The atomic clock and NTP Time Server

Many people have heard of atomic clocks, the accuracy and precision are well known. An atomic clock is able to keep time for hundreds of millions of years and not miss a second adrift. Drift is the process where the clocks lose or gain time because of inaccuracies in the mechanisms that operate them.

Mechanical watches, for example, have existed for hundreds of years, but also the most expensive and well designed will derive at least a second a day. While electronic watches are more accurate motion will also be about one second per week.

Atomic clocks can suffer no comparison when it comes to time. Due to an atomic clock is based on the oscillation of an atom (in most cases, the atom of cesium 133), which resonates perfectly accomplished (cesium is 9,192,631,770 times per second) which makes precision of a billionth of a second (one nanosecond).

Although this type of unprecedented accuracy has made possible the technologies and innovations that have changed the world. Satellite communication is possible only by time keeping atomic clocks, so the satellite navigation. As the speed of light (and therefore radio waves) to travel over 300,000 miles per second a few seconds of inaccuracy can see a navigation system of hundred thousand miles.

Offering precision is essential for many modern applications. World of communications, in particular, financial transactions must be done accurately. On Wall Street or the London Stock Exchange, a second, you can see the value of stock rise or fall by millions of people. Booking online also requires precision and perfect timing, as the atomic clocks can also provide the tickets may be sold several times and ATMs may end up paying two times his salary if you have found a distributor tickets with a slow clock.

Although this may seem desirable, the more dishonest of us, doesn, AOT much imagination to understand that the problems of lack of precision and timing can cause. For this reason, an international calendar based on the time told by atomic clocks has been developed.

UTC (Coordinated Universal Time) is the same everywhere and can explain the slowing of the Earth, the rotation of free radicals by adding leap seconds, as UTC time in line with GMT (Greenwich Meantime). All computer networks that are involved in the global communications network must be synchronized with UTC. Because the UTC is based on the time told by atomic clocks, is as accurate as possible. For a network of computers
receive and keep synchronized with the UTC must first access an atomic clock. Are expensive and large equipment and are usually only found in a physics laboratory scale.

Fortunately, time has told these clocks can still be received from a time server using fade in time and frequency long wave broadcasts issued by the national physics laboratories or GPS (Global Positioning System). NTP (Network Time Protocol) can then distribute this UTC time to the network and use the time signal to maintain all network devices in sync with UTC.

Satellite navigation for the NTP time server, atomic clocks are used around the world

Satellite navigation for the NTP time server, atomic clocks are used throughout the world.

We are all accustomed to our clocks in the management of one or two minutes, fast or slow. However, the odd doesn minutes, AOT affect our lives too and we are able to address. However, for some technologies and applications of a much higher level of precision required. Atomic clocks are more precise time keeping devices on earth. Have been invented fifty years ago, when it was discovered that the oscillations of atoms in certain energy levels, in particular, has never changed and vibrates at high frequency (more than 9 billion times per second for cesium).

Modern atomic clocks are so accurate that will not lose more than one second in 100 million years, but who on earth would need such precision? Atomic clocks are the basis for many applications and technologies and have contributed to our understanding of the physical universe.

Atomic clocks satellite systems, GPS navigation we use in our cars. The signals from atomic clocks on board satellites, which are used to triangulate an accurate position. E 'ca be made solely because of the very precise time signals. The inaccuracy of a second GPS clock could see demand of about 100,000 km in distance light can travel at that time.

Atomic clocks are also used as a method to test theories of Einstein and others. Using atomic clocks, we can accurately measure the severity and how it affects the weather. Modern clocks are so accurate that scientists can also measure the difference in gravity (and thus the time) in every inch above the soil surface next AOS. They can also be used to measure the slow process in motion, such as continental drift or slight changes in ODS rotation of the Earth.

Other applications where precision is essential to also rely on atomic clocks as the air traffic control, where the precise nature can follow a safe air traffic. Systems such as traffic lights are more and more time with servers connected to an atomic clock to ensure Synchonization perfect. Internet The Internet is based on atomic clocks, especially when it is used for time sensitive transactions such as banking, trading in stocks and shares and also book tickets online. Specified time, applications like this I laugh, AOT is possible that too many errors can occur in such a way that the seats of a double booking, selling shares were first purchased.

Networks of computers to synchronize the clock with Network Time Server. Often, these devices use the NTP protocol and receive the atomic clock time is the GPS or the radio. NTP time server to check and adjust all the clocks on the devices on a network to match the atomic clock time.

