Timing Mismatch Research Articles

Katekese Untuk Membangkitkan Antusias dan Keaktifan OMK Paroki Maria Bunda Karmel, Probolinggo

This paper departs from the author's anxiety to see the lack of enthusiasm and activeness of young people, especially the MBK parish OMK organization, Probolinggo in participating in church activities. The author collects data from the database of parishioners (the total number of young people), answers to questions on google forms, and the author's experience when he was one of the supervisors of OMK, Probolinggo. All the data collected were then analyzed using a qualitative-descriptive method. The author will show the results of the research based on the data that has been obtained through the MBK parish, various answers from young members of OMK, and the author's own observations. Through these data, it was found that there were gaps within the organization itself, and the time mismatch of existing activities with their respective statuses and activities. Not yet compact, lack of enthusiasm, and the activeness of OMK members is what then makes many young people in MBK parish not interested in becoming OMK members. Based on the formulation of the existing problems and the findings, it can be concluded that good, in-depth, and sustainable catechesis is very influential for young people to create cohesiveness in the OMK organization, so that they respect each other, relate closely, and are full of brotherhood with one another.

Towards circular manufacturing systems implementation: A complex adaptive systems perspective using modelling and simulation as a quantitative analysis tool

A transition towards circular manufacturing systems (CMS) has brought awareness of untapped economic and environmental benefits for the manufacturing industry. Conventional manufacturing systems already present a high level of complexity in terms of physical flows of materials and products as well as information and financial flows linked to them. Closing the loop of materials and products through multiple lifecycles, as proposed in CMS, increases this complexity manifold. To support practitioners in implementing CMS through enhanced decision-making, this research studies CMS from a complex adaptive systems (CAS) perspective and proposes to exploit methods and tools used in the study of CAS to characterise, model and analyse CMS. By viewing CMS as CAS composed of autonomous, interacting agents, this research proposes a multi-method model architecture for modelling and simulating CMS. The different CMS stakeholders are modelled individually as autonomous agents by integrating agent-based, discrete-event, and/or system dynamics modules within each agent to capture their diverse and heterogeneous nature. The applicability of the proposed multi-method approach is illustrated through a case study of a white goods manufacturing company implementing CMS in practice. This case study shows the relevance and feasibility of the proposed multi-method approach as a decision support tool for the systemic exploration and quantification of CMS. It also shows how a transition towards CMS necessitates a lifecycle approach in terms of costs, revenues and environmental impacts to identify hotspots and, therefore, design circular systems that are viable in both economic and environmental terms. In fact, the analyses of the simulation results indicate how decisions in terms of business models, product design, and supply chain might affect the CMS performance of the case company. For instance, implementing a service-based model led to a high number of usecycles (on average six usecycles per washing machine), which, in turn, led to high lifecycle costs and emissions due to more frequent transportation and recovery operations. Similarly, the deployment of long-lasting washing machines, which is a core principle of CMS, led to high manufacturing costs. Due to the high initial costs and a time mismatch between revenues and costs in the service-based model, it required a longer time for the company to reach the break-even point (approximately 23 months). Overall, the case study shows that multi-method simulation modelling can provide decision-making support for a successful implementation of CMS.

Technical and economic evaluation of a liquid air energy storage system with air precooling for compressor inlet

The intensification of carbon emissions and the energy crisis have made the safe and reliable application of renewable energy in the energy supply system significantly urgent. Liquid air energy storage (LAES) system is an effective means to solve the time and space mismatch between energy supply and demand. The LAES has the advantages of no geographical restrictions, high energy storage density and flexible operation, making it available to integrate with other industrial processes. In traditional LAES, the heat generated in the compression process is used to supplement the heat in the expansion process, and the excess heat is dissipated. In this study, the compressor inlet air is cooled by absorption refrigeration cycle to avoid excess compression heat, which reduces the power consumption of the compressor and improves the efficiency of the system. The sensitivity analysis of the ambient temperature and the compressor stages on the system efficiency is performed. Furthermore, a comparative analysis between the absorption refrigeration cycle driven by the waste heat and the compression refrigeration cycle driven by electricity for air precooling of the compressor inlet was carried out, and the system round-trip efficiency, exergy efficiency and initial investment cost was selected as indicators for system evaluation.

