振动信号的抗混叠跟踪滤波的实现

振动信号的采样频率常常与机器的转速成比例,传统的滤波技术很难自动跟踪机器的转速实现跟踪滤波。通过采用锁相环、复杂可编程逻辑器(Complex Programmable Logic Device,CPLD)和传统的低通滤波器等技术,能够实现自动跟踪采样频率的变化,解决了旋转机械在不同采样频率下的抗混叠滤波的问题。     

抗混叠滤波器的特性问题

本文讨论了抗混叠滤波器的特性和品质问题。并从仪器设计和工程应用的角度探讨了抗混叠滤波器的动态范围,过渡带宽度,最小阶数以及相频特性非线性等问题,文末给出了工程实例。     

旋转机械振动检测装置数据采集的实现

介绍用CPLD，AD和FIFO实现一时序严格的、由硬件自动完成数据采集的电路，它能够自动跟踪转速信号的变化．解决了旋转机械在不同转速下的抗混叠滤波的问题。     

基于数字式锁相环的双向差动相位解调法设计

设计了应用于高精度干涉测量系统的双向差动相位解调法,利用锁相环的分频特性对测量信号进行降频处理,增加计数脉冲的数量,再结合双向差动相位解调法对信号进行鉴相,从而提高测量分辨力.在He-Ne双频激光外差偏振干涉信号处理实验装置中进行了实验,证明了该方法能够提高测量精度.     

新单相位同步降压控制器

Intersil公司推出一款单位相位PWM同步降压控制器——ISL6269，该器件适用于移动图像处理单元（CPU），ISL6269集成了板载MOSFET驱动器，内部5V LDO，集成引导二极管和PWM音频频率滤波器，     

基于相位重合的全同步测频方法研究

文章对基于相位重合的全同步测频方法进行了研究。相位重合理论是目前比较流行的用于频率测量的理论,在检测被测信号与标频信号的相位重合脉冲后触发闸门,使计数闸门、被测信号和标频信号三者达到全同步,彻底消除了±1个字误差。相位重合检测电路、闸门、计数器等模块均在可编程逻辑器件FPGA中完成,使用方便,易于修改,经仿真达到了预期效果。     

风扇驱动齿轮箱行星轮偏心相位同步方法研究

为支撑我国齿轮传动涡扇发动机研制,针对五路分流人字齿星型风扇驱动齿轮箱,对影响均载系数的各项加工及装配误差进行分析并建立了星型齿轮传动系统静态均载系数计算模型.计算并分析了某星型齿轮传动系统试验件静态均载系数,得到了各项加工及装配误差的敏感度分析结果,提出了通过调整行星轮偏心相位进而降低静态均载系数的方法,并以某星型齿...     

高品质抗混叠滤波器的设计

本文介绍了在采样系统中如何设计高品质抗混叠滤波器。首先介绍了如何用分离元件来设计典型滤波器如贝塞尔滤波器．巴特沃斯滤波器．切比雪夫滤波器等的方法。然后讨论了采用集成电路芯片来设计抗混叠滤波器的方法。     

压电式传感器及其智能化适调技术研究

在分析压电式传感器的信号适调特征基础上,介绍了新研制的集截止频率可程控的抗混叠滤波器与电荷放大器模块于一体的新型多功能电荷放大器适调模块和集截止频率可程控的抗混叠滤波器与恒流源于一体的新型多功能ICP传感适调模块的原理、特点与主要技术指标.     

Wideband phase-locked loop circuit with real-time phase correction for frequency modulation atomic force microscopy

We have developed a wideband phase-locked loop (PLL) circuit with real-time phase correction for high-speed and accurate force measurements by frequency modulation atomic force microscopy (FM-AFM) in liquid. A high-speed operation of FM-AFM requires the use of a high frequency cantilever which, however, increases frequency-dependent phase delay caused by the signal delay within the cantilever excitation loop. Such phase delay leads to an error in the force measurements by FM-AFM especially with a low Q factor. Here, we present a method to compensate this phase delay in real time. Combined with a wideband PLL using a subtraction-based phase comparator, the method allows to perform an accurate and high-speed force measurement by FM-AFM. We demonstrate the improved performance by applying the developed PLL to three-dimensional force measurements at a mica/water interface.     

