Impact excitation level of
      In fact, all components of the frequency of the crystal are excited to some extent with the level change, in general, the frequency of the AT-cut crystal would be slightly increased with the increase in the level of the excitation. High excitation level will cause distortion temperature characteristics of the resonator, and activate parasitic mold. The excitation of the crystal is too high heat and stress is too large, resulting in irreversible frequency drift.
      Very low excitation level (number of micro-watts or less), the resonance resistance crystal element may be a lot higher than the rated excitation level lower resistance value, to cause oscillator start-up difficulties. This effect after a period of non-working state storage will increase, which is excitation level correlation (DLD). Therefore, the excitation level transistor actually used in the circuit should not be too large and too small.
 

      The following is a commonly used value of excitation power IEC recommended.
  2mw, 1mw, 0.1mw (100μw), 0.05mw (50μw), 0.02mw (20μw), 0.01mw (10μw), 0.001 mw (1μw)
       Preferred values ​​5MHz following 500μw, general 100μw