Use of a smartphone application for self-reporting in small-scale fisheries: Lessons learned during a fishing closure in the western Baltic Sea

There is a lack of data on the experience of the use of mobile devices in commercial small-scale fisheries but which are important to evaluate the suitability of these approaches for fisheries monitoring. In February and March 2018, the German Baltic small-scale fishery used a smartphone application for self-reporting of fishing activities to demonstrate compliance with the terms of a fishing closure of cod, which prohibited to fish deeper than 20 m. A total of 1618 trips and 7972 gear activities from 107 vessels were identified and categorized. Data review showed that not all data could be used directly due to operating or technical errors (e.g. mismatch in time and space of self-reported and actual gear activities and missing records on geographical positions). By editing during data evaluation, the proportion of useable trips and gear activities increased from 67 to 78% and from 29 to 69%, respectively. These data provided new insights into the activities of small-scale fishing vessels (<12 m), especially of the data-poor segment of vessels smaller than 8 m (e.g. for gillnets: mean net length of 664 m ± 538 SD, mean soak time of 30 h ± 12.9 SD, mean trip duration of 2.9 h ± 1.6 SD). Due to the high spatio-temporal resolution, the fishers could demonstrate compliance with the closure, with 99% of all recorded gear activities performed in areas shallower than 20 m. Based on the fast and short operation at sea observed, recording intervals of max. 1 min are advisable for small-scale vessels. Potential suggested improvements involve training of fishers, an independent GPS sensor, a remote control and tailored tools for data analysis to properly address future developments of smartphone applications for the use in data collection in small-scale fisheries.

An identification of the tolerable time-interleaved analog-to-digital converter timing mismatch level in high-speed orthogonal frequency division multiplexing systems

&lt;span&gt;High-speed Terahertz communication systems has recently employed orthogonal frequency division multiplexing approach as it provides high spectral efficiency and avoids inter-symbol interference caused by dispersive channels. Such high-speed systems require extremely high-sampling &lt;br /&gt; time-interleaved analog-to-digital converters at the receiver. However, timing mismatch of time-interleaved analog-to-digital converters significantly causes system performance degradation. In this paper, to avoid such performance degradation induced by timing mismatch, we theoretically determine maximum tolerable mismatch levels for orthogonal frequency division multiplexing communication systems. To obtain these levels, we first propose an analytical method to derive the bit error rate formula for quadrature and pulse amplitude modulations in Rayleigh fading channels, assuming binary reflected gray code (BRGC) mapping. Further, from the derived bit error rate (BER) expressions, we reveal a threshold of timing mismatch level for which error floors produced by the mismatch will be smaller than a given BER. Simulation results demonstrate that if we preserve mismatch level smaller than 25% of this obtained threshold, the BER performance degradation is smaller than 0.5 dB as compared to the case without timing mismatch.&lt;/span&gt;

Outcomes of Patients Bridged to Heart Transplantation with ECMO Following the UNOS Allocation Policy Change

<h3>Purpose</h3> ECMO utilization has been associated with considerable morbidity and mortality post heart transplant (HT). Heart allocation policy changes prioritize ECMO as highest urgency. Short-term outcomes have improved following this policy change. We sought to assess longer term outcomes in patients bridged with ECMO to HT. <h3>Methods</h3> Patients bridged to HT with ECMO were identified from the UNOS Registry two years before (n=36) and after (n=266) the heart allocation policy change (10/18/2018). Baseline characteristics were compared via standard statistical analysis. Survival analysis was censored at 1-year using Kaplan-Meier analysis. Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time, and HLA mismatch) was performed. <h3>Results</h3> Since the policy change, there has been a significant increase in ECMO utilization. Following the policy change, HT recipients bridged with ECMO were more likely to be male (74.8% vs 55.6%, p=0.015) with longer ischemic times (p<0.001). Notably, waitlist time was significantly lower following the policy change (5.0 days vs 13.5 days, p=0.001). Survival at 1 year was significantly improved post-policy change (Figure, p=0.0097). The policy change was associated with decreased mortality with HR 0.39 (0.18-0.82, p=0.013) and HR 0.32 (0.13-0.79, p=0.013) following adjustment. <h3>Conclusion</h3> Following heart allocation policy changes, heart transplant survival has improved in recipients bridged with ECMO with associated reduction in waitlist time. ECMO utilization has significantly increased since policy implementation. Further study is warranted to better understand the contributing factors.

