Patent ID: 6384757
Filing Date: 2002-05-07
Classification: H03M

Abstract:
A method of calibrating an analog-to-digital converter, whereingiving an initial value to a correction term of a digital value obtained in response to an analog signal supplied to the analog-to-digital converter, supplying an input to the analog-to-digital converter with an input voltage included in the voltage sector to be calibrated, said input voltage being selected such that a digital value corresponding to the input voltage is substantially of the same magnitude as a first digital value and a second digital value, supplying a first control code to the analog-to-digital converter, whereupon the first digital value is obtained as the output of the converter, supplying a second control code to the analog-to-digital converter, whereupon the second digital value is obtained as the output of the converter, calculating a residual of the voltage sector to be calibrated as a difference of the second and the first digital value, calculating a correction term related to the voltage sector, which correction term is the initial value of the correction term in the first voltage sector, by adding the correction term of the adjacent calibrated voltage sector to the residual of the voltage sector, storing in a memory the correction term related to the voltage sector, to be used in correcting the digital value obtained from the analog-to-digital converter with the correction term when the analog-to-digital converter is used to convert a signal included in the voltage sector of the voltage space from an analog into a digital form, replacing the voltage sector with the next voltage sector in the voltage space of the analog-to-digital converter, repeating the preceding seven steps until a correction term has been found for each voltage sector, reading from the converter the digital value obtained when the analog signal is converted into a digital signal, reading from the memory the correction term corresponding to the digital value, correcting said digital value with said correction term, repeating the preceding three steps during the conversion.