以变换识别法提取血液减压气泡信号

监测减压气泡信号可预报早期减压病。传统的多普勒超声检测仪是在心壁、血管壁及心脏瓣膜运动等形成的强大背景噪声下靠耳力辨听气泡音的，既欠客观也难定量。作者深入分析了气泡信号和背景噪声的本质区别，认为背景噪声的主要能量集中在６００Ｈｚ以下，属低频高幅心动噪声；气泡信号则高於此频段，且和血细胞滚动等形成的高频噪声相混叠，但后者幅度远低於气泡信号。基於此认识，提出了用变换识别法提取减压气泡信号的新方案，即利用精密的Ｆ／Ｖ变换器将原始的多普勒频移信号进行变换，使气泡信号呈尖峰波呈现出来，交换后用独特的截频滤波法将低频高幅噪声滤除。又在变换中调节变换输入幅值，利用变换阈限将高频噪声基本除去，这样气泡信号便较清晰地被提取出来。据此研制成的单机经动物和人体减压试验应用，效果较好，实现了实时定量监测目标。类似结果，国内外尚未见报道。

Extraction of Decompression Bubble Signals in Blood by an Identification Method with F/V Conversion

Monitoring decompression bubble signals in blood can help to predict early decompression sickness of human body. But using traditional Doppler ultrasonic detec-tor discrimination of bubble sound under strong background noise can hardly be objective and quantitative. After analysing essential differences between bubble signal and noise,a new scheme for extraction of decompression bubble signals by identification with F/ V con- version was proposed and an instrument for real time quantitative monitoring of bubble sig-nals was developed.