【摘要】 本文首次提出了HFBG-EMD的HHT改进算法,将滑动平均3次B样条求均值方法与改进的滤波终止条件相结合,大大减小了传统的EMD分解滤波次数,并提高了HHT的原有精度。对用该方法求出的各阶IMF函数进行瞬时频率变换后发现,它对减小各阶IMF瞬时频率的带宽和提高地震动主频特性的作用比较显著。此外,本文还采用了先在原始地震信号中加入高频正弦谐波再进行分解的方法,有效消除了传统方法中一直难以克服的IMF模态混叠及瞬时频率畸变现象。更多还原

【Abstract】 An improved algorithm HFBG-EMD is firstly brought up,which serves to adopt the method of means envelop form moving average three-order B-spline and modified G. Rilling filtering criteria,greatly reducing the filtering numbers in the EMD process and improving the precision of HHT. After an instantaneous frequency conversion of these IMF functions,which are obtained by this method,it was discovered that this method can be used to improve the dominant frequency characteristic and decrease the bandwidth of IMF instantaneous frequency. On the other hand,a high frequency harmonic wave is added into the original seismic signal,which can effectively eliminate the modal aliasing and the instantaneous frequency distortion of IMFs.更多还原