| 摘要 |
<p>PURPOSE:To perform correct blood pressure measurement by providing a gate setting means setting time zones recognizing the Korotkoff sound and noise in turn, based on the pulse wave and a means changing the threshold value. CONSTITUTION:A gate 81 for Korotkoff sound recognition is formed at the minimum point 80a and the next same level point 80b, based on the pressure signal 80 inputted from a pressure detecting section 18 and converted into a digital value by an A/D converting section 26. The Korotkoff sound is extracted by comparison between the digital Korotkoff sound signal 83 inputted via an A/D converting section 21 by a microphone 51 and the preset threshold value level 82 in the gate 81. Noise is extracted by comparison with the preset threshold value level 82 at the gate exterior 84. If the pulse wave signal is larger than the preset threshold value A in the second-pulse and third-pulse gate 81 of the pulse wave and the noise level of the pulse wave signal is smaller than the threshold value A at the second-pulse and third-pulse gate exterior 84, it is judged as deficient pressurization. If the noise level is larger than the threshold value A at the gate exterior 84, the threshold value is set to B (B>A), and judgment is performed again.</p> |
