过零

• The initial vsd process uses two main characters , the average instantaneous energy and the average instantaneous zero crossing rate ( zcr ) . to make the first recognition for the start and the end , the emphasis of which is to select the appropriate value of the threshold and the length of frame . in the final vsd process , the author compares several characters and confirms the new recognition character
  初步分段过程使用了能量和过零率这两个主要特征进行端点检测，重点是合理选择两个重要参数? ?门限和统计帧长度的取值；在最终分段过程中，笔者首先通过比较几种特征的识别效果，选择卡尔曼滤波参数作为再次分段的识别特征，还提出了一种新的识别特征? ?周期性缓变特征，使用这两个特征分别在子语音段内进行端点检测。
• A sample is given to illuminate design procedure , and to enhance shcan2000 system . new control methods are also suggested here . first , a new pid pressure step control method so - called " zero op oversighf ' which is highly accurate and low cost ; second , logical control method for producing procedure ; third , large control network for monitoring and management . all the methods have been tested to be pratically useful , stable and efficient
  在设计高效催化剂生产工控软件的过程中，提出了工业控制过程的新思路、新方法：新型“ op过零监视” pid分程调节技术、间歇生产过程的逻辑控制方法以及大型工控软件联网监控技术，这些技术经过生产实践检验证实方法先进，实用。
• The technology of identification based on iris is researched in the article , the key point of the technology is the iris characteristic acquisition and recognition , therefore based on the iris image texture characteristic , using the wavelet transforms to get the characteristic of iris image , a new method named zero - crossing detection and secondary circle coding is used in the article
  本文研究的就是用虹膜进行身份识别的技术,该技术的关键是虹膜特征提取和识别。基于虹膜图像的纹理特征,利用小波变换来提取虹膜图像的特征,本文提出了基于小波过零检测的循环二次编码的方法。
• On the base of ananlysing and studying the run mode of bldcm , we introduce the detecting back electromotiveforce , 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
  在对无位置传感器无刷直流电动机运行方式进行全面分析研究的基础上，详细的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。
• Voltage segment network constituted by electron switch of bta and controlled by single chip microcomputer constitutes a new fast electronic regulator . for bta cross zero touch off , sine wave which is exported is integrity . a new way to generate stable ac current is found with feed back control system by single chip microcomputer . so a new high power ac current regulator is developed
  采用单片机控制双向可控硅作为电子开关所组成的电压分节网络,组成新颖快速的电子调压器；由于双向可控硅过零触发,所以其输出是不失真的完整正弦波；再用单片机组成反馈控制系统,从而找到了交流稳流的新方法,研制出一个大功率交流稳流电源
• It was demonstrated that this sort of load - control apparatus has superior performance . we used a electric transmitter as the transducer to collect the sound signal , using the daq toolbox of the matlab to achieve the collection of the sound signal , and using the dsp toolbox of the matlab and the sound - launch technology to analyze the time - domain characteristic and the frequency - domain characteristic of the signal , chiefly analyze its short - time average amplitude , its short - time over - zero ratio and its estimate of the power chart and the average - period chart
  实验中使用了驻极体话筒作为球磨机声音拾取传感器，利用matlab中的数据采集( daq )工具箱实现对磨音的采集，利用matlab信号分析( dsp )工具箱和声发射技术对磨音进行时域和频域分析，主要分析磨音的短时平均幅度和能量、短时平均过零率、功率谱估计和平均周期图。