You've probably heard the statement: "It runs like clockwork." The meaning indicates reliability and accuracy, the subject is the epitome of excellence. In the world of synchronized clock systems, you could modify the statement this way: "It runs like master clockwork." The master clock provides the guide to the other clocks in the system so that time, and other devices connected to it, operate without problems 24 hours a day. But why is a master clock so reliable? It too, needs some help to keep it working correctly. Here are a few ways the master clock gets its precise time.
Master time from a GPS
A common source of accurate time for a master clock is a global positioning satellite (GPS) signal. Satellites in space broadcast precise time all over the world. This time is received from the atomic clock, which is located at the National Institute of Standards and Technology or NIST in Colorado. The master clock in a school or business must have an antenna located outdoors in order to receive the GPS time signal and synchronize to it. The master clock communicates with the GPS every hour to acquire the correct time, which it passes along to the other clocks within the environment.
Master time from a cellular phone tower
Cellular phone towers seem to be everywhere these days, and they serve a larger purpose beyond providing phone signals to hundreds of millions of cell phones. These towers also send out a time signal, which our cell phones receive to keep precise time. Master clocks also acquire these time signals, thanks to an internal module, which communicates with the tower, collects the time information, and passes it along to the clocks within the system. If you're curious about where the cell tower gets it's time — the atomic clock in Colorado is the source.
Master time from the internet
The internet is an incredible cauldron of information, and for the master clock: a reliable source of accurate time, which it acquires from a time server. The master clock communicates with that time server over a network connection. Again, the atomic clock at the NIST is the ultimate source of accurate time to the server.
So the common thread for synchronized time all over the United States is the atomic clock at NIST, which truly is the king of clocks. In order to ensure the master clock at your facility is getting this time, it must communicate with a GPS, cell tower or the internet once per hour. If you are considering a synchronized clock environment for your school or business, the type of master clock you need will be based on cost and logistics. To get more information about the type of synchronized clock system that works best for you, a clock consultation may be the way to go.