应用自适应对消实现激光陀螺抖动信号的剥除

去除抖动信号是机械抖动激光陀螺(MDRLG)信号处理部分的关键工作,传统的去抖方法限制了MDRLG在快速跟踪中的应用.文中基于自适应对消原理,建立了激光陀螺抖动信号剥除的模型,实现了系统硬件电路的设计,并编写了19阶有限脉冲响应滤波程序和最小均方算法、递归最小二乘算法的自适应解调程序.基于该系统,对转台上的激光陀螺从静...     

基于Multisim的机械抖动陀螺抖动环控制电路仿真分析

机械抖动机构是抖动偏频激光陀螺仪中的一个精密机电元件,为了提高陀螺的精度,消除抖动偏频的动态闭锁误差,需向正弦信号中注入随机噪声,使抖动幅度在一定范围内随机变化,达到消除动态闭锁误差的目的.通过Multisim软件对加入噪声以及锁相器的抖动环控制电路进行仿真分析,仿真结果得到了改进电路后抖动电路的驱动信号.     

基于FPGA的激光陀螺自适应抖动剥除

去除激光陀螺输出信号中的抖动信号是机械抖动偏频激光陀螺信号处理电路的主要工作之一。为了满足机械抖动偏频激光陀螺在快速跟踪中的应用要求,基于现场可编程芯片(FPGA)实现了激光陀螺自适应抖动剥除的软硬件设计,其次在静态条件下对系统抖动剥除效果和剥除后的激光陀螺零偏进行测试,最后进行动态试验,给出了LMS自适应抖动剥除的动态响应曲线,验证了LMS自适应抖动剥除的零延时性。实验结果表明,系统能有效去除陀螺输出信号中的抖动成分,其相位延迟几乎为0,完全可应用于需要实时输出角速率信息的场合。     

基于RLS算法实现激光陀螺抖动信号剥除

为了减小陀螺输出数据的时延,以满足机械抖动激光陀螺在快速跟踪中的应用,基于递归最小二乘(RLS)自适应滤波技术实现了激光陀螺抖动信号的剥除。首先对RLS自适应对消去抖算法进行了理论分析,其次通过通用串行总线接口将A/D采集的抖动反馈信号和激光陀螺计数脉冲信号传至上位机,最后基于MATLAB编写了RLS自适应程序,实现了激光陀螺抖动信号的剥除。剥除后的陀螺信号再经过11阶的有限脉冲响应滤波器和陀螺输出直接经过31阶的滤波器剩余的脉冲数基本相当,而时间延迟却明显减小。结果表明,该算法具有较快的收敛速度且能够有效去除激光陀螺计数脉冲中的抖动成分。     

一种优化的激光陀螺自适应抖动剥除算法

去除激光陀螺输出信号中的抖动信号是机械抖动偏频激光陀螺(MDRLG)信号处理电路的主要工作之一。文章对LMS算法中误差因子响应特性对LMS自适应抖动剥除效果的影响进行了研究。为改善抖动剥除效果,在自适应抖动剥除算法中引入了带通滤波器,并采用基于FPGA的激光陀螺自适应抖动剥除系统对误差因子采用带通滤波时的静态性能和动态响应特性进行了测试。试验结果表明,误差因子采用带通滤波时,LMS自适应抖动剥除的收敛速度和收敛精度都要优于差分运算,并且二者具有相同的动态频率响应曲线。     

抖动角振动对激光陀螺比例因子的影响

对采用抖动偏频技术的腔体机械抖动激光陀螺,在采用正弦抖动时,激光陀螺原来只集中在零转速附近的死区,在抖动的调制作用下,展开成一系列小的死区带。当抖动角振动的振幅被外加信号或噪声信号调制时,这些死区带将变小,将改善激光陀螺比例因子线性度;当抖动角振动除基波分量外,还包含有一系列高次谐波时,一般也使激光陀螺比例因子得到改     

