共查询到20条相似文献,搜索用时 19 毫秒
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高速长线阵CCD相机主要用于航天推扫系统等高速图像数据的采集。本文以DALSA公司生产的IL-P4线阵CCD为例,研究了一种基于FPGA的高速线阵CCD驱动电路的设计方法,首先,分析了线阵CCD的基本结构和工作原理,并阐述了IL-P4驱动信号的时序要求。在ISE 13.4开发系统上,运用Verilog描述的分频器,设计了基于Xilinx公司的Spartan 3E平台的驱动电路。最后,采用ISIM软件进行仿真,并用示波器测试出FPGA输出的驱动脉冲。仿真和实验结果表明,FPGA输出结果完全符合IL-P4的高速驱动信号时序要求。本研究对长线阵高速CCD驱动电路的设计与实现具有较好的参考价值。 相似文献
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为了定量地得到磁场梯度对a-Si∶H薄膜沉积速率的影响,对单磁场线圈分散场MWECR CVD系统等离子体室和沉积室中用三种方法得到的磁场形貌进行了研究.通过洛伦兹拟合的方法定量地得到了这些磁场形貌的磁场梯度.结果表明,样品台下面放置钐钴永磁体并使磁场线圈电流为137.7A时其衬底附近磁场梯度值最大,样品台下面无钐钴永磁时,磁场线圈电流分别为137.7A和115.2A的磁场梯度值依次为次之和最小.制备a-Si∶H薄膜时,在衬底附近具有高的磁场梯度值可以得到高的沉积速率.通过红外吸收谱技术分析,虽然样品台下面放置钐钴永磁体并使磁场线圈电流为137.7A下能得到最大的沉积速率,但是沿样品台半径方向沉积速率呈现很明显的不均匀分布. 相似文献
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增大传感器振子的质量和静态测试电容可以减小电容式MEMS惯性传感系统的噪声,而深度粒子反应刻蚀工艺由于复杂的工艺原因,当深宽比较大时,不能刻蚀出大质量和大初始电容的传感器.据此,本文研究了一种磁驱动增大检测电容的MEMS惯性传感器,通过电磁驱动器,传感器的静态测试电容可以大幅增加,在梳齿电容上刻蚀阻尼槽后,其机械噪声达到0.61μg每根号赫兹,仿真其共振频率为598Hz,静态位移灵敏度为0.7μm每重力加速度,基于硅 玻璃键合工艺,制作了栅形条电容式惯性传感器,并用电磁驱动的方式测试其品质因子达到715,从而验证了制作工艺的可行性和电磁驱动器改变传感器初始静态测试电容的可行性. 相似文献
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利用小波包理论对车载移动电话的接收信号进行小波包变换,通过设定一合适的阈值对变换后的信号进行量化处理.提取出主要由发动机产生的噪声信号,然后用实际检测信号减去小波包变换信号,得出汽车司机的语音信号.从而达到消除噪声的目的。利用MATLAB的小波工具箱对所提出的方法进行验证,结果表明提取后的信号与驾驶员的声音信号十分相似,误差较小,对发动机噪声有明显的抑制作用。 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1975,63(7):1077-1078
When a band of Gaussian noise is hard-limited and its frequency is divided by N, its bandwidth is divided by about N2. This experimental observation is verified by theoretical analysis and is explained heuristically. 相似文献
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The K&H algorithm for finding the p.i.'s of a noncoherent fault tree is too long and complicated for the purpose. The example that was used by K&H to illustrate the algorithm is reworked with known methods to show that alternatives are available that require less work. This correspondence is a series of four letters published as a sequel to a paper by Kumamoto & Henley (K&H) that presented an ``algorithm based on top-down analysis particularly designed for noncoherent fault trees'. The first of these letters is by Locks, claiming that the article is too complicated and that a shorter procedure is available. This is followed by Reply #1 by Ogunbiyi and Reply #2 by K&H. The note is concluded with a rebuttal by Locks to both replies. 相似文献
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宽带雷达目标一维距离像是实现目标识别的重要依据,提高距离维的分辨率对提高目标识别概率非常重要。针对超宽带雷达运动目标回波,采用分数阶傅里叶变换算法(FrFT)搜索并补偿带宽内的多普勒差异,同时将距离维时延信息转换为频域信息,采用多重信号分类(MUSIC)超分辨算法,针对FrFT处理后的数据进行超分辨。该方法实现了距离维信息的超分辨,其性能较传统的脉冲压缩技术或"去斜"技术有显著提高,可以应用到目标识别与分类中,提高正确识别概率。采用计算机仿真验证了所给出算法的有效性。 相似文献
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介绍一种基于ARM微控制器来实现无线分布式的数据传输系统。网络节点硬件主要使用NXP公司的LPC1766作为微控制器、Nordic公司的nRF905作为射频芯片。软件以C语言和汇编语言编制,采用多层次结构设计。由于nRF905芯片的各种优越性,该系统具有较强的抗干扰能力,具有较高的实用价值。 相似文献
