merely −2.98 to 3.23 LSB and the corresponding rms resolution is 4.99–6.72 ps. The proposed TDC is tested to be fully functional over 0 °C–50 °C ambient temperature range with extremely low resolution variation. Its performance is even superior to many full-custom-designed TDCs. [ABSTRACT FROM AUTHOR]

A wide band fractional-N digital PLL which uses a high resolution 2-dimension gated-Vernier time-to-digital converter (TDC) with 5.2 ps resolution is presented. The quantization noise shaping of the TDC greatly improves the in-band phase noise. While, in the same time, the 2-dimension structure makes the digital PLL (DPLL) be able to process large phase errors almost without the influence of latency time. Combined with a high figure-of-merit (FOM) class-D digitally controlled oscillator (DCO) and digital ΣΔ quantization noise cancellation based least mean square (LMS) algorithm, the DPLL achieves -110dBc/Hz and -140dBc/Hz for in-band and 10 MHz-offset phase noise, respectively, with carrier frequency of 3.5 GHz and 1 MHz bandwidth. The digital PLL is simulated in a 65 nm CMOS process, consuming 11.2 mW from a 1.0 V supply. [ABSTRACT FROM AUTHOR]

This paper proposes a low-power complementary metal–oxide–semiconductor (CMOS) smart temperature sensor in order to obtain self-refresh control for low-power memory cells. The multiple-block system is composed of a temperature-to-pulse generator (TPG), a time-to-digital converter (TDC), and a frequency selector. A pulse-shrinking system with an inverter-based delay line is used for feedback topology in the TDC. A temperature-independent current reference is applied for temperature compensation in the ring-oscillator and delay line in the TPG. The small-size time-mode temperature sensor is designed using a 0.35- \mu \textm CMOS process. Six different digital outputs are obtained for temperature ranging between −40 °C and 100 °C. Measurement shows that the proposed temperature sensor operates with a power dissipation of 0.075~\mu \textW per sample and a die area of 0.08 mm2. The output frequency is shown to increase exponentially with variations in temperature, while the shrinking pulse in the TDC shows linear dependence on temperature. [ABSTRACT FROM PUBLISHER]

In this article, a three-level resolution Vernier delay line time-to-digital converter (TDC) was proposed. The proposed TDC core was based on the pseudo-differential digital architecture that made it insensitive to nMOS and pMOS transistor mismatches. It also employed a Vernier delay line (VDL) in conjunction with an asynchronous read-out circuitry. The time interval resolution was equal to the difference of delay between buffers of upper and lower chains. Then, via the extra chain included in the lower delay line, resolution was controlled and power consumption was reduced. This method led to high resolution and low power consumption. The measurement results of TDC showed a resolution of 4.5 ps, 12-bit output dynamic range, and integral nonlinearity of 1.5 least significant bits. This TDC achieved the consumption of 68.43 µW from 1.1-V supply. [ABSTRACT FROM AUTHOR]

Phase noise performance of ring oscillator based digital fractional-N phase-locked loops (FNPLLs) is severely compromised by conflicting bandwidth requirements to simultaneously suppress oscillator phase and quantization noise introduced by the time-to-digital converter (TDC), $\Delta \Sigma $ fractional divider, and digital-to-analog converter (DAC). As a consequence, their figure-of-merit (FoMJ) that quantifies the power–jitter tradeoff is at least 25 dB worse than their LC-oscillator-based FNPLL counterparts. This paper seeks to close this performance gap by extending PLL bandwidth (BW) using quantization noise cancellation techniques and by employing a dual-path digital loop filter to suppress the detrimental impact of DAC quantization noise. Fabricated in 65 nm CMOS process, the proposed FNPLL operates over a wide frequency range of 2.0–5.5 GHz using a modified extended range multi-modulus divider with seamless switching. The proposed digital FNPLL achieves 1.9 psrms integrated jitter while consuming only 4 mW at 5 GHz output. The measured in-band phase noise is better than −96 dBc/Hz at 1 MHz offset. The proposed FNPLL achieves wide BW up to 6 MHz using a 50 MHz reference and its FoMJ is −228.5 dB, which is the best among all reported ring-based FNPLLs. [ABSTRACT FROM PUBLISHER]

