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Pulsar Timing Arrays use a set of millisecond pulsars in an attempt to directly detect nanohertz gravitational waves. For this purpose, high precision timing of the pulsars is essential and ultimately a precision of the order of ~100 ns is…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Lina Levin

In order to reach the sensitivity required to detect gravitational waves, pulsar timing array experiments need to mitigate as much noise as possible in timing data. A dominant amount of noise is likely due to variations in the dispersion…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 K. J. Lee , C. G. Bassa , G. H. Janssen , R. Karuppusamy , M. Kramer , K. Liu , D. Perrodin , R. Smits , B. W. Stappers , R. van Haasteren , L. Lentati

Detailed spectra of harmonics produced from ultra-intense, sub-picosecond, high-contrast laser pulses incident on solid targets have shown the first observation of regular red- and blue-shifted satellites. Their frequency shift is slightly…

With the severe spectrum shortage in conventional cellular bands, millimeter wave (mmW) frequencies between 30 and 300 GHz have been attracting growing attention as a possible candidate for next-generation micro- and picocellular wireless…

Networking and Internet Architecture · Computer Science 2014-04-29 Mustafa Riza Akdeniz , Yuanpeng Liu , Sundeep Rangan , Elza Erkip

A polarization switching pulse interleaver is shown to be effective in reducing timing noise due to polarization mode dispersion in time and frequency transfer based on mode-locked lasers and standard single-mode fibres. In closed-loop time…

The wave propagation in the partially ionized ionosphere plays an important role in the magnetosphere ionosphere coupling. For example, the ionosphere may supports very low-frequency Alfven wave which can be caused by a balance between the…

Plasma Physics · Physics 2016-10-13 B P Pandey

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…

Frequency dissemination and synchronization in free space plays an important role in global navigation satellite system, radio astronomy and synthetic aperture radar. In this paper, we demonstrate a portable radio frequency dissemination…

Instrumentation and Detectors · Physics 2015-05-20 Jing Miao , Bo Wang , Yu Bai , Yibo Yuan , Chao Gao , Lijun Wang

Radio pulsars emit regular bursts of radio radiation that propagate through the interstellar medium (ISM), the tenuous gas and plasma between the stars. Previously known dispersive properties of the ISM cause low frequency pulses to be…

Astrophysics of Galaxies · Physics 2014-11-20 F. A. Jenet , D. Fleckenstein , A. Ford , A. Garcia , R. Miller , J. Rivera , K. Stovall

The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the direction-dependent ionospheric effects, the time-varying…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 S. A. Brackenhoff , M. Mevius , L. V. E. Koopmans , A. Offringa , E. Ceccotti , J. K. Chege , B. K. Gehlot , S. Ghosh , C. Höfer , F. G. Mertens , S. Munshi , S. Zaroubi

The low-pass filter is a fundamental building block from which digital signal-processing systems (e.g. radio and radar) are built. Signals in the electromagnetic spectrum extend over all timescales/frequencies and are used to transmit and…

Signal Processing · Electrical Eng. & Systems 2023-06-26 Hugh L. Kennedy

The problem of radio wave reflection from an optically thick plane monotonous layer of magnetized plasma is considered at present work. The plasma electron density irregularities are described by spatial spectrum of an arbitrary form. The…

Plasma Physics · Physics 2009-10-31 N. A. Zabotin , A. G. Bronin , G. A. Zhbankov

Historically, solar flare detection has been dependent on methods that require the presence of expensive satellites or other Earth based costly equipment. In this paper, we propose a cost effective, terrestrial alternative that enables…

Instrumentation and Methods for Astrophysics · Physics 2025-11-26 George Dan Chita

For each photon wave packet of extragalactic light, the dispersion by line-of-sight intergalactic plasma causes an increase in the envelope width and a chirp (drift) in the carrier frequency. It is shown that for continuous emission of many…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Richard Lieu , Lingze Duan

Calibration of radio interferometric observations becomes increasingly difficult towards lower frequencies. Below ~300 MHz, spatially variant refractions and propagation delays of radio waves traveling through the ionosphere cause phase…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 H. T. Intema , S. van der Tol , W. D. Cotton , A. S. Cohen , I. M. van Bemmel , H. J. A. Rottgering

Our understanding of the universe relies mostly on electromagnetism. As photons are the messengers, fundamental physics is concerned in testing their properties. Photon mass upper limits have been earlier set through pulsar observations,…

Instrumentation and Methods for Astrophysics · Physics 2016-12-30 Mark J. Bentum , Luca Bonetti , Alessandro D. A. M. Spallicci

The optical fiber used as a microwave delay line exhibits high stability and low noise and makes accessible a long delay (>100 microseconds) in a wide bandwidth (about 40 GHz, limited by the optronic components). Hence, it finds…

We present a new method to study harmonic waves in the low ionosphere (60 - 90 km) by detecting their effects on reflection of very low frequency (VLF) radio waves. Our procedure is based on amplitude analysis of reflected VLF radio waves…

Earth and Planetary Astrophysics · Physics 2017-05-04 Aleksandra Nina , Vladimir Cadez

We present a study of scintillation induced by the mid-latitude ionosphere. By implementing methods currently used in Interplanetary Scintillation studies to measure amplitude scintillation at low frequencies, we have proven it is possible…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 A. Waszewski , J. Morgan , C. H. Jordan

The ionosphere is the main driver of a series of systematic effects that limit our ability to explore the low frequency (<1 GHz) sky with radio interferometers. Its effects become increasingly important towards lower frequencies and are…

Instrumentation and Methods for Astrophysics · Physics 2018-08-08 F. de Gasperin , M. Mevius , D. A. Rafferty , H. T. Intema , R. A. Fallows