Thursday, February 17, 2011
Time, clocks and getting work done...
If one wants to do work then something about the relationship of objects in nature has to change... (that's really all work is). In order for the relationship between objects to change one has to be able to discriminate between two different states and to know the order of those states. In the simplest case we can choose the two states as being 0 or 1 (it doesn't matter what the actual meaning of 0 and 1 are - they could be full and empty, hungry or satiated, hot or cold, having a positive charge or not - as long as we can tell the difference between them, as long as they can be measured they will "work").
If we look at what meaning we can derive from being able to measure two states of something, we find that there are four possible conditions: 1) the states over time could be stable and high 2) the states over time could be stable ad low 3) the states could change from low to high and 4) the states could change from high to low.
While the two stable conditions (high or low) could be used to consider whether or not something else could/should occur, they can not be used to do any work themselves... these form logical states. The transition states (either going from high to low or low to high) are more interesting though - since here we can measure time and that means that if we use these conditions as signals and since the rising and falling conditions must occur in a an interleaved sequential order (one can not have a rising edge following a rising edge) we can do work.
Clocks (no matter what kind of mechanism or power source) always measure time. It is the flow of energy from a higher potential to a lower potential or from a more ordered state to a less ordered state that allows work to be done. In electronics we often use crystals that oscillate when voltage is applied and when used as part of a resonant circuit a predictable number of changes in states over time occurs. It doesn't really matter that much exactly what the rate of oscillations in the natural resonator is because we can combine those transitions (the positive and negative edges) with other logical conditions to achieve just about any secondary pattern of signals we desire (which we will see in the next post).
The key concepts here are that in order to do work of any kind, we must be able to measure not only different states of something (logical conditions), but also the sequential changes (timing conditions) between those states.