Glossary - Technical Terms

AFNOR - AFNOR is a standardized French time code similar to IRIG-B but contains additional day, day-of-month and year information.

Atomic Clock - An atomic clock is a time counter, which is controlled by the oscillation frequency of certain atoms (e.g. caesium, rubidium), which are energized by an electromagnetic field or optical pumping.

CET - The Central European Time (CET) is the significant local time for Central Europe as Germany, Austria and Switzerland. It is commensurate to the central time of sun of the fifteenth degree of longitude eastside of Greenwich. Its difference to the UTC is plus one hour. In case of the Central European Summertime it is two hours ahead.

DCF 77 - DCF77 is a longwave time signal broadcast station at Mainflingen, Germany, about 25 km south-east of Frankfurt (50°01' North, 09°00' East). The DCF77 radio signals are derived from an atomic clock, and broadcasted on 77.5 kHz. The signal can be received up to a distance of 2000 km and more. There are 2 transmitters installed, so in case of failure of the first one it is possible to use the reserve system.

E1 - E1 (or E-1) is a European digital transmission format with a capacity of 2.048 Mbit/s from ITU-TS. It's like the North American T-carrier system format. Typically channelized into 30 D S0s channels, each capable of carrying a single voice conversation or data stream.

LWL Cable - LWL cable is nothing but Fiber Optics cable/patch cord which are used widely in modern telecommunication and network technology. Mobatime devices can be interlinked with LWL cable to achieve Master-Slave redundancy between two Master Clocks.

LWL Module - LWL module is nothing but small form-factor pluggable (SFP), a compact hot-pluggable network interface module used for both telecommunication and data communications applications.

GPS - The Global Positioning System is a satellite-based radio positioning, navigation, and time-transfer system. Theoretically three satellites are sufficient to find out an exact location and its height. Practically, however, most of the GPS-receivers have no source of time which is precise enough for correct runtime calculations. Therefore a fourth satellite that provides such a signal is strictly necessary.

GLONASS (Russian) - Global Navigation Satellite System, is a space-based satellite navigation system operated by the Russian Aerospace Defence Forces.

IRIG - The tele-communication Working Group (TCWG) of the American Inter Range Instrumentation Group (IRIG) was mandated in 1956 to standardize the different time codes. The different IRIG Formats are sorted as IRIG A/B/D/E/G/H.

IEEE 1588 - This standard protocol enable precise synchronization of clocks in measurement and control systems implemented with technologies such as network communication, local computing and Power generation & transmission. The protocol will be applicable to systems communicating by packet networks supporting multicast messaging including but not limited to Ethernet. The protocol will support system-wide synchronization accuracy in the sub-microsecond range with minimal network and local clock computing resources.

NTP - The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in current use. NTP was designed by David L. Mills.

UTC - UTC (Coordinated Universal Time) is the name of the international time standard and is identical to GMT (Greenwich Mean Time), which was commonly used as a world wide time base.