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Electronics Letters

Issue 15 • Date 18 July 1991

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Displaying Results 1 - 25 of 50
  • Synchronisation circuit for addition of two asynchronously changing digital values in digital motor control circuits

    Publication Year: 1991, Page(s):1313 - 1314
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (167 KB)

    Phased-based digital motor control circuits often require the addition of two asynchronously changing digital values, corresponding typically to the rotor angle and electrical field angle of the stator. When one angle is increasing and the other is decreasing, their sum is not monotonic and can lead to errors in subsequent circuits that rely on the edge transitions of the least significant bit of ... View full abstract»

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  • 10 Gbit/s D flipflop using AlInAs/InGaAs

    Publication Year: 1991, Page(s):1314 - 1315
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (249 KB)

    It is demonstrated that high speed circuits can be achieved in InGaAs HBT technology with relaxed transistor design rules. A 10 Gbit/s D flipflop has been realised using HBTs with a base thickness of 1500 AA and collector thickness of 5000 AA and with 4 mu m emitter stripe width. View full abstract»

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  • Point-matching method for reduction of anomalous radiation of log-periodic dipole array

    Publication Year: 1991, Page(s):1315 - 1317
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (337 KB)

    A point matching method is developed for the evaluation of the performance of the log-periodic dipole antenna (LPDA. Based on this method, the anomalous behaviour of the LPDA is studied and found to be improved at an optimum spacing factor and by selecting a small dipole length to diameter ratio; that is, an LPDA, operating over a given frequency band, must possess an optimum dimension that gives ... View full abstract»

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  • Broadband branchline coupler for S-band

    Publication Year: 1991, Page(s):1318 - 1319
    Cited by:  Papers (2)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (187 KB)

    The design of an S-band, broadband, microstrip 3 dB, 90 degrees branchline coupler is described and measured results for a prototype version are given. The design uses broadbanding stubs and three branches, with the central branch split into two of twice the characteristic impedance and separated by half wavelength transmission lines. This is a new technique to improve the bandwidth of which a the... View full abstract»

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  • Planar 1/8 splitter in glass by photoresist masked silver film ion exchange

    Publication Year: 1991, Page(s):1319 - 1320
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (200 KB)

    Fabrication of singlemode glass waveguide devices by silver film ion exchange with standard photoresist as a mask for the ion exchange is proposed. The process uses the advantages of the silver film ion exchange and the simple and accurate patterning when photoresist is used directly as a mask. As a component example, a singlemode 1/8 power splitter is fabricated and measured. View full abstract»

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  • Balanced directional loop receiving antenna

    Publication Year: 1991, Page(s):1320 - 1321
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (199 KB)

    Directional loop antennas have been used for some time for HF reception purposes. However, for stable performance they rely on a good ground connection. A modified form of such an antenna is described which has a balanced feed arrangement and thus does not suffer from the problems associated with the requirement for a solid ground connection. View full abstract»

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  • Error correction technique for multivalued MOS memory

    Publication Year: 1991, Page(s):1321 - 1323
    Cited by:  Papers (7)  |  Patents (26)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (290 KB)

    An error correction technique is proposed to increase the noise margin of a multivalued MOS memory. The stored voltage information is first converted to a binary representation. The noise margin of the store voltage is then increased by storing and comparing the least significant bits of the binary representation. View full abstract»

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  • Selftuning robot control laws

    Publication Year: 1991, Page(s):1323 - 1324
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (198 KB)

    An investigation of the initial conditions induced by a parameter change of a controlled-mechanism is introduced. This reveals the features of the parameter updating laws of robot controllers with selftuning capabilities. View full abstract»

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  • Semiconductor lasers fabricated by selective area epitaxy

    Publication Year: 1991, Page(s):1324 - 1326
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (313 KB)

    For the first time, semiconductor lasers grown entirely by selective area epitaxy are reported. The lasers were formed by in situ processing techniques and metal organic molecular beam epitaxy (MOMBE). A 50 AA thick layer of Si deposited on the InP substrate was used as a mask for both the selective growth and etching. Laser stripes, 6 mu m wide, were delineated by a focused Ga ion beam and transf... View full abstract»

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  • Direction finding in multipath environment using method of alternating projection

    Publication Year: 1991, Page(s):1326 - 1327
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (212 KB)

    In a coherent environment the problem of direction finding using arbitrary antenna array geometries always seems to be a multivariate optimisation problem. An estimator derived using suboptimal eigen techniques and optimised using the method of alternating projection (AP) is shown to be superior to the maximum likelihood method. View full abstract»

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  • Degenerate four wave mixing in polydiacetylene waveguides

    Publication Year: 1991, Page(s):1327 - 1329
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (283 KB)

    Degenerate four wave mixing of light at 1.055 mu m guided in poly(4,6-decadiyne-1,10 diol bis(n- butoxycarbonylmethylurethane)) planar waveguides has been observed. Diffraction efficiencies of up to 24% have been obtained, with a laser peak power of 2 W. Approximately 50% of the nonlinear mechanism can be attributed to the ultrafast molecular hyperpolarisability of the polymer. View full abstract»

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  • Multiple fault detection using single-fault tests

    Publication Year: 1991, Page(s):1329 - 1330
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (218 KB)

    A special class of two-pattern tests for single faults is defined using the Boolean difference approach to enhance the multiple fault detection ability for combinational circuits. It is shown that just a slight modification of the concurrent test generation method proposed by Agrawal et al. (1989) can derive such two-pattern tests. View full abstract»

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  • GaAs/AlGaAs dynamic random access memory cell

    Publication Year: 1991, Page(s):1330 - 1332
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (302 KB)

