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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 29, Issue 20, 30 September 1993

Volumes & issues:

Volume 29, Issue 20

30 September 1993

Conformal array synthesis using alternating projections, with maximal likelihood estimation used in one of the projection operators
Design of low VSWR axisymmetric subreflector
Fast synthesis of aperture distributions for contoured beam reflector antennas
CMOS four-quadrant multiplier using bias offset crosscoupled pairs
New high-compliance CMOS current mirror with low harmonic distortion for high-frequency circuits
  • Author(s): R.A.H. Balmford  and  W. Redman-White
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1738 –1739
  • DOI:  10.1049/el:19931157
  • Type: Article
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  • p. 1738 –1739 (2)
    A new low-distortion high-compliance CMOS current mirror is presented. The large-signal nonlinear characteristic of MOS transistors in saturation, combined with capacitances present in current mirror circuits, causes harmonic distortion. This effect is explained for a well-known current mirror circuit, and the new circuit is described which substantially reduces harmonic distortion while using only one extra standard process component.
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Bandpass line codes for q-ary alphabets
  • Author(s): S. Perkins
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1740 –1741
  • DOI:  10.1049/el:19931158
  • Type: Article
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  • p. 1740 –1741 (2)
    The Letter considers codes with higher order spectral zeros at DC for q-ary alphabets. A recurrence relation is derived for the number of codewords that exist for a given length and moment, which enables the correction of some recently published tables for q = 3 and q = 5. Some minimum distance properties are determined for first order codes and any alphabet, and again some recently published results are corrected.
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Coding of quadtree structures using runlength code
Extension of the BCH decodable class of DCT codes
Improved method for calculating mitigation bandwidth of DSPN signals
New 32-QAM trellis codes for fading channels
Optimum erasure threshold in Reed-Solomon coded differential 16 star-QAM modulation
  • Author(s): N.F. Zein  and  T.G. Clarkson
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1746 –1748
  • DOI:  10.1049/el:19931163
  • Type: Article
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  • p. 1746 –1748 (3)
    The performance of a Reed-Solomon (RS) coded differential 16 star-QAM modulation scheme with a decision-directed estimation (DDE) technique as the channel-fading parameter in a frequency hopping (FH) system is simulated. The optimum erasure threshold for an RS decoder is obtained. It is shown that with the optimum erasure threshold a bit-error probability of 10−5 can be achieved at Eb/No = 21.2 dB for using RS(63,31) and Eb/No = 21.5 dB for RS(31,15).
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Realisation of high-speed systolic IIR decimators and interpolators
  • Author(s): H.K. Kwan
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1748 –1749
  • DOI:  10.1049/el:19931164
  • Type: Article
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  • p. 1748 –1749 (2)
    Two novel systolic allpass digital filtering arrays for realising high-speed systolic IIR decimators and interpolators are described. The sampling period at the input of such a decimator by N and at the output of such an interpolator by N can be reduced to (Tm+2Ta)/(N−1) and (Tm+3Ta)/N, respectively, by the two arrays. (Tm and Tn respectively, represent the times for twoinput real multiplication and two-input real addition.) Other advantages include reduced latencies, and reduced numbers of multipliers and adders.
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Contractivity of fractal transforms for image coding
  • Author(s): B. Hürtgen
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1749 –1750
  • DOI:  10.1049/el:19931165
  • Type: Article
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  • p. 1749 –1750 (2)
    In the Letter the contractivity of existing fractal transforms for use in image compression schemes is examined. The coding process is described as nonlinear transformation in the finite-dimensional Euclidean vector space. Sufficient conditions are derived for contractivity based on the spectral norm and the spectral radius of the transformation matrix. As a result bounds for the encoding parameters can be formulated which are tighter than those ones known so far.
