Topic
Clock network
About: Clock network is a research topic. Over the lifetime, 755 publications have been published within this topic receiving 10847 citations. The topic is also known as: clock system.
Papers published on a yearly basis
Papers
TL;DR: The capability of performing high resolution international clock comparisons paves the way for a redefinition of the unit of time and an all-optical dissemination of the SI-second.
Abstract: Leveraging the unrivalled performance of optical clocks as key tools for geo-science, for astronomy and for fundamental physics beyond the standard model requires comparing the frequency of distant optical clocks faithfully. Here, we report on the comparison and agreement of two strontium optical clocks at an uncertainty of 5 × 10−17 via a newly established phase-coherent frequency link connecting Paris and Braunschweig using 1,415 km of telecom fibre. The remote comparison is limited only by the instability and uncertainty of the strontium lattice clocks themselves, with negligible contributions from the optical frequency transfer. A fractional precision of 3 × 10−17 is reached after only 1,000 s averaging time, which is already 10 times better and more than four orders of magnitude faster than any previous long-distance clock comparison. The capability of performing high resolution international clock comparisons paves the way for a redefinition of the unit of time and an all-optical dissemination of the SI-second. Comparing the frequency of two distant optical clocks will enable sensitive tests of fundamental physics. Here, the authors compare two strontium optical-lattice clocks 690 kilometres apart to a degree of accuracy that is limited only by the uncertainty of the individual clocks themselves.
463 citations
1 May 1998
TL;DR: The 21264 is a third generation Alpha microprocessor implementation, containing 15.2 million transistors and operating at 600 MHz, and the electrical design of the power, ground, and clock networks is presented.
Abstract: Power dissipation is rapidly becoming a limiting factor in high performance microprocessor design due to ever increasing device counts and clock rates. The 21264 is a third generation Alpha microprocessor implementation, containing 15.2 million transistors and operating at 600 MHz. This paper describes some of the techniques the Alpha design team utilized to help manage power dissipation. In addition, the electrical design of the power, ground, and clock networks is presented.
408 citations
TL;DR: A global clock distribution strategy implemented on several microprocessor chips is described, which consists of buffered, tunable tree networks, with the final trees all driving a common grid.
Abstract: A global clock distribution strategy used on several microprocessor chips is described. The clock network consists of buffered tunable trees or treelike networks, with the final level of trees all driving a single common grid covering most of the chip. This topology combines advantages of both trees and grids. A new tuning method was required to efficiently tune such a large strongly connected interconnect network consisting of up to 6 m of wire and modeled with 50000 resistors, capacitors, and inductors. Variations are described to handle different floor-planning styles. Global clock skew as low as 22 ps on large microprocessor chips has been measured.
324 citations
TL;DR: This Review covers optical clock networks that are established to synchronize remote optical clocks that may allow a future redefinition of the unit of time based on an optical reference transition.
Abstract: This Review covers optical clock networks that are established to synchronize remote optical clocks. Further upgrading of optical clock networks and their impact on a future redefinition of time are also discussed. Within the last decade, optical atomic clocks have surpassed the best cesium clocks, which are used to realize the unit of time and frequency, in terms of accuracy and stability by about two orders of magnitude. When remote optical atomic clocks are connected by links without degradation in the clock signals, an optical clock network is formed, with distinct advantages for the dissemination of time, geodesy, astronomy and basic and applied research. Different approaches for time and frequency transfer in the microwave and optical regime, via satellites and free-space links, optical fibre links, or transportable optical atomic clocks, can be used to form a hybrid clock network that may allow a future redefinition of the unit of time based on an optical reference transition.
278 citations
TL;DR: This work developed a novel strategy termed Gene Dosage Network Analysis (GDNA) in which small interfering RNA-induced dose-dependent changes in gene expression were used to build gene association networks consistent with known biochemical constraints, and uncovered several novel network features of the circadian clock, including proportional responses and signal propagation through interacting genetic modules.
Abstract: The mammalian circadian clock is a cell-autonomous system that drives oscillations in behavior and physiology in anticipation of daily environmental change. To assess the robustness of a human molecular clock, we systematically depleted known clock components and observed that circadian oscillations are maintained over a wide range of disruptions. We developed a novel strategy termed Gene Dosage Network Analysis (GDNA) in which small interfering RNA (siRNA)-induced dose-dependent changes in gene expression were used to build gene association networks consistent with known biochemical constraints. The use of multiple doses powered the analysis to uncover several novel network features of the circadian clock, including proportional responses and signal propagation through interacting genetic modules. We also observed several examples where a gene is up-regulated following knockdown of its paralog, suggesting the clock network utilizes active compensatory mechanisms rather than simple redundancy to confer robustness and maintain function. We propose that these network features act in concert as a genetic buffering system to maintain clock function in the face of genetic and environmental perturbation.
276 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 1 |
| 2024 | 6 |
| 2023 | 18 |
| 2022 | 12 |
| 2021 | 19 |
| 2020 | 32 |