LF Radio NTP Server: How to decode the DCF-77 Broadcast Schedule

The DCF-77 time of transmission and radio frequency Mainflingen near Frankfurt, Germany. The DCF-77 time may be used by devices to provide a precise reference time. Timing of the computer equipment, such as NTP server systems, providing a precise point of reference for computer networks may use the program as an external source of accurate time. This article describes how the DCF-77 can be decoded to provide a reference to a specific timetable for NTP servers and other computer timing applications.

Before describing the format of the transmission, it is worth remembering a little 'about the history of the issuer. German national standard time and frequency radio, called DCF-77 is in operation since 1959. The spread is currently managed by T-Systems, a division of German telecommunications company Telecom Deuce. Precise information about the course of the show is produced by a cesium atomic clock maintained by the German National Physics Laboratory. The transmitter has a power of 50W, which can be received up to 1900 km from Frankfurt. The reception can be easily obtained in most of central and north-west. The transmission is transmitted as amplitude modulation, pulse width encoded data signal. Information about the hours of streaming, repeated every minute. The data is transmitted as a series of 59 pulses, one pulse per second. Each pulse represents a bit 'of data or a binary zero or binary. One hundred milliseconds pulse represents a binary zero, while the pulse is two hundred binary millisecond. The pulses can be decoded at the end of the date of the minutes and hours.

Timing information is represented in the DCF-77 transmission encoded binary coded decimal. Data bits are encoded into the carriage as follows. Data bits 1 to 14 are reserved for future improvements. Bit 15 indicates that the transmitter in operation today - the main transmitter or backup transmitter. 16 bit is the announcement of the return of summer. 17 bits indicates if DST is currently in use. Bit 18 indicates the time standard and is the inverse of 17 bits. Bit 19 indicates an impending leap second is inserted. Bit 20 indicates the start date and time. Bits 21-27 are BCD coded minutes. Bits 29-34 are BCD coded hours. Bits 36-41 are BCD encoded day of month Bits 42-44 are BCD weekday Bits 45-49 are BCD encoded encrypted year. Bits 50-57 are BCD coded years. Finally, a number of parity bits are inserted encoded data as follows. Parity bits to 28 bits 21-27. Parity bit 35-bit covers 29-34. Parity bit covers 58 bits 36-57.

To summarize, the DCF-77 transmission time is a reliable and accurate time from NTP server systems and applications, timing of other computers. The signal can be received in the vicinity of the NTP server same time, thus reducing installation costs. Furthermore, the right line before encoding the date of synchronization of the transmission allows the simple implementation of NTP server software. In fact, the standard distribution NTP server software drivers for Linux includes a reference clock for DCF-77.

NTP Server Reference Clocks: What's Best Radio and GPS?

NTP server is a network device that provides network servers and other network infrastructure with a precise reference. NTP server gets the correct time from an external source, such as time and radio frequency or GPS. This article describes the external time references that are available to synchronize NTP servers and discusses the merits of each.

There are a number of time and frequency are available in various locations. The WWVB signal is a reference to US-based DCF-77 in Germany and MSF in the United Kingdom. This time the transmission of radio frequencies and to ensure a stable and accurate time. Furthermore, an indoor pool located radio antenna can be used to receive these signals - lowering installation costs. However, radio signals can be influenced by local topography - such as hills and valleys. There is no guarantee of receiving radio signals, even if within the range of signal transmission.

The MSF radio signal transmission in the United Kingdom by the National Physics Laboratory recently moved from Rugby in the East Midlands for Anthorn in Cumbria. Since the passage has been widely recognized that the signal reception in southern England has suffered - even if it is in the range of materials for signal reception.

The local environment can also affect radio signals. Radio antennas placed in metal cages or metal clad buildings can experience poor signal reception. Moreover, the antenna is located in a basement or underground may fail.

Uses the global positioning system GPS navigation around the world. Each GPS satellite has a very high precision on-board atomic clock synchronization - a point of ideal reference for NTP server synchronization.

The GPS is a constellation of 24 satellites in orbit around each time streaming and positioning information. This information can be received anywhere on the face of the planet, with an antenna can be supplied with the line of sight of satellites.

GPS has a number of benefits based on the time and frequency radio transmissions. First, the GPS can be received all over the world and is not limited by transmission power and reach of radio signal. Secondly, the GPS signal is much clearer than the solutions. Thirdly, the GPS timing information can be received from someone who can provide an antenna with a good view of the sky. However, GPS antennas must not be the line of sight with GPS satellites. Therefore, the ideal place for a GPS antenna is located on a roof with a full 360 degrees of the sky. Moreover, if the buildings or trees obscure the horizon in any case, it may compromise the integrity of receipt. Roof-mounted antennas can significantly increase the cost of installing an NTP server.