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Real-valued hankel transform approach to image reconstruction from projections
Text compression as rule based pattern recognition
  • Author(s): H.U. Khan ; J. Ahmad ; A. Mahood ; H.A. Fatmi
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1752 –1753
  • DOI:  10.1049/el:19931167
  • Type: Article
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  • p. 1752 –1753 (2)
    A novel algorithm for text compression is developed which consists of two parts. In the first part the text sample is encoded by the Ziv-Lempel asymptotic structured codebook. In the second part decoding is carried out by a novel rule based (RB) algorithm which improves the compression ratio for a given text sample by up to 50% when compared to the full text search as required by the Ziv-Lempel decoding algorithm.
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Correlation properties of extended m-sequences
  • Author(s): U.-C.G. Fiebig  and  M. Schnell
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1753 –1755
  • DOI:  10.1049/el:19931168
  • Type: Article
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  • p. 1753 –1755 (3)
    In the Letter the correlation properties of extended m-sequences are treated and compared to those of m-sequences. Extended m-sequences are obtained from m-sequences inserting an additional element per period yielding periods 2n, where n is an integer. It turns out that extended m-sequences provide good autocorrelation but poor crosscorrelation properties. This behaviour is similar to that of m-sequences.
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Triple correlation analysis of m-sequences
Analytical formulation of the capacitive coupling voltage contrast of a buried line
Characterisation of poly-Si/SiO2/Si(100) structure by variable-angle spectroscopic ellipsometry
  • Author(s): Y. Kawazu ; H. Fukuda ; T. Hayashi ; T. Iwabuchi
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1758 –1759
  • DOI:  10.1049/el:19931171
  • Type: Article
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  • p. 1758 –1759 (2)
    The structure of polycrystalline silicon (poly-Si)/SiO2/Si(100) was investigated using variable-angle spectroscopic ellipsometry (VASE) measurement with the Bruggeman effective medium approximation modei. In this structure, the poly-Si and SiO2 film thicknesses and poly-Si composition, as well as the top surface roughness, can be characterised well. The VASE results are very close -to those obtained by cross-sectional transmission electron microscopy.
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Refractive indices of wurtzite and zincblende GaN
  • Author(s): M.E. Lin ; B.N. Sverdlov ; S. Strite ; H. Morkoç ; A.E. Drakin
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1759 –1760
  • DOI:  10.1049/el:19931172
  • Type: Article
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  • p. 1759 –1760 (2)
    Refractive index measurements on both wurtzite and zincblende CaN films grown by plasma-enhanced molecular beam epitaxy are reported. For birefringent uniaxial wurtzite GaN samples the index of refraction was measured along the c crystalline axis. In this direction the index is 2.78 at 3.4eV. For cubic GaN films grown on GaAs substrates, the refractive index is 2.91 at 3.2eV. Estimation of the confinement factor for optimised waveguides based a combination of III–V nitrides indicates very favourable values for laser operation.
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Measuring high-bandwidth signals in CMOS circuits
MOSAIC 5SE: a 6 fJ high-performance bipolar technology
  • Author(s): J. Candelaria ; T. Hulsweh ; K. Papworth ; P. Pegler ; R. Pryor ; K. Sakamoto ; S. Sundaram ; V. de la Torre ; N. Tracht ; P. Zdebel
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1763 –1764
  • DOI:  10.1049/el:19931174
  • Type: Article
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  • p. 1763 –1764 (2)
    MOSAIC 5SE, Motorola's scaled and enhanced double polysilicon bipolar technology, has demonstrated world class performance in digital and analogue applications. A minimum power-delay product of 5.4 fJ in current mode logic (CML) ring oscillator circuits and a noise figure of 0.9 dB at 1.2 GHz with 18 dB of gain are the best reported results in the digital and analogue world. High-bit-rate (Gbit/s) communication, RF and low-voltage electronics will benefit by this advancement.