Impact of the 2018 UNOS Heart Allocation Policy Change on Post-Transplant Outcomes: Intermediate Term Analysis

<h3>Purpose</h3> The 2018 UNOS heart allocation policy intended to prioritize recipients of highest acuity in addition to broader geographic sharing. As such, 6 tiers were developed from 3 to try and account for this heterogeneous population. We sought to assess the impact of this change on post-transplant outcomes in the highest urgency statuses (Status 1-3 vs prior Status 1A). <h3>Methods</h3> 7710 patients were identified in the UNOS registry that were either prior status 1A (n=3764) or status 1-3 in the current system (n=3946) during a 2-year period immediately prior and following the policy change. Comparisons between cohorts were assessed using standard statistical methods, survival analysis was censored at 1-year using the Kaplan-Meier method, and multivariate Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time & HLA mismatch) were performed. <h3>Results</h3> Waitlist times were significantly shorter following the policy change for the status 1-3 group (21.0 vs 54.5 days, p<0.001). With the current policy, recipients were less likely to be female (24.1% vs 29.1%, p<0.001). Additionally, recipients were more likely to have longer ischemic times (p<0.001), to be supported with intraaortic ballon pumps (IABP) (p<0.001) as well as elevated pulmonary arterial pressures (p<0.001). Notably, recipients were less likely to be supported with an LVAD (35.8% vs 42.7%, p<0.001). There was no difference in survival (p=0.144). Unadjusted analysis demonstrated HR 1.13 (CI 0.96-1.32) and following adjustment HR 1.03 (CI 0.87-1.23). <h3>Conclusion</h3> The new UNOS heart allocation policy change did not adversely affect post-transplant outcomes in this intermediate term analysis. In the highest acuity statuses, waitlist time decreased. However, further study is warranted to better understand implications and perhaps unintended consequences for gender as well as change in therapeutic strategies (increased IABPs, less VADs).

Rethinking the Impact of Donor eGFR on Heart Transplant Outcomes

<h3>Purpose</h3> With limited evidence regarding the effect of donor renal function on outcomes post-cardiac transplant, this study sought to determine if donor eGFR has an impact on post-transplant outcomes in patients undergoing heart transplantation. <h3>Methods</h3> The UNOS Registry was queried for all cardiac transplant recipients and stratified into two groups by donor eGFR: eGFR >60 (high) or eGFR <60 (low). Baseline characteristics were compared via standard statistical analysis. Survival analysis was censored at 5-years using Kaplan-Meier analysis, and Cox proportional regression analysis was adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time, and HLA mismatch. <h3>Results</h3> 37205 subjects were grouped to high eGFR and 14892 subjects to low eGFR. Donors with low eGFR were more likely to be older (31.3 vs 32.9, p< 0.001). Recipients were more likely to be older (54.7 years vs 52.4, p<0.001) and male (77.2% vs 74.3% p<0.001). Compared to the high eGFR group, heart transplant recipients from donors in the low eGFR group showed no significant difference in mortality (p= 0.30) or causes of death (p= 0.054). Unadjusted analysis showed a hazard ratio of 0.978 (0.938-1.019 95% CI). Following adjustment, HR was 0.992 (0.948-1.039 95% CI). <h3>Conclusion</h3> Our study presents preliminary data to demonstrate cardiac donors with low eGFR have similar outcomes and life expectancy up to 60 months as compared to donors with high eGFR. With further research, there is an opportunity to expand the eligibility requirements for donor heart procurement and thereby increase the potential donor pool.

Heart Transplant Outcomes with Donation After Cardiac Death: UNOS Registry Analysis

<h3>Purpose</h3> Limitations in organ donation have led to approaches to expand the existing donor pool. Donation after cardiac death (DCD) has continued to increase after efforts led by the United Kingdom and Australia. We sought to describe the United States experience. <h3>Methods</h3> 5153 heart transplant (HT) recipients were identified in the UNOS Registry between 1/2019 and 6/2021, of which 229 were DCD recipients. HT recipients were grouped by DCD status or donation after brain death (DBD). Comparisons between groups were assessed using standard statistical methods, survival analysis was censored at 12-months via the Kaplan-Meier method. Multivariate Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time & HLA mismatch) were performed. <h3>Results</h3> Recipients of DCD donors were of lower UNOS status (p<0.001), increased VAD use (p=0.01), and less dialysis (p=0.011). Additionally, DCD donor recipients had longer wait times (46.0 vs 30.0d, p=0.007), longer ischemic times (p<0.001) but younger donors (29.8 vs 23.4y, p<0.001). There was no difference in 1-month or 1-year survival by donor type (p=0.720). Unadjusted analysis demonstrated HR 0.91 (0.52-1.57) and following adjustment HR 0.88 (0.48-1.61). <h3>Conclusion</h3> Short-term survival of DCD donors is similar to DBD donors in this UNOS Registry analysis. DCD donor use has potential to expand the donor pool. Further study is warranted to assess longer term outcomes as well as best strategies for donation.

