News Item
Optics
Jeffrey Moses, Shu-Wei Huang
Summary: Coherent multi-octave mid-infrared waveforms can be generated and manipulated using cascaded intrapulse difference-frequency generation, providing absolute phase control and expanding the techniques available for arbitrary light-wave control.
Article
Multidisciplinary Sciences
Milena Capiglioni, Federico Turco, Roland Wiest, Claus Kiefer
Summary: Extracting quantitative information of neuronal signals through non-invasive imaging is crucial for understanding brain function and pathology. This study simulated and analyzed the response of three spin-lock preparations to field inhomogeneities and found that the composite spin-lock preparation is more robust against field variations. They also tested its capability to recover spectral components of a composite signal.
SCIENTIFIC REPORTS
(2022)
Article
Computer Science, Information Systems
Mohsen Bayat, Arman Farhang
Summary: In this letter, we propose timing offset (TO) and carrier frequency offset (CFO) estimators for orthogonal time frequency space modulation (OTFS). The proposed estimators do not require any additional training overheads and utilize the periodic properties of the pilot signal to achieve synchronization. The TO estimator searches for a periodic sequence in delay and time dimensions to determine the start of each OTFS block, while the CFO is estimated by finding the mean of the angles of a two-dimensional correlation function. The channel's multipath diversity is leveraged to improve estimation accuracy.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Xinwei Du, Tianyu Song, Yan Li, Ming-Wei Wu, Pooi-Yuen Kam
Summary: Coherent orthogonal frequency-division multiplexing (OFDM) is a key technique for wireless and optical communications, with accurate synchronization being the main challenge. A joint maximum likelihood (ML) estimator is proposed for coherent optical OFDM (CO-OFDM) to address this issue, utilizing replica computation and matched-filtering in the frequency domain, as well as a simpler sequential approach.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Yunliang Ren, Caiqing Luo, Ibrahim Sitiwaldi
Summary: We investigate Schwinger pair production in combined electric fields using quantum field theoretical simulations, where static and oscillating electric fields are finitely extended and spatially separated. We find that the pair production can be dynamically assisted until the two fields are separated much farther than one Compton length. We show the signature of dynamical assistance, based on the position-based production rate, in the position of both static and oscillating fields. Moreover, we investigate the impact of spatial width on dynamical assistance and show that the production rate is suppressed when the width of either field exceeds one Compton length and the potential heights are constant.
Article
Engineering, Electrical & Electronic
Cristina RuedaSabater, Alejandro Rodriguez-Collado, Yolanda Larriba
Summary: This paper introduces a novel signal decomposition method to address the complexity of parameter adjustment and noise limitations in simulating oscillatory systems. The method demonstrates practical utility in analyzing signals in neuroscience.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2021)
Article
Computer Science, Information Systems
Dong-Woo Lim, Kyu-Min Kang
Summary: In this study, a robust LoRa modulation scheme is proposed to mitigate demodulation errors caused by residual carrier frequency offset (CFO). The asymptotic performance of the proposed scheme was also analyzed to provide useful insights. Numerical results confirm the performance analysis and advantages of the proposed scheme.
IEEE INTERNET OF THINGS JOURNAL
(2023)
Article
Chemistry, Analytical
Yanjie Xu, Chunyang Wang, Guimei Zheng, Ming Tan
Summary: The beam pattern of frequency diversity array (FDA) radar has a range-angle two-dimensional degree of freedom, which brings a new approach to anti-jamming of radars. The conventional linearly frequency-biased FDA radar has a range-angle-coupled and time-varying beam pattern, but adding nonlinear frequency bias among the array elements can eliminate this coupling property while still maintaining better beam performance. In this paper, a decoupled and time-invariant beam direction map is obtained using the FDA-multi-input-multi-output (FDA-MIMO) radar scheme, and a sharp pencil-shaped main sphere beam pattern with range-angle dependence is achieved using a linear frequency offset scheme weighted by a Chebyshev window. The anti-interference performance of the proposed method is verified in an experiment.
Article
Engineering, Multidisciplinary
Yuqi Huang, Dominique H. Li, Haoyi Niu, Donatello Conte
Summary: The approach based on computer vision and machine learning can successfully identify two-phase flow with complex flow patterns in oscillatory conditions, with a high accuracy rate of 94% using a Bayesian Network classifier. The method is not only useful for validating numerical simulation results, but also has wide applications in visualizing multiphase flow, especially in the basic research of heat transfer systems.
Article
Optics
Nicolas Bourbeau Hebert, Sarah K. Scholten, Ashby P. Hilton, Rachel F. Offer, Christopher Perrella, Andre N. Luiten
Summary: Frequency combs are essential for optical clocks, but non-orthogonality between control loops limits control bandwidth and increases optical phase noise. Orthogonalizing the feedback loops can reduce noise and improve performance of combs stabilized to optical frequency standards.
