抄録
In this study, a breath monitoring system is being developed using a contact type microphone attached the neck and measuring the sound at the time of respiration (breath sound). In this paper, I made s sound measuring amplifier with adjustable frequency bandwidth amplification degree, so it fits each subject properly as well as improving the sound measuring circuit. Then I demonstrated that normal breathing, apnea and hypopnea could be determined analysing the relation between nasal airflow and the amplitude of the sound produced at neck level doing respiration. In addition, I verified the efficacy of the breath monitoring system by comparing it to an equipment that can, in a simple manner, examine the sleep apnea.
