OVERALL DEVELOPMENT OF LUNG SOUND ANALYZING SYSTEM

我们以前的肺音记录和分析系统存在以下局限性：1）该系统的机械或操作复杂; 2）用于A-D转换的波的长度是固定和有限的（在20 KHz的采样频率下为25.6ms），3）由于存储器尺寸小，从追踪的肺音中任选地提取每个爆裂音并不容易，4）对每一个裂纹进行频谱分析需要较长的时间。为了解决这些问题，我们构建了一个新的分析系统，使用数字模拟磁带录音机和个人计算机。该系统采用了一种商用软件Wave Master，它具有以下优点：1）可以实时进行A-D转换或记录; 2）A-D转换时间长，可以在一个呼吸时相采集到爆裂音（6.553秒）;在20 KHz的采样频率下），3）在显示器上容易地识别一个呼吸相位中的每一个爆裂声，4）可以任意拾取任何爆裂声或进行FFT分析，5）也可以同时显示时间扩展波形和FFT。为了测试该系统的优越性，我们从16例无痰的IIP患者中检出了80个湿罗音，从9例有大量痰的慢性支气管炎患者中检出了43个湿罗音（范围为50-300 ml/d）。通过对肺音的分析，可方便地测定出各组肺音的6个参数（Tb、Tf、IDW、2CD、PF、MF）。结果表明，这种新设备似乎是一种功能强大的肺音分析工具。

Our previous recording and analyzing system of lung sounds had some limitations as follows: 1) the machinery or the operation of this system was complicated, 2) the length of the waves for A-D conversion was fixed and limited (25.6 ms. at sampling frequency of 20 KHz) due to a small size memory, 3) optional extractions of each crackle from traced lung sounds was not easy, 4) spectral analysis of each crackles required long time. To solve these problems, we constructed a new analyzing system using a digital-analogue tape recorder and a personal computer. In this system, we applied a commercial software, Wave Master.This new system has following merits: 1) real-time A-D conversion or recording is possible, 2) the duration of A-D conversion is long enough to sample crackles in one respiratory phase(6.553 sec. at sampling frequency of 20 KHz), 3) we easily identify every crackles in one respiratory phase on the display, 4) picking up any crackles or doing FFT analysis at will is possible, 5) it is also possible to display time expanded wave forms and FFT simultaneously.To test the superiority of this system, we picked up 80 crackles from 16 IIP patients without sputum production and 43 crackles from 9 patients with chronic bronchitis who had significant amount of sputum (range 50-300 ml/day). By analyses of cracKles, we could easily determine 6 parameters of lung sounds (Tb, Tf, IDW, 2CD, PF, MF) in each group. As the results, this new device was seemed to powerful, tool for the analysis of lung sounds.