Applied Mechanics and Materials Vol. 618

Abstract: Optical remote image is affected by thin cloud inevitably, which debases image definition. Traditional homomorphism filtering frequently used in thin cloud removing has affect on the cloud in low frequency region, but is not effective for those in high frequency region. An improved homomorphism filtering method is proposed on the basis of statistical characters of image information. Instead of the filtering in frequency field, it isolates the low frequency component of the image representing cloud information with calculating neighborhood average in spatial field. Then, the filtered image is enhanced based on rough set. The experiment results show that the proposed method compared to traditional methods can obtain good results and performs faster.

Abstract: In machine olfaction or electronic nose, sensor optimization is important to enhance pattern recognition efficiency and reduce redundant information. Highly correlated response of one sensor to two different odors implies less contribution of this sensor to the classification of these two odors. Variance difference is a significant index to measure the similarity of sensor responses. A sensor optimization method based on variance difference is proposed in this paper; both the average value of variance difference and cluster analysis of variance difference matrix were considered to identify several possible sensor subsets. Six Chinese herbal medicines and linear discrimination analysis (LDA) were applied to test the classification results in order to determine the best subset. LDA results indicated that the optimized sensor subset performed well in classification of the six Chinese medicines. The proposed sensor array optimization method could be applied to other kinds of odors classification as a novel method.

Abstract: Nowadays, most imaging simulation focus primarily on image quality, but the light path of an image sensor should be simulated in many application areas. So, light path simulation of aerial photography has been researched in the paper. The main idea is that the pixels of a known vertical image with known altitude will be transferred to the simulation photosurface along the light path. First, several coordinate systems are set up to describe the space coordinates of a pixel. Then, the relationship between the vertical image and the simulation photosurface are built based on the collinearity equation. Finally, the simulation image will be generated from the known vertical image by the method of indirect re-sampling. The theoretical analysis and experiment results show that the proposed method can simulate the light path very well.

Abstract: As an example of collapsible loess foundation treatment project in central and southern shanxi tunnels five railway culvert, the collapsible loess and harm of engineering properties, this paper introduces the construction method by cement-soil compaction pile to reinforce the foundation in order to ensure the quality and effect of the overloaded railway foundation.

Abstract: Main achievements in load balancing algorithm in a long-term-evolution (LTE) mobile communication system are presented. As result a self-optimizing system, that could be implement in the real networks. Basic target functions, such as the signal-to-noise ratio distribution, bit error rate, energy efficiency are derived as a figure of merit. The framework is exemplified by basic investigations on load balancing technology.

Abstract: A power amplifier (PA) for multi-mode multi-standard transceiver which is implemented in a TSMC 0.18μm process is presented. The proposed PA uses matching compensation, lossy matching network and negative feedback technique to improve bandwidth. To achieve the linearity performance, the two-stage PA operates in Class-A regime. Simulation results show that the power amplifier achieves maximum output power of more than 24dBm in 0.7~2.6GHz. The output P_1dB of the PA is larger than 22dBm. The simulated power gain is more than 27dB. The S11 is less than-10dB and the S22 is under-5dB.

Abstract: This paper presents a wideband low noise amplifier (LNA) for multi-standard radio application .The low noise amplifier achieves wideband matching with the structure of differential common gate .Meanwhile ,the low noise characteristic is achieved by noise canceling and capacitor cross-coupled. Fabricated in 0.18μm CMOS process, the LNA is designed to operate from 700MHz to 2.6GHz.As are shown in the results of simulation, when the LNA operates from 700MHz to 2.6GHz,the S11 is less than-10dB,the gain achieves 8.5 dB and the variation is within ±0.5dB.The noise figure is 2.2dB wih the supply voltage is 1.8v and the drain current is 8mA.

Abstract: This paper reports a reconfigurable wideband passive mixer for direct conversion multimode multi-standard receivers. Different from the traditional current-commutating passive mixers, transconductor stage of this design is variable. And the TIA stage is a second-order low-pass transimpedance amplifiers based on Tow-Thomas biquad topology, working as a current mode filter. The mixer is controlled by a 4-bit control word to realize the flexible gain and variable intermediate frequency bandwidth. Other characteristics such as power consumption, NF, and linearity is also reconfigurable according to different communication standard. Circuit is implementing in 0.18μm CMOS technology. Post-simulation results show that, with the radio frequency ranges from 700 MHz to 2.6 GHz, it provides four voltage conversion gains (10/16/22/28dB) and three-3 dB intermediate frequency bandwidth (5/7.5/10MHz). Under the maximum gain, the double sideband NF of the mixer is 8.4 dB. And under the minimum gain, IIP3 is 13 dBm. The chip occupies an area of 0.248 mm² and drains a current of 8.5mA from a 1.8 V supply when the mixer has highest gain.

Abstract: Voltage controlled oscillator has been used in every field of the electronics industry, and plays an indispensable role. In the fractional divider, in order to reduce the product size, voltage controlled ring oscillator is used to meet the design requirements, at the same time as much as possible to reduce the area. The design of wide tuning voltage-controlled ring oscillator was designed with the reference voltage source. This design not only could reduce the error brought by the external voltage reference, and was also very good realization structure innovation in the film. This design used 0.5 μ m CMOS Hua technology. The post simulation results show: when the coarse voltage and fine voltage are respectively 1V and 2V, voltage waveform oscillator output swing is 2.4V; when the coarse voltage and fine voltage are respectively 1.13V and 2V, voltage waveform oscillator output swing is 2.8V; when the coarse voltage and fine voltage are respectively 1.3V and 2V, voltage waveform oscillator output swing is 3V. After simulations, the frequency range of the voltage-controlled ring oscillator adjustment is 100 ~ 200MHz.

Abstract: This paper describes a design of high-speed and reusable SPI interface model which is used for Microcontroller. The SPI interface is designed by very simple but universally useful method, used a FIFO to improve transmission speed and supported data serial input and parallel output which other interface didn’t mentioned. The paper analyses the function of every module of SPI interface and standard 8051 microcontroller interface communication protocol, describes the design project of implement SPI logical function. After testbench and FPGA verification, the results indicate that the microcontroller SPI interface function and performance are all achieve design target, many communication tests indicate the design is reliable in performance and more universal.