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Electronics Letters

Issue 9 • Date April 26 2012

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Displaying Results 1 - 25 of 42
  • In brief

    Page(s): 466
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  • Interview

    Page(s): 466
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  • The power of VECSELs

    Page(s): 467
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (267 KB)  

    The first vertical external cavity surface emitting lasers (VECSELs) that have a continuous-wave power output over 100 W, even up to 3 C, have been reported in joint work from Philipps-Universita t Marburg in Germany and the University of Arizona in the US. Key changes to the design, growth procedure, chip mounting and thermal management allowed the researchers to reach 106 W at 1028 nm, which is over 30 W higher than their previous record set at 15 C. View full abstract»

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  • Routing for moore

    Page(s): 468
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (311 KB)  

    Researchers from the National Changhua University of Education in Taiwan have proposed a built-in self-routing scheme for through-silicon vias (TSVs). The scheme, to be applied in three-dimensional integrated circuits (3D IC), improves repair rate, performance and reduces area overheads. As Moore's law begins to reach its limits, 3D ICs are becoming increasingly important for industry, and efficient interconnections are essential for their development. View full abstract»

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  • Sub-structure characteristic mode concept for antenna shape synthesis

    Page(s): 471 - 472
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (335 KB)  

    A new sub-structure characteristic mode concept for electromagnetic systems is defined and used to extend the applicability of an existing antenna shape-synthesis technique that does not require the feedpoint location to be specified prior to shaping. Application of the procedure is successfully illustrated by a realistic example, with experimental results. View full abstract»

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  • Egg quantity determination based on characteristic polarisation state

    Page(s): 472 - 474
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    Due to the disability of the traditional complex natural resonant method, the characteristic polarisation state method is proposed to determine egg quantity in a box with a two by three egg configuration. Parameters are investigated for different egg quantity scenarios and the results show a potential way to determine number in terms of characteristic angle β. View full abstract»

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  • Performance analysis of PIFA based 4 x 4 MIMO antenna

    Page(s): 474 - 475
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (195 KB)  

    Presented is the design of a planar inverted-F antenna (PIFA) based 4×4 MIMO antenna working in the frequency range 2.4×2.8×GHz, along with its various performance measure parameters such as MEG (mean effective gain), correlation coefficient, TARC and channel capacity, that are calculated using simulation results and presented here for street grid communication applications. The aim of this design is to develop a wideband, compact and low profile MIMO antenna configuration which can be integrated easily with the rest of the system. The calculated value of MEG for all the antennas is around ×3.5×dB, the envelope correlation coefficient is less than 0.5 in all cases, the average TARC calculated using measured S-parameters is around ×7×dB in the desired frequency range, and the calculated channel capacity for the street grid urban scenario is 22×bits/s/Hz at 30×dB SNR. View full abstract»

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  • Photoresist-based polymer resonator antennas with permanent frame

    Page(s): 475 - 477
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (278 KB)  

    Photoresist-based polymer resonator antennas (PRAs) with permanent frame have been fabricated and measured. High-aspect-ratio frames were precisely fabricated by deep exposure lithography and subsequently filled with ceramic-polymer microcomposites. The antenna was fed by a slot on the ground plane and effects of the photoresist frame on antenna characteristics were investigated. Reflection coefficients of the antenna with/without frame are compared. The high-aspect-ratio photoresist frames with very low permittivity may have minimal impact of less than 1% on output antenna parameters. The frame-based PRAs can be precisely and inexpensively built with any shape using LIGA, an extension of deep lithography in combination with replication, which makes large-scale fabrication economically feasible. View full abstract»

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  • 202pJ/bit area-efficient ASK demodulator for high-density visual prostheses

    Page(s): 477 - 479
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (366 KB)  

    A fully integrated low-power and area-efficient ASK demodulator is presented. By using a controllable digital envelope detector and a self-biased clock extractor, the threshold-detection level of the demodulator can be adjusted and the clock from the wireless power carrier can be recovered. This implantable demodulator was fabricated in a 0.35 m CMOS process and tested using inductively-coupled coils with a resonant frequency of 13.56 MHz. View full abstract»

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  • 800 nW 43 nV/√Hz neural recording amplifier with enhanced noise efficiency factor

    Page(s): 479 - 480
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    Advances in neuroscience research and clinical applications have increasingly called for the low-power low-noise simultaneous recording of neural signals from a large number of electrodes. The neural interface IC is one of the essential blocks to capture the weak neural signals. Presented is an energy-efficient low-noise neural recording amplifier with enhanced noise efficiency factor (NEF) for neural recording systems. Based on the conventional capacitive feedback and pseudo-resistor structure, the fully differential neural amplifier employs the current-reuse technique to achieve low noise and high current efficiency, consuming 800 nA at 1 V power supply. The measured thermal noise floor is 43nV/ √Hz and the input-referred noise is 5.71 Vrms when integrated from 1 Hz to 50 kHz, leading to an NEF of 2.59. The entire neural amplifier has been fabricated using a 0.18 m CMOS technology, occupying an area of 0.05 mm2. View full abstract»

