The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Future tactical communications involves high data rate best effort traffic working alongside real-time traffic for time-critical applications with hard deadlines. Unavailable bandwidth and/or untimely responses may lead to undesired or even catastrophic outcomes. Ethernet-based communication systems are one of the major tactical network standards due to the higher bandwidth, better utilization, and...
This work studies a digital transmission system by fiber optic. We give special relevance to the synchronism block. The fiber is a transmission medium with large bandwidth and low attenuation. These characteristics allow high speed and long distances. The transmission, instead asynchronous, it is synchronous what provides a big efficiency of 100%. However, the synchronous transmission needs a synchronizer...
In both wired and wireless networks, time synchronization is an important service for a wide range of applications in distributed systems. This includes radio interferometry. However, literature researches show that many distributed protocols cannot satisfy sub-ns time synchronization accuracy due to asymmetric delay errors, accumulated jitters and because of the strategy used to compute and adjust...
More than two decades, circuit switched systems have been replaced by packet switched systems in telecommunication infrastructure. However, there are considerable amount of circuit switched equipment in telecommunication networks. Therefore, interconnection of existing circuit switched networks with packet switched networks is needed. For this reason, new methods are still being developed to transport...
Network based on OTN standard (ITU-T G.709), originally devised for core networks, are foreseen to play an important role also in metro and possibly access optical networks, because of the always increasing bandwidth needs as well as of some new (at least numerically) requirements like latency and jitter control. In a historical timeframe in which the standardization activity is primarily focused...
With the increasing number of clock domain crossings in modern VLSI circuits, the area, power and performance overheads introduced by synchronization have a rising impact on the overall system parameters. To minimize these overheads while still reaching the targeted system reliability, it is very important to precisely know the parameters of the circuit elements used for synchronization regarding...
Road safety applications heavily rely on periodic message exchanges known as beaconing in order to gain awareness about the current situation within the vehicle communication range. The high level of transmission contention in dense vehicular networks can induce successive beacon collisions. These collisions impede the vehicles to have an up-to-date view of the environment which can lead to bad decisions...
This paper is presenting how teleprotection applications via packet switched wide area networks can be implemented guaranteeing required application specific performance parameters. The following different approaches are analyzed for differential protection: a. ITU-T compliant standard circuit emulation (CE) using SAToP/ CESoPSN. b. A novel approach of CE technology, using explicit clocks, developed...
Design and implementation of a 15kV sub-nanosecond pulse generator using Trigatron type spark gap as a switch. Straightforward and compact trigger generator using pulse shaping network which produces a trigger pulse of sub-nanosecond rise time. A pulse power system requires delivering a high voltage, high coulomb in short rise time. This is achieved by using pulse shaping network comprises of parallel...
In this paper, we present a new radio frequency receiver dedicated for avionic signals which can be used for distance measuring and air control traffic system. The designed system, based on the direct radio frequency sampling approach, uses a smart sampling to digitize and demodulate the received signal at the same time. The presented design is composed of a Phase-Locked Loop and a Delta-Sigma modulator...
High-precision sensor networks and localization systems require precise time and frequency synchronization. In this paper, we present a novel high-precision frequency synchronization approach for wireless network devices. It adapts the local oscillator frequency of a receiver to the frequency of a transmitter and can be integrated into existing wireless communication systems. The measurement of frequency...
SpaceWire is integrated networking technology where the data packets and control traffic in the form of hard real-time signals are transmitted throw the same links of communication network. Last decades for hard real-time signals transmission in onboard networks the specialized buses like CAN and MIL-STD 155b and sideband signals were used. All buses have the property that the signal from the source...
This paper describes how SpaceWire Time Codes can be used for synchronizing time within various subsystems of a spacecraft as well as, maintaining a common time reference needed for coordinating operations within a spacecraft. The algorithms to account for inaccuracies in the time distribution method were based on the NASA-4009 Space Telecommunication Radio System (STRS) standard [1], which defined...
In a recently published paper, a novel ap-proach for blind feedback synchronization of the symbol tim-ing has been proposed. In order to avoid any jitter floor irre-spective of the selected modulation scheme, a filter with very particular properties has been developed and placed in par-allel to the receiver matched filter. Nevertheless, the jitter performance of this method degrades in case the carrier...
In this paper, an audiovisual quality assessment experiment was conducted on audiovisual clips collected using a PC-based videoconferencing application connected via a local IP network. The analyses of experimental results provided a better understanding of the influence of network impairments (packet loss, jitter, delay) on perceived audio and video qualities, as well as their interaction effect...
The characterization of the closed-loop delays in a wide-area control system (WACS) is an important foundation for further research. The method to estimate and measure the closed-loop delay in actual WACSs were proposed in this paper. Then, the closed-loop delays in the actual WACS in Guizhou Power Grid in China were measured and analyzed. Also, the measured delays were used to verify the normal distribution...
Symbol timing synchronization is an important component in communication systems. The quality and reliability of wireless network communication will improve with accurate symbol timing recovery. In this paper, we present a symbol timing synchronization method by interpolating the samples at the output of the matched filter to compute the desired time instants. Since interpolation jitter is the major...
The utilization of Ethernet in the cellular terrestrial cloud radio access network (C-RAN) fronthaul is considered as a way for improving C-RAN network reconfigurability and efficiency in terms of both capital and operational expenditures. Moreover CPRI line bit rate dynamic reconfiguration may spare further capital expenditures by avoiding a peak traffic capacity allocation. A possible solution for...
We report recent progress made in a synchronous multi-color mode-locked laser network over 4.7-km distance. Output of two remotely synchronized lasers shows only 0.6-fs RMS drift over 40 hours reaching 20th decimal uncertainty in less than 10000-s averaging time. This work will enable sub-fs synchronization of new generation photon science facilities and allow km-scale optical clock comparison with...
In earlier work, we suggested a low cost control communication scheme across half-duplex Ethernet allowing for reduced jitter and delay for an information sharing control communication bus. The principle advantage of half-duplex Ethernet is the reduced number of wires (two versus four wires) and the reduced cost of switch/router equipment. The basic principles for our communication has been the network...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.