摘要：A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current *** weight vector of the adaptive filter is updated by the probability of the speech *** performance measure of acoustic feedback cancellation is evaluated using normalized *** results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.

摘要：This paper proposes a novel Gm-C loop filter instead of a conventional passive loop filter used in a phase-locked loop. The innovative advantage of the proposed architecture is tunable loop filter bandwidth and hence the process variations of passive elements of resistance R and capacitance C can be overcome and the chip area is greatly reduced. Furthermore, the MASH 1-1-1 sigma-delta （ZA） modulator is adopted for performing the fractional division number and hence improves the phase noise as well. Measured results show that the locked phase noise is -114.1 dBc/Hz with lower Gm-C bandwidth and -111.7 dBm/C with higher Gm-C bandwidth at 1 MHz offset from carrier of 5.68 GHz. Including pads and built-in Gm-C filter, the chip area of the proposed frequency synthesizer is 1.06 mm2. The output power is -8.69 dBm at 5.68 CHz and consumes 56 mW with an off-chip buffer from 1.8-V supply voltage.

摘要：In application of tomography imaging, limited-angle problem is a quite practical and important *** this paper, an iterative reprojection-reconstruction(IRR) algorithm using a modified Papoulis-Gerchberg(PG)iterative scheme is developed for reconstruction from limited-angle projections which contain noise. The proposed algorithm has two iterative update processes, one is the extrapolation of unknown data, and the other is the modification of the known noisy observation data. And the algorithm introduces scaling factors to control the two processes, respectively. The convergence of the algorithm is guaranteed, and the method of choosing the scaling factors is given with energy constraints. The simulation result demonstrates our conclusions and indicates that the algorithm proposed in this paper can obviously improve the reconstruction quality.

摘要：Quantum-dot cellular automata (QCA) technology has been widely considered as an alternative to complementary metal-oxide-semiconductor (CMOS) due to QCA's inherent *** interesting QCA-based logic circuits with smaller feature size,higher operating frequency,and lower power consumption than CMOS have been ***,QCA is limited in its sequential circuit design with high performance *** on a brief introduction of QCA and dual-edge triggered (DET) flip-flop,we propose two original QCA-based D and JK DET flip-flops,offering the same data throughput of corresponding single-edge triggered (SET) flip-flops at half the clock pulse *** logic functionality of the two proposed flip-flops is verified with the QCADesigner *** the proposed QCA-based DET flip-flops show higher performance than their SET counterparts in terms of data ***,compared with a previous DET D flip-flop,the number of cells,covered area,and time delay of the proposed DET D flip-flop are reduced by 20.5%,23.5%,and 25%,*** using a lower clock pulse frequency,the proposed DET flip-flops are promising for constructing QCA sequential circuits and systems with high performance.

摘要：We studied the architecture of embedded computing systems from the viewpoint of power consumption in memory systems and used a selective-code-compression (SCC) approach to realize our *** on the LZW (Lempel-Ziv-Welch) compression algorithm,we propose a novel cost effective compression and decompression *** goal of our study was to develop a new SCC approach with an extended decision policy based on the prediction of power *** decompression method had to be easily implemented in hardware and to collaborate with the embedded *** hardware implementation of our decompression engine uses the TSMC 0.18μm-2p6m model and its cell-based *** calculate power consumption more accurately,we used a static analysis method to estimate the power overhead of the decompression *** also used variable sized branch blocks and considered several features of very long instruction word (VLIW) processors for our compression,including the instruction level parallelism (ILP) technique and the scheduling of *** code-compression methods are not limited to VLIW machines,and can be applied to other kinds of reduced instruction set computer (RISC) architecture.

摘要：A novel X-ray imaging system （NXRIS） and the design principles are given in this paper. Different from the existing digital X-ray imaging systems, the X-ray image intensifying system of NXRIS is a non-vacuum system composed of the intensifying screen and the brightness intensifier, and the brightness intensifier is named low light level image intensifier applied in military afffairs. This structure makes NXRIS of big visual field （15 inch, even to larger） and low cost. When designing NXRIS, the spectral compatibility of the component devices and the relation between the visual field and the spatial resolution of tile component devices are analyzed. The images produced by NXRIS are given and the image performance is good enough to be applied to security checking, non-destructive testing, and industry detection.

摘要：This paper is concerned with the practical application control of a pneumatically actuated Stewart-Gough platform with 6-degrees of freedom （6-DOF）. The control approach for motion control of the platform is presented using a modern control technique, namely, linear quadratic Gaussinn （LQG） with reference tracking. The LQG controller is the combination of a Kalman filter, i.e., a linear-quadratic estimator （LQE） with a linear-quadratic regulator （LQR）. The robustness of the control scheme is accessed under various load conditions, and the experimental results are shown.

摘要：A polarizing beam splitter （PBS） design based on a fused-silica lamellar subwavelength transmission grating is demonstrated with the modal method, where TE- and TM-polarized waves are mainly diffracted in the -1st and 0th orders, respectively. The physical explanation of the grating diffraction is illustrated by the interference of the corresponding parts of the two propagating modes, which is very similar to a Mach-Zehnder interferometer. It is shown that diffraction efficients over 99% for a TM-polarized wave in the -1st order and 90% for a TE-polarized wave in the 0th order are obtained at the wavelength of 1.053 μm. The polarization transmission extinction ratios are better than 33 dB and 51 dB for the order 0th and the -1st order, respectively. The splitting properties of the PBS grating designed by the modal method are in good agreement with the results simulated by the rigorous coupled wave analysis method.

摘要：We propose a medium access control(MAC) protocol for uplink transmissions in wireless local area networks(WLANs),where both stations and access points(APs) are equipped with multiple antennas. The protocol solves some common problems in utilizing multiple input multiple output(MIMO) under the 802.11 protocol,e.g.,how to deploy preamble(training sequence) used for channel estimation and how to enable simultaneous data transmissions,and facilitates two simultaneous uplink data transmissions via a cross-layer approach. Furthermore,we develop a 3D discrete-time Markov model to analyze the per-formance of the proposed WLAN scheme. The analytical results are verified by simulation,and numerical results show that the system throughput can be significantly improved by our proposed scheme as compared with conventional schemes.

摘要：To consider multi-objective optimization problem with the number of feed array elements and sidelobe level of large antenna array, multi-objective cross entropy(CE) algorithm is proposed by combining fuzzy c-mean clustering algorithm with traditional cross entropy algorithm, and specific program flow of the algorithm is *** the algorithm, large thinned array(200 elements) given sidelobe level(-10,-19 and-30 d B) problem is solved successfully. Compared with the traditional statistical algorithms, the optimization results of the algorithm validate that the number of feed array elements reduces by 51%, 11% and 6% respectively. In addition, compared with the particle swarm optimization(PSO) algorithm, the number of feed array elements from the algorithm is more similar, but the algorithm is more efficient.