Heart Transplant Outcomes by Donor HCV NAT Status: Intermediate Analysis

<h3>Purpose</h3> Donor hearts are a limited resource and inclusion of non-traditional donors such as those with hepatitis C (HCV) may help to increase transplantation rates. We sought to compare post-heart transplant outcomes of patients who received hearts from either HCV NAT positive or negative donors. <h3>Methods</h3> Recipients were identified from the UNOS Registry and stratified by donor HCV NAT status. Comparisons between cohorts were assessed using standard statistical methods, survival analysis was censored at 36 months using the Kaplan-Meier method, and multivariate Cox proportional hazard regression analysis (adjusted for age, sex, diabetes, race, ischemic time, dialysis, life support, waiting time and HLA mismatch. <h3>Results</h3> 18,828 recipients were identified of which 849 and 17,979 received HCV NAT positive (HCV+) and HCV NAT negative (HCV-) donors, respectively. HCV+ recipients were older (55.2 vs 53.5, p<0.001), male (77.4% vs 73.3%, p=0.008), and Caucasian (66.1% vs 62.1%, p=0.023). HCV+ recipients also had higher incidence of pre-transplant cardiac surgery (83.3% vs 77.9%, p<0.001), life support use (20.8% vs 16.5%, p<0.001), older donors (34.2 vs 32.1y, p<0.001), longer ischemic time (p<0.001), and with worse renal function (Cr 1.5 vs 1.4, p = 0.001). Notably, there was no difference in waitlist time. Recipients of HCV- donors were more likely to have diabetes (71.1% vs 66.4%, p = 0.004) and higher waitlist status (p<0.001). There was no difference in overall mortality between the two groups with cardiovascular (27.1% vs 26.4%) or non-cardiovascular (72.9% vs 73.6%, p=0.90) death. Unadjusted analysis demonstrated HR 0.98 (CI 0.78-1.22) and following adjustment HR 0.99 (0.78-1.24). <h3>Conclusion</h3> Utilization of HCV NAT positive donor hearts presents as a safe and effective way to expand the donor pool with no survival difference in this intermediate analysis. Further study is needed to understand the long-term outcomes of this population, particularly in the setting of widely available curative therapies.

Design of Improved Nonlinear Active Disturbance Rejection Controller for Hybrid Microgrid With Communication Delay

In this paper, an improved nonlinear active disturbance rejection control (INLADRC) approach is proposed for load frequency control of hybrid microgrid with communication delay. The INLADRC technique includes a nonlinear extended state observer (NESO) to estimate the system states and a nonlinear controller for the cancellation of the generalized disturbance acting on system. The effect of communication delay in the hybrid microgrid system is alleviated via the incorporation of an auxiliary structure that also restores the synchronization between the inputs of NESO. The efficacy of the proposed approach is validated via a comprehensive analysis, wherein step variations as well as random perturbations are considered in solar power, wind power and load demand. Further, the performance of proposed technique is also corroborated via consideration of real time solar and wind data. Moreover, the robustness of INLADRC technique is investigated in presence of parametric uncertainty, model-plant mismatch, delay time mismatch as well as varying communication delay. An extensive comparative analysis is a testimony to the effectiveness of INLADRC approach.

Research on the Dynamic Monitoring Technology of Road Subgrades with Time-Lapse Full-Coverage 3D Ground Penetrating Radar (GPR)

Road safety is important for the rapid development of the economy and society. Thus, it is of great significance to monitor the dynamic changing processes of road diseases, such as cavities, to provide a basis for the daily maintenance of roads and prevent any possible car accidents. The ground penetrating radar (GPR) technology is widely used in road disease detection due to its advantages of nondestructiveness, rapidness, and high resolution. Traditionally, one-time 2D GPR detection cannot obtain the 3D spatial changes of subgrades. Thus, we developed a road subgrade monitoring method based on the time-lapse full-coverage (TLFC) 3D GPR technique by focusing on solving the key problems of time and spatial position mismatches in experimental data. Moreover, we used the time zero consistency correction, 3D data combination, and spatial position matching methods, as they greatly improve the 3D imaging quality of underground spaces. Finally, the time-lapse attribute analysis method was used in the TLFC 3D GPR data to obtain detailed characteristics and an overall rule of the dynamic subgrade change. Overall, this research proves that TLFC 3D GPR is an optimal choice for road subgrade monitoring.

