Patent ID: 6445908
Filing Date: 2002-09-03
Classification: H04L

Abstract:
A method of estimating local oscillator frequency error over temperature in a mobile phone, comprising the steps:defining a temperature compensation table having locations for storage of a frequency error entry for each of a plurality of temperature settings; defining a temperature array, containing less elements than the temperature compensation array, having a plurality of locations for the storage of recent frequency error readings corresponding to temperature settings; measuring periodically a frequency error of a mobile phone local oscillator and a temperature of the mobile phone; writing the value of the measured frequency error into the temperature compensation table; writing the value of the measured frequency error into a least current location in the temperature array or preferably into a location within the temperature array corresponding to the same temperature if said location exists; estimating the local oscillator frequency error at a particular temperature to be a frequency error saved in the temperature array at the particular temperature if that temperature entry exists in the temperature array; and if the particular temperature does not exist in the temperature arrayestimating the local oscillator frequency error at the particular temperature to be a weighted sum of the frequency error stored in the temperature compensation table at the particular temperature plus the frequency errors in the temperature array at temperatures within a predetermined distance from the particular temperature.