By Topic

Electronics Letters

Issue 3 • Date February 3 2011

Filter Results

Displaying Results 1 - 25 of 47
  • In brief

    Publication Year: 2011 , Page(s): 156
    Save to Project icon | PDF file iconPDF (94 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interview

    Publication Year: 2011 , Page(s): 156
    Save to Project icon | PDF file iconPDF (98 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Inside view

    Publication Year: 2011 , Page(s): 157
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    Researchers at the University of Southampton, UK, have found a way to effectively shut down the current flow in graphene nanowires to produce a graphene channel transistor. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Terahertz crystals

    Publication Year: 2011 , Page(s): 158
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    An electromagnetic crystal terahertz horn antenna, fabricated on a silicon substrate, has been developed by collaborating researchers from the University of Arizona and the Beijing Institute of Technology. As was shown in their Letter in the previous issue of Electronics Letters, low attenuation and simple integrability confirm the suitability of such crystals for the successful implementation of terahertz technology. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Miniature RFID tri-band CPW-fed antenna optimised using ISPO algorithm

    Publication Year: 2011 , Page(s): 161 - 162
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (233 KB)  

    A novel tri-band CPW-fed antenna designed for RFID applications is reported. Limited to 30 × 30 × mm2 area on a PCBoard with εr = 4.4, the antenna has four U-shaped, two F-shaped and two L-shaped slots as additional resonators to achieve multi-band operation. The intelligent single particle optimisation (ISPO) algorithm is used to determine the optimised slot configuration for the best return loss at 0.92, 2.45, and 5.8 = GHz simultaneously. The performance of the designed antenna was characterised through simulations using the finite element method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Miniaturisation of λ/4 microstrip antenna using perturbation effect and plate loading for low-VHF-band applications

    Publication Year: 2011 , Page(s): 162 - 164
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    An electrically small microstrip antenna is proposed for low-VHF-band applications. The design is based on a λ/4 microstrip antenna in which the size of the ground plane is equal to that of the radiating patch. Miniaturisation is achieved by a combination of cavity perturbation and plate loading. The radiating edge of the microstrip antenna is modified to achieve the desired perturbation effect, and zigzag plates are loaded in the aperture to reduce the size further. The dimensions of the perturbed and plate-loaded microstrip antenna operating at 40 MHz are 55.5 × 30 × 30 cm, which correspond to an electrical size (kr) of 0.30. An omnidirectional radiation pattern is obtained for Eθ in the yz-plane, while a nearly omnidirectional pattern is obtained for Eφ in the xz-plane. The measured radiation efficiency of the antenna is 77.7%. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pattern reconfigurable square ring patch antenna actuated by hemispherical dielectric elastomer

    Publication Year: 2011 , Page(s): 164 - 165
    Cited by:  Papers (13)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (302 KB)  

    A pattern reconfigurable square ring patch antenna comprising a movable parasitic plate within the ring patch is presented. The plate is actuated using a hemispherical dielectric elastomer actuator. Small variations of the height of the parasitic plate (i.e. below, level, or above the ring patch) can significantly alter the antenna radiation pattern while maintaining reasonable impedance matching. Experimental results are presented for the radiation pattern and the return loss for different parasitic plate positions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 32 GS/s ultra-high-speed UWB sampling circuit for portable imaging system

    Publication Year: 2011 , Page(s): 165 - 167
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    A 32 GS/s ultra-high-speed ultra-wideband (UWB) sampling circuit has been developed by use of a 65 nm CMOS technology. An equivalent time sampling technique was applied using an internal clock generator to achieve its low power consumption and high sampling rate. The generator consists of an eight-stage 2 GHz phase-locked loop, a 16-to-1 multiplexer and a frequency divider. Both a 20 mW low power consumption and a 32 GS/s high sampling rate were achieved. Gaussian monocycle pulse signals with a centre frequency of 450 MHz could be successfully converted to digital codes. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-power and low-offset comparator using latch load

    Publication Year: 2011 , Page(s): 167 - 168
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (230 KB)  

    A low-power and low-offset latched comparator using dynamic offset cancellation and a latch load is proposed. A latch load at the first stage provides the second stage with a large conversion gain and large trigger voltage. It reduces the power consumption and offset voltage of the comparator. The effectiveness of the proposed structure was verified by SPECTRE simulations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Selective negative word line scheme for improving refresh

