中文摘要：

在长骨头的超声的信号包含相互的多重指导模式迭加。在长骨头的指导波浪的速度对外皮的厚度(CTh ) 很敏感。在这份报纸， Hilbert-Huang 变换(HHT ) 被建议分析指导的多模式挥动模式，它能把迭加的波浪分解成许多独立人士。然后，每个模式的组速度在相应频率被获得，它与短时间 Fourier 变换(STFT ) 的结果相比。CTh 被与理论计算作比较也获得。结果证明试验性的坚定的厚度与实际 CTh 一致，显示测量指导模式的速度能被用来估计 CTh。HHT 是一个有效方法鉴别 multimode 指导了波浪。

英文摘要：

The ultrasonic signals in long bones contain multiple guided modes which are mutual superposed.The velocities of guided waves in long bones are very sensitive to cortical thickness （CTh）.In this paper,Hilbert-Huang transform（HHT） was proposed to analyze multi-mode guided waves,which can decompose superposed waves into many independent modes.Then the group velocity of each mode was obtained at corresponding frequency,which was compared with the results of short time Fourier transform（STFT）.The CTh was also obtained by comparing with the theoretical calculation.The results showed that the experimental determined thickness was in agreement with the actual CTh,indicating that measuring the velocity of the guided mode can be used to estimate the CTh.The HHT is an effective method to identify multimode guided waves.