数字闭环光纤陀螺输出滤波器设计

在数字闭环光纤陀螺中,数字输出信号由高抽样率的反馈信号抽取得到,为避免抽取过程中发生频域混迭,应加入输出滤波器对信号进行低通滤波。根据多抽样率数字信号理论,采用多级抽取滤波器的设计方法,为陀螺设计输出滤波器。和一级低通滤波器比较说明,所设计的三级抽取滤波器,运算量小、滤波效果好。测试结果表明,加入输出滤波器不改变陀螺静态特性,抑制了振动时引起的高频误差,提高了陀螺精度。     

疲劳裂纹扩展的金属磁记忆信号特征

通过对Q235B钢缺口试件的方波载荷拉-拉疲劳试验,在不同循环次数下利用磁记忆检测仪在线测量试件表面的磁记忆信号。结果表明:未经处理试样沿缺口处的磁记忆信号在疲劳初始阶段随机分布;循环加载5000次后,磁记忆信号曲线转变为具有一个波峰-波谷的曲线波形;在循环稳定阶段,磁记忆信号曲线趋于稳定;宏观裂纹出现时,磁记忆信号曲线波形发散;最后阶段,磁记忆信号逐渐增强;磁机械效应能较好地解释循环初始阶段磁记忆信号变化规律。     

BEHRINGER的最新音频信号增强处理器

SONIC ULTRAMIZER SU99205、1高保真立体声音响增强处理器是家庭录音室、DJ系统、键盘使用、网络播放的理想选择。他提高了现有系统的音质和清晰度，音乐范围更广。低频的处理控制功能可以更好地提升音质和相位补尝，带来更好的音响效果。配有的精确的5段式LED显示表，便于监控。     

一种改进的低截获概率直扩信号设计

为了进一步降低直扩信号的截获概率,通过对伪随机码进行频域陷波处理,再由滤波后的伪随机码产生直扩信号。滤波后的随机码仍保持良好的自相关特性,而由其产生的直扩信号经平方等非线性变换后,载波倍频处能量得到抑制。因此改进的直扩信号具有更低的截获概率。通过计算机仿真验证了方法的有效性。     

不同应力集中系数下磁记忆信号影响因素研究

以45CrNiMoVA钢为实验材料,加工不同应力集中系数的试件进行拉拉疲劳实验,采用磁记忆检测仪检测不同载荷及疲劳周次时试件不同位置的磁记忆信号.结果表明:载荷及疲劳周次的增加,均会使磁曲线顺时针转动,且载荷的影响明显强于疲劳周次;不同位置磁记忆信号特征不同.出现疲劳裂纹后,在一定范围内异变峰峰值显著增大.     

泵房自动控制系统的信号设计

泵房作为水厂的主要组成部分,其设备的监控在水厂自动控制系统中具有重要的地位.合理设计泵房设备的监控信号,对充分发挥自控系统的功能具有重要的意义.我公司市北区净水厂2004年完成了自控系统,整个水厂采用三台sIEMENS公司生产的S7-300型PLC和二台上位机,组成以MP2高速现场总线为基础的监控系统.泵房由一台PLC控制,通过合理设置控制信号,取得了较好的监控效果.     

基于Hilbert变换的电压瞬变信号包络提取算法

针对电压瞬变信号计量测试数据量大,传统的电压瞬变信号包络提取算法计算时间长,不利于实际应用的缺点,提出了基于Hilbert变换与低通滤波器相结合的电压瞬变信号包络提取算法。对实际电压瞬变信号进行包络提取的结果表明,该算法在保证电压瞬变信号包络提取结果准确度的基础上,能够比传统电压瞬变信号包络提取算法缩短约60%的计算时间。     

低成本正弦信号发生器设计

设计以及称运算放大器LM324、LM331电压频率转换器为核心的函数信号发生器。该方法设计的函数信号发生器价格便宜,容易调试,可将其整合为一个可产生各种波形的系统电路,用于一些简单的实验。     

