高灰度级TFT-LCD显示系统的实现

提出了一种以FPGA为核心控制器的高灰度级TFT-LCD显示系统的设计方案。该系统采用幅值-帧速率控制调制-空间混合灰度调制方法,首先将10 bit的R、G、B信号分割成高8 bit数据和低2 bit数据,低2 bit数据经过空间处理后平均分到4个相邻的8 bit数据上,然后把这8 bit数据继续分割成高6 bit数据和低2 bit数据,其中高6 bit数据用于幅值调制,低2 bit数据用于帧速率控制调制,从而实现1 024个灰度等级显示。试验结果表明,该系统具有良好的显示效果和较高的显示灰度等级。     

FM中频数字化的FPGA实现

依照软件无线电数字化中频架构,采用音频采集芯片PCM1801、FPGA芯片X3S500E、数模转换器DA9654构建硬件平台,在此基础上实现了FM的中频数字调制。此外,通过对FPGA的配置,该平台还能实现其他方式的调制。与传统模拟调制相比,充分体现了软件无线电配置灵活、复用性高的优势。     

ADI推出双通道1.6Gsps数模转换器

ADI公司发布了一款双通道、16位、1.6Gsps数模转换器AD9142,它支持通信、测试、仪器仪表以及防务和航天系统所需的高数据速率和复杂调制方案。ADI的AD9142数模转换器具有片内32位NCO(数值控制振荡器),允许灵活放置IF(中间频率)载波,从而优化系统性能,超越了使用复杂DPD(数字预失真)技术、需要宽信号带宽的应用要求。     

基于FPGA的∑-△D/A转换器的设计与实现

数模转换器可以将一个二进制数字量转换成与该数字量成正比的电压值,可应用于可编程电压源、波形发生器等.本文采用数字化技术,用FPGA实现了一个简单的一阶8位∑-△型DAC,只占用几个CLB.FPGA的速度和柔性的输出结构非常适合该DAC的实现.     

基于Catalyst-200的串行DAC静态参数测试研究

文章基于大规模数模混合测试设备Catalyst-200,采用最佳拟合直线法,对串行数模转换器的测试方法进行研究,并以AD5317为例,进行其静态参数差分非线性和积分非线性的测试,通过合理设计数字pattern控制串行模数转换器的控制字和数据输入,同时对转换控制信号进行时序分析,最终得到相应的测试曲线和测试值,证明了测试方法的正确性。文章的研究成果为开展其它串行数模混合信号集成电路的测试研究奠定了基础。     

基于CPLD的场助热电子发射静态显示驱动系统

主要介绍了新型的平面显示技术--场助热电子发射显示的一种基于CPLD的静态多灰度驱动系统,以及两种芯片:双极性串并转换器HV6008和多灰度串并转换器HV633的工作原理和在该系统中的应用.     

基于遗传优化的网络组合算法的手写数字识别

目前,手写数字识别技术已被广泛应用.基于遗传优化的网络组合算法对经预处理的手写数字采用网络加权组合法进行识别,最佳网络初始权值由改进的遗传算法得到。灰度特征神经网中,首先对输入数据进行离散余弦变换以降低因二值化带来的冗余.实验表明该法是较有效的手写数字识别算法。     

图象中背景碎化前景不动的实现

在一些游戏软件中我们经常看见这样的场面:计算机屏幕在光怪陆离的背景下显示几个醒目大字之后,背景渐渐暗下去直至消失,而几个醒目大字巍然不动……,这种显示方式给软件本身增添了神秘的艺术效果。事实上,这种背景碎化前景不动的技巧是通过VGA数模转换器DAC来实现的。背景碎化与VGA灰度密切相关。VGA灰度色由同等数量的红绿蓝组成。白是最大的灰度值,黑是最小灰度值。VGA中每种颜色6位,共可产生64个可能的灰度数。这64级灰度可由颜色寄存器中的6位颜色字段获得。更重要的一点是,VGA中填装颜色寄存器的颜色可以转换成灰度。设任一时刻红绿蓝三     

基于FPGA的∑-ΔD/A转换器的设计与实现

数模转换器可以将一个二进制数字量转换成与该数字量成正比的电压值,可应用于可编程电压源、波形发生器等。本文采用数字化技术,用FPGA实现了一个简单的一阶8位∑-Δ型DAC,只占用几个CLB。FPGA的速度和柔性的输出结构非常适合该DAC的实现。     

