共查询到20条相似文献，搜索用时 187 毫秒
1.
王征 《宁波职业技术学院学报》2012,(5):13-14,45
DDR信号的阻抗匹配一般有两种方法:源端增加串联电阻和终端增加并联电阻。这两种方法各有利弊。其中源端串阻匹配会增加单板PCB的布板面积,终端并联匹配则会增加单板的功耗。本文则采用并联电容来替代并联电阻,这样即可以解决PCB布板面积的问题,也可以解决单板机功耗增加的问题,是DDR信号匹配的一种新方法。 相似文献
2.
采用无线摇控技术设计了能通过网络进行远程设置的时钟系统,该时钟具有无线遥控功能,时钟间可以进行组网来交换时间和温湿度等信息,系统运行稳定可靠,具有良好的推广应用价值。 相似文献
3.
《中国现代教育装备》2006,(3):98-98
双核心自推出以来,逐渐成为处理器的发展趋势。华硕推出TS300-E3和RS120-E3两款支持双核心处理器的服务器,不仅能支持双核心运算,还支持DDR2新一代内存技术,使两种新技术的完美结合。DDR2“PK”DDR众所周知,DDR2是由JEDEC(电子设备工程联合委员会)开发的新一代内存技术标准。它 相似文献
4.
详细讨论了狭义相对论里面两个极具启发性的问题,即观看运动的时钟和从小角度观看高速运动物体.说明了前者与狭义相对论中通常所说的"时间膨胀"之间的区别与联系,给出了运动时钟和静止时钟的时间间隔之间的关系.对后者,修正了前人讨论中的一处疏漏,从而说明在狭义相对论中涉及观看某现象时如何考虑光信号的传输限制. 相似文献
5.
脉搏检测实验装置的研制 总被引：3，自引：0，他引：3
卢超 《实验室研究与探索》2010,29(9)
研究了现有的脉搏信号处理方法及其测量技术,设计了一种脉搏检测实验装置。该装置由一个通道将时钟、脉搏测量和异常报警及效率定时报警结合起来,实现测定控制;另一个通道将处理后的信号通过USB接口送给上位机实现波形还原、脉搏波检测与控制。 相似文献
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基于微电子技术的不断发展,高速器件的使用和高速数字系统设计越来越多,系统数据速率、时钟速率和电路密集度都在不断增加.信号完整性分析的应用已经成为解决高速电路板设计的一个有效途径.介绍了高速电路板设计中信号完整性(SI)的定义、所要解决的主要问题、解决问题的基本方法和信号完整性分析模型. 相似文献
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从Linux内核实时性、实时调度策略以及时钟细粒度定时器三个方面,对Linux嵌入式实时化技术进行了探讨.在内核中插入抢占点或采用双内核系统,改善Linux的实时性能;通过动态优先级提高实时任务的调度性能;通过增加时钟中断频率或采用实时时钟一次性模式,实现时钟细粒度. 相似文献
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《实验室研究与探索》2020,(6):88-93
通过无线电信号检测发现无人机是预防无人机"黑飞"的有效手段,设计了一个基于FPGA的无人机遥控及图传信号的采集、存储、传输系统。该系统以FPGA芯片XC7K325T作为主控器,使用AD9361作为模/数转换器,对2.3～2.5GHz、5.7～5.9 GHz无人机常用频段信号进行快速扫频采集,采用DDR3对采集数据实施多通道缓存,结合千兆以太网口RTL8211EG将数据高速传输至上位机。上位机采用QT软件开发,完成了AD9361的寄存器配置、采集部分的扫频控制及DDR3多通道选择控制功能。测试结果表明,该系统能够对400 MHz带宽范围的无人机遥控及图传信号进行快速采集、实现DDR3存储数据异步防冲突读写功能、高速千兆以太网传输达到900 Mb/s以上,满足系统对无人机遥控及图传信号的采集存储传输要求,为后期无人机检测与识别的研究奠定硬件基础。 相似文献
9.
随着电力系统自动化技术的发展,电力系统授时钟同步精度的要求越来越高,电力系统也日趋网络化,如数字化变电站。而传统的时钟同步方法单一,不能使整个电力系统网内装置同步。为此,本文开发了一种既有网络同步授时功能、又有传统授时功能的嵌入式NTP网络同步时钟源,该时钟源能够为电网自动化设备如微机故障录波及事件记录等智能设备提供精确时间。 相似文献
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随着电力系统自动化技术的发展,电力系统授时钟同步精度的要求越来越高,电力系统也日趋网络化,如数字化变电站.而传统的时钟同步方法单一,不能使整个电力系统网内装置同步.为此,本文开发了一种既有网络同步授时功能、又有传统授时功能的嵌入式NTP网络同步时钟源,该时钟源能够为电网自动化设备如微机故障录波及事件记录等智能设备提精确时间. 相似文献
11.
由于自适应数字预失真具有稳定性好、适应能力强等优点,被广泛应用于实现功率放大器的线性化。而本文正是研究了基于多项式数字基带自适应预失真技术。首先,介绍了基于多项式数字基带自适应预失真技术;其次,分析了间接学习结构理论;最后,对OFDM信号进行了仿真实验。结果表明：预失真可以有效地抑制带外频谱以及补偿功放的非线性失真和记忆效应。 相似文献
12.