一种新的锁相测速方法

文中介绍了一种全新的精密数字锁相测量电机转速的方法和电路，此种方法不同于目前普遍采用的M／T测速方法。使用该方法，可以直接获得始终跟随电机速度变化的测速值，测速精度高、应用简单，目前已经成功地应用于笔者研制的交流伺服系统的反馈通道中。     

A dual phase-locked loop for vortex flow metering

A vortex-shedding flow meter produces an approximately sinusoidal signal whose average frequency is proportional to volumetric flow rate. The frequency of vortex shedding varies over a large range (up to 1:100), depending on the size of the flow meter. The conventional frequency estimator uses a zero-crossing algorithm (ZC), but this approach fails at low flows, where the signal-to-noise ratio is poor. An alternative is to use a phase-locked loop (PLL), but typical single PLL designs cannot cope with a wide frequency range at high noise levels. This paper describes a dual PLL structure that can be used to track the vortex shedding frequency over the flow meter’s full range of operation. This dual PLL provides improved accuracy and tracking ability compared with the conventional zero-crossing algorithm.     

光转换单元中锁相环带宽的优化

考虑光转换单元(OTU)中锁相环带宽同时受外部输入抖动和内部相位噪声抖动的影响,为克服锁相环带宽选择的矛盾性,本文对其带宽进行了优化设计.在同时考虑外部输入抖动和内部相位噪声的情况下,对锁相环带宽算法进行综合分析.通过改进前人的计算和分析方法推导得出OTU中锁相环带宽的优化算法,分析并得到锁相环路的优化带宽,使OTU的...     

基于DSP和CPLD的数字锁相技术研究

提出了一种基于数字信号处理技术(DSP)和可编程逻辑控制器件(CPLD)的全数字锁相方法.首先实现了DSP与CPLD的相互通信,在此基础上详细阐述了锁相的基本原理,并分别给出了DSP和CPLD的程序算法和设计流程,最后通过实验验证了该方法的正确性和可行性.实践证明,该技术具有广泛的推广应用前景.     

A phase-locked loop system for the difference frequency of two lasers

A system for phase locking of the difference frequency of two identifical lasers to an intermediate frequency (1–10 MHz) is described. The control channel is divided into two channels (fast and slow) for enhancing the speed of response at a significant range of the control effect. The system can be applied to different (gas and semiconductor) type of lasers. The phase is kept within an interval of 0.5 π at perturbations of up to 0.1 kg·m/s. The perturbation suppression coefficient at frequencies of 0.001–500 Hz isK(f)=10⁷/f.     

Application of a phase-locked loop counterpulsation control algorithm to a pneumatic pulsatile VAD

Journal of Mechanical Science and Technology - This study applied a counterpulsation (CP) control method based on a phase-locked loop (PLL) algorithm to synchronise a pneumatic pulsatile...     

基于软件锁相环无刷直流陀螺电机高精度稳速控制的研究

本文研究了软件锁相环技术在陀螺用无位置传感器BLDCM稳速控制系统中的应用。它是基于DSP通过软件算法来实现锁相功能。文章阐述了软件锁相环的工作原理,数学模型以及DSP实现方法,分析了软件锁相环的Z域模型,所设计的无刷直流电机稳速控制系统用电机控制专用芯片ML4428实觋了反电势的检测,按相和功率驱动;用高速的数字信号处理器TMS320LF2407A作为控制处理器,实现了系统的软件锁相环算法和电机的转速给定、转速检测。     

Collaborative simulation method with spatiotemporal synchronization process control

When designing a complex mechatronics system, such as high speed trains, it is relatively difficult to effectively simulate the entire system’s dynamic behaviors because it involves multi-disciplinary subsystems. Currently, a most practical approach for multi-disciplinary simulation is interface based coupling simulation method, but it faces a twofold challenge: spatial and time unsynchronizations among multi-directional coupling simulation of subsystems. A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms. The method consists of 1) a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems, and 2) a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner. The test results from a case study show that the proposed method 1) can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system, and 2) effectively supports multi-directional coupling simulation among multi-disciplinary subsystems. This method has been successfully applied in China high speed train design and development processes, demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.     

一种新型数字锁相环的设计

在传统锁相环74HCT297的基础上。提出一种非常适合于工业用的数字锁相环。使用FPGA内嵌入的数字锁相环74HCT297。并添加少量的数字电路来实现该锁相环的功能。最后给出仿真波形来验证该设计的合理性及有效性。现已应用于80khz／25kW高频感应加热上。