自适应滤波器在激光陀螺抖动解调中的应用

在激光陀螺信号解调领域,很难寻找到一种兼顾实时性和解调精度的方法,这大大限制了激光陀螺的应用领域。针对此问题研究了一种新的机械抖动激光陀螺的抖动解调方法。这种方法采用LMS自适应滤波器原理,分别将陀螺信号和角速率传感器的角位移信号作为基本输入和参考输入,经自适应滤波后得到解调结果。首先分析了这种新方法用于抖动解调的理论基础,并提出设计实现方法,最后给出一些与传统方法的对比结果。仿真结果表明,LMS自适应滤波器在静态和动态工作情况下都有很好的解调效果,解调残差明显减小,可有效降低系统解算负担。     

机械抖动激光陀螺的随机噪声注入效率问题的研究

向抖动中注入一定强度的随机噪声,以消除机械抖动浙江陀螺的动态闭锁误差。研究了噪声注入效率问题,通过理论推导得到了噪声注入效率与抖动系统品质因素的关系。     

机械抖动激光陀螺的随机噪声注入效率问题的研究

向抖动中注入一定强度的随机噪声,以消除机械抖动激光陀螺的动态闭锁误差。研究了噪声注入效率问题,通过理论推导得到了噪声注入效率与抖动系统品质因素的关系。     

基于改进Hopfield神经网络的自适应二维噪声对消器

提出了基于连续型Hopfield神经网络(CHNN)的自适应二维噪声对消器,讨论了神经网络的结构和原理及相应的自适应滤波算法,并从理论上进行了论证.仿真结果表明相对于采用最小均方算法的二维线性噪声对消器,CHNN噪声对消器能更有效实现二维噪声的消除,保持原信号的完整性,获得较好的去噪声效果.     

二频机抖陀螺的自锁相抖动剥除

采用抖动剥除算法能够使二频机抖陀螺的输出信号达到零延时。现有的抖动剥除算法无一例外地采用外部参考信号进行剥除运算,外部参考信号的获取会增加系统的复杂度。为了使抖动剥除更加容易实现,提出了一种新的基于自锁相的抖动剥除方法,用陀螺本身来获取抖动信号,不再需要外部参考信号。这种方法硬件结构简单,同时实验结果证明其输出结果不差于采用外部参考的方法。该方法使二频机抖陀螺可以很方便地应用于实时控制领域。     

加扰技术对模数转换器性能的影响

分析了加扰技术改善ADC性能的基本原理,通过选择合适的扰动信号注入到理想量化器模型中进行仿真,验证了加扰技术能够随机化量化误差的周期性三角形分布。在加扰技术的实际应用中,首先基于10 bit 25 MS/s Pipelined ADC模型完成加扰仿真,仿真得到ADC的SFDR由74.69 dB提高到了85 dB。然后对两种ADC芯片进行加扰实验,该加扰技术使两种ADC芯片的SFDR分别提高了8.29 dB和5.97 dB。理论仿真和实验验证了加扰技术可以明显提高ADC的SFDR,为后期ADC内部集成加扰电路模块做好了准备工作。     

The Action of Dither in a Polarity Coincidence Correlator

An analysis has been made of how dither added to the input of a polarity coincidence correlator eliminates capture of a weak signal by an unwanted signal. For certain interfering environments the output signal-to-noise ratio of various correlators with three specific input dithers is analyzed. The correlators considered were a polarity coincidence correlator with: 1) no dither, 2) dither of random, amplitude uniformly distributed between the chosen plus-and-minus peak values, 3) sinusoidal dither, and 4) Gaussian dither. Each correlator was analyzed for the cases of Gaussian-noise, rectangular-wave, and sinusoidal interference and compared with the classical correlator. The choice of dither amplitude based upon the measured value of the noise power was studied. A uniformly distributed dither is shown to be slightly superior to sinusoidal dither, and both superior to Gaussian noise.     