Integrated Volt/Var Control Method for Voltage Regulation and Voltage Unbalance Reduction in Active Distribution Networks

The emergence of distributed generation such as solar systems has introduced new challenges in distribution networks that are becoming more apparent with increasing penetration levels. The time mismatch between peak load and peak generation can make voltage levels in distribution networks swing towards extreme limits during a day. Distribution network service providers are struggling to cater for new distributed generation installations while ensuring that the quality of steady state supply voltage meets stipulated requirements. The segregation between medium and low voltage networks in control strategies may result in unnecessary or worse, opposing control actions leading to voltage issues and control on one side of the distribution network influencing the other. By developing an efficient volt/var control method, the steady state voltage level and voltage unbalance in a comprehensive distribution network can be controlled simultaneously. This paper analyses voltage issues and volt/var control in medium and low voltage networks as a whole, unabridged problem. This paper proposes a pragmatic and effective volt/var control method that addresses voltage regulation and voltage unbalance simultaneously using existing infrastructure. The proposed control method is implemented on three types of representative Australian distribution networks and results obtained demonstrate that the proposed volt/var control can simultaneously manage voltage level and voltage unbalance whilst reducing the number of tap change operations and maximizing solar penetration.

A time-interleaved ADC calibration technique for spectrum monitoring applications

A fully background estimation and calibration technique to reduce the spur powers caused by time-interleaved ADC architecture is presented. The estimations of mismatches are succeeded using easily generated calibration signals. The implementation details for the mismatch estimations and calibrations are provided using a 2.8 GSPS ADC and a FPGA device. Continuous operation of the spectrum monitoring applications is allowed while the mismatch estimation and the calibration process in progress. The offset mismatch calibration is realized using an adder circuit at the background and more than 10 dB spur power reduction is obtained from the proposed method. A digital multiplier circuit is used to realize the gain calibration. The timing skew calibration is fulfilled by the addition of a small offset to the DDS (Direct Digital Synthesizer) phase offset of DDC (Digital Down Converter). It is possible to get more than 6 dB power reduction at some critical spur signals after the application of proposed timing mismatch calibration technique when a single tone sine wave input is applied.

A 2.4–8 GHz Phase Rotator Delay-Locked Loop Using Cascading Structure for Direct Input–Output Phase Detection

This paper presents a phase rotator (PR)-based delay-locked loop (DLL) for a dynamic random-access memory interface in 28-nm CMOS technology. A direct input-output comparison using a sub-sampling technique reduces the effect of a timing mismatch of a replica delay line for synchronizing an input clock and output strobe clock. A divided clock samples the input clock for phase alignment. A 4-b analog-to-digital converter was used for input phase acquisition. The output phase is aligned with respect to the sampling clock phase using a bang-bang phase detector. Two DLLs for the input-output synchronization are implemented in a cascade structure, and the loop delay of the replica delay line is considerably reduced. In the proposed DLL, a PR delay line using an 8-phase clock generator is adopted for linearity to reduce the phase difference of the phase interpolation from π/2 to π/4. The resolution of the PR-DLL is 7-b of 2π, which consists of a 3-b coarse and a 4-b fine control. The DLL operates from 2.4 to 8 GHz, and the power dissipation at the maximum input frequency is 20.2 mW. The measured clock root mean square jitter was 1.68 ps. According to the simulation results, the phase mismatch between the input and output clocks was reduced by 80.5%.

