PROBLEM TO BE SOLVED: To enable a respiration impedance to be continuously measured with very high accuracy by eliminating the noise.SOLUTION: 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.COPYRIGHT: (C)2011,JPO&INPIT【課題】ノイズ除去を行って極めて高精度で呼吸インピーダンスの連続測定を可能とする。【解決手段】ラウドスピーカ21により口腔内に複数の異なる周波数から間引きして残った周波数成分のみを有するように周波数間引きされたオシレーション波であって呼気時と吸気時に応じてパルスの正負を異ならせて駆動するパルス信号によるオシレーション波による空気振動圧を加え、口腔内の圧力を検出し、呼吸の流量を検出し、この得られた信号をフーリエ変換手段32にてフーリエ変換してスペクトルを得て、このフーリエ変換結果について間引きした周波数成分対応のスペクトルにより雑音として寄与する呼吸高周波成分を抽出手段33にて求め、間引きにより残った周波数成分対応のスペクトルからこの呼吸高周波成分を減算してオシレーション波成分を抽出し、この抽出結果について周波数毎に圧力成分を流量成分で除算する演算を演算手段34において行って呼吸インピーダンスを得る。【選択図】図1