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为了降低超声波流量检测过程中噪声对检测精度的影响,采用FPGA器件构建了FIR滤波器,并提出一种新颖的查表法替代滤波器中的乘法运算。试验结果表明,该滤波器设计方法显著降低了FPGA的片内硬件开销,提高了滤波器的运算速度,并具有良好的降噪效果。 相似文献
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A rocket with removed access plate is simulated by a section of coaxial transmission line with a transverse elliptical slot cut in its sheath. The internal circuit consists of two arbitrary impedances in series with the inner conductor at its ends. The object is to find the currents in these impedances when the cylinder is illuminated from the outside by an electromagneticfield that enters the aperture and excites the internal circuit. The problem is solved by application of the reciprocal theorem. The current in a dipole antenna is determined when this is inthe far field maintained by the slotted coaxial line when driven by a generator in series with one of the load impedances. The field in the aperture is replaced by equivalent electric and magnetic dipoles. The reciprocal theorem gives the current in the load impedance when the distantdipole is driven. A numerical example is given. 相似文献
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A linear transport system, which is capable of reducing the weight of a moving carrier by separating power-supplying devices, is developed by using a new magnetic levitation technique. This system is designed to distribute a wafer between semiconductor fabrication process modules in clean rooms, because it can eliminate particles and oil contamination that normally exist in conventional transporter systems due to rubbing of mechanical components. The transport system consists of a wafer carrier, two levitation tracks, two stabilization tracks, and a propelling system. Levitation is achieved by using opposing forces produced between electromagnet tracks and permanent magnets. Stabilization is achieved by using a simple feedback control. The continuous propelling force is obtained by sending specific current patterns to the propulsion coils. The dynamic model of the transport system is presented, and it is verified by experiment. The system performance is experimentally investigated 相似文献
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在数字逻辑电路设计中,分频器是一种基本电路。通常用来对某个给定频率进行分频,以得到所需的频率。整数分频器的实现非常简单,可采用标准的计数器,也可以采用可编程逻辑器件设计实现。文中的设计利用VHDL硬件描述语言的编程方式,通过MAX+PLIS(Ⅱ)开发软件和ALTERA公司的FLEX系列EPF10K10LC84-4型FPGA方便地完成了各种类型分频比电路的设计。 相似文献
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为了降低老化的图像采集设备引入的加性噪声所带来的图像数据冗余,研究了加性噪声对图像和视频的影响,提出用三维块匹配(Block Matching 3D, BM3D)算法处理受噪的静态图像,验证了通过降噪来降低图像信息熵和数据量的方法,进而提出降噪-编码方案。首先采用四维视频块匹配(Video Block Matching 4D, VBM4D)算法对受噪视频进行降噪处理,随后进行H.264编码。经过此方案处理的图像信息熵降低16%,数据量减少38%;在视频质量未显著降低的前提下,编码码流减少59.5%。数据表明该方法能在保证视频质量的前提下显著提升H.264的编码压缩率,促进视频在小带宽通信系统中的传输。与H.264以及神经网络等编码方案相比,该方案复杂度低,能相对实时地处理视频。 相似文献