Qualitative frequency response calibration of sonocardiography system to sense wrist pulse

Abstract

The frequency response of the microphone of the Yu and Wang sonocardiography system is qualitatively proven to cover the 0.5 to 10 Hz zone which is in the traditional Chinese medicine's interesting range of the wrist pulse data and is beyond the announced range of most commercial product. The calibration system employs a small speaker and a small capacity type microphone to construct a small air cell to service as an acoustic wave transfer zone where the speaker is employed to simulate the wrist pulse input. In order to simulate the small air column enclosed by the microphone's membrane cell and a patient's skin, the air cell bounded by the speaker and microphone has tiny and/or small leakage through the bounding interface. The air leakage is employed to simulate the patient's soft tissue around the measuring point. The data picked by the microphone is treated by a Fourier sine spectrum/spectrogram generator. Experimental results show that both cases with tine and small air leakages have apparent responses in the interested frequency range. Two test cases were included to demonstrate the system performance: one had the spleen disease and the other had heart problem. According to the Wang frequency resonance theory of arterial and vascular system, their spectrograms show that every corresponding harmonic mode havs unstable amplitude variation with respect to time. In other words, the data acquisition system together with time-frequency analysis accurately reflects the connection between the abnormal harmonic mode and corresponding organ. © 2008 Springer-Verlag.