Showing papers in "Electronics Letters in 1970"
TL;DR: In this paper, the thickness-expander plate, the end-electroded bar, and the side-electrodebased bar are presented for three types of piezoelectric transducers.
Abstract: New equivalent circuits, having several advantages over previous circuits, are presented for three types of piezoelectric transducer: the thickness-expander plate, the end-electroded bar and the side-electroded bar. Each of the circuits involves an electrical network of frequency-dependent components connected to the centre of an acoustic transmission line.
825 citations
TL;DR: In this paper, a method for transforming non-recursive filters with equal-ripple attenuation in the passband, stopband and linear phase into those with minimum phase and half the degree was described.
Abstract: A method is described of transforming nonrecursive filters with equal-ripple attenuation in the passband, stopband and linear phase into those with minimum phase and half the degree, but again with equal-ripple attenuation in the passband and stopband.
151 citations
TL;DR: In this paper, an explicit upper bound on the variation rate of the system xi+1=Aixi is given, assuming that all eigenvalues of all matrices Ai (i=0, 1, 2,...) lie in a disc of radius < 1.
Abstract: If all eigenvalues of all matrices Ai (i=0, 1, 2, ...) lie in a disc of radius <1 and if the matrices Ai, vary sufficiently slowly, then the system xi+1=Aixi is exponentially stable. An explicit upper bound on the variation rate is given.
126 citations
TL;DR: In this paper, Monte Carlo calculations of the velocity/field characteristics for these materials are described and the necessary conditions should obtain in InP and InP-InAs and InSb-GaSb alloys.
Abstract: Electron transfer between three appropriately coupled sets of conduction-band valleys produces transport properties peculiarly favourable for transferred-electron devices. The necessary conditions should obtain in InP and in InP-InAs and InSb-GaSb alloys. Monte Carlo calculations of the velocity/field characteristics for these materials are described.
117 citations
TL;DR: In this paper, the continued fraction expansion technique used by Chen is modified to yield models of transfer functions which give more accurate initial responses, while still giving the correct steady-state responses.
Abstract: The continued-fraction-expansion technique used by Chen is modified to yield models of transfer functions which give more accurate initial responses, while still giving the correct steady-State responses. Also, stable models can sometimes be obtained even when Chen's method yields unstable models. Two examples are given.
103 citations
TL;DR: In this paper, a new class of selective nonrecursive digital filters with independently prescribed equiripple passband and stopband attenuation and linear phase is obtained by numerical solution of a set of nonlinear equations.
Abstract: A new class of selective nonrecursive digital filters with independently prescribed equiripple passband and stopband attenuation and linear phase is obtained by numerical solution of a set of nonlinear equations. Some examples are given, and a comparison is made of the new solutions and those previously known.
95 citations
TL;DR: In this paper, a technique for rigorously correcting for the effects of an arbitrary but known measuring antenna (or "probe") in determination of vectorial far-field antenna pattern and power-gain function from near-field measurements is described.
Abstract: We describe a technique for rigorously correcting for the effects of an arbitrary but known measuring antenna (or ‘probe’) in determination of vectorial far-field antenna pattern and power-gain function from near-field measurements.
79 citations
TL;DR: In this article, the results of a computational method for determining the propagation characteristics of a radially inhomogeneous dielectric cylinder are presented, where a continuous variation in permittivity is represented by means of a staircase function.
Abstract: The results of a computational method for determining the propagation characteristics of a radially inhomogeneous dielectric cylinder are presented. A continuous variation in permittivity is represented by means of a staircase function, and the corresponding propagation problem for a cylindrically stratified dielectric is solved using a digital computer. For refractive-index profiles commonly used in optical waveguides, the propagation coefficient differs negligibly from the asymptotic value when the number of layers is equal to five.
75 citations
TL;DR: A method of generating optimum and near-optimum binary block error-control codes by deleting certain columns from known optimum codes; the columns deleted form an anticode.
Abstract: A method of generating optimum and near-optimum binary block error-control codes is described. The method involves deleting certain columns from known optimum codes; the columns deleted form an anticode. The properties of anti-codes are described, and a Table of optimum anticodes is presented.
56 citations
TL;DR: In this article, a general method for finding optimal values of the constants occurring in the numerical inversion of Laplace transforms is given, and one particular set of constants obtained by this method ensures that the process of inversion is well adapted to transforms which arise frequently in the analysis of dynamical systems and in other applications.
Abstract: A general method is given for finding optimal values of the constants occurring in the numerical inversion of Laplace transforms. It is then shown that one particular set of constants obtained by this method ensures that the process of inversion is well adapted to transforms which arise frequently in the analysis of dynamical systems and in other applications.
