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Electronics Letters

Issue 6 • Date June 1967

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Displaying Results 1 - 25 of 49
  • Maximum and resonant gains in parametric amplifiers

    Publication Year: 1967
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (102 KB)  

    It has generally been assumed that, in three-frequency negative-resistance parametric amplifiers incorporating resonant circuits, maximum gain is obtained when the signal and idler circuits are resonant. It is shown that this assumption is not, in general, justified. View full abstract»

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  • Distortion of speech by quantising

    Publication Year: 1967 , Page(s): 230 - 231
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (254 KB)  

    The proper function of a communication system is to produce, at its output, any one of a number of acceptable alternatives for the exact form of the input message. Certain changes during transmission can therefore be accepted. This principle has been applied to the transmission of speech by a quantised system. View full abstract»

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  • Variationally computed antenna impedances and accuracy of resulting current distributions

    Publication Year: 1967 , Page(s): 231 - 233
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (466 KB)  

    The Criterion proposed by Galejs for establishing the accuracy of a given approximate distribution of Current in an antenna is shown to be unreliable. Conclusions based on an erroneous comparison of numerical and experimental results are corrected. View full abstract»

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  • Transistor transit-time oscillator

    Publication Year: 1967 , Page(s): 234 - 235
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (281 KB)  

    The letter describes the current/voltage characteristics of a transistor structure when controlled by space-charge and transit-time effects. It is shown that large negative conductances can be obtained at high frequencies. Operation is not limited by transit-time effects, and efficient high-power working at centimetre and millimetre wavelengths should be possible. View full abstract»

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  • Reciprocity in silicon Schottky-barrier diodes

    Publication Year: 1967 , Page(s): 236 - 237
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (197 KB)  

    Reciprocity has been examined at X band for low-noise silicon Schottky-barrier diodes by measuring the forward (r.f. to i.f.) and reverse (i.f. to r.f.) conversion losses by the heterodyne method. Reciprocity held for the silicon Schottky-barrier diodes, proving that their low conversion-loss behaviour is due to the nonlinear barrier resistance and not to parametric amplification caused by a nonlinear barrier capacitance. For comparison, silicon epitaxial point-contact and germanium point-contact diodes were also examined. View full abstract»

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  • Binary uniform codes

    Publication Year: 1967
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (150 KB)  

    An algorithm to construct all linear binary uniform codes is given. The algorithm makes use of block codes due to Macdonald. View full abstract»

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  • Spectral density of random signals corrupted by multiplicative noise

    Publication Year: 1967
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (143 KB)  

    A simple method of evaluating the spectral density of stationary random signals corrupted by multiplicative noise is presented. It is assumed that the multiplicative noise is also stationary, and that it is statistically independent of the signal. View full abstract»

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  • Spectral factorisation by means of augmented factors

    Publication Year: 1967 , Page(s): 238 - 239
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (211 KB)  

    A method of factorising rational spectral matrixes by means of a series of linear transformations, and by augmenting it with matrix factors, is presented. An example illustrating the method is included. View full abstract»

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  • Properties of state matrixes representing time-invariant lossless nports

    Publication Year: 1967 , Page(s): 239 - 240
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (167 KB)  

    The class of all finite, time-invariant, linear, passive, lossless networks which have state-equation representations are considered. The necessary and sufficient conditions for the state-equation matrixes to represent such networks are derived, and the consequences of reciprocity and non-reciprocity are brought out. View full abstract»

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  • Sensitivity properties of linear systems

    Publication Year: 1967 , Page(s): 241 - 242
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (213 KB)  

    The sensitivity of the properties of linear dynamic systems produced by matrix-element change is considered using Sylvester's expansion theorem. The methods illustrate the basic role of the constituent matrixes associated with the theory of linear systems. The inverse-eigenvalue-sensitivity problem relevant to control-system design is also illustrated. View full abstract»

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  • Sufficient condition of the asymptotic stability of nonlinear sampling systems

    Publication Year: 1967
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (110 KB)  

    The study of quadratic Lyapunov functions leads to a sufficient condition for the asymptotic stability of nonlinear sampling systems. View full abstract»

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  • Charged-particle production in the electrogasdynamic generator

    Publication Year: 1967 , Page(s): 242 - 243
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    Experiments have been performed on an electrogasdynamic generator utilising charged water droplets produced by using an atomiser in an electric-field region. This method of charged-particle production may offer certain advantages over corona systems. The mechanism of induction charging is well understood6 and Operates with a particularly simple electrode geometry. Problems of electrode errosion do not arise. View full abstract»

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  • Phase relation between offices in a mutually synchronised system

    Publication Year: 1967 , Page(s): 243 - 244
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (209 KB)  

    Although a common system frequency is established in mutually synchronised system, some phase difference exists between offices. Analyses of the phase difference and the system-frequency jump due to the change in transmission delay are given, assuming the sawtooth characteristics for the phase comparators. View full abstract»

