数码相机CMOS图像传感器的特性参数与选择

介绍了数码相机的核心器件———CMOS图像传感器的特性参数和在数码相机设计过程中CMOS图像传感器的选择。选择CMOS图像传感器,不仅需要考虑包括传感器的尺寸、像素总数和有效像素数、最小照度、动态范围、灵敏度、分辨力、光电响应不均匀性以及光谱响应等在内的特性参数,而且还要考虑电源管理和功耗、模数转换位数、开发的简便性以及成本等因素。     

Comparison of laser Doppler and laser speckle contrast imaging using a concurrent processing system

Full field laser Doppler imaging (LDI) and single exposure laser speckle contrast imaging (LSCI) are directly compared using a novel instrument which can concurrently image blood flow using both LDI and LSCI signal processing. Incorporating a commercial CMOS camera chip and a field programmable gate array (FPGA) the flow images of LDI and the contrast maps of LSCI are simultaneously processed by utilizing the same detected optical signals. The comparison was carried out by imaging a rotating diffuser. LDI has a linear response to the velocity. In contrast, LSCI is exposure time dependent and does not provide a linear response in the presence of static speckle. It is also demonstrated that the relationship between LDI and LSCI can be related through a power law which depends on the exposure time of LSCI.     

Building a Simple Model of a Pulse-Frequency-Modulation Photosensor and Demonstration of a 128 x 128-pixel Pulse-Frequency-Modulation Image Sensor Fabricated in a Standard 0.35-$mUm Complementary Metal-Oxide Semiconductor Technology

We present a simple model of the pulse-frequency-modulation (PFM) photosensor that provides explicit relationships between circuit parameters and output characteristics. The model treats the PFM photosensor with a feedback loop as an open loop circuit. Several characteristics such as output pulse frequency for light intensity and photosensitivity are expressed by device parameters of a photodiode, reset transistor, and chain of inverters. The relationships derived from the proposed model help us to comprehend the results by simulation program with integrated circuit emphasis (SPICE) or experiments. We design and fabricate a 128 x 128-pixel PFM image sensor with photosensitivity of 0.15 Hz/lux. As a demonstration, a figure of a dinosaur is captured using the fabricated image sensor to discuss its operation. Characteristics of a normal pixel and white and black defect pixels are measured and discussed based on the results of formulations.     

电流控阈技术及三值电流型 CMOS施密特电路

本文以开关信号理论为指导 ,对电流型 CM OS电路中如何实现阈值控制进行研究. 建立实现阈 值控制电路的电流传输开关运算 ,并用于指导电流型 CMOS施密特电路的开关级设计 .用 PSPICE程序 模拟证明了所设计的电路具有理想的施密特电路特性.     

CMOS星敏感器光学系统的设计

基于对恒星星表V/50的统计,在确保一定捕获概率的前提下,确定了星敏感器光学系统的视场角和所能探测的极限星等,在此基础上,结合所选用的STAR-250CMOS探测器的性能,在保证一定信噪比的前提下,确定了光学系统的通光孔径、焦距、工作光谱范围和中心波长、弥散元大小等主要参数。以改进双高斯型结构为初始结构,在ZE-MAX平台上实现了具有良好像质的大孔径(F/1.198)、大视场(22.6°)、宽光谱范围(0.5μm~0.8μm)的光学系统的设计,满足了对弥散斑、能量集中度等的特殊要求。     

Extraordinarily high drive currents in asymmetrical double-gate MOSFETs

Numerical simulation results derived from a Schrödinger–Poisson tool applied to scaled double-gate (DG) MOSFETs, supplemented by analytical characterizations of the pertinent physics, are presented to give insight concerning the near-ideal features of DG devices and to explain how the low-voltage drive current of the asymmetrical DG MOSFET, having only one predominant channel, can be comparable to, and even higher than, that of the symmetrical-gate counterpart designed to have the same off-state current.     

微波注入反相器基本电路的非线性效应

采用理论分析和微波注入实验相结合的方法,分别研究了以74HC04和74LVCU04A两种芯片为核心的反相器基本缓冲及数模转换电路的微波效应问题,通过反相器闩锁过程对非线性扰乱进行了机理分析,并利用微波注入实验详细分析了非线性扰乱效应的微波有效功率阈值及其随频率、脉冲宽度的变化。实验结果表明:在固定环境温度条件下,有效注入功率大于33 dBm,频率在3 GHz以下的微波均可使74HC04效应电路的非线性扰乱强度达到10%以上;有效注入功率大于30 dBm,频率在3 GHz以下的微波均可使74LVCU04A效应电路的非线性扰乱强度达到10%以上。相同非线性扰乱强度的注入有效功率阈值近似随频率的提高而增大。非线性扰乱阈值随注入微波信号脉宽变化明显,拐点为40~70 ns不等,与反相器中的互补型金属氧化物半导体器件寄生三级管的导通电流积累有关。     

静态存储器型现场可编程门阵列总剂量辐射损伤效应研究

本文从FPGA器件内部最基本的CMOS单元出发,分析了器件功能失效时反相器输出波形随累积剂量的变化关系,进而研究Altera SRAM型FPGA器件⁶⁰Co γ射线辐照后的总剂量辐射损伤效应.实验结果表明:由于场氧漏电和结构漏电的影响,随着累积剂量的增加输出波形发生畸变,峰峰值变为原来的十分之一左右,但输出波形还有相对的高低电平;同时,输出高电平不能保持原有的状态,迅速地向低电平转换,并且转换速度随着累积剂量的增加而加快,输出低电平相对初始值有一定程度抬高;由于栅氧厚度变薄,输出波形 关键词： 60Coγ')" href="#">⁶⁰Coγ 总剂量辐射损伤效应 SRAM型FPGA CMOS单元     

基于CCD与CMOS的图像传感技术

概述了CCD图像传感器的原理、特点及发展趋势。对CMOS图像传感器的结构和工作原理,尤其是CMOS与CCD两类图像传感之间的不同进行综述。重点介绍了CMOS图像传感器的研究现状和发展趋势。     

定量脉冲产生电路

采用CMOS数字集成电路设计了特殊的脉冲电路，该电路能够根据设定输出指定数目的脉冲。