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Process characterisation with dynamic test structures
  • Author(s): P. Coll ; M. Robert ; D. Auvergne ; X. Regnier
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1764 –1766
  • DOI:  10.1049/el:19931175
  • Type: Article
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  • p. 1764 –1766 (3)
    Using explicit delay formulation, the Letter proposes a method for process characterisation with simple dynamic test structures. Validation of this method is first obtained with different levels of simulation models. Application to the ring oscillator is presented to demonstrate the possibility of defining average correlated parameters with direct coupling between delay modelling, level of simulations and real structures.
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Trimming CMOS smart imager with tunneleffect nonvolatile analogue memory
  • Author(s): F. Devos ; M. Zhang ; J.-F. Pône ; Y. Ni
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1766 –1767
  • DOI:  10.1049/el:19931176
  • Type: Article
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  • p. 1766 –1767 (2)
    Amplified MOS imagers (AMIs) have the advantage of being compatible with conventional CMOS analogue/digital circuit design. One of the major problems in AMIs is their large fixed pattern noise compared to CCD imagers. The Letter presents the structure of a nonvolatile tunnel-effect analogue memory which is fully compatible with a standard CMOS process and which can reduce significantly the offset-like fixed pattern noise in AMI arrays.
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Polarisation-independent low-power integrated acousto-optic tunable filter/switch using APE/Ti polarisation splitters on lithium niobate
Monolithic, self-frequency doubled, neodymium-doped yttrium aluminium borate green laser with low intensity noise
  • Author(s): J.H. Zarrabi ; P. Gavrilovic ; S. Singh
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1769 –1770
  • DOI:  10.1049/el:19931178
  • Type: Article
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  • p. 1769 –1770 (2)
    A monolithic, self-frequency-doubled green laser is fabricated from neodymium-doped yttrium aluminum borate. The threshold pump power for green output is less than 10 mW, and up to 20 mW of green output (λ = 531 nm) in a TEM00 mode is generated when pumped by a 1 W GaAlAs laser diode. The green output is free of large-amplitude fluctuations with a relative intensity noise of –154 dB/Hz.
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Reduction of p-doped mirror electrical resistance of GaAs/AlGaAs vertical-cavity surface-emitting lasers by delta doping
Matching of active millimetre-wave slot-line antennas
  • Author(s): J.-F. Luy ; J. Buechler ; M. Thieme ; E.M. Biebl
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1772 –1774
  • DOI:  10.1049/el:19931180
  • Type: Article
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  • p. 1772 –1774 (3)
    The matching of a radiating, resonant structure to an active millimetre-wave device is investigated. As an active device, an IMPATT diode is considered to be matched to a planar slot-line structure. An analytical IMPATT diode model and an equivalent circuit of the slot line are used to calculate possible oscillation frequencies and large-signal modulation parametres of the diode. In the case of matching the output power is predicted. The results are in satisfactory agreement with experimental data and suggest a diode design with shorted drift regions and reduced diode area for optimum impedance matching.
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Adaptive device for synaptic connection with optical interconnections
  • Author(s): K. Tsuji ; H. Yonezu ; K. Shibao ; K. Hosono ; K. Pak
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1774 –1775
  • DOI:  10.1049/el:19931181
  • Type: Article
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  • p. 1774 –1775 (2)
    An adaptive device was newly developed for a synaptic connection circuit with learning ability. A synaptic weight was varied during operation when an optical correction signal was applied. The synaptic weight was varied from −0.7 to +0.7 proportionally to the applied duration of the optical correction signal and kept in a nonvolatile manner. It was clarified that artificial self-organising neural networks can be realised using the adaptive device.
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New learning strategies from the microscopic level of an artificial neural network
Comparison of performance of long-haul high-capacity optical systems
Photonic ATM switch using frequency-routing-type time-division interconnection network
  • Author(s): K. Sasayama ; K. Habara ; W. de Zhong ; K. Yukimatsu
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1778 –1780
  • DOI:  10.1049/el:19931184
  • Type: Article
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  • p. 1778 –1780 (3)
    The Letter describes a photonic asynchronous-transfer-mode (ATM) switch with an architecture composed of N tunable frequency convertors and N frequency-multiplexed output buffers connected through an N × N arrayed-waveguide grating multiplexer. This ATM switch features a novel output buffering scheme having the best possible performance and causing no splitting loss of optical power.
