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. A frequency 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 - 25 . (canceled) 
     
     
         26 . An apparatus for a mobile device, the mobile device comprising:
 a crystal configured to generate a reference frequency;   a temperature sensor configured to generate indications of a temperature of the crystal; and   a processor configured:
 to monitor the indications from the temperature sensor, 
 to estimate a temperature of the crystal using the indications, 
 to calculate a frequency change of the reference frequency based on the estimate of the temperature of the crystal; 
   to compensate the reference frequency for frequency drift using the frequency change to provide a compensated reference frequency; and   to process data signals using the compensated reference frequency.   
     
     
         27 . The apparatus of  claim 26 , including an analog-to-digital converter connected to the sensor and configured to provide digital indications of a temperature of the crystal. 
     
     
         28 . The apparatus of  claim 26 , including a positioning receiver configured to wirelessly receive position information from a satellite-based positioning system and to provide the position information to the processor. 
     
     
         29 . The apparatus of  claim 26 , wherein the processor includes a baseband oscillator configured to receive the compensated reference frequency and to generate a temperature compensated baseband signal. 
     
     
         30 . The apparatus of  claim 29 , wherein the baseband processor includes a mobile communication system baseband oscillator. 
     
     
         31 . The apparatus of  claim 26 , wherein a temperature drift of the crystal is based on a first indication and a second indication. 
     
     
         32 . The apparatus of  claim 26 , including a frequency drift configured to estimate a frequency drift of the oscillator signal based on the temperature drift of the crystal. 
     
     
         33 . The apparatus of  claim 32 , wherein the frequency drift estimator is configured to estimate the frequency drift using a stored temperature characteristic of the oscillator signal frequency. 
     
     
         34 . The apparatus of  claim 33 , wherein at least a part of the stored temperature characteristic is stored in the form of parameters of an approximating function to the temperature characteristic. 
     
     
         35 . The apparatus of  claim 33 , including update logic configured to adapt the stored temperature characteristic on the basis of measured values of the indications and corresponding evaluated frequency values of the crystal. 
     
     
         36 . An apparatus for a mobile communication device, the apparatus comprising:
 a crystal configured to provide a reference frequency;   a temperature sensor configured to provide temperature indications of a temperature of the crystal;   a wireless communication processor configured:
 to monitor the temperature indications, 
 to calculate a frequency change of the reference frequency based on a difference between first and second temperature indications of the temperature indications; and 
 to compensate the reference signal for frequency drift of the crystal using the frequency change to provide a compensated reference frequency; and 
 to process data signals using the compensated reference frequency. 
   
     
     
         37 . The apparatus of  claim 36 , wherein the wireless communication processor is configured to generate a compensation signal based on the frequency change. 
     
     
         38 . The apparatus of  claim 37 , wherein the wireless communication processor includes a phase-lock loop (PLL) configured to receive the reference frequency and the compensation signal and to provide a first compensated frequency signal. 
     
     
         39 . The apparatus of  claim 38 , wherein the compensation signal is configured to adjust a divider of the PLL. 
     
     
         40 . The apparatus of  claim 36 , wherein the wireless communication processor is configured to estimate the frequency drift based on a stored temperature characteristic of the oscillator signal frequency. 
     
     
         41 . The apparatus of  claim 40 , wherein at least a part of the temperature characteristic is stored in the form of parameters of an approximating function to the temperature characteristic. 
     
     
         42 . The apparatus of  claim 36 , wherein the wireless communication processor is a Universal Mobile Telecommunications System (UMTS) processor. 
     
     
         43 . The apparatus of  claim 36 , wherein the wireless communication processor s a global positioning system processor. 
     
     
         44 . At least one machine readable storage medium, comprising a plurality of instructions adapted for compensating temperature related frequency shift of a crystal, wherein the instructions, responsive to being executed with processor circuitry of a machine, cause the machine to perform operations that:
 monitor temperature indications of the crystal, the temperature indications received from a temperature sensor;   estimate a temperature of the crystal using the temperature indications;   calculate a frequency change of a reference frequency of the crystal based on the estimate of the temperature of the crystal;   compensate the reference frequency using the frequency change to provide a compensated reference frequency; and   process data signals using the compensated reference frequency.   
     
     
         45 . The machine readable storage medium of  claim 44  wherein the operations that cause the machine to calculate a frequency change include operations to calculate the frequency change of the reference frequency based on a difference between first and second temperature indications of the temperature indications 
     
     
         46 . The machine readable storage medium of  claim 44 , wherein the operations that cause the machine to calculate a frequency change include operations to estimate the frequency change using a stored temperature characteristic of the crystal signal frequency. 
     
     
         47 . The machine readable storage medium of  claim 46 , wherein at least a part of the stored temperature characteristic is stored in the form of parameters of an approximating function to a temperature characteristic.