In Experiment 1, four groups of rats were initially trained on a discrimination which established a stimulus as a signal for reinforcement. That signal was then presented during subsequent partial reinforcement training in a way that could potentially interfere with retrieval of the memory of nonreinforcement (SN) on the preceding trial either because (1) thestorage and retrieval contexts for SN were different (retrieval failure hypothesis), or (2) the memory of reinforcement produced by the signal acted as a competing memory (competing memory hypothesis). Experiment 1 supported the competing memory hypothesis. In Experiment 2, we investigated the effect of stimulus change on the capacity of the context to retrieve a competing memory of a temporally remote reinforcement event with which the context was strongly associated. Retrieval of a competing memory was impaired by differences between the storage and retrieval contexts in a manner analogous to the effect of context on retrieval of a reinforcement event memory from an immediately preceding trial. 相似文献
13.
设计了基于V2X(Vehicle To Everything,车与外界的信息交换)技术的自动泊车系统.该系统由人机交互单元、信号引导单元、车载泊车单元3部分构成.人机交互单元负责输入操作指令和采集存储用户身份信息,信号引导单元负责提供泊车路径信息与停车信号,车载泊车单元负责控制车辆运行.该系统具有一键存取、身份验证、车位记忆等功能,可用于传统车辆和无人驾驶汽车,是一种新型自动泊车系统. 相似文献
14.
在分析了传统DDFS应用中存在的资源利用率不高,输出频率不够精准、缺陷的基础上,提出了一种基于改进直接数字频率合成(DDFS)技术的谐波信号发生器的设计与实现方法.该方法从频率精度的提高和内存容量的压缩两方面进行一些有益的探讨.实践证明,通过优化DDFS结构和引进新的算法,在不影响系统速度和可靠性的前提下有效地提高了频率精度和实现了内存压缩. 相似文献
15.
To efficiently exploit the performance of single instruction multiple data （SIMD） architectures for video coding, a parallel memory architecture with power-of-two memory modules is proposed. It employs two novel skewing schemes to provide conflict-free access to adjacent elements （8-bit and 16-bit data types） or with power-of-two intervals in both horizontal and vertical directions, which were not possible in previous parallel memory architectures. Area consumptions and delay estimations are given respectively with 4, 8 and 16 memory modules. Under a 0.18-pm CMOS technology, the synthesis results show that the proposed system can achieve 230 MHz clock frequency with 16 memory modules at the cost of 19k gates when read and write latencies are 3 and 2 clock cycles, respectively. We implement the proposed parallel memory architecture on a video signal processor （VSP）. The results show that VSP enhanced with the proposed architecture achieves 1.28× speedups for H.264 real-time decoding. 相似文献
16.
词汇记忆是英语学习的一个重要组成部分。学生在记忆词汇方面,往往投入大量的时间、精力,但由于缺乏必要的记忆情境和学习策略,记忆效果不甚理想。传统记忆需要学生付出较多的注意,属于外显学习。本研究基于日本学者Nonaka的SECI模型,从隐性知识与显性知识转化的角度出发,借助现代信息技术,将词汇的记忆置于不同的知识场域中,构建符合SECI模型理念的专题学习网站,以实现学生对词汇高效且长久的记忆。 相似文献
17.
Steven J. Haggbloom LaNeel Lovelace Vickie R. Brewer Shelia M. Levins James D. Owens 《Learning & behavior》1990,18(3):315-322
Event-generated memory refers to the memory of a reinforcement (R) or nonreinforcement (N) event from an immediately preceding trial;signal-generated memory refers to the memory of a temporally remote R or N, retrieval of which is generated by presentation of a signal with which the memory is associated (Haggbloom, 1988). In each of three experiments, Group Signal-R received runway discrimination training in Phase 1 to establish a stimulus as a signal for R, and partial reinforcement training in Phase 2. An extinction test measured learning about the memory of nonreward (SN)—learning that occurs when SN is retrieved on R trials that follow N trials. In Group Signal-H, those R trials were accompanied by the signal for R, a treatment we hypothesized would generate retrieval of the memory of reinforcement (SR) so that signal-generated SR would replace event-generated SN as the operative memory, thereby eliminating the increased resistance to extinction normally produced by PRF training. In each experiment, Group Signal-R was less resistant to extinction than was a control group conditioned to respond to-event-generated SN. Extinction was as rapid in Group Signal-R as it was in a consistent reinforcement control group (Experiment 1) and in a group given intertrial reinforcements to interfere with learning about SN (Experiment 3). Experiment 2 tested two alternative interpretations of the failure to learn about SN in Group Signal-R. Those alternatives were found to be less viable than the hypothesis that the signal for R actively recruited retrieval of a competing memory. 相似文献
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对于软件设计中数据的呈现或界面设计,即使是在现代高度完善的软件开发平台上仍然是一项较为复杂的工作。文章讨论了在线考试系统的开发中如何实现试卷库中的试题从数据库到内存的映射,再通过控件的数据绑定来最终完成命题呈现的过程,这是设计在线考试系统的重要环节。针对考试过程中可能存在的试题丢失问题,文章给出了试题的持久化处理方法。 相似文献
20.
Vijnan Shastri 《Resonance》1996,1(11):76-82
Flash memories are not very new. Products based on flash memory have been around for more than 4 years now after the basic technology was introduced in 1988. Although flash-memories were initially thought of as replacements for magnetic storage, this has not happened. Instead, what is new are the different applications in which flash memory is being putting to use. What is flash memory? What are its features ? What are its advantages as compared to conventional memories? Where is it used ? This is what we’ll take a look at in this article. The actual internal structure of flash memory is illustrated at the end of the article. 相似文献