Showing papers in "Electronics Letters in 1975"
TL;DR: In this paper, the basic translinear principle is derived and several examples of translinear analogue circuits are given, including the translinear? group, which exploits the precise proportionality of transconductance to collector current in bipolar transistors to result in fundamentally exact, temperature-insensitive behaviour.
Abstract: An important and expanding branch of analogue circuits is the `translinear? group. Their primary function arises from the exploitation of the precise proportionality of transconductance to collector current in bipolar transistors so as to result in fundamentally exact, temperature-insensitive behaviour. The basic translinear principle is derived and several examples given.
456 citations
TL;DR: A circuit for detecting timing errors between a binary signal and a local clock pulse generator and logical control signals for the clock are derived.
Abstract: A circuit for detecting timing errors between a binary signal and a local clock pulse generator is described. Three binary samples are compared and logical control signals for the clock are derived.
328 citations
TL;DR: The material dispersion of optical fibres having cores of silica or phosphosilicate glass falls to zero at a wavelength between 1.2 and 1.3 µm as mentioned in this paper.
Abstract: The material dispersion of optical fibres having cores of silica or phosphosilicate glass falls to zero at a wavelength between 1.2 and 1.3µm. A considerable increase in bandwidth can be obtained, especially with an l.e.d. source, by operation in this region.
280 citations
TL;DR: The problem of finding binary sequences with autocorrelation sidelobes as small as possible for any given length of the sequence is still unsolved today, however, solutions were found up to length 40 by exhaustive searching with the aid of a special minicomputer.
Abstract: The problem of finding binary sequences with autocorrelation sidelobes as small as possible for any given length of the sequence is still unsolved today. However, solutions were found up to length 40 by exhaustive searching with the aid of a special minicomputer.
176 citations
TL;DR: In this paper, it was shown that spontaneous emission in a semiconductor injection laser has an important effect on the response of the laser to a step current and simple analytical approximations of the description of the transient response, also useful for the study of the response to other current waveforms, are derived.
Abstract: It will be shown that spontaneous emission in a semiconductor injection laser has an important effect on the response of the laser to a step current. Simple analytical approximations of the description of the transient response, also useful for the study of the response to other current waveforms, are derived.
127 citations
TL;DR: Sticklike figures can be obtained through the sequential application of a set of eight masks, each one applied in parallel, during the process, components neither disconnect nor vanish.
Abstract: Sticklike figures can be obtained through the sequential application of a set of eight masks, each one applied in parallel. During the process, components neither disconnect nor vanish. Particular emphasis is given to the simplicity and speed of the algorithm when implemented on a parallel machine.
124 citations
TL;DR: In this paper, a planar waveguide model with a frequency-dependent effective relative permittivity and a frequencydependent effective width was developed for the open microstrip line, which was shown by experimental results from measurements with a resonator and a sliding-load technique.
Abstract: A planar waveguide model with a frequency-dependent effective relative permittivity and a frequency-dependent effective width is developed for the open microstrip line. The validity of this waveguide model is shown by experimental results from measurements with a resonator and a sliding-load technique.
122 citations
TL;DR: Results suggest that the prescriptive method given here is useful when the plant is subject to time-varying parameter changes and unknown disturbances.
Abstract: A method of controlling a plant by a fuzzy algorithm has been proposed earlier. This method requires the complete description of the control policy as linguistic rules. Here we give a prescriptive method for deriving the best policy during run time. Results suggest the method is useful when the plant is subject to time-varying parameter changes and unknown disturbances.
116 citations
TL;DR: In this article, the authors present simplified optimal algorithms that lead to stationary gains, given by explicit expressions, for industrial process control problems with linear quadratic optimal regulators and Kalman estimators.
Abstract: Implementation of linear quadratic optimal regulators and Kalman estimators is not straightforward where industrial process control is concerned. This is mainly due to the requirement that many parameters (Q and R matrices, spectral-density matrices) having no direct physical meaning must be chosen a priori. The letter contains simplified optimal algorithms that lead to stationary gains, given by explicit expressions.
103 citations
TL;DR: In this article, a model is proposed in which the electrocoloration process is attributed to the formation of a ‘tungsten-blue’ phase following cathodic reduction by active hydrogen.
Abstract: Studies of electrochromism in evaporated and chemically prepared tungsten-oxide films have shown that electrocoloration takes place only in films containing H2O. A model is proposed in which the electrocoloration process is attributed to the formation of a ‘tungsten-blue’ phase following cathodic reduction by active hydrogen.
100 citations
TL;DR: In this article, a semi-insulating InP having a room-temperature resistivity of greater than 107 Ωcm was prepared by Fe doping and the current/voltage characteristic of the material changed from ohmic to V2 dependent at about 104 V/cm.
