By Topic

# Electronics Letters

## Filter Results

Displaying Results 1 - 25 of 32
• ### Use of current controlled GaAs l.p.e. for optimum doping profiles in l.s.a. diodes

Publication Year: 1978, Page(s):77 - 78
Cited by:  Papers (1)
| | PDF (361 KB)

Microwave device quality GaAs, grown by the electric current-controlled liquid-phase epitaxy method, is reported. Ratios of peak current to valley current near the theoretical limit for the corresponding layer doping and thickness are reported, along with high breakdown voltages in unloaded l.s.a. oscillators. View full abstract»

• ### The influence of a fibre structure on optical loss in a graded-index fibre

Publication Year: 1978, Page(s):78 - 80
Cited by:  Papers (1)
| | PDF (402 KB)

For designing a fibre structure, the influence of structural parameters on optical loss is investigated experimentally for a graded-index fibre. The fibre with large cladding/outer-layer index difference and small cladding thickness is found to have large excess loss near excitation points, such as a launching point and a splicing point. View full abstract»

• ### Low temperature electroplated Au-SnNi-Au ohmic contacts on n type GaAs

Publication Year: 1978, Page(s):80 - 81
Cited by:  Papers (1)
| | PDF (300 KB)

A method is described for fabricating ohmic contacts on n type GaAs by alloying electroplated layers of Au-SnNi-Au at 300Â°C, resulting in a contact resistance of approximately 3 x 10-5 Ω cm2. In applications for which this resistance is adequate, the technique has the advantage of requiring low-temperature alloying for short times. View full abstract»

• ### Quasi-optical channel diplexer using Fabry-Perot resonator

Publication Year: 1978, Page(s):81 - 82
Cited by:  Papers (1)
| | PDF (272 KB)

A new type of quasi-optical diplexer is presented. It consists of one polarisation splitter, two quarter-wave plates, and two plane-parallel Fabry-Perot resonators working under normal incidence. Measured dropped- and through-channel losses at 100 GHz frequency range were about 1 dB and 0.5 dB respectively. View full abstract»

• ### Binary baseband polar signals in combination with continuous and impulsive noise with i.s.i.

Publication Year: 1978, Page(s):82 - 83
| | PDF (220 KB)

This letter presents the performance of a binary baseband polar system in the presence of a mixture of continuous and impulsive noise and intersymbol interference (i.s.i.). The results obtained are very general and the system performance in special cases like purely continuous noise or purely impulsive noise with or without i.s.i. can be easily derived from the general results. View full abstract»

• ### Demonstration of a c.c.d. image processor for two-dimensional edge detection

Publication Year: 1978, Page(s):83 - 85
| | PDF (676 KB)

An analog technique for image processing that provides 2-dimensional edge detection is described. The algorithm implemented is the Sobel operator using a 3 Ã 3 array of picture elements. The implementation is unique in that a fully integrated circuit approach is employed which has the potential of being integrated directly into either an optical or infrared sensor. The n channel charge-coupled de... View full abstract»

• ### Pulsed laser annealing of zinc implanted GaAs

Publication Year: 1978, Page(s):85 - 87
| | PDF (568 KB)

Samples of n type GaAs implanted with 1015Zn+/cm2 at room temperature were irradiated with a ruby laser of pulse length 0.8 ms. For samples coated with Si3N4 a laser energy of 1.5Â¿2.5 J/cm2 produced electrical activity of 40Â¿50% of the implanted dose. Peak hole concentrations up to about 7 Ã 1019 cmÂ¿3 were measured. Uncoated samples irradiated with similar laser energies were not electrically ... View full abstract»

• ### A new d.h. laser configuration with passive transverse field confinement

Publication Year: 1978, Page(s):87 - 88
| | PDF (295 KB)

A new geometry is proposed which significantly improves the characteristics of single mode d.h. stripe geometry lasers, with regard to astigmatism of the near field, transverse field confinement, modal gain and threshold current. The advantages over other devices are discussed. Numerical results are presented for 5 and 10 Â¿m stripe lasers. View full abstract»

• ### Improved chemical vapour deposition method for long-length optical fibre

Publication Year: 1978, Page(s):89 - 90
Cited by:  Papers (6)
| | PDF (251 KB)

The deformation of the supporting tube during the c.v.d. process for optical fibre fabrication is completely suppressed by controlling the internal pressure of the tube. A 14 km length single-mode fibre with attenuation loss of about 3.2 dB/km at 0.85 Â¿m was fabricated by this improved method. View full abstract»

• ### Effect of wall thickness on radiation from circular waveguides

Publication Year: 1978, Page(s):90 - 91
Cited by:  Papers (10)
| | PDF (235 KB)

An experimental study shows that the thickness of a circular waveguide wall greatly affects its radiation characteristics. The exact solution of Weinstein for infinitely thin walls appears in practice to be valid only when the wall thickness is less than 0.01 Â¿. View full abstract»

• ### 20ps/Gate Gunn-effect high-speed carry finding device

Publication Year: 1978, Page(s):91 - 92
Cited by:  Papers (2)
| | PDF (353 KB)

Improvement was made on our recently reported Gunn-effect high-speed carry finding device, which can now perform logic operations with a minimum delay time of 20 ps/gate. The improvement is concerned with the means of nullifying the effect of the nonuniformity of the constituent m.e.s.f.e.t.s. View full abstract»

• ### A minterm interchange operation in the Walsh spectrum domain

Publication Year: 1978, Page(s):92 - 94
| | PDF (390 KB)

