Advanced Materials Research Vols. 834-836

Abstract: In order to digitize the signal of high frequency or ultra-high frequency, clock distribution technology with the same frequency but different phase is utilized as a solution to this difficulty. The principles of high-speed analog-to-digit converter (ADC) by the lower rate ADC module, key technology and key module of the data acquisition systems are studied. From the aspects of system architecture, clock distribution module based on the AD9520, ADC module based on the AD9480 and data processing, the design method of ultra-high-speed ADC by clock distribution mode are explored. The results show that: driving many ADC modules with serial clocks of the same frequency but different phase in parallel to sample the same signal, the sampling frequency of the ADC system is the sum of each ADC sampling frequency. Four AD9480 modules are driven by four-way 250MHz clocks with phase fault 90°, respectively. And 1GHz samples per second can be attained, which is four times of the sampling frequency by monolithic AD9480.

Abstract: A novel initialization method for nonlinear Kalman filter was proposed aimed at the defects of the ordinary initialization method. This method was stricter than the ordinary method in theory and could guarantee scientific compare between nonlinear Kalman filters based on Gaussian assumptions. Simulation results showed that the novel method greatly reduced the impact of initialization and reflected more the estimation error due to the type of nonlinear Kalman filters rather than initialization.

Abstract: This paper proposed a novel design method for a special kind of non-linear filters based on building block technique. Due to the introduction of such technique, the filter was successfully separated from the math model of the specific problem to be investigated thus can be designed independently. The difficult but important task of checking the correctness of the deigned filter was solved for a class of non-linear filters based on point selection technique. Simulation results proved the correctness and the effectiveness of the proposed design method.

Abstract: The article analyzes the quality checkout methods of different signals, carrying on the concrete analysis at the concrete characteristic about the signal of electromagnetic inductive communicating. Analyze the quality circumstances of waveform with the input / export signal contrast, and environmental influencing factors like power supply voltage and metal environment, transmission distance and electromagnetic environment could lead to transmit without thread fail, Get a mathematical model which can directly perceived the signal quality state with the threshold value law establishment.

Abstract: The wavelet packet decomposition and reconstruction technique is applied to time-frequency analysis of bite steel impact vibration signal by big rolling machine, it is obtained the bite steel impact signal wave packet. According to the size of the wavelet packet energy, it is reconstructed the signal of No.1 and No.2 wavelet packet. According to reconstruction of the signal time domain waveform and FFT spectrum chart, some meaningful conclusions are obtained.

Abstract: The early fault detection of mechanical equipment is the technical support of automation equipment to run efficiently. Because of various faults have the characteristics of sudden, transient degeneration, so the traditional Fourier transform based on signal processing method can't meet the needs of the transient signal. This paper discusses time-frequency analysis technology of local wave from signal denoising, signal singularity detection and signal frequency band energy distribution analysis to extract the transient signal characteristics, and the motor bearing fault is put forward as an example, the effectiveness of the proposed method is verified.

Abstract: Energy metering is an important part of the power system. As the most integrated communication standards of power system, IEC61850 has not completely cover the metering information yet. Based on the analysis of metering system in substation, this paper establishes a complete energy metering communication model with extended three logical nodes and new five logical nodes in accordance with the principle of IEC61850 data model extensions. An appropriate IEC61850 service model is also described. Especially the use of documents for freeze data communication transmission, chunks of frozen data index and upload issues is solved excellently.

Abstract: Real-time lifetime forecasting has extensive application in the fields of machine system manufacturing and integration, which is a good way to promote the dependability and operation stability. In this paper, a closed loop adaptive forecasting model with feedback channel of state monitoring information is built up for the real-time lifetime forecasting. The difference of working state between prediction and monitoring information is used to evaluate the prediction performance. The dynamic fuzzy neural network introduced into the prediction model, in which the fuzzy rule, membrane function and structure parameters can be adjusted according to the evaluate results. A service lifetime testing experiment of gear case is utilized to validate the prediction model. The proposed model achieved reasonable precision with an error of less than 1 hour between the failure time of experimental results and the forecasting remaining lifetime. The adaptive prediction method can deal with the real-time lifetime forecasting for multiple factors and nonlinear system without specific parameters structure.

Abstract: In this paper, the network architecture of wireless network systems survivability, the ideas based on intrusion tolerance, redundancy and diversity of technology will be combined, using threshold cryptography, presents a viable network server security architecture. This proposal implements key features of the system security and robustness, the database system to meet the survivability requirements for building a wireless network server architecture has important reference value.

Abstract: With the expansion of the network, especially in the case of the nodes frequently moving, clustering routing protocol can reduce the impact of the changed topology on routing protocols, and improve the network scalability and reduce routing overhead. Based on the analysis of the problems of CBRP clustering routing protocol, this paper presents a CRBAC clustering routing algorithm based on ant colony algorithm. The simulation results show that, in the circumstance that the algorithm doesnt significantly increase the routing overhead, improved clustering routing protocol CRBAC get better performance than CBRP. They reflect on the clusters structure more reasonable and stable, the average end-to-end delay and network lifetime significantly improved.