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# Electronics Letters

## Filter Results

Displaying Results 1 - 25 of 28
• ### Polarisation beat length measurement in a single-mode optical fibre by backward Rayleigh scattering

Publication Year: 1981, Page(s):513 - 515
Cited by:  Papers (7)
| | PDF (665 KB)

Polarisation fluctuation on the backward Rayleigh scattered signal measured by the POTDR (polarisation optical time domain reflectometer) has been investigated by means of the power spectrum. As a result, the spectrum is sharply peaked at the Fourier frequency of 8.3 Ã 106 Hz determined by the polarisation beat length of 12 m due to the difference in phase velocities between the orthogonal eHE11 ... View full abstract»

• ### Achievement of 1 MHz frequency stability of semiconductor lasers by double-loop AFC scheme

Publication Year: 1981, Page(s):515 - 516
Cited by:  Papers (6)
| | PDF (1003 KB)

A temperature-controlling AFC system has been developed to realise high-frequency stability with semiconductor lasers. The frequency drift in DC operation can be reduced to below 1 MHz peak-to-peak. When necessary, the laser frequency can be modulated directly in the AFC state while the centre frequency is kept stabilised within 3 MHz. A heterodyne experiment was also performed using two frequency... View full abstract»

• ### Groove-guide microwave detector for 100 GHz operation

Publication Year: 1981, Page(s):516 - 517
Cited by:  Papers (4)
| | PDF (761 KB)

A detector has been designed and constructed, using a beam-lead diode, directly in a groove guide. A triangular dipole, produced by photolithography on RT/Duroid 5880, is placed transversely across the guide. A GEC beam-lead Schottky diode, bonded across the dipole, acts as the rectifying element. When used with a cylindrical back short-circuit and an appropriate bias current, a voltage sensitivit... View full abstract»

• ### Optical transmission of 16 digitised TV channels over 21 km fibre at a bit rate of 1.12 Gbit/s

Publication Year: 1981, Page(s):517 - 519
Cited by:  Papers (4)
| | PDF (484 KB)

The letter describes an optical transmission system which carries 16 digitised TV channels over a distance of 21 km without repeater at a bit rate of 1.12 Gbit/s. View full abstract»

• ### Evaluation of the gallager adaptive convolutional codes on real channels

Publication Year: 1981, Page(s):519 - 520
| | PDF (291 KB)

In the letter the performances of Gallager codes, and hybrid systems based on these codes, are evaluated on real channels using the Monte Carlo simulation method. The new criteria are proposed for diffuse bursts as well as for hybrid systems. Test results demonstrate that these codes, if properly used, offer a significant reduction in the error rate. View full abstract»

• ### Linearly focused acoustic beams for acoustic microscopy

Publication Year: 1981, Page(s):520 - 522
Cited by:  Papers (10)
| | PDF (498 KB)

A linearly focused acoustic beam is investigated to be introduced into acoustic microscopy for characterising materials in the nonscanning version. The new acoustic beam enables us to detect acoustic anisotropies of materials to be measured successfully. For forming the acoustic beam, an acoustic sapphire lens with a cylindrical concave surface of 1.0 mm in radius is made and the acoustic field di... View full abstract»

• ### Analysis for optimum threshold voltage and load current of E-D-type GaAs DCFL circuits

Publication Year: 1981, Page(s):522 - 523
Cited by:  Papers (2)
| | PDF (241 KB)

A GaAs MESFET E-D invertor was analysed to estimate the optimum threshold voltage VT for a switching FET, and the optimum load current IL for a load FET, that will minimise the invertor switching time. The calculated results show that the optimum VT lies at around 0.2 V, and the optimum IL is about 55% of the saturation current of the switching FET. View full abstract»

• ### Interferometric current sensors using optical fibres

Publication Year: 1981, Page(s):523 - 525
Cited by:  Papers (10)
| | PDF (408 KB)

Two types of fibre-optic current sensor have been developed and successfully tested in the laboratory: magnetostrictive jacketing materials and a heating effect, to produce a phase shift in the optical fibre. A ruggedised all-fibre interferometer powered by a diode laser was used to detect the phase changes induced by the electrical current. View full abstract»

• ### Modified VAD method for optical-fibre fabrication

Publication Year: 1981, Page(s):525 - 526
Cited by:  Papers (3)
| | PDF (307 KB)

New techniques for protecting the burner flame and controlling gas pressure in a reaction vessel have been developed for the vapour-phase axial-deposition (VAD) method of soot preform. The growth of soot preform became more stable. It is found that there is a close correlation between the bottom shape of the soot preform and the refractive-index profile of a fibre preform. Optical fibres thus prod... View full abstract»

