Figure 4 | Scientific Reports

Figure 4

From: Extraction of apex beat waveform from acoustic pulse wave by sound sensing system using stochastic resonance

Figure 4

Extraction of CAB and CAS from F-APW and confirmation of BF. (a) According to Fig. 3, BF of the same subjects as Fig. 2 (heart rates are 58, 71, 79 and 93/min) were 14.8, 8.4, 8.5 and 15.0 Hz, respectively. CAB in the range of 0.5 Hz to BF and CAS in the range of BF to 50 Hz were extracted from F-APW collected from the precordial region based on BF. Front CAB (0.5-BF) resembles apex beat wave, and CAS resembles PCG. (b) Frequency analysis was conducted of Front CAB and Front CAS obtained from F-APW of the four same subjects based on BF determined in Fig. 3. It was revealed that the higher harmonic components of Front CAB decreased and converged in the vicinity of each BF.

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