DAC寄存器的直接读取和设置

VGA显示系统中的DAC寄存器,也称颜色寄存器或数模转换器,它在VGA显示系统中充当着相当重要的角色,相当多的在VGA显示系统上实现的屏幕特技,都是通过对DAC寄存器的巧妙设置而完成的.VGA中的数模转换器由256个18位的DAC寄存器组成,每个DAC寄存器中用6位分别表示G(红)、R(绿)、B(蓝)颜色值,每种颜色值可在0—63之间取值,所以通过R G B三基色可以合成256K种不同的色彩,能够显示出具有微小差别的颜色,基本上达到了模拟信号输出的效果.     

10‐bit source driver with resistor‐resistor‐string digital‐to‐analog converter

Abstract— A 10‐bit gray‐scale source driver using a resistor‐resistor‐string digital‐to‐analog converter (RR‐DAC) is proposed for a TFT‐LCD source driver. The 10‐bit RR‐DAC consists of an 8‐bit resistor‐string DAC and a two‐bit resistor‐string DAC without an intermediate unity‐gain buffer to isolate the parallel‐connected resistor string. The output deviation of the proposed source driver is less than ±3 mV. The chip area of the proposed 10‐bit source driver with an RR‐DAC is increased to 29% of that of an 8‐bit source driver.     

An area‐ratio gray‐scale method to achieve image uniformity in TFT‐LEPDs

Abstract— An area‐ratio gray‐scale method (ARG) has been developed for low‐temperature‐polysilicon thin‐film‐transistor‐driven light‐emitting‐polymer displays (LTPS TFT‐LEPDs). A pixel consists of plural sub‐pixels, which are controlled to be in either an on‐state or off‐state. The gray scale is acquired by selecting the number of the on‐state sub‐pixels, that is, the ratio of the light‐emitting area. One advantage of the ARG is to improve image uniformity. In the on‐state, since TFT resistance is negligible, the current is determined by the LEP diode resistance. Therefore, the TFT characteristic deviation has no effect on the current. Moreover, the dimensions of each sub‐pixel are the same, and the shapes of the sub‐pixel are circular in order to improve their uniformity. As a result, the image becomes uniform. Another advantage of the ARG is to achieve digital operation, which makes interfacing easy. A digital‐analog converter (DAC) automatically exists in the sub‐pixel and the naked eye.     

一种低成本的视频数字图象获取方法在微计算机系统中的实现

本文阐述一种用二值影象组合装配获取视频数字图象的方法.按照这一方法,用标准电 视摄象机和八位微处理器实现了一个价廉而灵活的微计算机图象处理系统.文中给出了系统 视频图象输入接口结构框图及软件操作命令.该系统获取图象的最大能力为256×256,十六 灰度级;具有两种可以灵活选择的程序控制方式;以每灰度级40ms的速度输入局部图象,或 以每灰度级1800ms的速度(采用2MHz的8080A MPU)获取整幅图象.     

图像清晰度评价方法研究

数字图像的清晰度评价一直是各类数字成像系统的一个关键问题，而在已有的一些的评价参数中，由于评价方法不同，均存在一些局限性，为此，针对图像的清晰程度提出一种新的评价方法，目的在于能够快速、准确地评价数字图像的清晰度。该评价方法评价参数可通过改进边缘锐度算法(EAV)得到，然后与机测MTF值的变化趋势一起做曲线回归分析，以便和其他传统清晰度评价参数做对比。通过上百幅各类数字图像的测试，结果表明，该评价参数与数字成像系统的MTF值变化有着很好的正相关关系，其不仅能够更准确地反应数字图像清晰度变化的趋势，而且便于简捷、快速地应用于各类数字图像的清晰度评价。     

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

Abstract— Early loss of image uniformity has been a critical drawback of active‐matrix organic light‐emitting‐diode (AMOLED) displays operated in time‐ratio gray‐scale mode. This problem is addressed with an analog calibration technique which measures the voltage across each OLED for a given current and subsequently controls the supply voltage of pixels and the voltage drop across the driving th in‐film transistor (TFT) of each OLED. The uniformity of test cells, which were aged to produce image sticking in a chessboard pattern, were improved. A measure of image sticking, called the extracted image‐sticking value (EISV), was formulated, which is developed and used for the quantitative evaluation of the calibration method. OLED voltages over a range of about 0.35 V were compensated to produce more uniform OLED currents than those before aging. The variation of luminance associated with image sticking was reduced by about 40% for a full‐white image after between 2 and 10 hours of accelerated aging with a constant voltage of 8 V across an OLED.     

