Analog

An analog system is a mathematical system in which numbers vary continuously instead of shifting between discrete states as a digital system does. For example,in an analog clock the little hand points to the hour and the big hand points to the minute and a bigger hand points to the second and all three of these hands move continuously. In a digital the numbers simply shift between discrete states. A slide rule is an analog calculator whereas an abacus is a digital calculator because the slide rule's numbers vary continuously whereas the abacus's numbers are either all the way up or all the way down, there is no meaning for a bead on an abacus that is half way up or down. Analog television are operated by machinery where the numbers vary continuously, whereas in digital television the numbers shift between discrete states, this is also true of analog computers and digital computers. The need to make fine measurements in analog devices severely limits their accuracy and digital devices are usually much more accurate.