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  • High-performance built-in self-routing for through-silicon vias

    Page(s): 480 - 482
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (193 KB)  

    In this reported work, a built-in self-routing scheme is developed for exploring the through-silicon via (TSV) redundancy to the extremes. A built-in self-router consists of a built-in self-tester for testing the TSVs, and a priority switching network for selecting from M TSVs to N inter-chip interconnects. A switching cell is developed to sequentially construct the priority switching network for area reduction and synthesis regularity. Although a long latency is needed for the encoding network, the best performance during inter-chip communication can be achieved due to only one switch per tier in normal operations. In a multiple fault model with no more than M-N defected TSVs, the repair rate can be always 100%. View full abstract»

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  • Low-energy and area-efficient tri-level switching scheme for SAR ADC

    Page(s): 482 - 483
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (165 KB)  

    A novel low-energy tri-level switching scheme for low-power successive approximation register (SAR) ADC is proposed. With the input common-mode voltage (Vcm) designed to be exactly half of the reference voltage (Vref), the switching energy of the proposed switching scheme is reduced by 96.89% as compared with the conventional architecture. Besides the large energy saving, the proposed switching scheme also reduces the number of capacitors in the ADC capacitor array by 75%, which in turn results in an area-efficient SAR ADC. View full abstract»

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  • Variable step-size affine projection sign algorithm

    Page(s): 483 - 485
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (143 KB)  

    Proposed is a variable step-size affine projection sign algorithm (APSA) based on the minimisation of mean-square deviation. Because the proposed algorithm calculates the optimum step size in every iteration, it ensures an improved performance in terms of convergence rate and misalignment, compared to conventional APSAs. The proposed algorithm is tested in a system identification scenario that includes impulsive noise. View full abstract»

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  • Optimised implementation of adaptive GPC for low-order systems with time delays

    Page(s): 485 - 487
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (162 KB)  

    In adaptive situations the comparatively large run-time computational burden and implementation complexity of the generalised predictive control (GPC) algorithm can prove troublesome. Presented is an optimised design to implement a GPC adaption mechanism for low-order systems. By adopting a compact state-space model and symbolically solving the underlying Riccati equations, an exact solution with a trivial code implementation is obtained. The proposed approach significantly reduces the computational and memory burden of the standard method, and gives improved performance over approximate schemes whilst exhibiting comparable overheads. View full abstract»

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  • Building visual memories of video streams

    Page(s): 487 - 488
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (242 KB)  

    A real-time method that automatically creates a visual memory of a scene using the growing neural gas (GNG) algorithm is described. The memory consists of a graph where nodes encode the visual information of a video stream as a limited set of representative images. GNG nodes are automatically generated and dynamically clustered. This method could be employed by robotic platforms in exploratory and rescue missions. View full abstract»

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  • Gait feature coupling for low-resolution face recognition

    Page(s): 488 - 489
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (291 KB)  

    A novel low-resolution (LR) face recognition method has been developed by coupling gait features. The proposed kernel-based manifold method is able to couple the nonlinear features of an LR face with gait and map them into a common space to minimise the distance between the two features extracted from the same individual. Experimental results demonstrate the effectiveness of the proposed method. View full abstract»

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  • Graph cuts based active contour model with selective local or global segmentation

    Page(s): 490 - 491
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    Graph cuts (GC) and the active contour model (ACM) have become two of the most important schemes in image segmentation. Recently, many researches tend to unify the two schemes to obtain new models for efficient calculation and global minimisation. However, the existing GC based ACMs not only cannot achieve local segmentation, but also suffer from the determination of the regularising parameter, which is used to balance the edge and region terms in the existing GC based ACMs. Proposed is a new GC based ACM (NGC-ACM) to solve the two problems above. First, a new energy function without the regularising parameter is proposed for segmentation, which avoids the edge and region balance problem. Secondly, through constructing a specified graph, the proposed model can achieve selective local or global segmentation, which not only can extract all the objects globally, but also can extract the desired object locally. Experiments on synthetic and real images demonstrate the advantages of the proposed NGC-ACM over the existing GC based ACMs like GC based geodesic active contours with region forces (GC-GACWRF) in solving the two problems above. View full abstract»

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  • Selective mathematical modelling algorithm for quarter-pixel motion estimation

    Page(s): 491 - 493
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (165 KB)  

    Proposed is an error surface based selective mathematical modelling algorithm for quarter-pixel motion estimation during video encoding. In this method, first the tendency of the error surface is assessed. Using the strength of the edge at the error surface, the error surface region is classified as plain or textured. For plain regions, interpolation-free mathematical modelling is appropriate for the quarter-pixel motion estimation method. For textured regions, half-pixel interpolation is needed for more accurate modelling. Additional half-pixel SAD values are calculated and more accurate modelling is completed to find the best motion vector (MV). Experimental results show that the proposed scheme is faster than conventional modelling algorithms, and the PSNR performance is also better than that of competitive algorithms. View full abstract»