Article
Multidisciplinary Sciences
Domenica Veniero, Joachim Gross, Stephanie Morand, Felix Duecker, Alexander T. Sack, Gregor Thut
Summary: The activation of the Frontal Eye Fields can shape visual cortex activity and perception through mechanisms of oscillatory realignment at the beta frequency.
NATURE COMMUNICATIONS
(2021)
Article
Neurosciences
Jason Samaha, Michael X. Cohen
Summary: Oscillatory neural dynamics are non-stationary and require methods capable of quantifying time-resolved changes in oscillatory activity. Frequency sliding, a method introduced to estimate the instantaneous frequency of oscillatory activity, systematically underestimates the true frequency in the presence of 1/f activity, with the magnitude of underestimation correlated with the steepness of the slope. The impact of slope on frequency estimates interacts with oscillation amplitude and analysis parameters, suggesting careful consideration of these factors when interpreting estimates obtained via frequency sliding.
Article
Engineering, Multidisciplinary
J. K. Jochum, A. Hecht, O. Soltwedel, C. Fuchs, J. Frank, E. Faulhaber, J. C. Leiner, C. Pfleiderer, C. Franz
Summary: This paper provides a comprehensive technical detail of the setup of resonant circuits at the longitudinal resonant spin-echo spectrometer RESEDA, demonstrating their capability to function at high frequencies and extract dynamical excitations.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Xiaobo Zeng, Huiling Ren, Mengfan Fu, Hexun Jiang, Lilin Yi, Weisheng Hu, Qunbi Zhuge
Summary: This paper proposes an optical frequency comb (OFC) based coherent architecture for high-capacity and wavelength division multiplexing (WDM) transmission in data centers, achieving large frequency offset (FO) tolerance. Extensive simulations and experiments verify the performance of the system.
Article
Telecommunications
Liguo Weng, Yanghui Zhang, Yong Yang, Min Fang, Zelong Yu
Summary: The concept of electricity Internet of Things (eIoT) has been proposed to assist the monitoring and inspection of power transmission line state and optimize asset utilization. Drones are introduced into the eIoT for fast inspection and data collection, acting as central communication control points to serve data exchange. A mobility compensation method is proposed to address the impact of drone mobility on signal transmission and position estimation, showing favorable gains in Monte Carlo simulations.
DIGITAL COMMUNICATIONS AND NETWORKS
(2021)
Article
Instruments & Instrumentation
S. Potnis, G. J. A. Edge, S. Jackson, M. Verma, A. C. Vutha
REVIEW OF SCIENTIFIC INSTRUMENTS
(2017)
Article
Education, Scientific Disciplines
Amar C. Vutha, Eliot A. Bohr, Anthony Ransford, Wesley C. Campbell, Paul Hamilton
EUROPEAN JOURNAL OF PHYSICS
(2018)
Article
Instruments & Instrumentation
Shira Jackson, Hiromitsu Sawaoka, Nishant Bhatt, Shreyas Potnis, Amar C. Vutha
REVIEW OF SCIENTIFIC INSTRUMENTS
(2018)
Article
Multidisciplinary Sciences
N. Bezginov, T. Valdez, M. Horbatsch, A. Marsman, A. C. Vutha, E. A. Hessels
Article
Physics, Multidisciplinary
Mohit Verma, Andrew M. Jayich, Amar C. Vutha
PHYSICAL REVIEW LETTERS
(2020)
Article
Optics
Nishant Bhatt, Kosuke Kato, Amar C. Vutha
Article
Physics, Multidisciplinary
Jack Davis, Pierre Dub, Amar C. Vutha
PHYSICAL REVIEW RESEARCH
(2019)
Article
Optics
Nishant Bhatt, Kosuke Kato, Amar C. Vutha
Article
Optics
Shira Jackson, Amar C. Vutha
Article
Optics
A. C. Vutha, M. Horbatsch, E. A. Hessels
Article
Physics, Atomic, Molecular & Chemical
A. C. Vutha, M. Horbatsch, E. A. Hessels
Article
Optics
Amro Dodin, Timur Tscherbul, Robert Alicki, Amar Vutha, Paul Brumer
Proceedings Paper
Automation & Control Systems
Amar C. Vutha, Tom Kirchnert, Pierre Dube
2017 JOINT CONFERENCE OF THE EUROPEAN FREQUENCY AND TIME FORUM AND IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM (EFTF/IFC)
(2017)
Proceedings Paper
Automation & Control Systems
Shreyas Potnis, Shira Jackson, Amar C. Vutha
2017 JOINT CONFERENCE OF THE EUROPEAN FREQUENCY AND TIME FORUM AND IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM (EFTF/IFC)
(2017)
Proceedings Paper
Automation & Control Systems
Graham J. A. Edge, Shreyas Potnis, Amar C. Vutha
2017 JOINT CONFERENCE OF THE EUROPEAN FREQUENCY AND TIME FORUM AND IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM (EFTF/IFC)
(2017)