Ultra-Stable RF Transmission Over Coaxial Cables via Phase Fluctuation Compensation

Article Quantum Science & Technology

Optical atomic clock aboard an Earth-orbiting space station (OACESS): enhancing searches for physics beyond the standard model in space

Vladimir Schkolnik et al.

Summary: This is a concept for a high-precision optical atomic clock operating on an Earth-orbiting space station, aiming to search for potential dark matter candidates near Earth's surface by comparing with terrestrial atomic clocks. It opens up the exploration of new physics models that are inaccessible to ground-based experiments.

QUANTUM SCIENCE AND TECHNOLOGY (2023)

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Article Engineering, Marine

Real-time single-frequency precise positioning with Galileo satellites

Berkay Bahadur

Summary: The performance assessment of real-time single-frequency precise positioning with Galileo satellites is the main objective of this research. The experimental tests show that Galileo provides a sufficient number of visible satellites for single-frequency positioning and has a lower noise level compared to GPS observations. The results also demonstrate that Galileo achieves better positioning accuracy and shorter convergence time than GPS for both code-based and code-phase combination single-frequency positioning.

JOURNAL OF NAVIGATION (2022)

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Article Multidisciplinary Sciences

Comparing ultrastable lasers at 7 x 10-17 fractional frequency instability through a 2220 km optical fibre network

M. Schioppo et al.

Summary: This study reports a comparison of two geographically separated ultrastable lasers over a 2220 km optical fibre link, achieving a fractional frequency instability of 7×10-17. These results are significant for the dissemination of ultrastable light to improve the performance of remote optical clocks.

NATURE COMMUNICATIONS (2022)

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Article Optics

Frequency comb-to-comb stabilization over a 1.3-km free-space atmospheric optical link

Jaewon Yang et al.

Summary: In this study, frequency comb-to-comb stabilization is achieved through coherent transfer of two separate comb lines via a freespace optical link, with strict control of atmospheric phase noise. This method has potential value in applications such as broadband molecular spectroscopy and ultra-stable microwave generation.

LIGHT-SCIENCE & APPLICATIONS (2022)

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Article Multidisciplinary Sciences

Free-space dissemination of time and frequency with 10-19 instability over 113 km

Qi Shen et al.

Summary: Networks of optical clocks are important for navigation, redefining time units, and gravitational tests. However, achieving a global-scale optical network with comparable performance requires the dissemination of time and frequency over a long-distance free-space link with matching instability. Previous attempts at high precision dissemination of time and frequency did not extend beyond dozens of kilometers. In this study, we report successful time-frequency dissemination over a free-space link of 113 km with an offset of 6.3 x 10(-20)+/- 3.4 x 10(-19) and an instability of less than 4 x 10(-19), using key technologies such as high-power frequency combs.

NATURE (2022)

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Article Engineering, Electrical & Electronic

A Novel Technique for Real-Time Estimation and Compensation of Phase-Drift of RF Signals Transmitting Through Coaxial Cables

H. K. Rathore et al.

Summary: The letter introduces a technique for real-time measurement of phase-drift in RF signal due to ambient conditions, and verification with a 10-MHz signal. It also demonstrates phase-stabilized RF signal transmission through coaxial cables by active phase compensation. The study highlights the sensitivity of RF signal phase to temperature variation during distribution through coaxial cables.

IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS (2021)

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Article Engineering, Electrical & Electronic

Absolutely Consistent Fiber-Optic Phase Synchronization Based On Fixed-Phase-Reference Optical Active Compensation

Rui Wu et al.

Summary: The proposed fiber-optic phase synchronization scheme utilizing fixed-phase-reference optical active compensation eliminates phase ambiguity and randomness, achieving stable and repeatable phase synchronization. Experimental results show high stability with minimal phase difference fluctuation and potential applications in radar networks and coherent detection based on time-frequency-phase synchronization.

IEEE PHOTONICS JOURNAL (2021)

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Proceedings Paper Electrochemistry

Modeling Reflections in a Complex Cable Structure with Impedance Mismatches

Dhia Haddad et al.

Summary: The research shows that there is minimal deviation between the simulation results and the analytical model, with soft faults contributing the most to the voltage deviation. For fault diagnostic in complex cables, simulating cable networks can accurately represent reflected signals. By simulating mismatch between the connected cables, accurate identification of faults in the reflected signals can be achieved.

PROCEEDINGS OF INTERNATIONAL WORKSHOP ON IMPEDANCE SPECTROSCOPY (IWIS 2021) (2021)

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Article Engineering, Electrical & Electronic