A nonlinearity error calibration technique based on an opamp distortion modeling

In this paper a new digital background distortion calibration technique based on an effective opamp distortion modeling is introduced. The gain curve of the amplifier is approximated using least square fitting method in which the unknown coefficients are estimated directly by using of a reference ADC, and consequently, extendibility toward higher order harmonics and fast calibration time are the major advantages of the proposed correction technique. The fitting process results confirm that the technique can be more effective in comparison to the correlation based methods which are based on injection a pseudo random noise sequence in the structure.