t is about 1% fast, it is hardly an accurate oscillator, and if used in a clock, the resulting time will not be accurate either, because you would expect it to be about 1% (or 864 seconds per day) too fast. Although not accurate, it is precise in that its performance is consistent or stable. If something like an oscillator is stable, it is a good candidate as a frequency source because it can be relied on to deliver the same output over time. Stability only indicates whether the frequency (or any other characteristic) stays the same and does not drift. The behavior of cesium atoms is very stable, which is why metrologists use it as a source of the second and to keep UTC time. Taking this oscillator that is always spinning at 20.2 MHz, it would be possible to build a very ac- curate clock out of it, since the designer could compensate for the 1% excessive frequency. One does this by either slowing it down (for example, by lowering the input voltage) or counting 20.2 million cycles for a second rather than 20.0. Designing a clock around this oscillator and using com- pensation for the inaccurate (but stable) frequency would result in a very accurate clock. When a stable clock behaves the same all day and every day, then it should be possible to com- pensate for any inaccuracy and make the device both accurate and stable. In contrast, a clock that fluctuates within a range of +5 minutes of the correct time every day is unstable, and although on occasion it might have the correct time, it could never be made accurate. As they say, even a stopped (analog) watch shows the correct time twice per day. 1.6 Summary This chapter covered the basic concepts of timing and synchronization. The next step is to learn why timing and synchronization is important and which use cases it can be applied to. Chapter 2 starts with some historical background before dealing with more modern use cases. It will introduce timing and synchronization applied to real-world problems. Chapter 2. Usage of Synchronization and Timing In this chapter,