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  • Sparse coding based feature optimisation for robust 3D object retrieval

    Page(s): 493 - 495
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    3D object retrieval is an important research issue in the area of computer graphics for applications such as computer-aided design, simulation, and visualisation. The performance of 3D object retrieval systems is dependent on the development of efficient and effective descriptors and similarity measures. Presented is an effective approach for supporting 3D object retrieval based on optimising the gradient descriptor which has recently been shown to perform among the state of the art. The approach relies on sparse coding and the effectiveness of the method is demonstrated by experimental evaluation. View full abstract»

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  • Sparsity level-aware threshold-based channel structure detection in OFDM systems

    Page(s): 495 - 496
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (129 KB)  

    The structure detection of sparse channel impulse response (CIR) is addressed in the frame of OFDM systems. Tap-tuned thresholds, exploiting a priori knowledge about the channel sparsity level (CSL), are designed to optimise the detection error probability. Compared to former proposed thresholds, the CSL-aware thresholds lead to higher CIR structure true detection rates and to lower channel response mean squares error. View full abstract»

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  • Affine projection algorithm with decremental projection order and optimally-designed step size

    Page(s): 496 - 498
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    The proposed algorithm introduces a novel scheme for obtaining an optimal step size and proposes a criterion for decrementing the projection order, which would lead to fast convergence and a small steady-state estimation error with low computational complexity. The scheme is based on an analysis of the mean square deviation (MSD) for the tap weight and its estimated value at each iteration. The criterion is obtained by calculating the steady-state MSD. Experimental results show that the proposed algorithm has faster convergence and a smaller steady-state error than the existing affine projection algorithms with a variable step size or variable projection order. View full abstract»

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  • Dynamic null-data subcarrier switching for OFDM PAPR reduction with low computational overhead

    Page(s): 498 - 499
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (193 KB)  

    A computationally efficient null-data subcarrier switching scheme for peak-to-average power ratio (PAPR) reduction of OFDM systems is proposed. By applying incremental searching within dynamically expanding subcarrier bands, the proposed method achieves significant reduction in computational requirement without sacrificing PAPR reduction capability. The effectiveness of the proposed scheme is demonstrated by presenting simulation results of PAPR and bit error ratio. View full abstract»

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  • List successive cancellation decoding of polar codes

    Page(s): 500 - 501
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    A list successive cancellation (LSC) decoding algorithm to boost the performance of polar codes is proposed. Compared with traditional successive cancellation decoding algorithms, LSC simultaneously produces at most L locally best candidates during the decoding process to reduce the chance of missing the correct codeword. The complexity of the proposed algorithm is O(LNlog N), where N and L are the code length and the list size, respectively. Simulation results of LSC decoding in the binary erasure channel and binary-input additive white Gaussian noise channel show a significant performance improvement. View full abstract»

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  • Tree-based backward pilot generation for sparse channel estimation

    Page(s): 501 - 503
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (141 KB)  

    A scheme of tree-based backward pilot generation for sparse channel estimation in orthogonal frequency division multiplexing (OFDM) systems is proposed. Instead of straightforward searching for the best from all possible pilot subsets, the scheme iteratively removes a subcarrier from all OFDM subcarriers in a backward manner. At each time, every subcarrier is tested by deleting it and calculating the coherence of the resulting matrix, where the subcarrier with the smallest coherence is picked up. Finally the subcarriers left make up the optimal pilot subset. Considering the greedy essence of the scheme, a tree structure is also incorporated to avoid the locally-optimal but globally-incorrect selections. Simulation results demonstrate that the proposed scheme can obtain substantial improvement for sparse channel estimation. View full abstract»

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  • Temperature sensor using BJT-MOSFET pair

    Page(s): 503 - 504
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    A temperature sensor using the cascade configuration of a pnp bipolar junction transistor (BJT) and a p-type metal-oxide-semiconductor field effect transistor (PMOSFET) was designed and measured. Under a biasing current proportional to absolute temperature for a pnp BJT and a temperature-stable biasing current for a PMOSFET, the plots of emitter-base and source-gate bias voltages against temperature show nearly complementary nonlinear characteristics. Therefore, a temperature sensor of which the output is the sum of the two bias voltages will exhibit good linearity. For a temperature range from 0 to 125°C, the fabricated temperature sensor has the sensitivity of °3.39°mV/°C or so with linearity up to 99.996°. View full abstract»

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Aims & Scope

Electronics Letters is internationally renowned for its rapid communication of new developments and emerging topics across the broad and interdisciplinary field of modern electronics and electrical engineering.

Full Aims & Scope

Meet Our Editors

Editors-in-Chief

Professor Chris Toumazou
Director of the Biomedical Institute
Imperial College, London, UK

Professor Ian White
Head of Photonics Research
University of Cambridge, UK