An atomic clock that provides a very accurate source of time. There are different types of atomic clock, which is located mostly in the laboratory: cesium clocks, watches, hydrogen and rubidium clocks. Longer commercially available systems atomic clock synchronization using a radio or GPS time signal that a precise time reference rate of interest is bound. In this way, a very accurate source of time is readily available for users of all days, excluding the costs of installing expensive and complexEquipment.
This article provides an overview of atomic clock systems with particular emphasis on their use with NTP server systems for PC and network synchronization of computer time.
Atomic Clock Radio
References Time Radio broadcasts time as MSF-60 (UK), DCF-77 (Germany) and WWVB (U.S.) time to transmit signals accurate time information from a radio transmitter. The period of coverage of a reference atomic clock time can be derived and received byTiming device with a radio-receivers at low cost. MSF-60 radio signal from Rugby in the UK, with coverage of the British Isles and throughout most of North-West Europe transferred. The DCF-77 from Frankfurt, Germany, transfer, and covers most of central Europe. While the WWVB signal in Fort Collins, Colorado, United States transferred.
MSF-60 time of transmission
MSF-60 time signal is a longwave time signal transmitted at 60 kHz fromRugby in the UK. The radio signal is maintained by BT Engineering Services. The MSF-60 time signal is generated from extremely accurate atomic clocks located at the National Physics Laboratory (NPL). When decoded, it provides a highly accurate timing reference for NTP servers, reference clocks and other computer timing equipment.
DCF-77 Time Transmission
The DCF-77 time signal is a long-wave radio time signal broadcast at 77.5kHz from Mainflingen, near Frankfurt, Germany. The radio signal is maintained by T-Systems, a division of Deuche Telecom and in operation since 1959. The DCF-77 highly accurate atomic clocks German National Physics Laboratory is generated. When decoded, provides a very precise timing reference for clocks and computer timing equipment.
WWVB transmission time
The WWVB time signal continuously transmits signals in time and frequency at 60 kHz from Fort Collins, Colorado, USA. TimeIs obtained from the U.S. National Institute of Standards and Technology. WWVB continuously transmits time and frequency since 1962 made available. The signal is a time reference with an accuracy of less than 100 microseconds.
GPS Time Atomic Clock Reference
The Global Positioning System (GPS) is a U.S. military for navigation around the world. The system consists of 24 satellites in orbit, each satellite has an extremely accurate atomic clock on board, synchronized with UTCTime. The satellites continuously transmit time and position data. The timing and location information can be obtained throughout the world with a GPS receiver and antenna. GPS works continuously, whether the conditions for everyone, everywhere in the world. In addition, there are no set-up fee or subscription charges to use GPS systems. Many computer timing systems and NTP server systems for use as a precise timing reference external GPS. GPS timing is generally much more accurate than radioReferences times Based.
Computer Time Synchronization
Computer time synchronization can be achieved by combining a precise timing GPS receiver and radio with RS232 or USB interface to achieve. Driver software can be installed on the host PC to obtain the correct time and the host PC, synchronize the system time. Most PC operating systems can be synchronized, including Microsoft Windows 2000, 2003 and XP, Linux, Unix and Novell. In many cases, the time of the PC's host system can be synchronized so thatwithin a few microseconds, at the right time.
Network Time Synchronization
The standard protocol for the implementation of the network synchronization of the computer time is the Network Time Protocol (NTP). NTP is the standard way to distribute the time on the Internet and other networks. Stratum 1 NTP server to receive an external reference time, such as GPS, MSF-60, WWVB or DCF-77. The external time reference is then used to set the NTP server to synchronize the system time. The matchingE 'then used by the NTP server to distribute the correct time to time, the network client on an IP network. NTP is a hierarchical way, less time to NTP server to get to higher level devices.
NTP server systems can be synchronized to less than a few microseconds, at the right time. Depending on network traffic you can synchronize NTP client, a few milliseconds of an NTP server.
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