电光调制器偏置点抖动控制对射频信号的影响

马赫-曾德尔电光调制器的偏置点控制是光载射频传输链路中一项十分关键的技术。为了分析马赫-曾德尔电光调制器偏置点抖动控制对射频信号的影响,用贝塞尔级数展开再进行频谱分析的方法对系统输出信号成分进行了理论分析,设计了马赫-曾德尔调制器任意点控制系统并进行了实验验证。用MATLAB进行仿真后可知,在输入射频功率为18dBm时,抖动信号幅度需小于45mV,2次射频信号对抖动信号引起的频率分量抑制比才能大于20dB;而在输入射频功率为10dBm时,这个幅度要小于19mV。改变抖动信号幅度进行实验,得到2次射频信号对抖动信号引起的频率分量抑制比与仿真结果误差始终保持在3dB~3.2dB左右。结果表明,马赫-曾德尔电光调制器工作在线性偏置点时,抖动信号引起的频率分量是可以忽略的;但将调制器偏置控制在最低偏置点时,对射频信号的影响不可忽略。     

Optical Phase Locking by Local Oscillator Phase Dithering

A new type of optical phase-locked loop (OPLL), called the dither loop, is mathematically analyzed. The dither loop extracts a phase-error signal by applying a small phase disturbance to the local oscillator laser, and synchronously demodulating the resulting power fluctuation in the output signal of the receiver. The dither loop is superior to other OPLL designs, because it does not need the transmission of a residual carrier, it employs a 180deg/3-dB hybrid, an ac-coupled front end, and it accepts a large variety of input signals. Furthermore, in a dither loop, the amount of power which is fed to the phase-locking branch can be adaptively controlled within the receiver. The analysis first focuses on an expression for the phase detector gain in a dither loop. Using a linearized model, the phase-error variance due to phase dithering, white frequency noise induced phase noise and shot noise is evaluated. A simplified expression for the power penalty generated by the phase dither signal is presented. In a more complex calculation, the overall power penalty due to phase dithering and the residual phase error is found. This allows us to synthesize a design rule for dither loops with optimum performance measures. The design rule determines all relevant system parameters, based on specified values of the system bit rate, the laser linewidth, the photodiode responsivity and the required bit-error rate     

过取样的空闲信道噪声及其消除

在数字音频技术中，过取样可以降低量化噪声，但却带来一种新的噪声，即空闲信道噪声。本文叙述空闲信道噪声的产生过程，以及有要用加上抖晃信号以消除空闲信道噪声的方法。并以数字调幅发射机为例来说明抖晃信号的应用。     

Signal stabilization of relay control systems by use of square-wave dither

The amplitude of high-frequency square-wave dither necessary to quench limit cycles in a class of relay control systems is shown to be less than the amplitude required with any other periodic, odd, half-wave symmetric, high-frequency dither signal A general expression for the minimum dither amplitude is also given.     

Digital background calibration of pipeline ADC based on correlation

Two novel calibration techniques based on dither injection and correlation are proposed. The first calibration algorithm utilises digital windows around the residue folding points by adding more comparators. Then all the capacitor mismatches and the linear gain error of the residue amplifier (RA) are calibrated by injecting dither signal in the windows. This new scheme would not change the key analogue signal path and thus brings no dither leakage in the digital domain. The other calibration algorithm injects dither signal into the split sampling capacitors to estimate the nonlinear kick-back error, which always exists in sample-hold amplifier less (SHA-less) structure. In addition, three other dither signals are injected into the added capacitors to calibrate the linear and nonlinear errors of the RA, which relaxes gain requirement in multiplying digtital-analogue-converter . Both the algorithms and the corresponding analogue-digital-converters (ADCs) are constructed and simulated in MATLAB. According to the simulation results, the first calibration technique increases signal-noise-distortion-ratio (SNDR) and spurious-free-dynamic-range (SFDR) by 40 and 42 dB, respectively. The second calibration scheme improves SNDR and SFDR by 19 and 34 dB in a SHA-less ADC.