Advanced Materials Research Vols. 588-589

Abstract: In order to improve the SINR of the beam-former in the case of DOA mismatch, the paper raises the probability of constraint beam-forming algorithm based on mutative scale chaos optimization in connection with the worst performance of the best sound beam-forming algorithm. By introducing the probability constraints confidence interval and the signal vector error distribution law in the beam-forming, the constrained optimization problem is eventually turned into a nonlinear optimization problem. Then the global optimal weight is searched by the mutative scale chaos optimization method. Simulations have shown that the algorithm can significantly improve the SINR.

Abstract: The signal can be divided into a number of intrinsic mode components (IMF) through local wave decomposition. The decomposition process is equivalent to the adaptive filter for signal. The frequencies of each IMF have reduced with the decomposition order. This paper established judgment criteria of signal, noise and pseudo component based on the local wave decomposition, used the characteristics of cross-correlation coefficient and autocorrelation sequence, combined with the power spectral density. The dominant mode function was extracted effectively and the final effects are used gear reducer in the JZQ250 of fault rolling bearing inner ring. It provides a new method for non-stationary signal adaptive noise reduction and fault diagnosis of rotating machinery.

Abstract: This paper demonstrates a new Low Temperature Co-fired Ceramic (LTCC) U-shape resonator. Based on this 3D structure, a Ka-band Substrate Integrated Waveguidebandpass filter isdesigned. Compared with the conventional two dimensional PCB, LTCC technology achieveshigher Qe factor, higher density, smaller size, and lower cost. EM simulator HFSS is employed in determining and optimizingthephysical dimension of the filter.The filter's simulation results showfractional bandwidth (FBW) of3.94% centered at 34.7 GHzwith insertion loss of -1.2 dB and return loss of -20 dB in the passband. The attenuation of -30dB is obtained at 32.8 GHz and 36.8 GHz.

Abstract: To estimate parameters of poly-phase coded radar signals, a modified Fractional Fourier transform (FrFT) is advanced. This algorithm employs Integrated Quadratic Phase function (IQPF) to estimate frequency rate with which the best degree for Frft is computed. Its computational cost is lower than that of Radon-Wigner transform (RWT) and Radon-Ambiguity transform (RAT). When the signal-to-noise ratio (SNR) is -7 dB, Simulations show its parameter estimation performance closes to the Cramer-Rao Lower Bounds (CRLB).

Abstract: A three-channel high temperature superconducting filter is designed for channelized receiver front-end systems. The principle and equivalent model of the filter has been demonstrated. There is 6-pole for each channel of the desired three-channel filter. The bandwidth of each channel is 40MHz.The simulation result is good agreement with theoretical analysis, illustrating the feasibility of this design. Such a structure of high temperature superconducting filters will have a wide application in communication fields

Abstract: This paper introduces a kind of intelligent battery charger based design based on MCU. The charger can complete real-time acquisition of battery voltage and current, and the charging process under intelligent control. It can automatically calculate the remaining charging time of the battery and adjust the parameters to adapt to a variety of battery charging. System management circuit also has a protective function, which can prevent the damage to the battery from overcharge and overtime.

Abstract: For the shortcomings that computation speed of the DDS decreases with iterations increasing in CORDIC algorithm., the traditional algorithm of multiple iterations is displaced by a point of decompose predict the direction of rotation and multi-level iterative parallel computing method in this paper. The function simulation results show that the improved algorithm enhance the computation speed and maintain data high precision. This design has high computing speed, high precision and simple hardware implementation etc.

Abstract: This letter delivered an analysis and design method of signal cancellation loop for feedforward power amplifier. To begin with the inherent defects of feedforward amplifier, it stated the merits and drawbacks of existing feedforward amplifier loop control methods, then put forward a new signal cancellation loop control method, namely separating amplitude feedback and phase feedback in signal cancellation loop, then advanced the theoretical analysis and calculation. The result of theoretical calculation was in line with the outcome of simulation, which confirmed through ADS (Advanced Design System) simulation. This method has multiple advantages: high feedback convergence rate, readily implementation and high linearity.

Abstract: This paper introduces the method of design a USB On-The-Go (OTG) mass storage module according to USB 2.0 specification, which bases on embedded systems LM3S9B90. This module’s hardware system and software system is described, focusing on the implementation of USB host system. The module realizes USB OTG function, not only can realize functions of read and write USB mass storage devices, but also can exchange data with USB host as a USB mass storage device, can be used as an extension of USB system and has good application value.

Abstract: A class of methods is presented for wholly estimating direction of arrival (DOA) of convolutively mixed sources in the frequency domain, which is based on independent component analysis (ICA). Convolutive mixtures of multiple sources in the spatio-temporal domain are firstly reduced to instantaneous mixtures by using the well-known short-time Fourier transformation (STFT) technique. From the time-frequency mixture in each frequency bin, one frequency respond matrix of the mixing system from sources to sensors is identified by some instantaneous ICA algorithms. Furthermore, DOAs of the multiple sources is estimated by using a whole estimating strategy. Consequently, all mixtures in total frequency bins contribute to a final estimation set, in which the source directions are shown as several direction clusters and/or local maxima. Experimental results indicate that the ICA based methods have some advantages over the well-known MUSIC (MUltiple SIgnal Classification) method not only on estimation precision of multiple source directions, but also on potential applicability under some especial conditions.