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Soliton transmission with long amplifier spacing under soliton control
Throughput analysis of a CDMA protocol with channel sensing and overload detection for fibre optic LANs
Wideband 32×32 star coupler module with gain
Accurate physical fusion taper shape model for waveguide analyses
Arrayed hybrid filter/coupler device for inservice fibre line testing
  • Author(s): T. Oguchi ; F. Hanawa ; N. Takato ; N. Tomita ; N. Atobe
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1786 –1787
  • DOI:  10.1049/el:19931189
  • Type: Article
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  • p. 1786 –1787 (2)
    An arrayed hybrid filter/coupler consisting of four waveguide-type wavelength-insensitive couplers and a thin dielectric filter has been developed for application to an in-service optical fibre testing system. The device was designed to combine a 1.31 μm communication light and a 1.55 μm test light with a ratio of 80:20%. The measured performance of a prototype device exhibited an excess loss of 0.6 dB, a return loss attenuation of >45dB and a crosstalk attenuation for the test light of >60dB.
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Integrated all optical fibre source of multigigahertz soliton pulse train
  • Author(s): S.V. Chernikov ; J.R. Taylor ; R. Kashyap
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1788 –1789
  • DOI:  10.1049/el:19931190
  • Type: Article
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  • p. 1788 –1789 (2)
    A 59.1 GHz train of 2.2 ps solitons with low phase noise (<5×10−5) is generated by a novel, passive, all optical fibre source. The technique is based on transformation of a dual frequency beat signal generated by a 16 kHz line width erbium fibre DBR laser having a selectable and highly stable frequency separation, into a soliton train in a comblike dispersion profiled fibre, a novel fibre design which uses conventional optical fibres.
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Phase stepping in projected-fringe fibre-based moiré interferometry
Dependence of internal differential quantum efficiency on cavity length and its implications in measuring optical losses of laser diodes
  • Author(s): K. Sang-Bae ; H. Yong-Su ; D. Man-Hee
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1791 –1792
  • DOI:  10.1049/el:19931192
  • Type: Article
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  • p. 1791 –1792 (2)
    The conventional method of measuring the internal optical loss, using the dependence of the reciprocal external quantum efficiency on the cavity length in laser diodes, is examined. It is shown that the implicit assumption of constant internal differential quantum efficiency ηid, which has been customarily misinterpreted as internal quantum efficiency ηi is not valid for devices with short cavity length. Therefore, for reliable measurements, long cavity data should be used.
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Novel type submicrometre resolution pseudorandom position optical encoder
  • Author(s): M. Duruna ; R. Gallay ; Ph. Robert ; F.-C. Pruvot
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1792 –1794
  • DOI:  10.1049/el:19931193
  • Type: Article
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  • p. 1792 –1794 (3)
    A novel absolute position optical encoder using two, pseudorandom and periodic, synchronously engraved tracks on a glass slab is presented. The encoded track is read with a GRIN lens and a linear CCD array together with the appropriate signal processing. The spatial coupling of both tracks gives submicrometre resolution when the periodic track is read with the standard Moiré technique.
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Ionospheric mapping by computer contouring techniques
  • Author(s): T. Samardjiev ; P.A. Bradley ; Lj.R. Cander ; M.I. Dick
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1794 –1795
  • DOI:  10.1049/el:19931194
  • Type: Article
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  • p. 1794 –1795 (2)
    Established methods of generating uniform grids of scalar quantities from irregularly disposed known values are applied to the development of regional maps of ionospheric characteristics for individual instants of time. Figure-of-merit comparisons are presented to show the general superiority of one particular technique. Ways of supplementing measured input values with ‘screen-point’ synthesised data are outlined.