A mathematical operation is investigated in the Walsh spectrum domain which corresponds to the interchange of any minterms of a Boolean function. View full abstract»

• ### Effect of rain in the near field of an antenna

Publication Year: 1978, Page(s):94 - 96
| | PDF (400 KB)

The effect of rain on the field at a point irradiated by a microwave antenna is found, in contrast with previous work, to be effectively independent of the parameters of the antenna. The standard Fresnel zone criterion for the active rain volumeÂ¿ has been extended to treat rain in the near field of the antenna. View full abstract»

• ### Application of super-resolution techniques to time domain reflectometry systems

Publication Year: 1978, Page(s):97 - 98
Cited by:  Papers (1)
| | PDF (276 KB)

By application of the principles of super timing (i.e. sharpening of the time resolution for a given bandwidth) it is shown that the resolution of a t.d.r. system can be improved beyond the classical limit imposed by the rise time of the step generator. The discussion is supported by experimental results. View full abstract»

• ### Prediction of dual-shaped-reflector antenna crosspolarisation

Publication Year: 1978
| | PDF (402 KB)

An efficient computer program for the analysis of dual-shaped-reflector antennas is described. This is used to predict the crosspolarisation of a typical earth station antenna. Employing a feed with intrinsic crosspolarisation, it is shown that the crosspolar performance of the antenna may be reflector depolarisation limited. The effect of subreflector beam steering on the crosspolar response is a... View full abstract»

• ### Investigation into the survival of epitaxial bipolar transistors in current mode second breakdown

Publication Year: 1978, Page(s):100 - 101
Cited by:  Papers (2)
| | PDF (282 KB)

Measurements have been obtained of the time for which epitaxial transistors are able to survive when pulsed into the current mode second breakdown condition. The results have been analysed to provide information on the nature of the constricted current distribution. The work indicates the effects that emitter geometry has on the extent of the current constriction. View full abstract»

• ### Groove guide propagation characteristics at 3mm wavelength

Publication Year: 1978, Page(s):101 - 102
Cited by:  Papers (2)
| | PDF (287 KB)

Measurements of moding characteristics and attenuation on groove guide with appropriate dimensions for 3 mm wavelength operation show that it can be made with convenient dimensions, can operate with only the single dominant mode, and have a loss less than 1 dB/m. View full abstract»

• ### Switching conduction in ion-irradiated layers in GaAs

Publication Year: 1978, Page(s):102 - 103
| | PDF (271 KB)

Experiments have been performed to investigate whether switching phenomena are observable in ion-irradiated GaAs. It is found that the V/I characteristics of H2+-and N+-irradiated layers show both negative resistance and switching from a high resistance to a low resistance state. Ion irradiation may thus be a useful method of fabricating switching devices. View full abstract»

• ### Discrete radiation from curved single-mode fibres: a comparison of theories

Publication Year: 1978, Page(s):103 - 104
| | PDF (288 KB)

An apparent discrepancy between coupled-mode and whispering-galleryÂ¿ theories for the radiation of discrete beams from curved single-mode fibres is resolved. It is shown that the two formally different approaches are in very good agreement with each other in predicting the periodicity of the radiation. View full abstract»

• ### Optimum decoding of M-ary polarisation modulated laser signal

Publication Year: 1978, Page(s):104 - 105
| | PDF (293 KB)

A decision rule has been derived for optimum decoding of an M-ary polarisation modulated signal in a laser communication system. View full abstract»

• ### Relative phase measurements at 30 GHz between copolar and induced crosspolar signals produced by ice particles on a satellite-to-ground link

Publication Year: 1978, Page(s):105 - 107
Cited by:  Papers (4)
| | PDF (365 KB)

Observations of relative phase variations between the copolar and crosspolar signals, produced by ice particles, on a 30 GHz satellite-to-ground link are presented. A mechanism, involving differential phase shift between orthogonal components of a linearly polarised wave, is discussed. View full abstract»

• ### Computer display of vowel quadrilateral with real-time representation of articulation

Publication Year: 1978, Page(s):107 - 109
Cited by:  Papers (1)
| | PDF (451 KB)

The classical characterisation of vowel sounds used by phoneticians is the vowel quadrilateral, which originally was assumed to be the locus of the tongue body between its four extreme vowel positions. A method of real-time computer analysis and display which represents the vowel quadrilateral is described. This has application in computer-based speech training aids, but may have wider use in spee... View full abstract»

• ### Adaptive instantaneous pitch detector with microcomputer error correction

Publication Year: 1978, Page(s):109 - 110
| | PDF (296 KB)

A microcomputer is interfaced with an analogue circuit to detect the pitch of voiced speech over a 50 to 500 Hz range in real time. View full abstract»

• ### Crossovers in microstrip

Publication Year: 1978, Page(s):110 - 111
| | PDF (311 KB)

The fabrication and characterisation of a crossover structure in microstrip is described. The results indicate the means to achieve either high isolation between physically intersecting signal paths, or a controlled amount of coupling for applications where this is desirable. View full abstract»

• ### Optimum single-zero lead compensation of systems having two dominant poles

Publication Year: 1978, Page(s):111 - 113
| | PDF (372 KB)

For multipole feedback systems having two dominant poles, simple approximations are given for the zero which is optimum in the sense that gain margin is maximised, and for the corresponding maximum marginal gain. The formulas permit rapid design of optimum single-zero lead compensation for such systems. 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