Crystal oscillator A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock ...

s can be manufactured for oscillation over a wide range of frequencies, from a few kilohertz up to several hundred megahertz. Many applications call for a crystal oscillator frequency conveniently related to some other desired frequency, so hundreds of standard crystal frequencies are made in large quantities and stocked by electronics distributors. Using

frequency divider A frequency divider, also called a clock divider or scaler or prescaler, is a circuit that takes an input signal of a frequency, f_, and generates an output signal of a frequency: : f_ = \frac where n is an integer. Phase-locked loop frequency ...

frequency multiplier In electronics, a frequency multiplier is an electronic circuit that generates an output signal and that output frequency is a harmonic (multiple) of its input frequency. Frequency multipliers consist of a nonlinear circuit that distorts the in ...

s and

phase locked loop A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal. There are several different types; the simplest is an electronic circuit consisting of a ...

circuits, it is practical to derive a wide range of frequencies from one reference frequency. The

UART A universal asynchronous receiver-transmitter (UART ) is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. It sends data bits one by one, from the least signific ...

column shows the highest common

baud rate In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modul ...

(under 1,000,000), assuming a clock pre-divider of 16 is resolved to an exact integer baud rate. Though some UART variations have fractional dividers, those concepts are ignored to simplify this table.

References

{{Reflist Electronic oscillators Electrical components