# Electronics Letters

## Filter Results

Displaying Results 1 - 25 of 35
• ### AgSn cathode contact in gallium-arsenide transferred-electron devices

Publication Year: 1973, Page(s):189 - 190
Cited by:  Papers (4)
| |PDF (302 KB)

Simple observations of the temperature dependence of the threshold current of AgSn-contacted gallium-arsenide transferred-electron devices are interpreted in terms of Schottky-barrier cathodes. From the measurements, the barrier heights are deduced and a mechanism is suggested for their formation. The consequences of the presence of the barrier on the operation of oscillators and amplifiers are di... View full abstract»

• ### Digital-phase-shifter performance

Publication Year: 1973, Page(s):190 - 191
| |PDF (353 KB)

The performance of a new type of digital phase shifter is compared with that of analogue systems of comparable complexity. The digital method results in greater stability and precision and is particularly applicable to digitally controlled systems that require a large number of phase-shifted signals. View full abstract»

• ### Measurement of external Q factor of microwave oscillators using frequency pulling or frequency locking

Publication Year: 1973, Page(s):191 - 193
Cited by:  Papers (3)
| |PDF (436 KB)

Conditions are identified for the measurement of the external Q factor of microwave oscillators by use of frequency pulling or locking techniques. A small modification to a technique proposed previously for frequency locking is derived, and is extended to the case of frequency pulling. It is shown that measurements of the full locking or pulling bandwidths give information on the first derivatives... View full abstract»

• ### Monolithically integrated Bragg deflector for an optical guided wave made of zinc-oxide film

Publication Year: 1973, Page(s):193 - 194
Cited by:  Papers (7)
| |PDF (326 KB)

A new film Bragg deflector has been fabricated on a non-piezoelectric substrate. The deflector is made of ZnO film, so that both an optical waveguide and acoustic-surface-wave transducers are monolithically integrated. High diffraction efficiencies (more than 90%) are obtained with this device. View full abstract»

• ### Piecewise-linear-signal representation

Publication Year: 1973, Page(s):194 - 195
| |PDF (344 KB)

A new method for representing a signal is provided. An exact representation of a piecewise linear approximation of the signal with a finite number of basis functions is presented. View full abstract»

• ### Surface-acoustic-wave oscillators: mode selection and frequency modulation

Publication Year: 1973, Page(s):195 - 197
Cited by:  Papers (21)
| |PDF (456 KB)

The letter discusses various aspects of the design and performance of surface-acoustic-wave oscillators, including two proved solutions to the mode-selection problem and a demonstration of the wide frequency-modulation capability. View full abstract»

• ### Rain-attenuation measurements of millimetre waves over short paths

Publication Year: 1973, Page(s):198 - 199
Cited by:  Papers (1)
| |PDF (245 KB)

Results of rain-attenuation measurements at millimetre waves are presented that have been obtained with a shuttle-pulse technique. This technique requires a path length through rain of only a few metres, so that the rainfall rate and drop-size distribution can be considered to be uniform along this path. View full abstract»

• ### Active surface-wave directional coupler

Publication Year: 1973, Page(s):199 - 201
Cited by:  Papers (1)
| |PDF (488 KB)

We report experimental results which show that noncollinear surface-wave mixing on [111]-cut bismuthÂ¿germanium oxide can be used to realise an active, switchable directional coupler. For low-level inputs, the coupling is enhanced by as much as 20 dB by a semiconductor placed over the interaction region. The directivity is found to be greater than 40 dB. View full abstract»

• ### Bias-dependent phase delay of Schottky contact microstrip line

Publication Year: 1973, Page(s):201 - 203
Cited by:  Papers (21)
| |PDF (339 KB)

Schottky contact lines are a form of microstrip on a semiconducting substrate, the strip of which forms a rectifying metalÂ¿semiconductor contact. Such a line has an extremely low phase velocity that is determined by the ratio of the depletion-region width to the substrate thickness, i.e. by the bias. Measurements agree well with theoretical expressions that are deduced from a parallel-plate-waveg... View full abstract»

• ### Numerical computation of the input impedance of a finite helix

Publication Year: 1973, Page(s):203 - 205
Cited by:  Papers (1)
| |PDF (330 KB)

A numerical method is given for the determination of the input impedance of a thin-wire helix. The problem is approximated by a frequency-dependent matrix equation whose solution is an approximation to the current distribution and is used in a variational expression for the impedance. Experimental and theoretical results for the determination of the resonant frequency are included. View full abstract»

• ### Direct microwave imaging with enhanced resolution

Publication Year: 1973, Page(s):205 - 206
Cited by:  Papers (1)
| |PDF (261 KB)

A means of direct imaging with a microwave lens is described in which the object is scanned by the focused source/receiver unit. Enhanced resolution of the object is demonstrated by the closely spaced image-intensity contours obtained. View full abstract»

• ### Application of Howitt transformations to 2-element-kind networks

Publication Year: 1973, Page(s):206 - 208
Cited by:  Papers (1)
| |PDF (342 KB)

A relationship is obtained for the nonsingular T transformation that exists between two minimal realisations of the state equations and the Howitt transformation between the corresponding 2-element-kind networks. It is proved that the Howitt transformation can generate all the passive minimal RC or RL equivalent networks that can be generated by the nonsingular T transformation. View full abstract»

