Nearly all electronics require devices called oscillators
that create precise frequencies—frequencies used to keep time in wristwatches
or to transmit reliable signals to radios. For nearly 100 years, these
oscillators have relied upon quartz crystals to provide a frequency reference,
much like a tuning fork is used as a reference to tune a piano. However, future
high-end navigation systems, radar systems, and even possibly tomorrow's
consumer electronics will require references beyond the performance of quartz.