    Publication Year: 2011 , Page(s): 168 - 169
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (190 KB)  

    Proposed is a new selective negative word line scheme that yields almost 2.7% of the fail bit count (FBC) in a DRAM chip with a conventional negative word line scheme in the pause refresh state. It has a superior dynamic refresh characteristic, which is almost 0.3% of the FBC in a DRAM chip using the ground word line scheme. This scheme leads to a very low cell VTH (threshold voltage). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • D/A conversion networks for high-resolution SAR A/D converters

    Publication Year: 2011 , Page(s): 169 - 171
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (158 KB)  

    An intermittent-sleeping C-R hybrid structure and a resistor-reusing R-C hybrid structure are presented for high-resolution SAR A/D converters. The switching power of these conversion networks and the matching requirements of their internal passive components are researched based on high-level Matlab modelling. Their applicability to high-resolution SAR ADCs is proven by realisation of two SAR A/D converters with these two novel D/A networks. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Feedforward spectral shaping technique for clock-jitter induced errors in digital-to-analogue converters

    Publication Year: 2011 , Page(s): 171 - 172
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (155 KB)  

    A simple feedforward spectral shaping technique for the pulsewidth jitter induced errors in digital-to-analogue converters (DACs) is presented. The proposed technique features a feedforward combination of the conventional rectangular-pulse switched-current DAC and a discrete-time switched-capacitor DAC to achieve spectral shaping for the jitter induced error. The benefit of this hybrid DAC solution using error specral shaping is illustrated in the context of feedback DACs used in continuous-time ΔΔ modulators. Simulation results show that the jitter tolerance of the proposed DAC solution is equivalent to that of the commonly used jitter-tolerant exponentially-decaying waveform switched-capacitor-resistor DAC structure, but at much more relaxed slew-rate requirement on the op-amp used in the DAC load circuit, which translates into significant power savings. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reducing noise in relaxation oscillators through high-order synchronisation

    Publication Year: 2011 , Page(s): 172 - 174
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (161 KB)  

    A method to reduce phase noise in relaxation oscillators via the injection of small-amplitude synchronisation signals is investigated. It is shown that high-order synchronisation results in a significant phase-noise reduction over a wide frequency range. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved 3D full-wave multilevel Green's function interpolation method

    Publication Year: 2011 , Page(s): 174 - 175
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    A subset of infinitely smooth radial basis functions (RBFs), Bessel (BSL) RBF is proposed to improve the computational efficiency of the multilevel Green's function interpolation method for the solution of 3D complex full-wave electromagnetic problems. Numerical results reveal that the interpolation accuracy and efficiency, and computer memory storage requirement are greatly enhanced using the proposed BSL RBF when compared to previously used RBFs. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 3D registration of point clouds from time-of-flight cameras

    Publication Year: 2011 , Page(s): 175 - 177
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (287 KB)  

    A novel approach for aligning two 3D point clouds acquired by time-of-flight (TOF) cameras is presented. Given that the density of 3D data of these devices is not high, the alignment will be carried out using descriptors based on a direct encoding of the environment of a set of previously selected points-of-interest. This will allow the design of a similarity measure that behaves correctly when both the density of the point clouds and the overlap between them are low. Furthermore, this combination of descriptor and similarity measure facilitates the alignment of point clouds from devices with different accuracy and resolution (such as a laser scanner and a TOF camera). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 6-DOF tracker using LED directivity

    Publication Year: 2011 , Page(s): 177 - 178
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (202 KB)  

    Proposed is a new concept for a 6-DOF optical tracker exploiting the directivity of an LED. To verify the concept, a low-noise, linear optical sensor was designed, a working prototype was built that solves a source-localisation problem in real time, and its performance, compared with a reference tracker, was evaluated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Median centred difference gradient operator and its application in watershed segmentation

    Publication Year: 2011 , Page(s): 178 - 180
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (165 KB)  

    A new gradient operator for greyscale images is proposed, the output of which is based on the median centred difference of the intensities within a local mask. The operator is a simplified form of the robust colour morphological gradient and, as such, is robust to impulsive noise and provides well-localised gradient estimates. A quantitative evaluation using simulated images shows that the new operator is particularly suitable for the watershed transform, producing significantly better watershed segmentation results than conventional edge operators such as the morphological gradient and the Sobel. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Formula for Harris corner detector

