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Current and future ground-based interferometers require knowledge of the atmospheric time constant t_0, but this parameter has diverse definitions. Moreover, adequate techniques for monitoring t_0 still have to be implemented. We derive a…

Astrophysics · Physics 2016-08-31 A. Kellerer , A. Tokovinin

Terahertz (THz) communication is widely deemed the next frontier of wireless networks owing to the abundant spectrum resources in the THz band. Whilst THz signals suffer from severe propagation losses, a massive antenna array can be…

Information Theory · Computer Science 2023-08-30 Konstantinos Dovelos , Stylianos D. Assimonis , Hien Quoc Ngo , Michail Matthaiou

Large antenna arrays can steer narrow beams towards a target area, and thus improve the communications capacity of wireless channels and the fidelity of radio sensing. Hardware that is capable of continuously-variable phase shifts is…

Information Theory · Computer Science 2024-01-04 Minsung Kim , Annalise Stockley , Keith Briggs , Kyle Jamieson

The influence of topological defects on phase synchronization and phase coherence in two-dimensional arrays of locally-coupled, nonidentical, chaotic oscillators is investigated. The motion of topological defects leads to a breakdown of…

Statistical Mechanics · Physics 2009-11-07 J. Davidsen , R. Kapral

We investigate the temperature and voltage dependence of the quantum interference in an electronic Mach-Zehnder interferometer using edge channels in the integer quantum-Hall-regime. The amplitude of the interference fringes is…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 L. V. Litvin , H. -P. Tranitz , W. Wegscheider , C. Strunk

The spatial-frequency coverage of a radio interferometer is increased by combining samples acquired at different times and observing frequencies. However, astrophysical sources often contain complicated spatial structure that varies within…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 U. Rau

In most multiple-input multiple-output (MIMO) communication systems, antennas are spaced at least half a wavelength apart to reduce mutual coupling. In this configuration, the maximum array gain is equal to the number of antennas. However,…

Information Theory · Computer Science 2024-11-12 Liangcheng Han , Haifan Yin , Mengying Gao , Jingcheng Xie

Guided-wave atom interferometers measure interference effects using atoms held in a confining potential. In one common implementation, the confinement is primarily two-dimensional, and the atoms move along the nearly free dimension under…

Atomic Physics · Physics 2009-11-13 J. H. T. Burke , B. Deissler , K. J. Hughes , C. A. Sackett

An efficient interference alignment (IA) scheme is developed for $K$-user single-input single-output frequency selective fading interference channels. The main idea is to steer the transmit beamforming matrices such that at each receiver…

Information Theory · Computer Science 2009-06-23 Sang Won Choi , Syed A. Jafar , Sae-Young Chung

Channel measurements in MIMO systems hinge on precise synchronization. While methods for time and frequency synchronization are well established, maintaining real-time phase coherence remains an open requirement for many MIMO systems. Phase…

Signal Processing · Electrical Eng. & Systems 2026-02-19 Carl Collmann , Ahmad Nimr , Gerhard Fettweis

Accurate calibration of acoustic sensing systems made of multiple asynchronous microphone arrays is essential for satisfactory performance in sound source localization and tracking. State-of-the-art calibration methods for this type of…

Sound · Computer Science 2025-02-11 Chengjie Zhang , Wenda Pan , Xinyang Han , He Kong

X-ray interferometry is an emerging imaging modality with a wide variety of potential clinical applications, including lung and breast imaging, as well as in non-destructive testing, such as additive manufacturing and porosimetry. A grating…

This paper presents the basic principle and theoretical relationships of an original method allowing to retrieve the Wavefront Errors (WFE) of a ground or space-borne telescope when combining its main pupil with a second, decentered…

Optics · Physics 2011-05-19 Francois Henault

Calibration is an essential step in radio interferometric data processing that corrects the data for systematic errors and in addition, subtracts bright foreground interference to reveal weak signals hidden in the residual. These weak and…

Instrumentation and Methods for Astrophysics · Physics 2019-05-08 Sarod Yatawatta

Digital radio antenna arrays, like LOPES (LOFAR PrototypE Station), detect high-energy cosmic rays via the radio emission from atmospheric extensive air showers. LOPES is an array of dipole antennas placed within and triggered by the…

Instrumentation and Methods for Astrophysics · Physics 2012-05-14 F. G. Schröder , T. Asch , L. Bähren , J. Blümer , H. Bozdog , H. Falcke , A. Haungs , A. Horneffer , T. Huege , P. G. Isar , O. Krömer , S. Nehls

In conventional colocated multiple-input multiple-output (MIMO) radars, practical waveform constraints including peak-to-average power ratio, constant or bounded modulus lead to a significant performance reduction of transmit beampattern,…

Signal Processing · Electrical Eng. & Systems 2024-10-08 Shengyao Chen , Minghui He , Longyao Ran , Hongtao Li , Feng Xi , Sirui Tian , Zhong Liu

In the context of the Laser Interferometer Space Antenna (LISA), the laser subsystems exhibit frequency fluctuations that introduce significant levels of noise into the measurements, surpassing the gravitational wave signal by several…

Instrumentation and Detectors · Physics 2024-01-15 Philipp Euringer , Niklas Houba , Gerald Hechenblaikner , Oliver Mandel , Francis Soualle , Walter Fichter

Astronomic line mapping with single-pixel instruments is usually performed in an on-the-fly (OTF) or a raster-mapping mode depending on the capabilities of the telescope and the instrument. The observing efficiency can be increased by…

Instrumentation and Methods for Astrophysics · Physics 2009-11-13 V. Ossenkopf

Astronomers usually need the highest angular resolution possible, but the blurring effect of diffraction imposes a fundamental limit on the image quality from any single telescope. Interferometry allows light collected at widely-separated…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John D. Monnier , Ronald J. Allen

The exquisite precision of atom interferometers has sparked the interest of a large community for use cases ranging from fundamental physics to geodesy and inertial navigation. However, their practical use for onboard applications is still…