Figure 1
From: Quantification of acceleration as activity counts in ActiGraph wearable
Conceptual schematic of the computational pipeline for generating counts for five generations of ActiGraph accelerometer models (rows). Raw data measures acceleration in free fall acceleration (g) units. Functions performed by the microprocessor, the accelerometer and in the CentrePoint cloud are highlighted in yellow, gray and orange, respectively. The analog band-pass filters in AM7146 are implemented using a series of cascaded op amp circuits, the half magnitude points for the lower and upper cutoff frequencies are 0.21 and 2.28 Hz, respectively14. For the analog low-pass filters the − 3 dB cutoff frequency is shown in parenthesis for each block. A/D is the analog-to-digital converter (white blocks), shown together with the bit size of the quantizer. The counts data blocks are highlighted in boldface.