To summarize, the radio and GPS based time and frequency references for NTP server systems for both advantages and disadvantages. However, the accuracy of GPS and hospitality assured, but with the roof-mounted antennas, make the choice of reference for NTP server systems.

Clocks - From the Sundial to the NTP server

Time is a concept that occupies the thoughts of humans since the earliest civilizations. One can only have been during the last century that we began to understand the time, thanks to the work of Albert Einstein, but the extent of his visit was an important element of society.

Historically, the time has been measured with the rotation of the Earth and other astronomical cycles such as the phases of the moon. The measurement of time and thus the identification of key events during the day, month or year has been crucial to the development of agriculture, religion, and complex societies.

While the calendars have been used for millennia, prehistoric monuments like Stonehenge, thought to indicate the winter solstice and summer and then locate the longest and shortest days of planting cultures, with small increments of time measurement is been a technological challenge.

The first watches were nothing but the timers, using water, burning candles and sand. They were able to measure a defined period, but less useful for identifying how much time left until expiration or other important events.

The sundial was the first real that you can watch (on a sunny day), to divide the day into equal portions, and thus provide a consistent measure of the day.

The mechanical clock appeared in the fourteenth century. While their technology is based on simple mechanics and were less accurate than sundials exist, they provide a solution to the obvious disadvantages of (day dial opaque).

Mechanical clocks really came into their own once the pendulum was developed in 1600 that provided the existing mechanical clocks can provide better accuracy. The development of mechanical clocks, pendulum engine went up over the centuries to come, and have become increasingly accurate.

However, once it was discovered that some crystals will oscillate at an exact price under the influence of an electric current, electronic watches resume as soon as he realized that the people provided much better precision.

However, during 1950, the atomic clock was developed, they used the oscillation of a single atom (usually cesium) which vibrates at a precise speed per second. Thank you to the atomic clocks that we have just discovered that the traditional way of using the rotation of the Earth and other celestial bodies as the basis of time-keeping would soon cause problems like Earth, was discovered, it would slow or speed up its rotation due to the effects of gravity on the moon.

If nothing is done, then the time told by atomic clocks (International Atomic Time, TAI) would be out of sync with the Earth and slowly becomes a date night.

A solution was found in UTC (Coordinated Universal Time), when leap seconds were added to compensate for the slowing of Earth's rotation.

UTC and atomic clocks have made it possible technologies such as satellites, global communication and the Internet. Most computer networks are governed by an atomic clock using NTP (Network Time Protocol). NTP servers receive the time signal from an atomic clock is a radio signal from the United States or GPS (Global Positioning System) network. This allows computers around the world to be synchronized at the same time scale (UTC), allowing time-sensitive operations, such as stock market and Internet commerce.

NTP - Using an atomic clock receiver for synchronization

Atomic clocks are devices for measuring time more accurately developed by man. Modern atomic clocks are so accurate that even in 100 million years less than a second time would be lost.

This specification refers to an ideal server NTP (Network Time Protocol). NTP is a protocol widely used to synchronize computer networks through the Internet network (LAN).

This article explains how to synchronize a computer network using the NTP protocol to a source of atomic clock.

Atomic clocks are so accurate that the universal calendar has been developed called UTC (Coordinated Universal Time), which is based on the time told by atomic clocks. UTC is used throughout the world and is the same everywhere, allowing various computer networks to synchronize the time.

Unfortunately, atomic clocks are extremely expensive, extremely delicate and rather large pieces of material, so they are actually found in physics laboratories of large or highly technical pieces of equipment such as satellites.

Fortunately a dedicated NTP server can be synchronized to UTC time with an atomic clock as a reference source by one of us the time and frequency broadcasts national and GPS (Global Positioning System) network.

Many national physics laboratories such as NPL in the United Kingdom, Germany NPL and NIST in the United States, issued a UTC time reference to the long-wave radio. These signals can be captured by an NTP server using a radio receiver. Unfortunately, radio transmissions are not transmitted from all countries and signals are more.

Fortunately, the constellation of satellites that make up the Union Sports Network all have a GPS atomic clock on board. This signal is used by satellite navigation receivers to work on the site, but can also be used by a GPS NTP server as a source of synchronization.