52 citations
TL;DR: In this paper, several conditions must be satisfied by a linear time-invariant continuous-time system if it is to remain controllable in the presence of feedback involving the integrals of state variables.
Abstract: Several conditions are derived which must be satisfied by a linear time-invariant continuous-time system if it is to remain controllable in the presence of feedback involving the integrals of state variables.
TL;DR: The results extend recent work by Porter and Power on establishing necessary conditions for controllability of linear multivariable time-invariant systems incorporating feedback of the integrals of some or all of the state variables.
Abstract: Necessary and sufficient conditions are derived for controllability of linear multivariable time-invariant systems incorporating feedback of the integrals of some or all of the state variables. The results extend recent work by Porter and Power on establishing necessary conditions for controllability of such systems.
TL;DR: In this article, the authors predicted the attenuation characteristics of the dominant hybrid mode in a corrugated circular waveguide with and without corrugations, and they showed that over a substantial frequency band, which includes the optimum frequency for antenna-feed applications, attenuation is lower than that of a circular wave-guide with corrugation.
Abstract: The attenuation characteristics are predicted for the dominant hybrid mode in corrugated circular waveguide. Over a substantial frequency band, which includes the optimum frequency for antenna-feed applications, the attenuation is lower than that of the dominant mode in a circular wave-guide without corrugations.
IBM1
TL;DR: In this paper, it was shown that gallium arsenide is a well suited material for high-frequency field effect transistors and that the frequency limit for power amplification is considerably higher than for other known transistors.
Abstract: The letter shows that gallium arsenide is a well suited material for high-frequency field-effect transistors. From preliminary measurements on realised transistors, it is shown that the frequency limit for power amplification is considerably higher than for other known transistors. The processes involved are briefly described.
TL;DR: In this paper, the authors show that spatial fluctuations of the oxide built-in charge are effectively responsible for surface potential fluctuations, which result in an apparent density of interface states increasing with the mean image charge.
Abstract: The authors report experimental results in support of probabilistic theory to show that spatial fluctuations of the oxide built-in charge are effectively responsible for surface potential fluctuations, which result in an apparent density of interface states increasing with the mean image charge.
TL;DR: The anomalous behavior of chalcogenide-glass switches, in the thin-film limit, is incorporated into the electrothermal switching model by taking account of both temperature and field dependences of the electrical conductivity as mentioned in this paper.
Abstract: The anomalous behaviour of chalcogenide-glass switches, in the thin-film limit, is incorporated into the electrothermal switching model by taking account of both temperature and field dependences of the electrical conductivity. Calculations of the critical field as a function of temperature and thickness are compared with experimental observations.
TL;DR: An algorithm for designing a precompensating dynamic system is proposed which results in a new system that can be decoupled by state-variable feedback.
Abstract: For a class of linear time-invariant multivariable systems which cannot be decoupled by state-variable feedback, but which are invertible, an algorithm for designing a precompensating dynamic system is proposed which results in a new system that can be decoupled by state-variable feedback.
TL;DR: Finite-range effects are incorporated into Schelkunoff's pyramidal horn gain formula, which is arranged as the product of in-phase aperture gain and E and H plane range and slant-length gain reduction factors.
Abstract: Finite-range effects are incorporated into Schelkunoff's pyramidal-horn gain formula, which is arranged as the product of in-phase aperture gain and E and H plane range and slant-length gain-reduction factors. These factors, readily computed, permit the on-axis gain of a horn to be obtained from two single-line curves.
TL;DR: In this paper, a general model for the transient behaviour of m.i.s. memory transistors is presented and applied to a practical memory transistor which has an insulator layer consisting of 500-1000 A silicon nitride on 15-25 A silicon dioxide.
Abstract: A general model for the transient behaviour of m.i.s. memory transistors is presented. The model is applied to a practical memory transistor which has an insulator layer consisting of 500–1000 A silicon nitride on 15–25 A silicon dioxide. The properties of this device are calculated and are shown to agree with experimental data.
TL;DR: A multivariable feedback controller may be synthetised by first designing a set of single-loop controllers for these characteristic systems, and then transforming the results to obtain the required multivariably controller.
Abstract: If a linear time-invariant multiple-input multiple-output plant is represented by a square transfer-function matrix G(s), a spectral analysis may be carried out to determine a set of system characteristic transfer functions. A multivariable feedback controller may then be synthetised by first designing a set of single-loop controllers for these characteristic systems, and then transforming the results to obtain the required multivariable controller.