Abstract: Semi-insulating InP having a room-temperature resistivity of greater than 107 Ωcm was prepared by Fe doping. The current/voltage characteristic of the material changed from ohmic to V2 dependent at about 104 V/cm. Temperature dependence of the resistivity gave an activation energy of 0.66 eV. The Hall effect was negative, and the observed electron concentration was about 109 cm−3.
TL;DR: In this paper, the authors describe a new class of primary-feed antennas which overcome the offset reflectors' depolarising and beam-squinting properties, which offer a significant improvement in the cross-polar and beamsquinted properties of the primary reflector antenna, without adding significantly to the complexity or mass.
Abstract: In many practical applications the performance of an offset parabolic-reflector antenna is limited by the offset reflectors' depolarising and beam-squinting properties. The letter describes a new class of primary-feed antennas which overcome these limitations. The new primary-feed types offer a significant improvement in the crosspolar and beam-squinting properties of the offset reflector antenna, without adding significantly to the complexity or mass of the primary-feed system.
TL;DR: In this paper, a simple method for determining the radiation losses due to the bending of an optical waveguide is presented, which circumvents the use of continuous modes and reduces the problem to elementary antenna theory in which radiation is found from a known surface current distribution.
Abstract: A simple method is presented for determining the radiation losses due to the bending of an optical waveguide. This method circumvents the use of continuous modes and reduces the problem to elementary antenna theory in which radiation is found from a known surface-current distribution. Practical results are given for the bent fibre of circular cross-section. i.e. a toroidal geometry, both for the HE11 mode and for rays in an overmoded fibre.
TL;DR: In this article, the authors describe a pulse generator with epitaxial silicon planar transistors working in the avalanche-breakdown mode, which can be varied continuously between 0.3 and 120 ns, without changing the maximum amplitude of about 15 V.
Abstract: The letter describes a pulse generator with epitaxial silicon planar transistors working in the avalanche-breakdown mode. The risetime is 150 ps and the fall time 200 ps. The pulse-width can be varied continuously between 0.3 and 120 ns, without changing the maximum amplitude of about 15 V. Simple rules for the exact design of the circuitry are given.
TL;DR: In this paper, a method for coupling a diode laser to an optical fiber was described, which uses a cylindrical glass fibre as a focusing element and showed that optical feedback from the fiber endface has an influence on the laser output power.
Abstract: A new method for coupling a diode laser to an optical fibre is described. This uses a cylindrical glass fibre as a focusing element. Optical feedback from the fibre endface has been found to have an influence on the laser output power. As a result, the light power launched into a single-mode fibre was higher than that obtainable from the laser during normal operation.
TL;DR: In this paper, the majority-carrier traps are characterised for n-and p-type GaAs and the capture cross-section and density of these centres have also been determined.
Abstract: Majority-carrier traps are characterised for n- and p-type GaAs. Bulk and vapour-phase-epitaxial n GaAs show the same electron-trap centre (0.83 eV). No electron traps were detected in liquid-phase epitaxial n GaAs, but three hole trap centres (0.64, 0.44 and ∼ 0.6 eV) were found in p GaAs. The capture cross-section and density of these centres have also been determined.
TL;DR: Theoretical analysis of an acousto-optic filter using noncollinear interaction is presented in this article, where various characteristics of the filter, including tuning curve, resolution, angular aperture and deflection angle, are determined.
Abstract: Theoretical analysis of an acousto-optic filter using noncollinear interaction is presented. The various characteristics of the filter, including tuning curve, resolution, angular aperture and deflection angle, are determined. The theoretical calculations are in good agreement with the measured results of a TeO2 filter.
TL;DR: In this paper, a new and better electrolyte for anodic oxidation of GaAs is described, which is an aqueous solution of tartaric or citric acid mixed with glycol and can produce native oxide films with remarkably improved dielectric properties.
Abstract: A new and better electrolyte for anodic oxidation of GaAs is described. It is an aqueous solution of tartaric or citric acid mixed with glycol and can produce, in an extremely stable manner, native oxide films with remarkably improved dielectric properties.
TL;DR: In this paper, the dependence of resonance frequencies on number of turns is reported, and a lumped circuit model which accounts approximately for the effects is presented, which can be used to account for self-resonant behavior in the range 0.5-20 MHz.
Abstract: Coils having aluminium-foil windings exhibit multiple self-resonant behaviour in the range 0.5–20 MHz. The dependence of resonance frequencies on number of turns is reported, and a lumped circuit model which accounts approximately for the effects is presented.
TL;DR: In this paper, the threshold voltage of an m.o.s. field effect transistor is modulated by the source-to-substrate reverse bias, and an analytical expression for threshold voltage as a function of geometry and bias is derived.
Abstract: The threshold vollage of an m.o.s. field-effect transistor is modulated by the source-to-substrate reverse bias. In the letter, the theory for long- and short-channel transistors is extended to include the influence of the channel width. The result is an analytical expression for the threshold voltage as a function of geometry and bias that agrees well with experimental data.