Using a radio or reference NTP server GPS time server, synchronize in a few milliseconds of UTC is possible.

Atomic clocks using as external NTP Timing Reference

Atomic clocks have been around for over fifty years or more. They have clocks that use a resonant frequency as the element's atomic timekeeping, rather than conventional crystal oscillating as quartz.

Most atomic clocks use the resonance of cesium-133, which resonates at a frequency of exactly 9,192,631,770 every second. Since 1967, the international system of Units (SI) has defined the oscillators as the number of cycles of cesium atomic clocks, which is -133 (sometimes called cesium seconds) standard for measuring time.

Because the resonance of cesium 133 is so precise, which makes atomic clocks accurate to less than 2 nanoseconds per day, equivalent to about one second in 1.4 million years.

That the atomic clocks are so accurate, a scale capable of maintaining stable and continuous time, universal time, UTC (Coordinated Universal Time or Universal Time Coordinated), was prepared and supports features such as leap seconds - added to compensate for the slowing rotation of the Earth.

However, atomic clocks are extremely expensive and are usually found in the physics laboratory scale. However, the NTP (Network Time Protocol), the standard way to obtain time synchronization networks of computers, you can synchronize with an atomic clock, using the Global Positioning System (GPS) network or specialist radio transmissions .

The most used is the GPS (Global Positioning System), developed by the U.S. Army. Contains at least 24 GPS satellites in orbit to provide high precision positioning and location information. Each GPS satellite can be done using an atomic clock, which in turn can be used as reference.

A GPS time server is the ideal time and frequency source because it is capable of providing highly accurate time anywhere in the world using relatively cheap components. Each GPS satellite transmits two frequencies of level 2 for military use and L1 for use by civilians transmitted at 1575 MHz, the antennas at low cost GPS receivers have become widely available.

There are also a number of national terms and the radio frequency that can be used to synchronize an NTP server. In Britain the signal (called MSF) is broadcast by National Physical Laboratory in Cumbria which serves as the national reference time of the United Kingdom, there are also similar systems in Colorado, USA (WWVB) and Frankfurt, Germany (DCF-77) . These signals provides UTC time to an accuracy of 100 microseconds, however, the radio signal has a limited scope and is vulnerable to interference.

Using a GPS NTP server or a radio based NTP time server, network client in turn can be synchronized within milliseconds of UTC based on network traffic.

Installing a NTP Server using a reference source radio

Network Time Protocol (NTP) is one of the oldest Internet protocols still in use, invented by Dr. David Mills University of Delaware, has been used since 1985. NTP is a protocol designed to synchronize the clocks of computers and networks through the Internet or local area networks (LANs).

NTP (version 4) can maintain time over the public Internet for less than 10 milliseconds (1/100th of a second) and maybe even better on LAN with accuracies of 200 microseconds (1/5000th of a second) under ideal conditions.

NTP works within the TCP / IP and UDP on the basis of a less complex form of NTP exists called Simple Network Time Protocol (SNTP) that does not require the storage of information about previous communications, needed to NTP. E 'used in some devices and applications where high accuracy timing is not so important.

Synchronization with NTP is relatively simple, it synchronises time with reference to a reliable source of clock. This source can be relative (a computer's internal clock or time on a clock) or absolute (UTC - Universal Coordinated Time - clock source that is accurate as is humanly possible).

E 'strongly recommended by Microsoft and others, that the timing of external funds should be used instead of the Internet because it can not be authenticated. Specialist NTP servers are available that can synchronize the time on the networks using the MSF (or equivalent) or the GPS signal.

Atomic clocks are the most absolute maintenance devices, but are very expensive and are usually only found in a physics laboratory scale. However, NTP can synchronize networks of an atomic clock, using the Global Positioning System (GPS) network or specialist radio transmission (MSF Italy).

The period of national and radio frequency used MSF to synchronize an NTP server is published by the National Physical Laboratory in Cumbria which serves as the national reference time of the United Kingdom, there are also similar systems in Colorado, USA (WWVB) and the Frankfurt in Germany (DCF-77).

A radio based NTP time server usually consists of a rack-mountable server time and an antenna, consisting of an iron bar in a plastic bag, which received the broadcasting time and frequency radio. The antenna should always be mounted horizontally, perpendicular to the transmission of the signal optimally. The data is sent in pulses, 60 of a second. These signals provides UTC time to an accuracy of 100 microseconds, however, the radio signal has a limited scope and is vulnerable to interference.

Radio time server reference is easy to install and can provide an organization with a precise reference for the synchronization of networks around the