共查询到18条相似文献,搜索用时 171 毫秒
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针对NAND型闪存大容量图像存储器存在无效块的问题,提出了一种无效块快速检测与管理算法.在分析闪存写入无效块和非写入无效块的基础上,采用基于CAM的无效块信息分类匹配检测机制.闪存在擦除、写入和读取操作过程中采用CAM和SRAM匹配检测无效块,并存储新增长无效块.另外高速图像写入闪存过程中,提出了基于SRAM数据备份的方法,防止图像数据存储错误.通过搭建基于FPGA的闪存图像存储器硬件平台,实验证明该算法能够在5个系统时钟周期内匹配无效块,能够在3个系统时钟周期内存储新增无效块,能够匹配连续无效块信息,并实现数据备份. 相似文献
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为了测定NAND Flash 图像记录系统的稳定性以及峰值记录速度指标,减少人工测试量,设计了压力测试系统。针对稳定性测试问题,设计了基于指数回归的速度压力模型和基于对数正态分布的测试时长控制模型;针对峰值记录速度测定问题,提出了基于爬山搜索算法和速率二分法的软硬件协同测试方法。基于有效数据占空比机制设计速率软件可调的硬件数据产生器,用爬山算法粗略确定峰值记录速度区间,再用速率二分法逼近峰值记录速度;系统测试报告通过串口和千兆网输出至上位机显示。实验结果表明:测试系统速度压力调整精度可达0.1MB/s;速度压力范围为0~1 600MB/s;回读数据硬件检验无时钟延迟;被测NAND Flash 记录系统挂载8 片SLC NAND Flash 芯片的峰值记录速度为240.12MB/s,在200MB/s 速度压力下,可以连续工作24 h 以上。测试系统架构为通用化设计,可以对其他传输和记录系统进行压力测试。 相似文献
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We propose a fast macroblock (MB) mode prediction and decision algorithm based on temporal correlation for P‐slices in the H.264/AVC video standard. There are eight block types for temporal decorrelation, including SKIP mode based on rate‐distortion (RD) optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a thresholding method for fast inter mode decision using a MB tracking scheme to find the most correlated block and RD cost of the correlated block is suggested for early stop of the inter mode determination. We propose a two‐step inter mode candidate selection method using statistical analysis. In the first step, a mode is selected based on the mode information of the co‐located MB from the previous frame. Then, an adaptive thresholding scheme is applied using the RD cost of the most correlated MB. Secondly, additional candidate modes are considered to determine the best mode of the initial candidate modes that does not satisfy the designed thresholding rule. Comparative analysis shows that a speed‐up factor of up to 70.59% is obtained when compared with the full mode search method with a negligible bit increment and a minimal loss of image quality. 相似文献
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介绍了一种高速光突发模式接收机。整形电路采用直流耦合跨阻抗前馈式结构。突发同步恢复电路采用一种新颖的固定相位调节振荡器。仿真表明:在传输速率为1.25Gb/s,误码率BER≤10^-9时,接收灵敏度为-25dBm(平均光功率)。最大可接收光功率-1dBm,动态范围可高达24dB,两分组信号保护时间为20ns。对速率为5Gb/s的NRZ突发数据可在10ps之内建立比特同步。 相似文献
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基于ARM9内核Processor对外部NAND FLASH的控制实现 总被引:2,自引:0,他引:2
目前流行的ARM9 CPU中,没有集成NAND FLASH的控制器,可以通过使用NOR FLASH的控制器或者VLIO的控制器,实现对外部NAND FLASH的控制。实测结果显示,用8bI/O的NAND FLASH,在文件系统下读/写的速度为3MB/s,擦除的速度为65MB/s,满足现在流行手持设备对Memory的要求。 相似文献
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All‐Optical Operation Cycle on Molecular Bits with 250‐GHz Clock‐Rate Based on Photochromic Fulgides
S. Malkmus F. O. Koller S. Draxler T. E. Schrader W. J. Schreier T. Brust J. A. DiGirolamo W. J. Lees W. Zinth M. Braun 《Advanced functional materials》2007,17(17):3657-3662
The prototype operation of an ultrafast write–readout–erase–readout cycle of an all‐optical system based on photochromic indolylfulgides is demonstrated. In the employed dye the molecular structure is switched using light of different wavelengths between two thermally stable states to allow binary encoding of information. Non‐destructive readout of the bit states using infrared light completes the scheme of an all‐optical memory. For ultrafast operation femtosecond light pulses are applied and it is demonstrated that two consecutive write/erase processes separated by less than 4 ps still allow the defined readout of the bit state. The short time between the write/erase and readout actions demonstrates that an all‐optical data storage system based on indolylfulgides may be operated at memory clock rates that exceed 250 GHz. 相似文献
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Eldering C.A. Herrerias-Martin F. Martin-Gomez R. Garcia-Arribas P.J. 《Lightwave Technology, Journal of》1994,12(2):271-279
We present a clock recovery technique for burst mode systems that performs the functions of clock phase recovery, burst synchronization (to determine the first data bit in the burst), and timing alarm generation (to maintain bursts within their designated time slots). The method is based on the use of a correlation algorithm in which the incoming preamble containing a `0 1 0' bit sequence is sampled with multiple clock phases and correlated with stored, time delayed versions of the same sequence. The method was implemented in a 0.7 μm CMOS Application Specific Integrated Circuit (ASIC). Measurements of the phase tracking characteristics over the frequency range of 38 to 90 MHz are presented. Bit error rate measurements made using the device in a burst mode fiber-optic receiver operating at 51.84 Mb/s were also performed, where it was found that the device performed well and was able to perform clock extraction with a penalty of approximately 2 dB with respect to an ideal clock extraction system 相似文献
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介绍了传统高速存储的实现方式,分析了用Nandflash实现海量存储的优点,实现了基于Nandflash阵列的实时高速存储模块。存储模块采用光纤FC作为数据输入端,在FPGA控制下实时存储到Nandflash阵列中,并将存储的数据通过CPCIE总线下传给其他模块作实时或事后分析、判读、处理、回放。实验结果表明,基于Nandflash的存储阵列,存储速度可达到900MB/s以上,满足高分辨率高帧频CCD相机及SAR成像存储需求。 相似文献
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基于VHDL的异步FIFO设计 总被引:1,自引:0,他引:1
FIFO经常应用于从一个时钟域传输数据到另一个异步时钟域。为解决异步FIFO设计过程中空满标志判断难以及FPGA亚稳态的问题,提出一种新颖的设计方案,即利用格雷码计数器(每次时钟到来仅有1位发生改变)表示读/写指针,设计二级同步链为跨越不同时钟域的读/写指针,以提供充足的稳定时间,并通过对比格雷码指针产生空满标志位。该设计采用VHDL语言进行设计,利用ALTERA公司的FPGA得以实现。经验证进一步表明,模块化的设计不仅避免了亚稳态的产生,增大平均无故障工作时间(MBTF),也使工作效率大为提升。 相似文献