Applied Mechanics and Materials Vols. 336-338

Abstract: A portable mind wave monitor which is a special made headband for intellectual disabled children is proposed. The headband could make the children easier to be understood by the teachers and researchers. The EEG (electroencephalogram-graph) sensor, live camera, microphone and a series of sensors is consisted in the headband. With the Wi-Fi or 3G network, the headband could connect to server though the internet at any time. The teachers and researchers can access on the website or apps on smartphone to manage the children daily testing data. Intellectual disable children always have low self-control ability, limited language ability and self-associated complications, and this system meets the special needs for the teachers and researchers. This headband enable teachers and parents have the same perspective as the intellectual disabled children.

Abstract: Clamp meter is widely used in the production. It is divided into the current clamp meter, voltage clamp meter and resistance clamp meter according to its function. In this article, design idea and design method of a resistance clamp meter are given. Taking the resistance clamp meter as the object, from signal generation, sensing, detection, filtering, and other aspects the design principle and circuit model is described, the actual data measured, and the reason of measurement error analyzed.

Abstract: This paper gives the system design diagram, and made a detailed explanation to its structure and the basic principle. System consists of hardware and software design, hardware part mainly includes S3C2410, Flash, SDRAM memory interface, the software includes the compilation and transplantation of Mplayer, the QTE graphical use interface design and transplant. At the same time, this paper also studies the key technologies of the system software, including Bootloader design, kernel cutting and root file system design. Finally, the actual effect of the system is given, implement the thought of VOD, achieve the design purpose of the system. The system can make the students online learning at any time, relieve the teaching difficulties effectively, the system combine embedded technology and streaming media technology, it has the advantages of small volume, convenient operation, low cost and good stability.

Abstract: The electrical characteristic of MOS device is susceptible to the external mechanical stress. In order to investigate the effect, the four-point bending technique has been used by many researchers to apply stress on the device. In this paper, a new way for applying stress to MOS device has been presented. The stress is applied by a metallic film which is deposited on the backside of the chip. Its convenient to apply different stress to each chip on the wafer. The above method is used to study the influence of stress on the performance of VDMOS device. The results show that the on-resistance decreases about 3% and 8% with the compressive stress of 50MPa and 70MPa respectively.

Abstract: At present, most of the stage lighting console designs are based on MCU(Micro Control Unit), but its technique advances, information storage and real-time performances are deficient. This paper proposed that using the technique of ARM-Linux can realize the function of lighting console. This technique adopted S3C2440 processor as the main control chip of the hardware. The transmission of dimming data followed the DMX512 agreements. The low-level driver programs were developed under linux2.6.12, it provided interfaces for upper layer application. Testing results show that this system has perfect dimming performance and scalability, which is easy to upgrade. Our design has important theoretical significance and practical value for stage lighting control.

Abstract: This article describes an arbitrary waveform generator based on DDS (Direct Digital frequency Synthesis) technology. The arbitrary waveform generator can easily generate DC, square wave, sine wave or any other arbitrary waveform in mill volt or even microvolt level. The generator uses ARM and 51MCU dual-processor system framework. In the system design, we use multiple reference frequency source and dynamically generated waveform data method to generate waveform, which can effectively improve the stability and reduce the distortion of the output waveform.

Abstract: The common modulation signal generator is mainly composed of STC12C5A60S2 SCM (single-chip microcomputer), DAC0832 chip and their peripheral circuits. Controlled by the SCM, the required analog current is produced by DAC0832, then the current is converted a-5V~5V voltage by the amplifier OP07. Through the control of the switches, the triangle, square, sine and pulse waves can be outputted from generator. Among which, the amplitude of triangle and square and sine waves can be adjusted. The width of square wave and the pulse can be adjusted. Many modulation cases can be showed on the LCD screen. It is proved that the design on the generator is reasonable, the generator performance is stable and reliable, its structure is simple, and its function is high versatility. Admittedly, the designing on modulation signal generator accords with requirement.

Abstract: In order to reduce the power consumption of household appliances resulted from standby; an intelligent wireless remote terminal assembly is hereby designed on the basis of such chips as MSP430F4152, HCS301, TDH6301 and so on. This paper introduces MSP430F4152 as a core processing chip, and a scheme integrating wireless control with intelligent control is adopted. The scheme presents power circuit, wireless transmission and receiving circuit, sensor circuit, keystroke and LCD display, etc, as well as master control program, which are characterized of great function, convenient application, high safety factor, low power consumption and so on, and can be applied in many places.

Abstract: Aiming at the nonlinear characteristics and memory effects of power amplifier, a memory rational function behavioral model, which based on the memory polynomial model and memoryless rational function model, is proposed. The model coefficients are identified by conjugate gradient method. The estimation of the best model nonlinearity order and the best memory depth is carried out by minimized the normalized mean squared error (MNSE). The model is validated using multi-carrier WCDMA signal and a MRF6S21140H power amplifier by measurement. The result indicates that the proposed model can achieve better model performance with less number of coefficients compared to the memory polynomial model and memoryless rational function model

Abstract: Covert communication can effectively improve the security of communication content, which has been widely used in wireless communication systems. Most approaches for covert communication are based on the principle of text-embedded in upper layer of the OSI model. In this paper, a novel covert communication scheme is proposed. This method takes advantage of scramble codes and message processing rules of the WCDMA system. It uses a downlink scramble code in the normal WCDMA uplink signal, so that the covert messages will not be received by the base station (BS) and the user equipment (UE). Simulation result shows that the proposed covert communication method has a low bit error rate (BER) performance, and will only make the signals of different business to a slightly lower data transmission rate.