信号调理器自动计量装置设计

介绍了一种信号调理器自动计量装置的设计思路,对信号调理器的计量过程进行了介绍。     

外置式非标准视频同步信号发生器的设计

采用TMS320F206作为USB接口芯片PDIUSBD12的控制器,实现对高速数据采集卡的同步控制。主机从荻得的非标准视频数据中提取同步信号参数,通过USB接口及时传输给DSP,DSP对分频系数实行模糊控制,产生精度可达7ps的视频同步信号,实现非标准视频信号的采集和稳定显示。分别对行频为15．625kHz、场频为50Hz的CCD视频信号,及行频为48．656kHz、场频为60Hz的计算机显示器视频泄漏信号进行了采集与显示,证实了此方案的可行性。     

A Comparison of Integration and Low-Pass Filtering

A comparison of the ideal integrator and low-pass filters has been made. Many experimenters use an integrator to filter out high-frequency noise from their data, whereas a properly designed low-pass filter will remove more noise and distort the signal less. Viewed as a low-pass filter, the integrator is superior to the RC filter but inferior to higher order filters. An integrating digital voltmeter (DVM) integrates and samples the input signal. If the signal has a varying component and is mixed with noise, it would be more accurate to use a low-pass filter followed by a sampler, than the integrating DVM.     

套管爆炸修复设计及安全技术

对爆炸修井的炸药种类、起爆系统、药量计算、装药结构及技术工艺进行介绍,用实验资料进行了验证,并对爆炸修井安全问题进行了讨论,可作为爆炸修井实践的参考。     

一种油套管接箍拧接机校准装置的研究

本文主要阐述在一种油套管接箍拧接机校准装置的研究及研究过程中的一些问题。     

EMD-Based Signal Filtering

In this paper, a signal-filtering method based on empirical mode decomposition is proposed. The filtering method is a fully data-driven approach. A noisy signal is adaptively decomposed into intrinsic oscillatory components called intrinsic mode functions (IMFs) by means of an algorithm referred to as a sifting process. The basic principle of the method is to make use of partial reconstructions of the signal, with the relevant IMFs corresponding to the most important structures of the signal (low-frequency components). A criterion is proposed to determine the IMF, after which, the energy distribution of the important structures of the signal overcomes that of the noise and that of the high-frequency components of the signal. The method is illustrated on simulated and real data, and the results are compared to well-known filtering methods. The study is limited to signals that were corrupted by additive white Gaussian noise and is conducted on the basis of extended numerical experiments.     

气井用套管螺纹接头失效分析

针对某气田开采井使用的N80钢级套管在下井后保压过程中出现的泄压事故,通过对失效接头进行了宏观观察、管材力学性能和化学成分分析,并对同批次未使用的套管接头进行了螺纹参数及外观检验,综合现场施工情况对螺纹接头失效的原因进行了分析。结果表明:产品存在缺陷和上扣扭矩过大是螺纹接头失效的原因,并提出了保证气井用套管使用安全的建议。     

Disorder-Induced Signal Filtering with Topological Metamaterials

Disorder, ubiquitously present in realistic structures, is generally thought to disturb the performance of analog wave devices, as it often causes strong multiple scattering effects that largely arrest wave transportation. Contrary to this general view, here, it is shown that, in some wave systems with nontrivial topological character, strong randomness can be highly beneficial, acting as a powerful stimulator to enable desired analog filtering operations. This is achieved in a topological Anderson sonic crystal that, in the regime of dominating randomness, provides a well-defined filtering response characterized by a Lorentzian spectral line-shape. The theoretical and experimental results, serving as the first realization of topological Anderson insulator phase in acoustics, suggest the striking possibility of achieving specific, nonrandom analog filtering operations by adding randomness to clean structures.     

有源低通滤波器的优化设计

本文以有源低通滤波器设计为例介绍了一种电路优化设计的方法 ,通过优化设计能使某些性能要求比较高、调试比较困难的电路 ,使其降低元器件精度要求、简化调试、提高性能     

Numerical Simulation of Casing Strength in Salt-Gypsum Stratum Deep Well

Strength of Materials - In order to clarify the stress variation law of casing in salt-paste stratum and provide theoretical basis for wellbore structure design, the model of salt-gypsum stratum...     

An Integrated Methodology for Wavelet Filtering of a Pulse Wave Signal

Measurement Techniques - The problem of digital filtering of a pulse wave signal relevant in cardiological diagnostics is considered, which is affected by various physiological interferences, such...