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. Author manuscript; available in PMC: 2020 May 25.
Published in final edited form as: Nat Biomed Eng. 2019 Nov 25;4(2):148–158. doi: 10.1038/s41551-019-0480-6

Fig. 2 |. Representative mechano-acoustic (MA) data in the form of accelerations measured along three orthogonal axes from a device mounted on the suprasternal notch (SN) of a healthy normal subject.

Fig. 2 |

a, Power spectral analysis of data (z-axis acceleration) collected from a device vertically resting on an elastomer and interfaced to the SN of a subject sitting quietly. The power spectrum of the measurement from the SN shows high power below 100 Hz associated with various involuntary physiological events. b, 3-axes time series data simultaneously recorded over a 60 second interval as a subject engages in various activities that include sitting at rest, talking, drinking water, changing body orientation, walking and jumping. c, Sample time series data, spectrograms, and spectral information corresponding to cardiac activity, talking, swallowing, and walking. The frequency analysis uses a Hanning window with a width of 0.1 s moving in time steps of 0.02 s.