    A single-transistor dynamic random access memory circuit using a GaAs/AlGaAs structure as the storage cell and modulation-doped field-effect transistors for memory accessing and output sensing has been developed. The functionality of the memory is demonstrated and a storage time of 5.4s is measured at room temperature. View full abstract»

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  • Perfect energy efficient sequences

    Publication Year: 1991, Page(s):1332 - 1334
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (292 KB)

    Time discrete sequences are termed perfect if their periodic autocorrelation function sidelobes are zero. Such sequences have constant magnitude spectra in the Fourier domain. An iteration scheme is introduced for optimising the energy efficiency of perfect real valued sequences. Perfect real valued sequences are synthesised in two steps. In the first step perfect sequences are generated in the Fo... View full abstract»

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  • Sporadic partitions of binomial coefficients

    Publication Year: 1991, Page(s):1334 - 1336
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (255 KB)

    It is shown that certain families of 'sporadic' partitions of binomial coefficients exist and some results of Bruer (1984) and Mitchell (1990) are extended for enumerating balanced symmetric Boolean functions. View full abstract»

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  • Variable-ratio, polarisation-insensitive, 3*3 fused biconical tapered couplers

    Publication Year: 1991, Page(s):1336 - 1337
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (172 KB)

    The authors present a polarisation-insensitive, 3*3 fused biconical tapered coupler with a variable screw gauge that can change the coupling ratios from a splitting percentage of 11%-44%-45% to a uniformity of 33%-33%-34%, with excess loss maintained below 1.1 dB. The fabrication and packaging methods are described and wavelength tunability of the coupler is demonstrated. View full abstract»

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  • Optimum germanium profile for SiGe/int

    Publication Year: 1991, Page(s):1337 - 1338
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (181 KB)

    The thermal stability of an SiGe base HBT is closely related to the integrated Ge content in the base. It is therefore appropriate to consider what form the Ge profile should take to minimise the base transit time tau B for a given total Ge content. It is shown that a linear increase in Ge content from the base-emitter to the base-collector junction is required to minimise. View full abstract»

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  • BiCMOS operational amplifier with precise and stable DC gain for high-frequency switched capacitor circuits

    Publication Year: 1991, Page(s):1338 - 1340
    Cited by:  Papers (10)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (289 KB)

    A novel approach in the design of high-frequency switched capacitor (SC) circuits is presented. It is based on the use of simple and fast amplifiers with low but precisely controlled gain value. The effect of the precisely known and stable opamp gain is compensated for by changing the capacitor values during the synthesis of the SC cell. An example of an opamp with these features and the synthesis... View full abstract»

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  • Design of symmetrical polylithic crystal filters

    Publication Year: 1991
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (98 KB)

    For the original article see ibid., vol.12, no.25, p203-3 (1976). C.C. Lin Provided an algorithm for designing symmetrical even-order all-pole bandpass polylithic crystal filters using dual-resonator monolithic crystal filter (MCF) elements. The commenter points out a couple of omissions in the algorithm given. With the corrections suggested, it was verified that the algorithm did provide a design... View full abstract»

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  • Higher order modes in dieletric resonators

    Publication Year: 1991, Page(s):1340 - 1342
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (282 KB)

    Higher order modes excited in oversized dielectric resonators are investigated using an expansion in terms of orthogonal eigenfunctions. Radiation and material losses are taken into account. The calculated results are in excellent agreement with measurements. Different modes are easily identified by plots showing fields and energy distribution. Novel mode charts helpful for resonator design are pr... View full abstract»

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  • Polymer channel waveguides with low loss at 1.3 mu m

    Publication Year: 1991, Page(s):1342 - 1343
    Cited by:  Papers (13)  |  Patents (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (208 KB)

    Highly transparent polymers in the 0.6-1.3 mu m wavelength region have been synthesised from deuterated or halogenated methacrylate monomers. Low loss waveguides of less than 0.1 dB/cm at a wavelength of 1.3 mu m have been fabricated using the polymers. View full abstract»

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  • Experimental study of saw quartz cuts with low sensitivity to dynamical thermal effects

    Publication Year: 1991, Page(s):1343 - 1345
    Cited by:  Papers (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (283 KB)

    Surface acoustic wave (SAW) quartz cuts with a low sensitivity to temperature and planar isotropic stresses have been found. SAW oscillators based on stress- and temperature-compensated cuts have been experimentally tested and compared to the classical (ST, X) cut. A significant reduction (by one order of magnitude) of the sensitivity to dynamic thermal effects is demonstrated. View full abstract»

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  • Realisation of voltage-mode biquads using CCIIs

    Publication Year: 1991, Page(s):1345 - 1346
    Cited by:  Papers (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (172 KB)

    A method for realising biquadratic transfer functions using current conveyors (CCIIs) is presented, and two novel networks which realise the general second-order transfer function are given. The networks are composed of solely plus-type CCIIs with grounded capacitors, and offer high input impedances. View full abstract»

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  • Vector dark spatial solitons

    Publication Year: 1991, Page(s):1346 - 1348
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (275 KB)

    The dark spatial solution of TM type is shown to exist in a uniform selfdefocusing nonlinear medium in the range of the beam effective index neff from 0.82n0 to n0 of the linear refractive index of the medium. This contrasts with the dark spatial soliton of TE type which exists over all the possible values of neff ranging from 0 to n0. The fie... View full abstract»

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  • Relation of CLSS algorithm to KT and music methods

    Publication Year: 1991, Page(s):1348 - 1350
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (272 KB)

    The relation of the constrained least square subspace (CLSS) algorithm, which was proposed for high resolution array processing previously, to the more classic subspace approaches of MUSIC and KT is shown. The MUSIC and KT algorithms are shown to be special cases of the proposed constrained least square subspace approach. This provides further insight into the new algorithm. Additional simulation ... View full abstract»

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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.

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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