**Oscilent Corporation
- Technical References**

Introduction to Quartz Frequency Standards

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**Introduction to Quartz Frequency Standards - Index of
Figures**

- Crystal oscillator - simplified circuit diagram.
- Equivalent circuit of a mechanically vibrating system.
- Equivalent circuit of crystal unit with load capacitor.
- Reactance versus frequency of a crystal unit.
- Zero-temperature-coefficient cuts of quartz.
- Typical constructions of AT-cut and SC-cut crystal units: (a) two-point mount package; (b) three- and four-point mount package.
- Resonator vibration amplitude distribution for a circular plate with circular electrodes.
- Drive level dependence of frequency.
- Drive level dependence of crystal unit resistance.
- Modes of motion of a quartz resonator.
- Frequency versus temperature characteristics of ATcut crystals, showing AT and BTcut plates in Ybar quartz.
- Crystal oscillator categories based on the crystal unit's frequency versus temperature characteristic.
- Oscillator circuit types.
- Oscillator outputs.
- Accuracy, stability and precision examples for a marksman, top, and for a frequency source, bottom.
- Computer-simulated typical aging behaviors; where A(t) and B(t) are logarithmic functions with different coefficients.
- Low-Noise SAW and BAW multiplied to 10 GHz (in a nonvibrating environment).
- Low-Noise SAW and BAW multiplied to 10 GHz (in a vibrating environment).
- Wristwatch accuracy as it is affected by temperature.
- Effects of harmonics on f vs. T.
- Activity dips in the frequency versus temperature
and resistance versus temperature characteristics, with and without C
_{L}. - Warmup characteristics of AT-cut and SC-cut crystal oscillators (OCXOs).
- Temperature-compensated crystal oscillator (TCXO) thermal hysteresis showing that the f vs. T characteristic upon increasing temperature differs from the characteristic upon decreasing temperature.
- Oven-controlled crystal oscillator (OCXO) retrace
example, showing that upon restarting the oscillator after a 14 day off-period,
the frequency was about 7x10
^{-9}lower than it was just before turn-off, and that the aging rate had increased significantly upon the restart. About a month elapsed before the pre-turn-off aging rate was reached again. (Figure shows Df/f in parts in 10^{9}vs. time in days.) - 2-g tipover test (Df vs. attitude about three axes).
- Vibration-induced "sidebands'' (i.e., spectral lines).
- Resonance in the acceleration sensitivity vs. vibration frequency characteristic.
- Random-vibration-induced phase-noise degradation.
- Coherent radar probability of detection as a function of reference oscillator phase noise.
- The effect of a shock at t = t
_{1}on oscillator frequency. - Crystal oscillator's response to a pulse of ionizing
radiation: f
_{0}= original preirradiation frequency, Df_{SS}= steady-state frequency offset (0.2 hours to 24 hours after exposure), f_{t}= instantaneous frequency at time t. - Change in compensating frequency versus temperature
due to C
_{L}change. - Temperature-compensated crystal oscillator (TCXO) trim effect.
- Relationship between accuracy and power requirements (XO = simple crystal oscillator; TCXO = temperature-compensated crystal oscillator; OCXO = oven-controlled crystal oscillator; Rb = rubidium frequency standard; Cs = cesium beam frequency standard).
- Stability as a function of averaging time comparison of frequency standards.
- Phase instability comparison of frequency standards.