Temperature compensation for an oscillator crystal

Abstract

An electronic device is equipped with an oscillator interface to be coupled to an oscillator crystal of an oscillator element. The electronic device includes an oscillator circuit which is coupled to the oscillator interface and generates an oscillator signal. The electronic device is further provided with a temperature measurement interface to be coupled to a temperature sensor of the oscillator element so as to receive the temperature signal. For accomplishing temperature compensation, the electronic device is provided with a measurement controller coupled to the measurement: interface and configured to measure a first value of the temperature signal at a first point of time and a. second value of the temperature signal at a second point of time. Afrequency drift estimator is provided so as to estimate a frequency drift of the oscillator signal on the basis of the first value of the temperature signal and a second value of the temperature signal. By means of a compensation logic, a frequency compensation signal for the oscillator circuit is generated on the basis of the estimated frequency drift.

1 - 9 . (canceled) 
     
     
         10 . An apparatus for a mobile communication device, the apparatus comprising:
 a crystal configured to provide a reference frequency;   a temperature sensor configured to provide an analog signal indicative of temperature of the crystal;   a processor configured to receive the analog signal, to provide a temperature drift of the crystal, to estimate a frequency error of the reference frequency using the temperature drift and to generate compensated output signals based on the frequency error.   
     
     
         11 . The apparatus of  claim 10 , wherein the processor includes a receiver phase-lock loop configured to receive one of the compensated output signals and to generate a temperature compensated local oscillator signal. 
     
     
         12 . The apparatus of  claim 11 , wherein the phase-lock loop is a global positioning system receiver phase-lock loop. 
     
     
         13 . The apparatus of  claim 10 , wherein the processor includes a baseband oscillator configured to receive one of the compensated output signals and to generate a temperature compensated baseband signal. 
     
     
         14 . The apparatus of  claim 13 , wherein the baseband processor includes a global positioning system baseband oscillator. 
     
     
         15 . The apparatus of  claim 10 , wherein the temperature drift of the crystal is based on a first value of the analog signal signal and a second value of the analog signal. 
     
     
         16 . The apparatus of  claim 10 , including a frequency drift estimator configured to estimate a frequency drift of the oscillator signal on the basis of the temperature drift of the crystal. 
     
     
         17 . The apparatus of  claim 16 , wherein the frequency drift estimator is configured to estimate the frequency drift on the basis of a stored temperature characteristic of the oscillator signal frequency. 
     
     
         18 . The apparatus of  claim 17 , wherein at least a part of the temperature characteristic is stored in the form of parameters of an approximating function to the temperature characteristic. 
     
     
         19 . The apparatus of  claim 17 , including update logic configured to adapt the stored temperature characteristic On the basis of measured values of the analog signal and corresponding evaluated frequency values of the crystal. 
     
     
         20 . An apparatus for a mobile communication device, the apparatus comprising:
 a crystal configured to provide a reference frequency;   a temperature sensor to provide an analog signal indicative of temperature of the crystal;   a global positioning system configured to receive the analog signal, to provide a temperature drift of the crystal, to estimate a frequency error of the reference frequency using the temperature drift and to generate a compensation signal based on the frequency error.   
     
     
         21 . The apparatus of  claim 20 , wherein the global positioning system includes phase-lock loop (PLL) configured to receive the reference signal and the compensation signal and to provide a first compensated frequency signal. 
     
     
         22 . The apparatus of  claim 21 , wherein the compensation signal is configured to adjust a divider of the PLL. 
     
     
         23 . The apparatus of  claim 20 , wherein the temperature drift of the crystal is based on a first value of the analog signal and a second value of the analog signal. 
     
     
         24 . The apparatus of  claim 20 , including a frequency drift estimator configured to estimate a frequency drift of the oscillator signal on the basis of the temperature drift of the crystal. 
     
     
         25 . The apparatus of  claim 24 , wherein the frequency drift estimator is configured to estimate the frequency drift on the basis of a stored temperature characteristic of the oscillator signal frequency. 
     
     
         26 . The apparatus of  claim 25 , wherein at least a part of the temperature characteristic is stored in the form of parameters of an approximating function to the temperature characteristic.