Pulse‐width modulation with current uniformization for AM‐OLED micro‐displays on Si LSI chips

We have developed pulse‐width modulation (PWM) with current uniformization for active‐matrix organic light‐emitting diode (AM‐OLED) micro‐displays on Si large‐scale integration (LSI) chips. This driving method can simultaneously solve luminance unevenness and image sticking due to characteristic deviations and degradations of driving transistors and OLEDs. With the use of circuit simulation, it is verified that the PWM with current uniformization (PWM‐CU) can simultaneously achieve precise gray scale and exceedingly improve luminance uniformity. Moreover, an actual panel is designed and fabricated, where the OLEDs are layered on the Si LSI chip. It is found that the luminance uniformity can be improved within 2% to 3%. It is meaningful that the correct images can be displayed using the PWM‐CU for the first time for AM‐OLED micro‐displays on Si LSI chips.     

LED显示屏高灰度扫描控制的FPGA实现

本文在分析LED显示屏的显示扫描控制方法的基础上,提出了用并行结构实现高灰度扫描控制的方案,设计了基于FPGA的8位并行输入LED扫描控制芯片,并结合外围电路、显示面板及计算机构成了LED大屏幕显示系统,实现了LED显示屏的256级灰度显示,在简化系统硬件结构的前提下取得了清晰稳定的画面显示。     

Clamped‐inverter circuit architecture for luminescent‐period‐control driving of active‐matrix OLED displays

Abstract— An innovative pixel‐driving technology for high‐performance active‐matrix OLED flat‐panel displays is described. Called “clamped‐inverter circuit architecture,” it uses luminescent‐period‐control driving to reduce the inter‐pixel non‐uniformity caused by the device‐to‐device variability of low‐temperature poly‐Si TFTs. A prototype full‐color display shows a luminous deviation of less than 1.6%, which corresponds to only the LSB‐error in 6‐bit gray‐scale.     

MULTITUNING FUZZY CONTROL SYSTEMS DESIGN

A multituning fuzzy control system structure that involves two simple, but effective tuning mechanisms, is proposed: one is called fuzzy control rule tuning mechanism (FCRTM); the other is called dynamic scalar tuning mechanism (DSTM). In FCRTM, it is used to generate the necessary control rules with a center extension method. In DSTM, it contains three fuzzy IF-THEN rules for determining the appropriate scaling factors for the fuzzy control system. In this paper, a method based on the genetic algorithm (GA) is proposed to simultaneously choose the appropriate parameters in FCRTM and DSTM. That is, the proposed GA-based method can automatically generate the required rule base of fuzzy controller and efficiently determine the appropriate map for building the dynamic scalars of fuzzy controller. A multiobjective fitness function is proposed to determine an appropriate parameter set such that not only the selected fuzzy control structure has fewer fuzzy rules, but also the controlled system has a good control performance. Finally, an inverted pendulum control problem is given to illustrate the effectiveness of the proposed control scheme.     

Multicast in Wormhole-Switched Torus Networks Using Edge-Disjoint Spanning Trees

A tree-based multicast algorithm for wormhole-switched networks which makes use of multiple edge-disjoint spanning trees is presented. The disjoint spanning-tree multicast, or DSTM, algorithm provides deadlock-free multicast routing that is fully compatible with unicast. The application of the DSTM algorithm to 2-dimensional torus networks is considered. A family of constructions of two spanning trees in the torus is given along with a formal proof of their edge-disjointness. Two constructions from this family are selected and shown to produce diameters no greater than twice that of the torus. Flit-level simulation results are presented to show that DSTM outperforms the best single spanning tree multicast approach by up to a factor of two. The DSTM algorithm is also simulated for different spanning tree constructions. The results show that our novel tree construction is significantly better for multicast than those produced by a general tree construction method that applies to arbitrary-topology networks (J. Roskind and R. Tarjan, Math. Oper. Res.10 (Nov. 1985), 701–708). Finally, two approaches to providing single link fault tolerance with DSTM are presented and evaluated.