MEMS accelerometers can be classified by the number of
axis (1, 2 or 3 axis) and the type of the output signals (analog
or digital). Only 2-axis accelerometers where available
previously because of the difficulty of silicon micro
manufacturing. Analog sensors require an ADC stage on the
microcontroller being used to process the signals. It will
impose its sampling frequency. Special care must be taken to
avoid the introduction of supplementary noise on the
acceleration signals being sampled. The ADC resolution is
chosen in consequence