    Publication Year: 2011 , Page(s): 180 - 181
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    A new cornerness formula for the well-known Harris corner detector is proposed. The new formula is used to analyse the corner angle range detectable by the Harris detector for some applications and find out the actual corner angle. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Accelerating non-local means algorithm with random projection

    Publication Year: 2011 , Page(s): 182 - 183
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (56 KB)  

    The non-local means (NLM) algorithm suppresses noise via replacing the noisy pixel by the weighted average of all the pixels with similar neighbourhood vectors. However, the weights calculation is computationally expensive, as a result of which the NLM algorithm is quite slow for practical applications. A random projection approach is introduced to reduce the dimension of neighbourhood vectors used in the NLM filtering process, which yields a faster and more accurate denoising effect. Experimental results illustrate the effectiveness of the proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved line detection algorithm for locating road lane markings

    Publication Year: 2011 , Page(s): 183 - 184
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (150 KB)  

    An improved line detection algorithm for locating road lane markings is described. After scanning images to find mid-points of potential lane markings, they are passed to the line detection algorithm. This makes multiple hypotheses of lines based on random pairs of potential line features and selects the one having the greatest support. After finding each line the algorithm deletes not only the inliers within a `fit tolerance` distance df but also the innermost outliers lying within a `delete tolerance` distance dd. It is found that as dd - df is increased the final result becomes more robust because elimination of remanent points near each line prevents them from confusing the algorithm when searching for further lines. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simple QoE estimation model for low capacity VoIP phones

    Publication Year: 2011 , Page(s): 184 - 186
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (195 KB)  

    Proposed is a simple quality of experience (QoE) estimations model for VoIP applications in end devices such as IP phones. It is a model based on the accumulated burst metric, which corresponds to the fraction of the sum of the whole burst periods within all alternating gap/burst periods that have occurred since the beginning of the packet stream reception. Estimation errors caused when using only the accumulated burst metric as the input metric of the VoIP quality estimation model are explored. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cosh window behaviour of wavelet Tsallis q-entropies in 1/fα signals

    Publication Year: 2011 , Page(s): 186 - 187
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (143 KB)  

    It is demonstrated that wavelet Tsallis q-entropies of 1/fα signals behave in accordance with a sum-cosh window. Closed-form expressions for such windowing functions, defined in the α domain, are obtained and potential applications in the analysis of power-law processes discussed. An example application using pure power-law models validates its utility. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Source coding with Tsallis entropy

    Publication Year: 2011 , Page(s): 187 - 188
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (59 KB)  

    An extension is presented to the source coding theorem traditionally based on the Shannon entropy and later generalised to the Rényi entropy. Another possible generalisation is demonstrated, with a lower bound realised by the Tsallis entropy, when the performance is measured by the generalised average coding length which is exhibited, and with the optimal codelengths expressed from the escort probability distribution, also known in nonextensive thermodynamics. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compact dual-band power divider using non-uniform transmission line

    Publication Year: 2011 , Page(s): 188 - 190
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (287 KB)  

    A compact dual-band power divider using a non-uniform transmission line (NTL) is presented. The realisation of this dual-band impedance matching NTL is evolved from a direct synthesis method. Corresponding design equations are proposed to calculate the design parameters and a 0.915 GHz/2.45 GHz power divider is fabricated for proving the validity of this design. The measured data and anticipated results demonstrate good agreement. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compact wideband LC VCO with active inductor harmonic filtering technique

    Publication Year: 2011 , Page(s): 190 - 191
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (399 KB)  

    Presented is an active inductor harmonic filtering technique that improves the phase noise of the wideband LC voltage controlled oscillator (VCO). A Wu folded active inductor structure was chosen to design a wideband filtering device that consists of a single NMOS transistor and a resistor. Using an active inductor can reduce chip area by 37.68% while performing wideband harmonic filtering compared to existing LC filtering techniques. The chip was fabricated in 130%nm CMOS technology. The measured phase noise of the VCO is %119.21%dBc/Hz at a 1%MHz offset frequency at the 4.28%GHz carrier. The VCO is activated by a 3-bit digitally controlled switched capacitor array to achieve a 39% wideband tuning range from 3.8 to 5.6%GHz. A current of 4.2%mA flows continuously for the whole frequency from a 1.2%V supply voltage. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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