共查询到20条相似文献，搜索用时 281 毫秒
1.
Yin-jun Wang Cheng Zhuo Jun-yong Deng Jin-fang Zhou Kang-sheng Chen 《浙江大学学报(A卷英文版)》2008,9(6):849-857
Power integrity （PI） has become a limiting factor for the chip＇s overall performance, and how to place in-package decoupling capacitors to improve a chip＇s PI performance has become a hot issue. In this paper, we propose an improved transmission matrix method （TMM） for fast decoupling capacitance allocation. An irregular grid partition mechanism is proposed, which helps speed up the impedance computation and complies better with the irregular power/ground （P/G） plane or planes with many vias and decoupling capacitors. Furthermore, we also ameliorate the computation procedure of the impedance matrix whenever decoupling capacitors are inserted or removed at specific ports. With the fast computation of impedance change, in-package decoupling capacitor allocation is done with an efficient change based method in the frequency domain. Experimental results show that our approach can gain about 5× speedup compared with a general TMM, and is efficient in restraining the noise on the P/G plane. 相似文献
2.
An error correction technique to achieve a 14-bit successive approximation register analog-to-digital converter（SAR ADC） is proposed. A tunable split capacitor is designed to eliminate the mismatches caused by parasitic capacitors. The linearity error of capacitor array caused by process mismatch is calibrated by a novel calibration capacitor array that can improve the sampling rate. The dual-comparator topology ensures both the speed and precision of the ADC. The simulation results show that the SAR ADC after calibration achieves 83.07 dB SNDR and 13.5 bit ENOB at 500 kilosamples/s. 相似文献
3.
权力、制度与经济增长 总被引：4，自引：0，他引：4
权力是经济运行的重要变量,它是主体对资源的控制力;权力结构可分为正式权力和非正式权力。权力作为一种资本,它具有“服从性”、“乘数效应”、“稀缺性和刚性”的特征。市场本身并不配置资源,资源配置是在市场背后由权力主休进行的,市场失灵的根源是权力边界的破坏和结构的失衡。权力决定着制度的形成,并因此而成为经济增长的核心要素。 相似文献
4.
高速ADC电路的电磁兼容设计 总被引：3，自引：0，他引：3
针对高速ADC电路设计的特点，重点讨论了包含高速ADC的硬件电路设计中印刷电路板布局时所必须引起注意的电磁兼容问题，包括数字地和模拟地、数字电源和模拟电源的隔离，ADC输入信号、输出信号的处理以及采样时钟的处理等，并给出了一个成功布局的例子。 相似文献
5.
张小燕 《北京工业职业技术学院学报》2014,13(1):48-53
在功率测量中,由于非整周期采样、随机噪声、通道延时的存在,会降低测量准确度.针对这个问题,首先设计算法来减小这些因素的影响;然后在Labview平台上编写数据采集和数据处理程序;接着用信号发生器作为信号源和噪声源,NI ELVISⅡ作为数据采集设备采集电信号,并用所设计的采样整周期性算法、去除随机噪声算法、修正通道延时算法处理采集的数据,测量出源信号的有效电压值、有效电流值、平均功率、视在功率、无效功率和功率因数;最后进行数据分析和讨论.结果证明,所设计的功率测量算法能够减小上述3种因素对功率测量的影响,得到具有较高准确性的功率测量值. 相似文献
6.
夏淑丽 《中国教育技术装备》2008,(22)
在微弱信号检测中,以提高检测信号的信噪比来获取有用信号。重点介绍ADC在微弱信号检测中提高检测手段的2种技术—抖动技术与过采样和平均技术,并做简单总结。 相似文献
7.
吴贻文 《武汉职业技术学院学报》2014,(3):51-54
功率因数监测与补偿教学系统以C8051F020高集成智能型单片机为控制核心,实现对电压、电流、频率、有功功率、无功功率、功率因数的检测以及完成对功率因数自动补偿控制。系统采用模块化设计,设计中运用交流采样技术对交流电压、电流信号直接采样以确保精度,用高精度的真有效值转换芯片AD637对取样信号进行转换,采用电平移位采集电流峰值测量瞬态电流,采用在电路中增减并入电容的方法进行功率因数的自动调节,提高功率因数。 相似文献
8.
