Dependence of Blood Pulse Shapes on Attachment Diameters of a Condenser Microphone

Blood pulse shapes were determined as a function of diameter d of attachments for a condenser microphone. Our findings are summarized as follows: (1) Sensitivity for measuring the pulse was best for d ~9.3- 16mm within the experiment conditions adopted. (2) The pulse shapes were different for different d. (3) Times for appearances of the second and the third peaks in a pulse wave gradually increased for increasing d, reached their maximum at d =16mm, then decreased. (4) Height of the second peak in a pulse wave gradually decreased for increasing d, reached its minimum at d = 14-16mm, then increased. The dependence of the pulse height of the third peak on d showed a complicated characteristic.