TL;DR: In this paper, a simple formula was proposed to predict the magnitude of the beam-squint effect to an accuracy of better than 0.01 of the antenna half-power beamwidth.
Abstract: The beam-squint phenomenon, which is observed when offset portions of parabolic reflector surfaces are illuminated by circularly polarised primary feeds, can be a critical factor in the design of antennas employing frequency-reuse techniques. The letter describes the derivation of a very simple formula which can be employed to predict the magnitude of the beam-squint effect to an accuracy of better than 0.01 of the antenna halfpower beamwidth. Verification of the formula has been obtained using both computed and experimental data.
TL;DR: It is shown that it is possible to regard stochastic and fuzzy logics as being derived from two different constraints on a probability logic: statistical independence (stochastic) and logical implication (fuzzy).
Abstract: It is shown that it is possible to regard stochastic and fuzzy logics as being derived from two different constraints on a probability logic: statistical independence (stochastic) and logical implication (fuzzy). To contrast the merits of the two logics, some published data on a fuzzy-logic controller is reanalysed using stochastic logic and it is shown that no significant difference results in the control policy.
TL;DR: In this paper, the local plane-wave decomposition approach used to analyse optical fibres of arbitrary refractive-index profiles has been extended to include the case of so-called ''leaky´ rays.
Abstract: The local plane-wave decomposition approach used to analyse optical fibres of arbitrary refractive-index profiles has been extended to include the case of so called `leaky´ rays. The result thus obtained for acceptance angle represents a generalisation of results derived previously for simple forms of the profile by geometrical-optics methods.
TL;DR: In this article, a counterexample is presented disproving the conjecture that the planar least squares inverse of a 2-variable polynomial is devoid of zeros when both variables are inside or on the unit circle.
Abstract: A counterexample is presented disproving the conjecture that the planar least-squares inverse of a 2-variable polynomial is devoid of zeros when both variables are inside or on the unit circle.
TL;DR: In this article, the degradation of Au-GaAs Schottky-barriers after annealing is due to the outmigration of gallium into the gold, resulting in the formation of an n+ region beneath the contact.
Abstract: Experimental evidence is presented which suggests that the degradation of Au-GaAs Schottky-barriers after annealing is due to the outmigration of gallium into the gold, resulting in the formation of an n+ region beneath the contact.
TL;DR: In this article, a novel technique for achieving variable phase shift in surface-acoustic-wave devices is demonstrated by depositing a thin film of magnetostrictive material onto the surface of a conventional SAW delay line, the wave velocity can be varied by adjusting an externally applied magnetic field.
Abstract: A novel technique for achieving variable phase shift in surface-acoustic-wave devices is demonstrated. By depositing a thin film of magnetostrictive material onto the surface of a conventional surface-acoustic-wave delay line, the wave velocity can be varied by adjusting an externally applied magnetic field. Experimental results are presented for a nickel film on a lithium-niobate substrate, and several possible applications are mentioned.
TL;DR: In this article, a fast-response bulk photoconductor that can be used as a photodetector and as an optically gated switch was presented, with an estimated detector transition time of 92 ps or less.
Abstract: The letter reports the development of a fast-response bulk photoconductor that can be used as a photodetector and as an optically gated switch. The photoconducting material used is semi-insulating, chromium-doped GaAs, a sample of which is mounted in a 50Ω stripline holder. An estimated detector transition time of 92 ps or less was obtained from tests made with a mode-locked dye laser.
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TL;DR: A method is described and implemented for the derivation of active RC filters from analogue passive filters of the lossless ladder doubly terminated kind using scattering-parameter formulation.
Abstract: A method is described and implemented for the derivation of active RC filters from analogue passive filters of the lossless ladder doubly terminated kind. The method is based on scattering-parameter formulation and the active RC filters thus derived are referred to as wave active filters.
TL;DR: In this article, a procedure is described which, through linear state feedback, both assigns pole locations (eigenvalues) and specifies parts of the closed-loop modal structure, illustrated by synthesising a controller for the lateral dynamics of a high-performance aircraft.
Abstract: A procedure is described which, through linear state feedback, both assigns pole locations (eigenvalues) and specifies parts of the closed-loop modal (eigenvector) structure. The technique is illustrated by synthesising a controller for the lateral dynamics of a high-performance aircraft.
TL;DR: In this paper, a clip-on piezoelectric transducer is described which may be easily attached to a plastics-coated optical fibre and used to phase modulate signals within the glass fibre.
Abstract: A clip-on piezoelectric transducer is described which may be easily attached to a plastics-coated optical fibre and used to phase modulate signals within the glass fibre. The technique is applicable to a 1-way optical telemetry highway.