Nonlinear Time Domain Relation between Respiratory Phase and Timing of the First Heart Sound

Figure 3

Nonlinear relation between the timing and the phase. (a) Two series of the timings and the phases are shown in time domain. (b) Scatter plot in the joint plane of timing and phase. EXP: expiration, INS: inspiration. (c) The nonlinear relation is approximated by a Hammerstein-Wiener model.

(a)

(b)

(c)