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81.
82.
人们对信息的获得百分之九十以上来自于眼睛,LED具有颜色丰富、亮度可大范围调节、功耗低、可靠性高、寿命长等特点,以LED为发光光源的信息显示设备在监控系统、信息发布系统中得到越来越广泛的应用。设计LED信息显示,需考虑的问题之一是点距,文章从讨论人眼的视觉特性着手,研究了LED信息显示设备的等效发光面积及点距的设计。 相似文献
83.
Jeffrey Beck Richard Scritchfield Billy Sullivan Jamie Teherani Chang-Feng Wan Mike Kinch Martha Ohlson Mark Skokan Lewis Wood Pradip Mitra Mike Goodwin Jim Robinson 《Journal of Electronic Materials》2009,38(8):1579-1592
The operation of the mid-wave infrared (MWIR) HgCdTe cylindrical electron injection avalanche photodiode (e-APD) is described.
The measured gain and excess noise factor are related to the collection region fill factor. A two-dimensional diffusion model
calculates the time-dependent response and steady-state pixel point spread function for cylindrical diodes, and predicts bandwidths
near 1 GHz for small geometries. A 2 μm diameter spot scan system was developed for point spread function and crosstalk measurements at 80 K. An electron diffusion
length of 13.4 μm was extracted from spot scan data. Bandwidth data are shown that indicate bandwidths in excess of 300 MHz for small unit
cells geometries. Dark current data, at high gain levels, indicate an effective gain normalized dark density count as low
as 1000 counts/μs/cm2 at an APD gain of 444. A junction doping profile was determined from capacitance–voltage data. Spectral response data shows
a gain-independent characteristic. 相似文献
84.
Henk Martijn Urban Halldin Per Helander Jan Y. Andersson 《Analog Integrated Circuits and Signal Processing》2000,22(1):71-79
A readout circuit for a 640 × 480 pixels FPA (focal plane array) has been successfully designed, fabricated and tested. The circuit solution is based on a per pixel source-follower direct injection (SFDI) pre-amplifier. Signal multiplexing is performed in both X and Y direction. The pixel size is 25 m × 25m. The chip is optimized for a QWIP (quantum well infrared photodetector) operating at a temperature of 70 K. The circuit has been realized in a standard 0.8 m CMOS process. 相似文献
85.
A combination of two conventional junction isolation structures is used to produce a device, which significantly improves the blocking of minority carriers injected into the substrate of a power IC due to switching of an inductive load. Simulation results show that the connection scheme employed greatly enhances the efficiency of the structures. A substrate current reduction of up to four orders of magnitude compared to conventional junction isolation structures is achieved. The significance of doping profiles in the p-sinker region is evaluated. 相似文献
86.
87.
通过对CATV双向电缆网络反向回传通道中汇集噪声和汇集均衡的产生、影响和解决办法的探讨,说明双向电缆传输网络的设计要点和方法步骤. 相似文献
88.
ZHANG Qi-zhi LIAO Jian-xin ZHU Xiao-min State Key Laboratory of Networking Switching Beijing University of Posts Telecommunications Beijing P.R. China 《中国邮电高校学报(英文版)》2005,12(2)
1IntroductionIntelligent network,an affiliated network over com-munication network,is introduced for the quick provi-sion of newservices[1 ~2].In the structure of intelligentnetwork,a Service Control Point(SCP) serves a lot ofService Switch Point(SSPs)[3 ~4].It is a veryi mportanttopic that howto guarantee the Qos of SCP (e .g.thenumber of successfully processed calls per unit ti me)whenthe network becomes overloadedinthis centralizednetwork structure . There were many studies about the… 相似文献
89.
移动网络随着竞争的需要和移动互联网的发展,原有CS业务网络也逐步向IP化方向发展。目前,信令网络中存在由LSTP/HSTP点组成的E1信令链路网和NGN软交换组成的IP路由、本文对移动网中存在的双路由业务情况进行了深入的分析说明,对于信令网维护人员有一定参考价值,对提高信令监测系统数据的完整性有促进作用。 相似文献
90.
New implementation of a high linear low-noise amplifier (LNA) using the improved derivative superposition (DS) method is proposed. The input stage is formed by two transistors connected in parallel. One transistor is biased in the strong inversion region as usual and another one is biased in the moderate inversion region instead of the weak inversion region, thus allowing a feasible source degeneration inductance at the sources of the two transistors to achieve a good input impedance matching and low noise figure (NF) while keeping high third-order input intercept point (IIP3) improvement with the DS method. The new implementation has been used in a 0.18-μm CMOS high linear LNA. The measured results show that the LNA achieves +11.92 dBm IIP3 with 9.36 dB gain, 2.25 dB NF and 7.5 mA at 1.8 V power consumption. 相似文献