• ### Estimation of discrete-time systems using pseudorandom sequences

Publication Year: 1973, Page(s):208 - 209
Cited by:  Papers (1)
| |PDF (263 KB)

The pseudorandom binary sequence is applied to the parameter estimation of discrete-time systems. The proposed method, based on correlation analysis and system theory, requires a smaller number of correlators than the other methods. The estimates of the parameters are shown to be asymptotically unbiased. View full abstract»

• ### Estimation of weighting-sequence matrices by correlation method

Publication Year: 1973, Page(s):209 - 210
| |PDF (214 KB)

The pseudorandom binary sequence transformed by the Hadamard matrix is applied to the estimation of weighting-sequence matrices of multi-input and multioutput discrete-time systems. The method is based on the correlation analysis and matrix algebra. The weighting-sequence matrix is obtained directly from the measured-correlation matrix. View full abstract»

• ### Characteristics of ion-implanted hybrid voltage-variable capacitors

Publication Year: 1973, Page(s):210 - 212
| |PDF (365 KB)

Hybrid voltage-variable capacitors were fabricated with hyperabrupt ion-implanted doping profiles. The capacitance uniformity was within 2% over the operating voltage range. Losses in the low-bias-voltage range were reduced by a factor of 3 by a 475Â°C anneal in N2Â¿H2. A small bias-temperature instability was observed. View full abstract»

• ### Comment on Active RC realisation of a 3rd-order lowpass Butterworth characteristic

Publication Year: 1973
| |PDF (185 KB)

First Page of the Article
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• ### Generalised autocorrelation theorem

Publication Year: 1973, Page(s):212 - 214
| |PDF (388 KB)

It is shown that the modified generalised discrete transform of the autocorrelation of a sequence yields the shift-invariant spectral modes within some scale factors. This is a fundamental result, as it is a logical extension of the well known autocorrelation theorem for the discrete Fourier transform. View full abstract»

• ### Comment on New definition of multiple-root sensitivity

Publication Year: 1973
| |PDF (144 KB)

First Page of the Article
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• ### New method for the testing of capacitors for internal ionisation discharges

Publication Year: 1973, Page(s):215 - 216
| |PDF (256 KB)

The letter concerns the development of a method for testing dielectric capacitors for the presence of internal discharges that can lead to breakdown of the insulation and failure of the capacitor. This method is suitable for rapid, production-line testing of capacitors; minor modification only would be necessary for it to be applied to other insulation media, e.g. in power cables. View full abstract»

• ### Method for measuring the anisotropy of precipitation media

Publication Year: 1973, Page(s):216 - 218
Cited by:  Papers (2)
| |PDF (339 KB)

A system for measuring both the differential phase shift and differential attenuation through precipitation over a 1-way transmission link is discussed. An example of observations of a summer shower is given. A general formula for cross-polarisation is derived. View full abstract»

• ### Coaxially fed hollow cylindrical monopole in a rectangular waveguide

Publication Year: 1973, Page(s):218 - 220
Cited by:  Papers (17)
| |PDF (407 KB)

A formally exact solution that can easily be put in a form suitable for accurate numerical calculation is presented for a hollow coaxially fed cylindrical monopole in a rectangular waveguide. The solution utilises a well known Fourier-transform technique in conjunction with a ChebyÂ¿shev polynomial representation for the unknown function. The result is an almost diagonalised infinite matrixÂ¿a for... View full abstract»

• ### Equivalence of the Box--Jenkins--Astrom control law to the Kalman linear regulator

Publication Year: 1973, Page(s):220 - 221
| |PDF (257 KB)

The letter demonstrates the equivalence of the BJA control law to the Kalman linear regulator for a class of single-input single-output stochastic LQP control problems. The result is obtained by comparing explicitly the two control laws derived for the same problem. View full abstract»

• ### Time-domain reflectometry from Smith-chart plotting

Publication Year: 1973, Page(s):221 - 222
Cited by:  Papers (1)
| |PDF (238 KB)

Attention is drawn to the fact that time-domain reflectometry may be carried out without any special apparatus by measuring the input impedances of a transmission-line system at a number of frequencies, using a slotted line for instance. When these impedances are referred to different planes along the line, and the corresponding plots on the Smith charts are produced, the centroids of these plots ... View full abstract»

• ### Fast high-input-impedance unity-gain buffer stage

Publication Year: 1973, Page(s):223 - 224
| |PDF (318 KB)

The interconnection of a monolithic matched-f.e.t. pair and a high-frequency bipolar-transistor array permits the design of a fast high-input-impedance unity-gain buffer stage that does not employ passive components. Typical performance data are: input direct bias current <50 pA, output impedance <50 Â¿, power consumption <60 mW. View full abstract»

• ### State-space approach to the multiplication error in a digital filter

Publication Year: 1973, Page(s):224 - 226
| |PDF (291 KB)

The state-space method has been used to evaluate the statistical error due to the finite-precision arithmetic in a digital filter. The actual error of a 2nd-order filter obtained from computer simulation has also been plotted against the expected error View full abstract»

## Aims & Scope

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.

Full Aims & Scope

## Meet Our Editors

Editors-in-Chief

Professor Chris Toumazou
Director of the Biomedical Institute
Imperial College, London, UK

Professor Ian White