介绍一种采用USB2.0接口与PC机进行数据传输的高速数据采集卡的设计。采集卡由可变增益放大器对采样信号进行预处理,使用异步并行的A/D转换技术实现40 Msps的数据采集,由FPGA实现时序控制和数据高速FIFO,由内嵌MCU的USB控制器实现USB2.0接口功能。文章给出了硬件的基本结构和软件固件设计的基本方法,并对用FPGA设计FIFO作了重点阐述,同时对使用异步并行A/D转换与使用采样率为40 Msps的ADC器件的采样数据在FIFO内的数据传输进行了时序仿真,分析了仿真结果。 相似文献
9.
A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN) cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling(CDS),pixel FPN is cancelled and column FPN is stored and eliminated by the sampleand-hold operation of digitally programmable gain amplifier(DPGA).The bandwidth balance technology based on operational amplifier(op-amp) sharing is also introduced to decrease the power dissipation of traditional multi-stage switched capacitor DPGA.The circuit is designed and simulated using 1P6M 0.18 μm 1.8 V/3.3 V process.Simulation results indicate that the proposed CDS scheme can achieve an FPN of less than 1 mV.The total sampling capacitor per column is 0.9 pF and no column-wise power is dissipated.The die area and FPN value are cut by 70% and 41% respectively compared with amplifier-based CDS.The op-amp sharing gain stage can achieve a 12-bit precision and also implement an 8-bit gain controlling within a gain range of 24 dB.Its power consumption is 1.4 mW,which is reduced by 57% compared with traditional schemes.The proposed readout circuit is suitable for the application of low power cost-sensitive imaging systems. 相似文献
10.
与传统的频率变换器相比,矩阵变换器能够实现功率的双向流动,驱动电机四象限运行,输入端功率因数可调节为1,输出电压幅值、相位和频率可独立调节等优点。由于矩阵变换器的一般控制算法为开环控制,使当输入存在干扰时,输出电压的质量就会受到影响。采用一种基于电压滞环控制的闭环控制策略,对电压进行闭环控制,并在Matlab环境下建立仿真模型,仿真结果表明该控制算法是可行和有效的。 相似文献
11.
将功率因数校正设计作为课程设计的基本内容,在该过程中可以掌握以下几个方面的技术细节:正确测量容性整流滤波电路的功率因数;大功率整流滤波电路有源功率因数校正工作原理;电源线共模与串模干扰噪声抑制技术;地阻抗干扰抑制技术和磁路设计等.有源功率因数校正是一种实用的电子系统,需要综合应用电磁学、电路、模拟电子技术、数字电子技术、高频电路、功率电子器件等多方面知识.经过这样的课程设计培训,能明显提高解决实际工程问题的能力. 相似文献
12.
本文首先基于三相静止坐标系的典型控制方案与基于d-q同步旋转坐标系的矢量控制方案作了比较,然后运用功率平衡的原理对本文给出的矢量控制方案进行了系统设计,并在此基础上提出一种前馈控制策略并进行了仿真验证。 相似文献
13.
A high speed column-parallel CDS/ADC circuit with nonlinearity compensation is proposed in this paper.The correlated double sampling (CDS) and analog-to-digital converter (ADC) functions are integrated in a threephase column-parallel circuit based on two floating gate inverters and switched-capacitor network.The conversion rate of traditional single-slope ADC is speeded up by dividing quantization to coarse step and fine step.A storage capacitor is used to store the result of coarse step and locate the section of ramp signal of fine step,which can reduce the clock step from 2 n to 2 (n/2+1).The floating gate inverters are implemented to reduce the power consumption.Its induced nonlinear offset is cancelled by introducing a compensation module to the input of inverter,which can equalize the coupling path in three phases of the proposed circuit.This circuit is designed and simulated for CMOS image sensor with 640×480 pixel array using Chartered 0.18μm process.Simulation results indicate that the resolution can reach 10-bit and the maximum frame rate can reach 200 frames/s with a main clock of 10MHz.The power consumption of this circuit is less than 36.5μW with a 3.3V power supply.The proposed CDS/ADC circuit is suitable for high resolution and high speed image sensors. 相似文献
14.
