Patent ID: 7800457
Filing Date: 2010-09-21
Classification: H03L

Abstract:
1. A self-calibrating temperature compensated oscillator, comprising: a first resonator, a second resonator, and a heating element adapted to heat the first and second resonators in response to a heater control signal, where a temperature coefficient of the second resonator is substantially greater than a temperature coefficient of the first resonator; a first oscillator circuit adapted to operate in conjunction with the first resonator and to output a first oscillator output signal having a first oscillating frequency, the first oscillating frequency being variable in response to a control signal; a second oscillator circuit adapted to operate in conjunction with the second resonator and to output a second oscillator output signal having a second oscillating frequency; a temperature determining circuit for determining a temperature of the first resonator using the second oscillating frequency; and a temperature compensator adapted to provide the control signal to the first oscillator in response to the determined temperature to maintain the first oscillator output signal at a desired operating frequency, wherein the temperature determining circuit includes a counter for receiving the second oscillator output signal and being clocked by the first oscillator output signal to produce a signal indicating the second oscillating frequency, where the second oscillating frequency corresponds to the temperature of the first resonator.