Method and apparatus for correction of A/D converted output data
AssigneeDenso Corporation
InventorsMitsuo Nakamura, Takamoto Watanabe, Sumio Masuda
Life of this patent
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Abstract
A method for correcting A/D converted output data which corrects digital data obtained by A/D conversion of an analog signal, comprising forming an at least first order polynomial curve approximating an input/output characteristic curve of A/D conversion in a range of input of the analog signal, setting an ideal input/output characteristic line of A/D conversion, deriving a conversion equation for converting coordinates of a point on the approximation polynomial curve to a point of the ideal input/output characteristic line for the same analog signal value, and using this conversion equation to convert A/D converted digital data so as to correct non-linearity of the output data.
Claims20
A method of correction of A/D converted output data for correcting digital data obtained by A/D conversion of an analog signal, comprising the steps of:
- forming at least a first order approximation polynomial curve approximating an input/output characteristic curve of A/D conversion in a predetermined input range of said analog signal,
- setting an ideal input/output characteristic line corresponding to said input/output characteristic curve of A/D conversion in said predetermined input range of said analog signal,
- deriving a conversion equation for converting coordinates of a point on said approximation polynomial curve to coordinates of a point on said ideal input/output characteristic line corresponding to the same analog signal value, and
- converting said A/D converted digital data by said conversion equation.
An apparatus for correction of A/D converted output data for correcting digital data obtained inputting an analog signal to an A/D converter, comprising:
- a reference signal input unit for inputting a plurality of analog signal values as reference signals to said A/D converter in a predetermined input range of said analog signal,
- an approximation polynomial curve forming unit for obtaining at least a first order approximation polynomial curve for approximating an input/output characteristic curve of said A/D conversion based on reference digital data output from said A/D converter for input of said reference signals,
- an ideal input/output characteristic line setting unit for setting an ideal input/output characteristic line corresponding to said input/output characteristic curve of said A/D conversion in said predetermined input range of said analog signal,
- a conversion equation deriving unit for deriving a conversion equation for converting coordinates of a point on said approximation polynomial curve to coordinates of a point on said ideal input/output characteristic line corresponding to the same analog signal value, and
- a data converting unit for converting digital data output from said A/D converter by said conversion equation.
An A/D conversion system comprising:
- an A/D converting unit for converting an analog signal to digital data,
- a reference signal input unit for inputting a plurality of analog signal values as reference signals to said A/D converting unit in a predetermined input range of said analog signal,
- an approximation polynomial curve forming unit for obtaining an approximation polynomial curve for approximating an input/output characteristic curve of said A/D conversion based on reference digital data output from said A/D converting unit for input of said reference signal,
- an ideal input/output characteristic line setting unit for setting an ideal input/output characteristic line corresponding to said input/output characteristic curve of said A/D conversion in said predetermined input range of said analog signal,
- a conversion equation deriving unit for deriving a conversion equation for converting coordinates of a point on said approximation polynomial curve to coordinates of a point on said ideal input/output characteristic line corresponding to the same analog signal value, and
- a data converting unit for converting digital data output from said A/D converting unit by said conversion equation.
Dependencies are inferred from the claim text.