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Comparison of InGaAs transistors as optoelectronic mixers
Effect of pad and interconnection parasitics on phase delay of transconductance in advanced bipolar transistors
  • Author(s): S. Lee ; B.R. Ryum ; O.-J. Kwon ; J.-H. Lee
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1797 –1799
  • DOI:  10.1049/el:19931196
  • Type: Article
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  • p. 1797 –1799 (3)
    An analytical expression is developed for determining the accurate phase delay of transconductance or current gain in a small-signal equivalent circuit, including RF probe pad and interconnection parasitics and HBT extrinsic elements. Using this new expression, it is demonstrated that collector resistance, collector interconnection resistance, and pad capacitances have a significant influence on the phase delay.
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Investigation of emitter current crowding effect in heterojunction bipolar transistors
  • Author(s): V. Fournier ; J. Dangla ; C. Dubon-Chevallier
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1799 –1800
  • DOI:  10.1049/el:19931197
  • Type: Article
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  • p. 1799 –1800 (2)
    The emitter current crowding effect in heterojunction bipolar transistors (HBTs) has been investigated using a specific test device. This test device, which is a heterojunction bipolar transistor with two separate base fingers, also allows evaluation of the HBT base resistance. By use of this test device, the Letter demonstrate that a 3μm large HBT does not exhibit the emitter current crowding effect. An analysis of the saturated regime is also presented.
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LWIP: a long-wavelength infra-red phototransistor
  • Author(s): N. Chand
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1800 –1802
  • DOI:  10.1049/el:19931198
  • Type: Article
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  • p. 1800 –1802 (3)
    A novel device is proposed that combines the principles, functions and advantages of a quantum-well infra-red photodiode and phototransistor for detection of long wavelength infra-red radiation (6–20 μm). This device is called an LWIP: a longwavelength infra-red phototransistor. Si1−xGex/Si is an ideal candidate for this heterostructure. An optimised device is expected to exhibit very low leakage/dark current, high gain and high detectivity, and has the potential of operating at a relatively higher temperature.
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Room-temperature resonant tunnelling bipolar transistor XNOR and XOR integrated circuits
  • Author(s): A.C. Seabaugh ; A.H. Taddiken ; E.A. Beam ; J.N. Randall ; Y.-C Kao ; B. Newell
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1802 –1803
  • DOI:  10.1049/el:19931199
  • Type: Article
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  • p. 1802 –1803 (2)
    The first resonant tunnelling bipolar transistor integrated circuits operating at room temperature are demonstrated. The circuits are composed of cointegrated resonant tunnelling bipolar transistors and double heterojunction bipolar transistors based on InP substrates. Both a three-transistor XNOR and a seven-transistor XOR logic gate have been demonstrated using a 3 V power supply.
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W-band monolithic pseudomorphic AlGaAs/InGaAs/GaAs HEMT CBCPW LNA
  • Author(s): T.-N. Ton ; H. Wang ; S. Chen ; K.L. Tan ; G.S. Dow ; B.R. Allen ; J. Berenz
  • Source: Electronics Letters, Volume 29, Issue 20, p. 1804 –1805
  • DOI:  10.1049/el:19931200
  • Type: Article
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  • p. 1804 –1805 (2)
    We have developed a W-band monolithic two-stage conductor-backed coplanar waveguide (CBCPW) low-noise amplifier using pseudomorphic AlGaAs/InGaAs/GaAs HEMT devices. The amplifier exhibits a noise figure of 4.2–4.8 dB with an associated gain of 12 dB from 92 to 96 GHz. The circuit was tested using a W-band on-wafer noise figure measurement system. The result is encouraging and shows promise for future MMIC implementation using the CBCPW structure.
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Extension of matrix method for complete multipoint Padé approximation
Thick-film acoustic wave sensor structure

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