Abstract: Continuous measurement of breathing impedance with extremely high precision is enabled by executing noise elimination. A loudspeaker applies an air vibration pressure by an oscillation wave to an oral cavity, the oscillation wave being obtained by frequency-cuffing so executed that the oscillation wave has only the frequency component that is left after the culling is executed from a plurality of different frequencies and being generated by a pulse signal for pulse drive with pulses made positive and negative separately in correspondence to the time of exhalation and the time of inhalation. A pressure inside the oral cavity is detected and a breathing flow is detected, and a signal obtained by the detection is Fourier-transformed to obtain a spectrum. Analysis of the spectrum is performed to obtain breathing impedance.

Abstract: Continuous measurement of breathing impedance with extremely high precision is enabled by executing noise elimination. A loudspeaker 21 applies an air vibration pressure by an oscillation wave to an oral cavity, the oscillation wave being obtained by frequency-culling so executed that the oscillation wave has only the frequency component that is left after the culling is executed from a plurality of different frequencies and being generated by a pulse signal for pulse drive with pulses made positive and negative separately in correspondence to the time of exhalation and the time of inhalation. A pressure inside the oral cavity is detected and a breathing flow is detected, and a signal obtained by the detection is Fourier-transformed by a Fourier transforming means 32 to obtain a spectrum. A breathing high frequency component that contributes as a noise is obtained by an extracting means 33, using a spectrum that corresponds to a frequency component culled from the result of the Fourier transformation.

Abstract: Continuous measurement of respiratory impedance with very high precision is enabled by executing noise removal. An air vibration pressure by an oscillation wave obtained by frequency culling such that the oscillation wave has only frequency components left by the culling from a plurality of different frequencies, is applied by a loudspeaker 21 to the inside of an oral cavity. The pressure in the oral cavity is detected and the flow of breathing is detected. These signals obtained are Fourier-transformed by a Fourier transforming means 32 and, thereby, a spectrum is obtained. A breathing high frequency component that contributes as a noise is obtained by the extracting means 33 using a spectrum that corresponds to the frequency components culled from the result of the Fourier transformation. The breathing high frequency component is subtracted from the spectrum that corresponds to the frequency components left by the culling and, thereby, the oscillation wave component is extracted.