Oscilent Corporation - Technical References
Introduction to Quartz Frequency Standards

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Introduction to Quartz Frequency Standards - Index of Figures

1. Crystal oscillator - simplified circuit diagram.
2. Equivalent circuit of a mechanically vibrating system.
3. Equivalent circuit of crystal unit with load capacitor.
4. Reactance versus frequency of a crystal unit.
5. Zero-temperature-coefficient cuts of quartz.
6. Typical constructions of AT-cut and SC-cut crystal units: (a) two-point mount package; (b) three- and four-point mount package.
7. Resonator vibration amplitude distribution for a circular plate with circular electrodes.
8. Drive level dependence of frequency.
9. Drive level dependence of crystal unit resistance.
10. Modes of motion of a quartz resonator.
11. Frequency versus temperature characteristics of AT­cut crystals, showing AT­ and BT­cut plates in Y­bar quartz.
12. Crystal oscillator categories based on the crystal unit's frequency versus temperature characteristic.
13. Oscillator circuit types.
14. Oscillator outputs.
15. Accuracy, stability and precision examples for a marksman, top, and for a frequency source, bottom.
16. Computer-simulated typical aging behaviors; where A(t) and B(t) are logarithmic functions with different coefficients.
17. Low-Noise SAW and BAW multiplied to 10 GHz (in a nonvibrating environment).
18. Low-Noise SAW and BAW multiplied to 10 GHz (in a vibrating environment).
19. Wristwatch accuracy as it is affected by temperature.
20. Effects of harmonics on f vs. T.
21. Activity dips in the frequency versus temperature and resistance versus temperature characteristics, with and without C_L.
22. Warmup characteristics of AT-cut and SC-cut crystal oscillators (OCXOs).
23. Temperature-compensated crystal oscillator (TCXO) thermal hysteresis showing that the f vs. T characteristic upon increasing temperature differs from the characteristic upon decreasing temperature.
24. 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 10⁹ vs. time in days.)
25. 2-g tipover test (Df vs. attitude about three axes).
26. Vibration-induced "sidebands'' (i.e., spectral lines).
27. Resonance in the acceleration sensitivity vs. vibration frequency characteristic.
28. Random-vibration-induced phase-noise degradation.
29. Coherent radar probability of detection as a function of reference oscillator phase noise.
30. The effect of a shock at t = t₁ on oscillator frequency.
31. Crystal oscillator's response to a pulse of ionizing radiation: f₀ = original preirradiation frequency, Df_SS = steady-state frequency offset (0.2 hours to 24 hours after exposure), f_t = instantaneous frequency at time t.
32. Change in compensating frequency versus temperature due to C_L change.
33. Temperature-compensated crystal oscillator (TCXO) trim effect.
34. 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).
35. Stability as a function of averaging time comparison of frequency standards.
36. Phase instability comparison of frequency standards.