AX3 sensitivities and bit depths

The AX3 can be configured to log with various range settings (±4,8,16g). This range should be set such that the largest experienced accelerations does not cause clipping. At each range setting, the AX3 has a limited or fixed amount of bits to represent the data; this is termed the bit-depth. The AX3 has 2 bit depth modes; 10bit (or packed) and 13bit (un-packed) and the difference is how fast the memory gets eaten when logging.

At each bit depth, the range of accelerations is quantised into discrete levels. The width of each one of these levels is often called the < strong>sensitivity. To calculate the sensitivity you can simply use the following:

2^10 = 1024 levels in packed mode 2^13 = 8192 levels in un-packed mode.

Then divide the range by the number of levels. For example at ±8g, there is a dynamic range of 16g. Therefore 16g/8192 in un-packed mode gives 0.0019g (or 1.9mg).