This paper presents the design of an all-digital delay-locked loop (ADDLL) with duty-cycle correction using reusable time-to-digital converter (TDC). The proposed ADDLL uses a reusable TDC for achieving a wide-operating frequency range. In addition, it achieves the frequency doubling output clock easily by changing the quantization interval. It is implemented in a 0.18-µm complementary metal-oxide semiconductor technology. This circuit corrects the duty cycle and synchronizes the input and output clocks in 10 clock cycles. The output duty cycle is corrected to 50 ± 1.5% as the input duty cycle ranges from 25% to 75%. The acceptable input frequency range is from 300 to 900 MHz without frequency doubling. The acceptable input frequency range is from 150 to 450 MHz when using frequency doubling. It dissipates 6.2 mW from a 1.8-V supply at 900 MHz. The peak-to-peak and RMS jitters at 900 MHz are 14 and 1.8 ps, respectively. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This brief describes a self-calibrated bang–bang phase detector that has been implemented in a delay-locked loop (DLL) stabilized time-to-digital converter for high-energy physics applications. A two-state architecture is proposed, with a dedicated calibration state that measures the internal static phase offset and compensates for this offset in the other measurement state. The calibration is transparent to the DLL, runs continuously to compensate for radiation induced drifts, and shows a measured static phase offset variation of only 0.5 ps over different samples. The circuit has been designed and processed in a 40-nm CMOS technology. [ABSTRACT FROM AUTHOR]

This study presents the design of wide‐area fractional order damping controller for low frequency inter‐area oscillations in Western Electricity Coordinating Council (WECC) system. The developed wide‐area damping control scheme is implemented in a decentralised manner by examining the entire system through decentralised identification at the level of each generator bus and FACTS devices in large‐scale system. The decentralised identification is done by applying n4sid (Subspace State Space System Identification) algorithm to the time‐domain simulated response of WECC system. The main features of the proposed approach are: (a) measurement‐based control which does not require complete model of WECC; (b) minimise the communicating signals required for damping controller and incorporate practical method of time‐delay compensator (TDC) design to reduce the effect of time‐varying delay. The performance of wide‐area control (WAC) scheme is tested on the practical WECC system and verified by non‐linear time‐domain simulation. The proposed decentralised WAC scheme is compared with local and centralised control scheme, which enhances the damping of inter‐area oscillation effectively compared to local control scheme and more reliable compared to centralised control scheme and its robustness is verified over a wide‐range of operating conditions. [ABSTRACT FROM AUTHOR]

The LinoSPAD camera system is a modular, compact and versatile time-resolved camera system, combining a linear 256 high fill factor pixel CMOS SPAD (single-photon avalanche diode) sensor with an FPGA (field-programmable gate array) and USB 3.0 transceiver board. This modularization permits the separate optimization or exchange of either the sensor front-end or the processing back-end, depending on the intended application, thus removing the traditional compromise between optimal SPAD technology on the one hand and time-stamping technology on the other hand. The FPGA firmware implements an array of 64 TDCs (time-to-digital converters) with histogram accumulators and a correction module to reduce non-linearities. Each TDC is capable of processing over 80 million photon detections per second and has an average timing resolution better than 50 ps. This article presents a complete and detailed characterization, covering all aspects of the system, from the SPAD array light sensitivity and noise to TDC linearity, from hardware/firmware/software co-design to signal processing, e.g., non-linearity correction, from power consumption to performance non-uniformity.

