Patent ID: 8659361
Filing Date: 2014-02-25
Classification: H03L

Abstract:
1. A function generator circuit for outputting a control signal to an oscillating circuit that causes a quartz crystal to oscillate, the function generator circuit comprising: an adjusting circuit configured to adjust a temperature at an inflection point of the control signal to match a temperature at the inflection point determined by a temperature characteristic of the quartz crystal; a temperature detecting circuit configured to output a detection voltage corresponding to an ambient temperature and having a linear temperature characteristic; a zeroth-order component generating circuit configured to generate a zeroth-order component of the control signal; a first-order component generating circuit configured to generate a first-order component of the control signal; a second-order component generating circuit configured to generate a second-order component of the control signal; a third-order component generating circuit configured to generate a third-order component of the control signal based on the detection voltage; and an adder-subtractor configured to generate the control signal by obtaining a sum of the zeroth-order component, the first-order component, and the third-order component and adding or subtracting the second-order component to or from the sum, wherein the second-order component generating circuit is configured to correct the temperature at the inflection point of the control signal adjusted by the adjusting circuit to match the temperature at the inflection point determined by the temperature characteristic of the quartz crystal according to product-specific adjustment data.