| 摘要 |
An apparatus and a method are provided to obtain oscillations from a crystal at a particular frequency by introducing real and imaginary components of voltage to the crystal. The imaginary component of voltage is different from the real component of voltage by a particular phase angle such as 90 DEG . The voltage introduced to the crystal is processed to produce a first current having characteristics corresponding to such voltage and to produce a second current having characteristics related to the imaginary component of such voltage. The first and second currents are combined to produce a first current corresponding to the real component of the voltage introduced to the crystal. This current is shifted through a phase angle of 90 DEG to produce a second current corresponding to the imaginary component of the voltage introduced to the crystal. The first current is converted to a first voltage which is regulated to provide a particular gain. This regulated voltage corresponds to the real component of the voltage introduced to the crystal. The second current is converted to a second voltage which can be adjusted to adjust the frequency of the oscillations from the oscillator. The second voltage corresponds to the imaginary component of the voltage introduced to the crystal. The first and second voltages are combined to produce the voltage for introduction to the crystal.
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