Applied Mechanics and Materials Vols. 602-605

Abstract: STM32 as an embedded processor is utilized as the control unit of the handheld oscilloscope, and the data is processed by the FPGA. Voltage signal is collected by probes, and then converted into digital signal after being amplified. Digital signal is showed on the TFT screen after the FIFO processing in FPGA and digital signal processing .The dual ADCs are used to convert analog signal into digital signal so as to double sampling rate, which is an effective and economic way to improve the performance of oscilloscope. At the same time, the figure displayed on the screen can be adjusted manually and provide the information of voltage and frequency. The test results show that the oscilloscope has very good performance.

Abstract: Injection-locking technique is receiving increasing interest in industrial applications, which is especially suitable for smart antenna array, but relative experiments are complicated. The article focuses on the theory and experiment of the technique. Firstly, section 2 reviews the theory of injection-locking technique, and summarizes two useful conclusions on injection-locking bandwidth and phase difference adjusting bound of the phenomena. Secondly, section 3 describes experiments using commercial microwave integrated circuit (MMIC) voltage controlled oscillator (VCO), which is reduces the experimental conditions. Experiments results perform very well.

Abstract: For the needs of laboratory equipment management, combined with development of RFID, a laboratory equipment management system is designed based on RFID. System design is briefly described. UHF RFID reader design is described in detail. The anti-collision algorithm of ISO 18000-6C protocol is partially improved, so that the reader is able to make real-time adaptations of the anti-collision algorithm using IAP according to the quantity of laboratory equipments, thus raising the efficiency of algorithm recognition. Experimental results prove that the system design has reliability, stability and certain practical value.

Abstract: The turbidity of water is one of primary indexes for water quality measurement. Existing main methods for measuring turbidity include scattering method and transmission method. The scattering method is effective for the measurement of low turbidity. Conversely, the transmission method is only suitable for the measurement of high turbidity. In this work, scattering method, transmission method and ratio method are integrated, an on-line turbidity sensor is presented. According to ISO7027 international standards, the sensor’s layout of optical path structure is realized. The detectors are laid in the direction of light source 0 degrees and 90 degrees respectively. Furthermore, the influences of temperature and light on the sensor precision are considered. Least squares support vector machine is introduced to model the turbidity sensor. The experimental results show that this method has much higher precision than the classic methods.

Abstract: With the continuous expansion of the grid size, the number of checkpoints metering device is also increased workload and difficulty inspectors also increasing, to carry out verification and monitoring of remote metering devices mark significant. Discusses the remote calibration and monitoring system principle, function and application metering device at checkpoints, and also describes the configuration and functions of the system back-office support software, scientifically demonstrated the remote meter error, PT secondary circuit drop, CT and secondary circuit admittance verification and monitoring of significance.

Abstract: Recently, with the rapid development of the Internet industry, wireless sensor network technology has received much attention of researchers both at home and abroad. Wireless sensor network node has become one of the basic researches of wireless sensor network. Because there are many problems to be solved, such as a balance of power, transmission efficiency, routing mechanism, cost control and node management, it also has always been the hot spot of the researchers. Wireless sensor network applications, such as navigation guides, object recognition, object positioning all require information service based on location, so wireless sensor network positioning technology is the precondition of the application implementation.

Abstract: The hydroacoustic transponder based on the principle of laser interferometry is investigated, which consists of three parts: 1) the front-end module, which is a signal receiving and pre-processing module, and consists of a laser interferometric receiver and a filter group; 2) the signal processing module, which consists of the data acquisition module and a data processing system; 3) the back-pulse module, which consists of an automatic gain adjustment module, a transmitter module and a back-transducer. We give the detailed designing flow charts of the hardware and software programs.

Abstract: This paper combines the maglev concept and commodity display. The commodity and the permanent magnet are hanged together and put under electromagnet, the distance from permanent magnet to magnet detected by Holzer components, and then the magnet position signal is amplified and formed a strong negative feedback control loop which can control the current of solenoid coil, at last we can hang on the different weight goods through changing the size of the electromagnet attraction.

Abstract: In order to obtain high-precision navigation satellite system time, the errors of navigation satellite system signal need to be calibrated during its transmission, among which, troposphere delay is one of the major errors of navigation satellite system precision positioning. The calibration of troposphere delay has been compared and studied on the basis of model function theory. The troposphere models described include Marini model, Hopfield model, Saastamoinen model, Black model, and the impact extent of meteorological parameters like temperature, pressure, humidity and geographic information of observation station have been analysed quantitatively, which have been systematically analysed the characteristic of troposphere delay and the accuracy of error calibration model. Moreover, by using the data collected by IGS tracking stations to validate the analysis results of models, which has shown that Black model is better than other models when it comes to the extent of meteorological influence and also superior to the troposphere delay generated by the internal calibration model in GPS receiver.

Abstract: According to the requirement of large complex structure monitoring, the principle of wavelength demodulation of fiber Bragg grating (FBG) has been researched. A system model has been designed based on virtual instrument technique. The technology schemes are proposed in main aspect, such as signal processing, network communication, data storage and so on. By experimentation, the FBG Sensing Net Analyzer can measure exceed 1000 points and gives a wavelength accuracy of about ±10 pm. The strain range is ±800×10^-6 and the temperature range is ±100°C, that can meet the stringent requirements of engineering practice of large complex structure.