具有不同色散分布链路的高速CO-OFDM系统中非线性损伤的研究

由于相干光正交频分复用(CO-OFDM)系统很高的峰均功率比(PAPR)以及非常近的子载波间隔,使得链路色散导致的子载波走离对光纤非线性损伤的影响更加明显。研究了不同色散分布、不同残余色散情况下,无色散补偿光纤(DCF)和有色散补偿光纤的光纤链路时CO-OFDM系统的非线性损伤以及系统性能。针对单信道40 Gb/s CO-OFDM系统,无DCF链路比完全补偿DCF链路,Q因子高5.1 dB;对于DCF链路,当残余色散从0变为到1200ps/nm时,最大Q因子提高了4dB,非线性阈值提高了4 dBm,1200ps/nm时性能几乎和无色散补偿系统相同。     

基于MSP430的直线导轨定位装置的设计与实现

直线导轨是数控技术的重要组成部件,它的精确程度非常重要。以MSP430单片机为核心,设计了一个直线导轨精确定位装置。此装置采用两相四线的ST57型步进电机和60CM的螺纹丝杆组成一个直线导轨组,选用M7128驱动器驱动步进电机,使用PWM波精确定位算法程序精确控制电机转速。MSP430的IO端口控制步进电机的正反转,使得步进电机带动螺纹丝杆转动,让滚动丝杠上的物体往复移动,并在电脑上显示当前位移值。试验证明,其定位精度为0.01cm,具有较高的可靠性和准确性,低成本,稳定性好。     

危化品仓储激光扫描差值去噪算法的研究

为了实现对危化品仓储堆垛安全距离的实时监测和预警,采用由激光测距、旋转云台、编码器等组成的激光扫描监控阵列对垛距进行安全监测。针对激光测距扫描点云数据中异常噪声的问题,采用差值去噪算法。该算法是将扫描得到的激光测距数据点按角度值进行从小到大排序后,相邻两点的距离值依次取差值,然后对距离差值与预设阈值进行比较,滤掉噪点数据。针对几种不同尺寸和形状的障碍物进行了实验研究,结果表明差值去噪方差值明显小于加权二乘、Savitzky-Golay等拟合算法,该算法不仅能有效去除扫描点云数据中的异常噪声,同时较另外两个算法,数据完整性和可靠性更高。     

中间链路光学相位共轭补偿相干光正交频分复用系统的光纤非线性损伤

由于相干光正交频分复用(CO-OFDM)系统具有很高的峰均功率比(PAPR)以及非常近的子载波间隔,使得光纤非线性损伤成为系统的决定因素。提出中间位置光学相位共轭(OPC)补偿算法补偿CO-OFDM的Kerr损伤,由于OPC两端链路对称,可以最大限度地保证满足补偿条件,具有很好的非线性补偿效果。而且无链路色散补偿和有链路色散补偿系统均适用。该算法能使单信道40 Gb/s CO-OFDM的最大Q因子提高3 dB,非线性阈值提高4 dB;波分复用(WDM)系统的最大Q因子能提高1.1 dB,非线性阈值提高1 dB。     

Joint nonlinearity and chromatic dispersion pre-compensation for coherent optical orthogonal frequency-division multiplexing systems

This paper introduces a joint nonlinearity and chromatic dispersion pre-compensation method for coherent optical orthogonal frequency-division multiplexing systems. The research results show that this method can reduce the walk-off effect and can therefore equalize the nonlinear impairments effectively. Compared with the only other existing nonlinearity pre-compensation method, the joint nonlinearity and chromatic dispersion pre-compensation method is not only suitable for low-dispersion optical orthogonal frequency-division multiplexing system, but also effective for high-dispersion optical orthogonal frequency-division multiplexing transmission system with higher input power but without optical dispersion compensation. The suggested solution does not increase computation complexity compared with only nonlinearity pre-compensation method. For 40 Gbit/s coherent optical orthogonal frequency-division multiplexing 20×80 km standard single-mode fibre system, the suggested method can improve the nonlinear threshold (for Q > 10 dB) about 2.7, 1.2 and 1.0 dB, and the maximum Q factor about 1.2, 0.4 and 0.3 dB, for 2, 8 and 16 ps/(nm·km) dispersion coefficients.     

塑料光纤直径控制系统

研究了塑料光纤直径控制系统的工作原理，其中牵伸电机转速控制系统为本系统核心，硬件电路设计为专用集成电路和单片机相结合构成的闭环速度控制，并与光纤直径测量设备的前馈直径闭环组成双闭环控制系统，软件部分主要介绍了自行设计的偏差取值算法与采用诸多改进措施的PID(比例-积分-微分)算法。     

Electronic compensator for 100-Gb/s PDM-CO-OFDM long-haul transmission systems

We study an electronic compensator (EC) as a receiver for a 100-Gb/s polarization division multiplexing coherent optical orthogonal frequency division multiplexing (PDM-CO-OFDM) system without optical dispersion compensation.EC,including electrical dispersion compensation (EDC),least squares channel estimation and compensation (LSCEC),and phase compensation (PC),is used to compensate for chromatic dispersion (CD),phase noise,polarization mode dispersion (PMD),and channel impairments,respectively.Simulations show that EC is highly effective in compensating for those impairments and that the performance is close to the theoretical limitation of optical signal-to-noise rate (OSNR),CD,and PMD.Its robustness against those transmission impairments and fiber nonlinearity are also systematically studied.     

基于MSP430的无线充电系统设计

随着科技的发展,无线电技术越来越广泛应用到生活中。文章采用电磁感应式手机充电原理,在发送和接收端各有一个感应线圈,发送端连接有线电源,通过振荡电路使得发送线圈产生振荡电磁波信号,接收端线圈感受该信号,经过整流滤波电路,将振荡信号变成直流量,进行电池的充电。同时采用CN3068芯片,设计了电流充电的监控电路,使用MSP430G2553超低功耗单片机作为无线充电系统的检测控制核心,电能充满后给出充满提示且自动停止充电。     

危化品仓库堆垛安全距离的精确扫描定位监控算法的研究

根据危化品仓库码垛安全距离需要精确监控的需求,设计开发了一种精确扫描定位装置,将仓库划分为若干网格,对每个监测面测距扫描,获得每一个点的距离值和角度值,根据对应点是否与安全状态数值一致来判断堆垛的安全状态。硬件由控制器、细分驱动、步进电机、涡轮螺杆、工作台等组成。电机定位控制采用指数型加减速算法和闭环反馈调节相结合的控制算法,首先获得一个起跳频率,经过加减速控制阶段,到达目标位置附近,之后进入反馈调节阶段,控制步进电机到达指定位置。指数型加减速算法降低了启动和停止时加速度突变大小,避免了由于步进电机频率变化过快引起失步和堵转。实验结果表明,该装置及算法运行稳定,定位精度在 0.022度左右,定位精度高,满足仓库安全距离扫描监控的精度要求。