FUNDAMENTAL LIMITS ON THE FREQUENCY STABILITIES OF CRYSTAL-OSCILLATORS

The frequency instabilities of precision bulk acoustic wave (BAW) quar tz crystal oscillators are reviewed, The fundamental limits on the ach ievable frequency stabilities, and the degree to which the fundamental limits have been approached to date are examined, Included are the in stabilities as a function of time, temperature, acceleration, ionizing radiation, electromagnetic fields, humidity, atmospheric pressure, po wer supply, and load impedance. Most of the fundamental limits are zer o or negligibly small, a few are finite, We speculate about the progre ss which may be achievable in the future with respect to approaching t he fundamental limits, Suggestions are provided about the paths that m ay lead to significant stability improvements.