通过采样两点的电压、电流瞬时值信号,采取特定的算法,直接推算出功率因数;实验验证和工程应用表明,该算法运算快、实时性好、精度高,可在工业计量和数字化检测、控制中推广应用。 相似文献
15.
While it is easy to assume that university students who wait until the last minute to complete surveys for their class research requirements provide low-quality data, this issue has not been empirically examined. The goal of the present study was to examine the relation between student research procrastination and two important data quality issues—careless responding and measurement noninvariance. Data gathered from university students across two semesters tentatively indicated that procrastination is related to low-quality survey data. Procrastination was slightly more problematic for certain data quality issues (measurement noninvariance) than others (careless responding). These relations, however, were small and contingent on how procrastination and careless responding were measured. Accordingly, it seems more beneficial for researchers to select a sampling window that supports their research goals and statistical power requirements rather than select a sampling window that attempts to minimize careless survey responding or other measurement issues. 相似文献
16.
用不同方法进行发动机噪声源识别的研究 总被引：9，自引：0，他引：9
发动机噪声源识别对于制定发动机降噪措施十分重要 ,而像油底壳、气门罩、前齿轮室盖等罩壳类零件通常是发动机的主要噪声源 .本文用铅覆盖法和表面振动测量法对一台六缸工程机械用柴油机进行了表面噪声源识别的研究 ,得到了罩壳类零件按噪声能量大小的排列顺序 ,文中首先在半消声条件下利用铅覆盖技术测量了这些罩壳类零件的声功率 ,然后又研究了它们的振动特性 ,并通过表面振动速度的面积时间均方值预测了其声功率 .两种方法的测量结果吻合较好 ,说明了它们在工程领域应用的有效性 相似文献
17.
论成人教学质量管理中的闭环控制 总被引：1，自引：0，他引：1
成人教学是一个闭环控制系统。如何利用各种反馈信息对教学质量目标进行诃整，如何对各种影响因素进行协调控制，是闭环控制在成人教学质量管理中应用意义之所在。 相似文献
18.
Compared with traditional charge coupled device(CCD) imagers, CMOS image sensor (CIS) usingphotodiode to detectphoto signal has the advantages ofhigh photo-sensitivity, reduced blooming, highspeed, integrating signal processing circuit on chip,and lowpower and system cost[1,2]. But fixed patternnoise (FPN) caused by the mismatch in pixels or col-umns circuit severely limits image quality (1 mV—30mV)[3]. FPN is spatial and does not change betweenframes, so it is difficult to be eliminate… 相似文献
19.
高潮 《深圳信息职业技术学院学报》2014,(3):93-96
基于开关功率开关变流器技术,光能并网发电电工技术的可靠变换正在进一步发展,另一方面功率开关器件装置组成系统已经成为许多领域不可或缺的基本设备。在信息数字革命时代的二十一世纪上半叶,对电功调节光能联网发电,并网型兆瓦级电功调节光能联网发电,无功补偿及控制技术要求也相对提高。论文讨论了具有电功调节的光能联网发电与无功补偿及控制技术的应用和发展。 相似文献
20.
Multisiim2001在电力电子仿真技术中的应用 总被引：8，自引：0，他引：8
范爱平 《实验室研究与探索》2004,23(5):11-13
本文介绍电路分析与设计软件Multisim2001的性能及特点,重点介绍它在电力电子电路计算机仿真中的应用。该软件提供了晶闸管、IGBT、功率MOSFET等多种电力电子器件模型、非常丰富的信号源和多种虚拟仪器,且绘制电路方便,分析功能齐全,为电力电子电路的计算机仿真提供了一种新方法。 相似文献