I was use ADXL313 for digital angle meter, and has non-linearity issue.
If the angle meter has good offset calibration, assume i put the angle at 45 degree,
sin(45) = 0.707, ideally the AccX = 1024 * 0.707 = 724, but after the offset calibration, i get the AccX = 720,
it has 4 lsb deviation between 724 and 720, asin(724/1024) = 44.99, but asin(720/1024) = 44.67,
I checked the ADXL313 datasheet, found the nonlinearity is +-0.5%, I guess this is because nonlinearity issue, how to calibrate the non-linearity issue?