Applied Mechanics and Materials Vols. 602-605

Abstract: A fiber filter based on side-polished method is proposed. Using Fresnel's law explains how it works. The filter output the following wavelengths, 1514.9 nm, 1532.9 nm, 1551.7 nm and 1569.0 nm and the isolation between channels up to 18 dB.

Abstract: In this paper, a 16 bit 250MSPS pipelined ADC is presented. To alleviate noise induced by mismatching of the MDAC sampling network and comparator sampling network, scaling network structure is applied; to implement high-speed sampling, a high-efficient front-end circuit structure is presented; to further improve the sampling rate, a double duty cycle clock circuit is presented; to improve the linearity of the ADC, the sample and hold circuit is removed and the improved clock controlled boost circuit is used. Simulation confirms that the ADC shows more than 95dB of SFDR for a 25.39-MHz sinusoidal input at 2Vpp at full sampling rate from a 0.18um CMOS process.

Abstract: This paper studies and implementation of positioning system based on GPS.The system consists of hardware platforms, positioning terminal software, positioning and monitoring service center. One of positioning terminal is based on Samsung's S3C2440 ARM9 processor, G600 communication module and u-blox GPS positioning module. Positioning terminal software Linux-based development of embedded real-time operating system, it's multi-tasking, real-time characteristics of software provides a good platform. Running on the Linux operating system is the terminal software, by driving the hardware platforms and Linux, the terminal software to complete the GPS positioning, and communications with control centers and other functions. The second type of positioning terminal is based on Android platform for mobile phones and other android pads. Such terminals can use the rich resources of the Android platform to achieve the map display, GPS positioning, communications with control centers. Monitoring platform is a GIS-based management platform, including the integration of the electronic map, and track positioning terminal location query.

Abstract: Detecting circuit consists of both a sensing circuit and a compensating circuit. Using digital amplification and filtration, detected signals were input to SCM with high-accuracy data acquisition. SMC substituted for a sensing circuit and a compensating circuit, an integration of design of structure was achieved. Volume of sensor is diminished obviously. Simultaneously, zero drift is decreased under ensuring high sensitivity and resolution ratio. Integrated design also enlarges the range of work temperature, and reduces cost of products.

Abstract: The system selected OmniVisiON company's CMOS chip OV7620, it is an integrated color camera chip, a 640 × 480 (300,000 pixels) image matrix. Considered that the CPLD control system is similar to the DMA mode of data transmission; Cypress's USB 2.0 chip is used by CY7C68013 chip. Finally, it is become the microcontroller firmware and device driver. The paper presents the design of Image acquisition system based on CMOS image sensor USB interface. Design an image acquisition and transmission system, and describes its firmware as well as the development of USB device drivers and PC-side application .

Abstract: This article in detail on the basis of the algorithm of JPEG2000 standard upon, is put forward based on the FPGA embedded processor MicroBlaze and ADV212 compression chip with the combination of high speed, real time image compression scheme. Experiments show that the scheme can realize the data rate of 520 Mbps largest real-time compression of image data, when the image compression ratio is 53:1, reconstruction image PSNR value can reach 36 dB.

Abstract: Large-scale electronic circuits need to collect shorted signal to meet the control requirements of closing phase angle in high voltage circuit breaker testing process. . In this paper, by using photovoltaic technology and the design of a new synchronous voltage signal acquisition device, a stable, accurate voltage signal is got. This paper mainly introduces the principle, structure, advantages and applications of signal transmission interference problems of the new synchronous voltage signal acquisition device. The practical application showed that the functions of synchronization acquisition device have reached the designed requirements, which highly improves the stability of the short-circuit signal acquisition.

Abstract: A low-voltage distribution box with both energy monitoring and carrier communication capability is developed to collect , store and transmit multi-channel current, voltage , power, and electrical degree surveillance and other information, and the detail of its hardware design is described, ARM9 chip is used as a microcontroller, AD8364 with six channels is applied to ensure the speed and accuracy of data acquisition, the carrier chip ST7538 is adopted to transmit the acquired information to concentrator at specific time. The investment cost of the distribution box is low, and easy to be installed and maintained, and can be widely used in various industries for middle and small-sized enterprises.

Abstract: The traditional embedded system networking technology ignores the security of network systems, either ignores fast networking requirements of network system, these requirements can be achieved at the same time. A embedded dynamic security networking technology based on fast jump and trust degree is proposed, when systems is networking, the use of random beating from multiple network nodes and fast switching optimize network search methods. Experimental results show that the proposed method can detect distribution of systems security risks accurately, and has a good application value for network security.

Abstract: In order to effectively extract signal information from underwater acoustic environment and complete ability to denoise, based on EMD’s denoising and differences of respective autocorrelation functions between noise and signal, aiming at shortcomings of absence from stability in demarcation point between noise and signal that are in line with energy change curve, the paper puts forward a kind of EMD’s new-type denoising method that is based on characteristics of autocorrelation functions. Moreover, it verifies effectiveness of this method through a large number of simulation experiments.