Stopwatch Timebase

The type of time base used is usually important to name the type of watch. The most common are:
Network pattern. No reference oscillator and used in the 50 Hz (or 60 Hz) network. It is the simplest, but it is quite accurate in the medium term, as the changes in grid frequency are compensated throughout the day. It has two major drawbacks:
You need a "clean" signal, which is usually to filter before applying to the counters.
Need network, which does not allow portable use also frenta to online stopwatch a power outage, the time lost. There are models that include an oscillator and batteries, so the oscillator and counters still work during cutting, so no time is lost.
Issuer pattern. The time base is to be any type of PLL, coupled with one of the stations time. They put in hours alone and change to winter time or summer autonomously. Its drawback is that it requires the time signal, so that even at "dark" no major advantages.
Watch fingerboard. The oscillator is controlled by a tuning fork inserted in the feedback loop. It has fallen into disuse, but at the time were high end, and Bulova, eg pitch available wrist watches.

Quartz clock. Fingerboard replaced by a quartz oscillator, usually at 32768 Hz, being exact power of two, which simplifies the frequency divider. For stability and economy has displaced all other clock in typical applications.
Atomic Clock (Ammonia, cesium, etc) is to include in the feedback loop with a cavity suitable molecules of the substance, so that excite the resonance of one of its atoms.
The mechanical timepiece is based on a pushbutton which may be 1 Hz or submultiple. Usually this switch was a mechanical escapement mechanism in which the energy stored in a spring was released steadily and slowly. The sound of the clock ticking corresponds to the exhaust system that is responsible for generating the time base clock and provides the second movement, both the minute as the hours are driven by gear trains that transform the relationship of the second in 1/60 for the minute and this 1/60 for schedule (see image).
A digital clock consists of an oscillator, which usually means quartz frequency divider, a similarity of gear trains, signals generated 1 Hz, 1/60 Hz and 1/3600 Hz for the seconds and minutes and hours respectively . In this case the different electrical pulses pass cascade 3 counters on the screen correspond to the seconds, minutes and hours respectively. These counters are coupled to allow the necessary sequence of counting and signaling between an accountant and another, namely 0 to 59 for seconds and minutes and 0-24 or 1-12 for hours, according to the particular design or configuration in models that allow both.