I’m sure your heard about atomic clock, this kind of clock is very accurate. Why not have atomic clock at your desktop. If it works properly you will be able to synchronize your computer clock with atomic time servers. If you do decide to operate a timeserver, be sure to calibrate your atomic clock regularly. If you don’t have an atomic clock, build one. The atomic clock signal will penetrate almost all buildings, except typically commercial steel buildings that have few windows. Conventional personal computers are required to be connected to the Internet in order to obtain an atomic clock signal that can update a clock of the personal computer (PC). Current operating system software permits access to the atomic clock broadcast to update the PC clock as long as there is an Internet connection for broadcasting the atomic clock signal to the computer. Also, heat can have an affect on crystal operation, and this condition may lead to inaccuracy in the clock time output of the time-keeper clock. The computer includes a tuner that can receive a broadcast signal with the atomic clock signal. The logic circuit includes a standard circuit that compares the time values of the atomic clock signal,clock time output, and a standard circuit that generates a control signal with a value that is dependent on the difference between the time values of the atomic clock signal and clock time output.
All PCs have a built-in electronic clock and calendar. In the old days there were just clocks in system tray, telling the time, now in some programs you will find nice looking analog clock with looks more wrist watches. The internal clock value is obtained through an operating system, it is in an hour-minute-millisecond format. However, while internal clocks of computers are very accurate in terms of measuring elapsed time, the indicated time on any particular computer is probably not correct in the absolute sense.But like the watch on your wrist and the clock on your wall, most computer clocks are off by a few seconds or minutes. Also computer internal clocks are not synchronized with each other.