Applied Mechanics and Materials Vols. 716-717

Abstract: An analog-digital clock delay locked loop (DLL) control circuit is proposed to detect and adjust the analog-digital clock phase difference in real time in a 14-bit 2GSPS digital-to-analog converter (DAC). To achieve a reasonable analog-digital clock phase difference, a digitally controlled delay line (DCDL) should be able to provide a total clock delay up to 1024ps. Such fine control is realized by a control block tracking and maintaining the precise phase relationship between analog and digital clock domains. The control circuit is realized by designing a digital finite state machine (FSM) carefully. The proposed circuit is implemented in 0.18μm CMOS technology. Simulation results show that the proposed circuit performs well in various conditions in high speed data transmission applications.

Abstract: This paper proposes that arrays of spatio-temporal data matrix was constructed by the arrays of the received signal delayed in time gradient, Meanwhile, applying the method of ESPIRT to get the twiddle factor of the received signal array element and the array element of the time and the space, finally get the final information of Doppler frequency and the information of arrival angle though applying least squares method.

Abstract: The nature of the vlf atmospheric noise can have a dramatic effect on the performance of the vlf receivers. To understanding how the receivers will perform in different locations and time, the key is proper predicting the critical parameters of the vlf atmospheric noise. Based on the purpose, according to the historical data and the corresponding frequency and parameter variation chart, established the data fitting algorithm to predict the critical parameters of the vlf atmospheric noise. By simulating and comparing with the measured data, testified the effectiveness of the vlf atmospheric noise prediction method. To grasp the change rule of critical vlf noise parameters with time and geographical position is helpful to improve the vlf communication effectiveness.

Abstract: In the traditional motor-side converter control strategy of double-fed induction generator, because of the stator resistance led to the observation of the accuracy of the stator flux is affected. Academia therefore put forward a lot of improvements, but little attention to the impact of the iron loss. Due to the iron loss exists of double-fed induction generator during operation, and the size of the iron loss change with the wind speed will led to the accuracy of Maximum Power Point Tracking. This paper presents a new control strategy and through MATLAB simulation demonstrates the effective of the strategy.

Abstract: Energy efficient resource allocation is one of the critical issues for the coordinated multipoint (CoMP) transmission system, where the signal received by each mobile station needs to be converged among multiple base stations (BSs) in the same cluster. However, as the interaction of the system is frequent, the overhead of the backhaul signaling will be enormous. In this paper, an iterative resource allocation and scheduling algorithm (IRASA) with dual method is proposed to solve the optimization problem aiming to maximize the system energy efficiency, which considers the backhaul capacity constraints, circuit power consumption and zero forcing pre-coding (ZFP). Simulation results show that our proposed IRASA can significantly improve the energy efficiency of the system with the backhaul capacity constraints.

Abstract: A new and effective analytical perturbation method is presented for the multipole acoustic logging in a transversely isotropic medium (TIM) whose symmetric principal axis is parallel to the borehole axis although the exact solutions could be found. In this paper, the new perturbation method is adopted to simulate the dispersion characteristic in a borehole surrounded by a TIM for the first time. The TIM is regarded as a reference unperturbed isotropic state added to the perturbations, and three perturbation quantities about moduli deviated from the isotropic medium are introduced. By selecting a group of displacement potentials and a cylindrical coordinate system oriented along the borehole axis, the zero-, first-order and second-order perturbation solutions of the multipole acoustic field are derived for the weak transversely isotropic elastic solid which has its symmetric principal axis parallel to the borehole axis. It is found that the dispersion characteristic by the perturbation method inside the borehole excited by monopole, dipole sources and quadrupole source are similar to obtained by the exact solution.

Abstract: Sensor positioning is a fundamental block in various location-dependent applications of wireless sensor networks. In order to improve the positioning accuracy without increasing the complex and cost of sensor nodes, an improve sensor positioning method is proposed for wireless sensor networks. In the method, after receiving the broadcasting message of the neighboring anchor nodes, the sensor nodes calculate a modifying factor of the change of the signal strength. And they modify the distances between themselves and neighboring anchor nodes with the modifying factor. Simulation results show that the proposed method can obtain a high positioning accuracy.

Abstract: A method for building the finite element model of the lower hybrid wave antenna was proposed according to the situation of the Experimental Advanced Superconducting Tokamak (EAST) and its LHW antenna. Temperature properties of 2.45GHz lower hybrid wave antenna on EAST are investigated. The temperature distribution of antenna is performed using the finite element code. The influences of some parameters on the temperature of the antenna are studied and discussed. The simulated results lay the solid foundation for design and improvement for the lower hybrid wave antenna.

Abstract: For the museum artifacts management,designs a Android RFID reader, based on ARM and ImpinjR2000. This paper provides the main hardware’s circuit design, and RFID reader application software design’s process.

Abstract: For the pulse wave signal acquired by the pulse analyzer, it’s necessary to remove the large number of noise signal by noise reduction processing. For signal noising processing using wavelet transform method in the time domain and frequency domain and the signals can characterize the ability of local information, and it is self-adaptive. Determine the main wave peak and trough points based on extreme value method and pulse wave periodicity, using the threshold method to determine the dicrotic wave starting point and dicrotic wave peaks, we also use the MATLAB programming to implement the algorithm.