正常心音的第一、第二心音频率检测

Frequency Detection of the First and Second Heart Sound of Normal Heartbeats

为了观察心音的改变和心脏杂音的出现,从而分辨正常和异常心音,本研究针对第一心音和第二心音的频率特性进行了分析。我们分别采用小波变换和Choi-Williams分布两种方法对六例正常第一、第二心音和一例异常心音的频率特性进行了研究。两种分析方法的实验结果表明：正常心音的第一、第二心音频率成份主要集中在20-100Hz以内,与文献中提到的频率范围十分相似,由此验证了这两种方法对心音频率分析的正确性及可行性。

In order to observe the change of heart sound and the emergence of heart murmur, and distinguish the normal and abnormal heart sounds, we analyzed the frequency characteristics of the first heart sound and the second heart sound. In this paper, the frequency characteristics of six eases of normal first and second heart sounds and one ease of abnormal heart sound were analyzed by using wavelet transform and Choi - Williams distribution. The experimental results of this two methods show that the frequency components of normal first and second heart sounds mainly concentrate in a range from 20 to 100 Hz, which is similar to the experimental data of cited literatures, it proves that the two methods are correct and feasible in analyzing the frequency characteristics of heart sound signals.