TL;DR: In this article, the design of an integrated thin-film inductor suitable for use at 10 MHz is described, and some operational characteristics are given; the inductor has the shape of a square spiral and is surrounded by permalloy thin films according to a certain pattern.
Abstract: The design of an integrated thin-film inductor suitable for use at 10 MHz is described, and some operational characteristics are given. The inductor has the shape of a square spiral and is surrounded by permalloy thin films according to a certain pattern. This pattern allows these films to be driven in the hard direction and thus utilises the hard-direction permeability which is quite large (?2700).
TL;DR: In this article, a liquid crystal light valve has been built in which a relatively weak signal image controls the flow of light to a much brighter projected image, and the brightness of the projection light is limited only by heating in the light valve, and so great optical gain is possible.
Abstract: Liquid-crystal light valves have been built in which a relatively weak-signal image controls the flow of light to a much brighter projected image. The brightness of the projection light is limited only by heating in the light valve, and so great optical gain is possible. Brightness gains of 10–20 have been achieved with 30μW/cm2 of signal light at an efficiency of 15%. Resolutions of 5 line pairs per mm on the light valve and contrast ratios of 10:1 have been obtained, with a response time of about 0.1 s. With improvements, resolutions of 10–20 line pairs per mm relatively fast response and sensitivity to signal-light levels of nW/cm2 may be expected.
TL;DR: In this article, a simpler solution for spherical hybrid modes in corrugated conical horns has been shown to have a deviation from the rigorous solution of less than 0.7 dB for the case considered by Clarricoats.
Abstract: A simpler solution for spherical hybrid modes in corrugated conical horns has been shown to have a deviation from the rigorous solution of less than 0.7 dB for the case considered by Clarricoats. Expressions for the radiation pattern and gain of such a horn with small flare angle have been obtained under balanced hybrid conditions.
TL;DR: In this article, experimental results on determination of antenna pattern and power gain from near-field measurements are described, and two new antenna measurement theorems are applied; the results were made on an electrically large horn lens, a standard gain horn and a nominal duplicate of the measuring antenna.
Abstract: Recent experimental results on determination of antenna pattern and power gain from near-field measurements are described. Two new antenna measurement theorems were applied. Measurements were made on an electrically large horn lens, a standard-gain horn and a nominal duplicate of the measuring antenna. Some comparisons with direct far-field measurement results were made.
TL;DR: An iterative array for nonrestoring division uses a logic cell which has been proposed for an array for binary square-root extraction and is fully iterative in terms of cell logic and in the interconnection pattern between the cells.
Abstract: An iterative array for nonrestoring division is described. It uses a logic cell which has been proposed for an array for binary square-root extraction. The array for binary division is fully iterative in terms of cell logic and in the interconnection pattern between the cells.
TL;DR: In this paper, a solid-state travelling-wave amplifier was fabricated in 1 µm n type epitaxial GaAs on a semi-insulating substrate, with a net gain around 5, 7.5, 9 and 11.5 GHz.
Abstract: A solid-state travelling-wave amplifier has been fabricated in 1 µm n type epitaxial GaAs on a semi-insulating substrate. It shows a net gain around 5, 7.5, 9 and 11.5 GHz, with a maximum value of 13 dB at 11.5 GHz. Other features include c.w. operation, 20-30 dB isolation, and voltage-controlled phase shifting with constant gain.
TL;DR: Two new aspects of the well known star-mesh transformation are studied: the necessary and sufficient conditions for the transformation of a given general mesh network into an equivalent star network and an extension to networks containing sources.
Abstract: Two new aspects of the well known star-mesh transformation are studied: (a) the necessary and sufficient conditions for the transformation of a given general mesh network into an equivalent star network; (b) an extension to networks containing sources.
TL;DR: In this paper, a thermally stimulated charge release has been used in the m.o.s. capacitor to study electron and hole states in the metaloxide-silicon system.
Abstract: The experiment of thermally stimulated charge release has been used in the m.o.s. capacitor to study electron and hole states in the metal-oxide-silicon system. Broadly similar results have been obtained for ‘wet’ and ‘dry’ oxides on ‘mechanically’ and ‘chemically’ polished silicon surfaces. A representative spectrum is presented showing electron and hole interface states spread over most of the energy band gap.
TL;DR: In this article, the time delay of magnetostatic surface waves is studied experimentally and theoretically, and the effect of chemical polishing on the attenuation of the waves investigated.
Abstract: The time delay of magnetostatic surface waves is studied experimentally and theoretically, and the effect of chemical polishing on the attenuation of the waves investigated.