Applied Mechanics and Materials Vols. 182-183

Abstract: This paper analyzes the operational principle of airborne radio system on unmanned aerial vehicle, puts forward a design plan for excitation source of airborne radio system on unmanned aerial vehicle based on USB bus, realizes the performance detection and failure isolation of airborne radio system on unmanned aerial vehicle, and provides the detailed introduction for the key units. The experiments show that the excitation source can meet the maintenance and training requirements of airborne radio system on unmanned aerial vehicle.

Abstract: The effect of all-digital phase-locked loop (ADPLL) digital filter parameters on the jitter is investigated in time domain, and a systematic design procedure for ADPLL is presented. The pro-posed method not only estimates the output jitter of an ADPLL, but also finds the optimal filter pa-rameter minimizing the overall ADPLL timing jitter. To verify the theoretic analysis, an ADPLL behavior model in matlab is designed. The simulation shows significant performance improvement on the timing jitter.

Abstract: Blueweb is a self-organizing Bluetooth-based multihop network equipped with a scatternet formation algorithm and a hybrid routing protocol. The routing protocol combines the reactive method globally and the proactive method locally to discover the optimal path for packet transmission. In Blueweb, the route master maintains the global topology information and each master maintains its own N-tier routing information. In this paper, a tier number decision algorithm is used in Blueweb to determine the optimal number of tiers for all the other masters. Our computer simulation results show that this algorithm can efficiently improve the routing performance and reduce the routing maintenance cost for Blueweb routing protocol.

Abstract: Due to salt deposition on the packing and subsequent airflow block, thermal performance of the tower declines after a period of time. Eliminating the fill makes the tower fully empty which is of far-reaching significance in circulating seawater with high temperature, high turbidity. Application of PCTs to industry is not practical due to salt deposition on the packing and subsequent blockage. Analysis of seawater characteristics main includes temperature, salinity, density, specific heat and other properties, which is of great significance in the seawater cooling performance. The results provide necessary theoretical bases for the extensive application of seawater cycling and cooling technology, and at the same time lay foundation for the design of seawater cooling tower.

Abstract: Hardware-in-the-loop communication equipment simulation is an important step of the development about communications and electromagnetic environment simulation. Reference to the "software radio" design thinking, the source library is generated by the software and different communication signals are generated by the fixed hardware frame. The system achieves “versatility”. GMSK in wireless communications has been widely applied. It is one of the important signals generated by the simulator. Based on analysis of the structure, the paper introduces the design of the simulator. It also provides the software simulation of Matlab. It provides a reference simulation for communications equipment and electromagnetic environment simulation.

Abstract: Y-waveguide is widely used in the integrated optics,among which the beam-splitting ratio and insertion loss are the most critical parameters. The measurement setups and methods for the two parameters are introduced. The temperature is the most important factor to the stability of Y-waveguide. As for the insertion loss, the measurement setup was built up based on the measurement principle, and the factors which affected the measurement of the insertion loss were analyzed. As for the beam-splitting ratio, the output luminous power for two tail fibers of Y-waveguide was measured respectively. In different temperature condition, we study the error of FOG by various beam-splitting ratio after working out the beam-splitting ratio according to the formula. Then put into compensation implement.

Abstract: Because of external environment or man-made factors influence, the input signal and data of master elevator controller can not be judged and computed basis directly, but needs the corresponding processing .Therefore an operating system task should be assigned for input signal processing data, in order to deal with input signal. In this paper it realized switch quantity software filter and processing, analog quantities and high-speed counting input treatment of elevator master controller based on LPC2292 .

Abstract: A wireless self-organizing network for heat metering system is designed based on ZigBee in this paper. XBee-Pro module is used for terminal nodes. Such nodes set up wireless mesh network, collecting heating meter data on one hand and realizing remote transmission of data though setting up mesh network with Router and Coordinator. The test is showing that wireless network system based on XBee-Pro module is convenient to use, reliable to transmit data and applies to collect spot discrete data and wireless transmission and meet requirement of heating meter remote transmission, realizing informatization and automation of controlling and monitoring of heating meter system.

Abstract: During these years, as the digital TV (DTV) broadcasting technique is developed, the number of set-top box (STB) consumers is increasing quickly, and they spend more money on pay-TV. Conditional Access System is the key technology to realize pay-TV and interact-TV. This paper introduces Man-Machine Interface (MMI) standard of En50221[1] for conditional access system and it’s a method of realization on STB of DTV.

Abstract: This paper concerns the plant leaf area measurement based on improved image processing. Firstly, the referenced rectangle was detected with 2-side scanning method. Then the leaf region was segmented according to 2G-R-B of every pixel with two different thresholds, and by using of dilatation operation, the trimap of leaf image was got. Next the pixels in unknown area were classified to the foreground or background area with improved knockout method and the exact leaf was segmented. Lastly, the leaf area was calculated according to the pixels proportion between leaf region and the referenced rectangle. Experiment results show this method has good accuracy and rapid speed.