Calibration of gain and timing mismatch for TI-ADCs with signals in all Nyquist zones using adaptive noise canceller

This paper presents a novel all-digital background calibration technique for general Time-Interleaved Analog-to-Digital Converters (TIADCs). Calibration of gain and timing mismatch of TIADCs using the estimation technique is designed based on the principle of the Adaptive Noise Canceller (ANC). In this ANC, there are two stages in gain, timing mismatch estimation in which a cascade structure of the correction and estimation is proposed to guarantee that our calibration achieves high performance. Besides the first Nyquit zone, the input signal at different Nyquist zones is also experimented. It is shown through the result that our calibration performs excellently on all chosen Nyquist zones. It achieves the SNDR (Signal to Noise Ratio) and SFDR (Spurious Free Dynamic Range) improvement of 19dB and 49dB, respectively. Moreover, the synthesized design with hardware co-simulation carried on the Xilinx Kintex-7 field-programmable gate array (FPGA) platform consumes only 7.36 % of the hardware resources of the FPGA chip and reduces the mismatch tone level to -87 dB. In addition, our convergence speed of SNDR during calibration is approximately 1/3 others.

Sensitivities to Chill Durations and No-Chill Temperatures Regulating Eclosion Responses Differ Between Rhagoletis zephyria (Diptera: Tephritidae) and its Braconid Parasitoids (Hymenoptera: Braconidae).

Seasonal temperatures select for eclosion timing of temperate insects and their parasitoids. In western North America, the fruit fly Rhagoletis zephyria Snow (Diptera: Tephritidae) is parasitized by the hymenopterous wasps Utetes lectoides (Gahan), an egg parasite, and Opius downesi Gahan, a larval parasite (both Braconidae). Eclosion of wasps should be timed with the presence of susceptible fly stages, but reports indicate U. lectoides ecloses in the absence of flies under no-chill conditions. Based on this, we tested the hypotheses that chill durations and no-chill temperatures both differentially regulate eclosion times of R. zephyria and its parasitic wasps. When fly puparia were chilled at ~3°C for 130-180 d, U. lectoides and O. downesi always eclosed on average later than flies. However, after 180-d chill, flies eclosed on average earlier than after 130- and 150-d chill, whereas eclosion times of U. lectoides and O. downesi were less or not affected by chill duration. When fly puparia were exposed to 20-22°C (no chill), U. lectoides eclosed before flies, with 88.9% of U. lectoides versus only 0.61% of flies eclosing. Taken together, findings show that eclosion times of flies are more sensitive to changes in chill duration than those of wasps. Flies are less sensitive than wasps to no-chill in that most flies do not respond by eclosing after no-chill while most wasps do. Our results suggest that shorter winters and longer summers due to climate change could cause mismatches in eclosion times of flies and wasps, with potentially significant evolutionary consequences.

Finite time thermodynamics analysis and research of pulsating heat pipe cold storage device

Phase change energy storage technology can effectively solve the energy mismatch in space and time. There are many disadvantages of phase change materials (PCMs), such as high supercooling, phase separation and poor heat transfer performance. As a new type of heat exchange structure, pulsating heat pipe has the advantages of simple structure, high heat transfer coefficient and good economic behavior. The system efficiency can be greatly improved by using pulsating heat pipe combined with cold storage technology. A set of pulsating heat pipe type cold storage device is developed, the finite time thermodynamic analysis is carried out, and the correlation between heat pipe efficiency and power is established. The three-dimensional physical model of pulsating heat pipe is simulated and verified by experiments. The experimental results show that in the cold storage stage, with the increase of the filling rate, the greater the pressure is, the better the heat transfer effect is; in the cold release stage, with the decrease of the filling rate, the smaller the pressure is, the better the heat transfer effect is.

Fully Digital On-Chip Wideband Background Calibration for Channel Mismatches in Time-Interleaved Time-Based ADCs

This letter presents a fully integrated on-chip digital mismatch compensation system for time-based time-interleaved (TI) data converters. The proposed digital compensation features blind calibration of gain, offset, and timing mismatches. The implemented system uses time-based sampling clock mismatch detection, achieving convergence within 32K samples, which is on par with analog-assisted background methods. A specialized filter structure compensates for timing mismatches of magnitude up to 0.21 of the sampling period, nearly triple the range of other published digital compensation methods, and is effective for input signals up to 0.92 Nyquist bandwidth. The on-chip digital correction achieves suppression of all mismatch tones to levels below −60 dBc while running fully in the background. The operation is demonstrated with an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> TI 2-GS/s analog-to-digital converter (ADC) prototype chip implemented in a 28-nm CMOS process.

On the Compensation of Timing Mismatch in Two-Channel Time-Interleaved ADCs: Strategies and a Novel Parallel Compensation Structure

On the Compensation of Timing Mismatch in Two-Channel Time-Interleaved ADCs: Strategies and a Novel Parallel Compensation Structure