Method and apparatus for compensating local oscillator frequency error
First Claim
1. A device for compensating Local Oscillator (LO) frequency error comprising:
- a wireless phone receiver for receiving a base station signal;
a GPS receiver including an LO;
a circuit for receiving said base station signal and calculating an LO frequency error based thereupon;
at least one sensor for monitoring a temperature gradient that contributes to LO frequency error; and
an oscillator characterization circuit for receiving the calculated LO frequency error and readings from the at least one sensor, wherein the oscillator characterization circuit generates a compensation signal based upon the calculated LO frequency error and the readings from the at least one sensor.
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Accused Products
Abstract
The frequency error of an oscillator is minimized by characterizing the oscillator. A reference signal from an external source containing a minimal frequency error is provided to an electronic device. The external signal is used as a reference frequency to estimate the frequency error of an internal frequency source. The electronic device monitors parameters that are determined to have an effect on the frequency accuracy of the internal frequency source. Temperature is one parameter known to have an effect on the frequency of the internal frequency source. The electronic device collects and stores the values of the parameters as well as the corresponding output frequency or frequency error of the internal frequency source. The resultant characterization of the internal frequency source is used to compensate the internal frequency source when the internal frequency source is not provided the external reference signal.
79 Citations
15 Claims
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1. A device for compensating Local Oscillator (LO) frequency error comprising:
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a wireless phone receiver for receiving a base station signal; a GPS receiver including an LO; a circuit for receiving said base station signal and calculating an LO frequency error based thereupon; at least one sensor for monitoring a temperature gradient that contributes to LO frequency error; and an oscillator characterization circuit for receiving the calculated LO frequency error and readings from the at least one sensor, wherein the oscillator characterization circuit generates a compensation signal based upon the calculated LO frequency error and the readings from the at least one sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for compensating Local Oscillator (LO) frequency error in a mobile phone system having a mobile phone receiver and a GPS receiver comprising:
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monitoring in a mobile phone operation mode at least one sensor reading of a temperature gradient in said mobile phone system and an LO frequency error, comprising; receiving with said mobile phone receiver a base station signal having a high frequency stability; generating the LO frequency error by comparing the base station signal to an LO frequency; receiving readings from the at least one sensor; and compensating in a GPS operation mode an estimated LO frequency error based upon the at least one sensor reading and the LO frequency error monitored in the mobile phone operation mode. - View Dependent Claims (12, 13, 14, 15)
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Specification