Background The clinical efficacy of a compression application has been often limited to the assessment of the change in limb volume, change in clinical symptoms (i.e., wound size, pain, range of motion, incidence of cellulitis), or vascular hemodynamics of the whole limb. Assessing compression-related biophysical changes of a localized area, such as around a wound, or in an area outside of an extremity cannot be objectively assessed by these measurements. Tissue dielectric constant (TDC) values, which provide a measure of the local tissue water (LTW) content, offer an alternative method to document variation in the LTW content of the skin in a specific location. The goals of the present research were (1) to characterize TDC values, expressed as percentage tissue water, from multiple areas along the medial aspect of the lower leg of healthy volunteers and (2) to explore the potential utilization of the TDC values to assess change in tissue water content in a localized area following compression applications. Methods TDC was measured at 10, 20, 30, and 40 cm proximal to the medial malleolus on the medial aspect of the right leg of 18 young adult healthy women with an age range of 18-23 years and a body mass index of 18.7 to 30.7kg/m 2. . TDC was measured at baseline and after 10 minutes of exercise with compression in place on three separate days during which three different compression applications were assessed: a longitudinal elastic stockinette, a two-layer cohesive compression kit, and a combination of the two. Leg circumferences and compression-related interface pressures were also measured. Results Test-Retest Reliability of circumferential measurements and TDC values evaluated using Intraclass correlation coefficient (ICC 3,1 ) revealed excellent and moderate-to-good reliability, respectively. Analysis of TDC values along the length of the limb using Friedman's test, revealed a small but statistically significant overall difference among baseline TDC values attributable to a smaller value at 40 cm. The largest difference in cumulative average was 7.7% which occurred between 20 and 40 cm, with all other differences between locations less than 1%. No significant differences between the compression applications were observed. Conclusion  The present findings demonstrate the utility of TDC measurements as a modality to assess compression-related changes in the legs of healthy women as a foundation for their potential use in assessing outcomes of compression treatments for persons with lower extremity edema or lymphedema. The absence of a significant change in TDC values in these healthy non-edematous conditions and the demonstrated reliability of the TDC measurements on three different days provides further support for the utility of such applications of TDC measurements. The extension to patients with lower extremity edema or lymphedema needs to be evaluated., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2023, Ehmann et al.)

The present study aimed to investigate the histological changes caused by neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC), and to demonstrate the use of time‑density curves (TDCs) of dynamic contrast‑enhanced computed tomography (CECT) for determination of the histological therapeutic effects of NAC for PDAC. A total of 96 patients with PDAC were examined; 46 underwent NAC (NAC group) and 50 did not undergo NAC (non‑NAC group). Based on histological therapeutic effect and using the area of residual tumor (ART) grading system, the NAC group was divided into low‑responders and high‑responders. Histological analysis was used to evaluate the densities of cancer cells, cancer‑associated fibroblasts (CAFs), microvessels and stromal collagen fibers in the NAC and non‑NAC groups. Radiological analysis was used to evaluate the TDCs of three slopes of the NAC group, namely slopes between the non‑contrast and arterial phases (δ1 and δ1'), between the arterial and portal phases (δ2 and δ2'), and between the portal and equilibrium phases (δ3 and δ3'). δ1‑δ3 were before NAC, whereas δ1'‑δ3' were after NAC. Changes in δ1, δ2 and δ3 before and after NAC were denoted as δδ1 (=δ1'‑δ1), δδ2 (=δ2'‑δ2) and δδ3 (=δ3'‑δ3). ART grading system, histological examination and radiological examination data were also statistically analyzed. Histological examination revealed a significant decrease in cancer cells and CAFs, and a significant increase in stromal collagen fibers due to NAC (P<0.01). Radiological examination revealed that δ1' was significantly higher than δ1 in low‑responders (P<0.05), whereas δ2' was significantly lower than δ2 in high‑responders (P<0.01). δδ2 was significantly lower and δδ3 was significantly higher in high‑responders than in low‑responders (P<0.01 and P<0.05, respectively). Receiver operating characteristic curve showed that δδ2 and δδ3 were effective indicators of the histological therapeutic effect of NAC. In conclusion, the TDC of dynamic CECT may be useful for determining the histological therapeutic effect of NAC for PDAC.

The SeaQuest experiment (Fermilab E906) detects pairs of energetic μ + and μ − produced in 120 GeV/c proton–nucleon interactions in a high rate environment. The trigger system consists of several arrays of scintillator hodoscopes and a set of field-programmable gate array (FPGA) based VMEbus modules. Signals from up to 96 channels of hodoscope are digitized by each FPGA with a 1-ns resolution using the time-to-digital convertor (TDC) firmware. The delay of the TDC output can be adjusted channel-by-channel in 1-ns step and then re-aligned with the beam RF clock. The hit pattern on the hodoscope planes is then examined against pre-determined trigger matrices to identify candidate muon tracks. Information on the candidate tracks is sent to the 2nd-level FPGA-based track correlator to find candidate di-muon events. The design and implementation of the FPGA-based trigger system for SeaQuest experiment are presented. [ABSTRACT FROM AUTHOR]