| 摘要 |
<p>The respiration impedance can be continuously measured with very high accuracy by eliminating the noise. An air vibration pressure caused by an oscillation wave which is subjected to frequency thinning so that the oscillation wave has only frequency component left after different frequencies are thinned and which is produced by a pulse signal driven in such a way that the polarity of the pulse is changed depending on whether the respiration is inspiration or expiration is applied into a buccal cavity by means of a loudspeaker (21), the pressure inside the buccal cavity is detected, the flow rate of the respiration is detected, a thus obtained signal is Fourier-transformed by means of a Fourier transform means (32), thereby a spectrum is acquired, the respiration high-frequency component contributing as noise using the spectrum corresponding to the frequency component removed by the thinning is obtained by means of an extracting means (33) with respect to the result of the Fourier transform, the respiration high-frequency component is subtracted from the spectrum corresponding to the frequency component left by the thinning, the oscillation wave component is thus extracted, a calculation of dividing the pressure component by the flow rate component for each frequency is performed by means of a calculating means (34) with respect to the result of the extraction, and thereby the respiration impedance is determined.</p> |
