Current Issue : October - December Volume : 2012 Issue Number : 4 Articles : 6 Articles
A decorrelation and analog-to-digital conversion scheme aiming to reduce the power consumption of infrared image sensors is\r\npresented in this paper. To exploit both intraframe redundancy and inherent photon shot noise characteristics, a column based 1D\r\nHaar analog wavelet transform combined with variable gain amplification prior to A/D conversion is used. This allows to use only\r\nan 11-bit ADC, instead of a 13-bit one, and to save 15% of data transfer. An 8Ã?â??16 pixels test circuit demonstrates this functionality....
This paper presents a complete analysis of the kink effect in SOI MOSFET and proposes a method for eliminating kink effect\r\nobserved in the current-voltage output characteristics of a partially depleted SOI MOSFET device. In this method, back oxide\r\nfor the device is introduced at selected regions below the source and drain and not continuously as in an SOI device giving rise\r\nto what is termed a ââ?¬Å?SELBOXââ?¬Â structure. Selective back oxide structure with different gap lengths and thicknesses was studied.\r\nResults obtained through numerical simulations indicate that the proposed structure can significantly reduce the kink while still\r\npreserving major advantages offered by conventional SOI structure. Although the new structure is capable of eliminating kink,\r\nfor narrow gaps the device may still exhibit some kink effect. A device model that explains the kink behavior of the structure for\r\nvarying gap lengths is also developed....
The major problems affecting the service life of bridges are related to various factors such as fatigue-sensitive details, increased\r\nservice loads, corrosion deterioration, and the lack of proper maintenance. Among them, corrosion deterioration and fatigue\r\ndamages of structures particularly to steel girder bridges are the most common ones. Bridges of different structural forms, at\r\ndifferent locations or under different climates, may suffer from various degrees of deterioration. Steel girders at different positions\r\nof a bridge may also suffer from different degrees of damage.How to effectively maintain the bridge asset at a minimal cost and how\r\nto predict the time for future works are crucial, particularly when government funding sources become stretched. A comprehensive\r\nbridge management framework assisting stakeholders to appropriately and reasonably prioritize their future maintenance-related\r\nworks in their bridge stocks, such that stakeholders can better allocate the limited resources, is utmost concerned. This paper\r\nproposes an integrated life-cycle management (LCM) strategy on steel girders in bridges in which corrosion deterioration and\r\nfatigue damage prediction models are mapped with girders� performance conditions. A practical example to demonstrate the\r\napplicability of the proposed LCM strategy is also illustrated....
An analytical model of the silicon on insulator photoactivated modulator (SOI-PAM) device is presented in order to describe\nthe concept of this novel device in which the information is electronic while the modulation command is optical. The model,\nrelying on the classic Shockleyââ?¬â?¢s analysis, is simple and useful for analyzing and synthesizing the voltage-current relations of\nthe device at low drain voltage. Analytical expressions were derived for the output current as function of the input drain and\ngate voltages with a parameterization of the physical values such as the doping concentrations, channel and oxide thicknesses,\nand the optical control energy. A prototype SOI-PAM device having an area of 4 Ã?µm Ã?â?? 3 Ã?µm with known parameters is used to\nexperimentally validate and support the model. Finally, the model allows the understanding of the physical mechanisms inside the\ndevice for both dark and under illumination conditions, and it will be used to optimize and to find the performance limits of the\ndevice....
In recent years, many articles came out where one could find the analysis of oscillatory systems of electric sinusoid signals\r\ngenerators with amplifiers called CFOAââ?¬â?current feedback operational amplifiers. As a rule, the analysis of such systems is made by\r\napplying mathematical modeling methods on the basis of the amplifier linear model, which does not allow estimating advantages\r\nand disadvantages of the systems realized with those amplifiers in comparison with classical systems. A nonlinear model of a\r\ncurrent feedback operational amplifier (CFOA) is introduced in the paper; nonlinearity of ââ?¬Å?current mirrorââ?¬Â is reflected in the\r\nform of current double limiting. The analysis of two known oscillatory systems has been carried out with the use of this nonlinear\r\nmodel. Dependence between current limiting level, output voltage amplitude, and maximum oscillation frequency has been\r\nobtained. The paper shows that output current limiting under current output connection of capacitive load reduces frequency\r\nrange and output voltage amplitude considerably and increases harmonic distortions in comparison with classical oscillatory\r\nsystems. The research done has found that the application of new amplifiers does not give considerable advantages to the oscillatory\r\nsystems with CFOA....
The concept of time-domain predistortion method based on raised cosine signaling is applied in real transmission channels. The\r\nproposed PWM-RC method uses raised-cosine pulse shaping instead of conventional rectangular digital signals and pulse-width\r\nmodulation (PWM) scheme to achieve better output channel data response in harsh channel environment. The conventional\r\npredistortion methods based on pulse amplitude adjusting are not compatible with modern low-power CMOS design. Currently\r\nexisting time-domain predistortion methods which are only based on a PWM scheme show many highfrequency signal harmonic\r\ncomponents for both fast and slow signal transitions. It can cause more system crosstalk susceptibility if the crosstalk is dominant\r\nfactor in transmission channel. In this case, the additional preemphasis boosted undesirable high-frequency components. Finally,\r\nthe real channel transfer functions in connection with ADS Agilent development studio are used to compare the performance of\r\nproposed method with other predistortion methods....
Loading....