The major work and achievement of this paper are presented as follows : ( 1 ) we review the main methods of audio retrieval at home and abroad 对音频信号的短时过零率、短时能量、 mel倒谱系数等进行主要分析。提出均值mfcc系数作为音频特征的方法。
As to the software , it realized feature extraction and target identification from the seismic signals of representative moving targets using the zero - crossing method in time domain 软件采用时域上的过零算法对典型地面运动目标(如车辆、人员)的地震动信号进行特征提取，目标识别。
The merit of travelling waves location is its high precision , but it has dead line if the fault location is close to the line terminal or the fault occurs at the time close to zero point of current 行波法测距的优点是精度高，但对近区故障或电流过零附近时刻发生的故障存在测距死区。
Whereas if the contacts are in series with the alternating circuit , due to the passing zero property of voltage , we must evaluate the condition of contacts according to voltage value 但当触头接入交流电路中时，由于电压有过零的特征，所以要根据电压有效值来判断触头是打开还是闭合。
In view of theproperties of infrared thermal images , narrow - range zero - crossing edge detection method was applied to detect the edges of welding flaws and good results were obtained 针对红外热图象的灰度特性，提出了窄范围二阶导数过零边缘检测用于焊接缺陷的边缘提取，获得了较好的效果。
The characteristics of three - level ( tl ) converter and its effect to the zero - crossing distortion are analyzed , and extended it to ml converters , which are suitable for the high input frequency pfc application 文章详细分析了三电平( three - level , tl )变换器的特点和对输入电流过零畸变的改善作用,并推广至多电平变换器。
Data pre - processing , digital filter with window function , and lagrange equations smooth curve are programmed by software in the thesis . the aircraft power supply parameters are designed by software in details 完成采集数据的预处理、 fft变换、加窗函数数字滤波的实现、过零测频法、插值拟合曲线、飞机供电系统参数数据处理的编程。
This topic discusses the back - emf zero - crossing detection , the method of phase judging and compensation in detail . in order to improve the speeding performance we adopt the digital closed - loop speed control strategy 详细介绍了反电动势过零检测、相位判断及相位补偿的原理及实现方法，并且为了在较宽范围内提高bldcm的调速性能，采用了数字式转速闭环控制。
The cross - zero detection of wavelet transform could detect the gradation image sudden change information , at the same time it could be express the characteristic information the original map ( namely image function plants " jump point " ) 小波过零检测可以很好的检测到灰度图像的突变信息,同时可以很好的表示出原图像灰度跳变(即图像函数种的“拐点” )的特征信息。
In this article , double threshold , iteration is applied to improve segmentation algorithm based on signal energy , and short - time zero - crossing rate is proposed for the first time to determine the exact boundaries between different components of heart sound 本文通过使用双门限、迭代等方法，改进了基于信号能量的分段算法，并首次引入短时过零率以更准确地定位分段边界。