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  • Wave propagation in a moving plasma

    Publication Year: 1967 , Page(s): 244 - 246
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (337 KB)  

    This letter comments on previous work by Scarf on wave propagation in a moving plasma and also adds new results. View full abstract»

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  • Dependence of the propagation loss in laser ranging systems on the meteorological visibility and target/receiver range

    Publication Year: 1967 , Page(s): 246 - 247
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (243 KB)  

    The relationship between meteorological visual range and the propagation loss in laser beams has been studied at wavelengths of 0.6943 ¿m and 1.065 ¿m. For visual ranges of 1¿10 km, the laser propagation loss is found to be compatible with that predicted by existing equations relating extinction coefficient to visual range and wavelength. The inverse-square law relating received signal strength to target/receiver range is confirmed. View full abstract»

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  • High-frequency current oscillations in vapour-deposited CdS thin films

    Publication Year: 1967 , Page(s): 247 - 248
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (253 KB)  

    High-frequency small-amplitude current modulation has been observed in a vapour-deposited CdS thin film subjected to high electric stress in the ruby substrate plane. The possibility that this modulation may be attributed to travelling-charge domains formed by acoustoelectric interaction in the acoustic waveguide system is discussed. View full abstract»

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  • 200 MHz counter/shift-register stage

    Publication Year: 1967 , Page(s): 248 - 250
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (631 KB)  

    The letter describes the principles of operation and practical design of a 200 MHz counter/shift register with only 50mW power consumption. The performance is achieved by using stacked long-tailed pairs to realise a double-rank or master¿slave logic function. It is shown that this circuit arrangement is such as to fully exploit present integrated-circuit-fabrication techniques. View full abstract»

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  • Tolerance of nonlinearities in time-varying optimal systems

    Publication Year: 1967 , Page(s): 250 - 251
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (429 KB)  

    Nominally linear optimal-control regulating systems are examined with a view to assessing the amount of nonlinearity which can be tolerated in the input transducer. Using a suitable Lyapunov function, it is found that a large degree of nonlinearity will not disturb the stability of the system. View full abstract»

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  • Radiation from surface-wave antennas

    Publication Year: 1967 , Page(s): 251 - 252
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (259 KB)  

    A recent paper by James on radiation from a dielectric antenna seems to contain some erroneous statements concerning the application of radiation formulas. These erroneous statements are pointed out and related to other theories of surface-wave antennas. View full abstract»

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  • Wide bandwidth Butler matrix network

    Publication Year: 1967 , Page(s): 252 - 253
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Butler matrix networks, used for forming multiple beams from linear aerial arrays, are limited in their bandwidth of operation by their requirement for components with constant values of phase shift over this bandwidth. This letter describes a method for designing such networks for wide-bandwidth operation by employing particular combinations of directional couplers and hybrid tees, thus eliminating the need for separate phase shifts. Results are given for a 4×4port matrix operating over an octave range of frequency. View full abstract»

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  • Longitudinal resonances of plasma surface waves in noble gases

    Publication Year: 1967 , Page(s): 253 - 255
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (342 KB)  

    The excitation and propagation of axially symmetric surface plasma waves along a plasma column are investigated at frequencies from 100 to 200MHz. There are experimentally obtained dispersion curves for such waves in gas-discharge plasmas of He, Ne and Kr at pressures of 0.03¿0.20torr. The results are in good agreement with the theory of surface waves in quasistatic approximation. View full abstract»

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  • Elliptic digital filters

    Publication Year: 1967 , Page(s): 255 - 256
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (197 KB)  

    A synthesis procedure is given for elliptic digital filters of order 2q, q=1, 2, 3¿. The pulse transfer function is obtained in the form of biquadratic products in z¿1. An example illustrates how this method is used to synthetise an elliptic digital filter. View full abstract»

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  • Harmonic stabilisation of a.c. servos

    Publication Year: 1967 , Page(s): 256 - 257
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (259 KB)  

    A simple method of stabilising an a.c. servo has been demonstrated in a recent laboratory experiment. View full abstract»

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  • Theoretical analysis of the monolithic-crystal filter

    Publication Year: 1967 , Page(s): 257 - 258
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (319 KB)  

    Two or more resonant regions in a piezoelectric material may be coupled mechanically by regions operating as mechanical waveguides below cutoff. A method of analysis based on the piezoelectric and mechanical equations is described and illustrated with a typical attenuation/frequency characteristic and equivalent electrical circuit of a 3-resonator filter. View full abstract»

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  • Behaviour of n-type gallium arsenide in strong microwave fields

    Publication Year: 1967 , Page(s): 258 - 259
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (226 KB)  

    Results are presented concerning the change of attenuation and generation of harmonics in n-type gallium arsenide, subjected to a strong microwave electric field. 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