• ### TSRMA Â¿ a communication protocol for data transmission by radio channels

Publication Year: 1981, Page(s):526 - 527
| | PDF (274 KB)

The time slot reservation multiple access (TSRMA) protocol proposed here fits today's real environment, is easy to implement, and performs well in terms of channel utilisation and expected packet delay. View full abstract»

• ### High rate pulse generation from InGaAsP laser in selfoc lens external resonator

Publication Year: 1981, Page(s):527 - 529
Cited by:  Papers (3)
| | PDF (413 KB)

High rate modulation of an InGaAsP diode laser at rates of 5Â¿10 GHz was demonstrated using a selfoc microlens external resonator. At a rate of 5.3 GHz modelocked pulses of 30 ps duration were obtained, whereas deeply modulated output was observed at 8.1 and 9.4 GHz rates. View full abstract»

• ### Operational amplifier with compensation pole as basis for active networks

Publication Year: 1981, Page(s):529 - 530
Cited by:  Papers (1)
| | PDF (521 KB)

Controversy concerning the use of the Â¿T/s idealisation of the characteristics of operational amplifiers is reviewed. Measurements of the variation of Â¿T with various factors are reported and conclusions are reached relating to the validity of this approach to the engineering design of active networks. View full abstract»

• ### Low-loss single polarisation fibres with asymmetrical strain birefringence

Publication Year: 1981, Page(s):530 - 531
Cited by:  Papers (50)
| | PDF (377 KB)

Low-loss and highly birefringent single polarisation fibres have been fabricated. The minimum transmission loss and the modal birefringence of the fibre with refractive-index difference Â¿=0.61% was 0.62 dB/km at Â¿=1.52 Â¿m and 8.5Ã10Â¿5 at Â¿=1.15 Â¿m, respectively. The state of linear polarisation was stable against the handling conditions such as bending, twists, concentrated force, and tempe... View full abstract»

• ### Diffusion of transition elements in GaAs and InP

Publication Year: 1981, Page(s):532 - 533
Cited by:  Papers (3)
| | PDF (281 KB)

A technique is presented for studying the diffusion of iron and chromium in GaAs and InP at temperatures down to 600Â°C. The technique is reproducible, and results are presented which show that in all four cases very fast diffusion occurs. View full abstract»

• ### New commutated Doppler radar system

Publication Year: 1981, Page(s):533 - 534
| | PDF (310 KB)

A new design for a double-sideband commutated Doppler primary radar system for detecting a target is proposed. Target information is obtained by the measurement of various Doppler frequencies, and a unique feature of the system is its combined use of frequency diversity, space diversity and time diversity to achieve a better overall performance. View full abstract»

• ### Anisotropy detection in sapphire by acoustic microscope using line-focus beam

Publication Year: 1981, Page(s):534 - 536
Cited by:  Papers (13)
| | PDF (478 KB)

Nonscanning reflection acoustic microscopes can be satisfactorily applied to detect the anisotropy of acoustic properties of solid materials using a line-focus beam. As a demonstration, the anisotropic dependence of leaky surfac-acoustic-wave velocities on the propagation directions are measured on the water/Z-cut-sapphire boundary at a frequency of 200 MHz. The measured values are in good agreeme... View full abstract»

• ### Low-noise two-dimensional electron gas FET

Publication Year: 1981, Page(s):536 - 537
Cited by:  Papers (8)
| | PDF (321 KB)

Two-dimensional electron gas FETs (TEGFETs) have been fabricated on an N-AlGaAs-GaAs heterojunction. Microwave results at 10 GHz are: NF=2.3 dB, Gass=10.3 dB and Gmax=13.2 dB. These first results obtained on nonoptimised material and processing suggest that TEGFET can be superior to a conventional GaAs FET. View full abstract»

• ### Offset voltage, CMRR and PSRR of a long-tailed pair: an integrated approach

Publication Year: 1981, Page(s):537 - 539
| | PDF (422 KB)

An integrated treatment of the input offset-voltage Vos, common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR) of a simple resistively loaded bipolar differential amplifier establishes the basic theoretical relationships between these parameters and indicates that Early-voltageÂ¿ mismatch of the constituent devices limits the attainable CMRR and PSRR. View full abstract»

• ### Transferred-electron oscillators at very high frequencies

Publication Year: 1981, Page(s):539 - 540
Cited by:  Papers (4)
| | PDF (285 KB)

The high-frequency characteristics of transferred-electron oscillators have been examined by computer simulation. Maximum frequencies in the range 100 to 200 GHz (for GaAs) and contact effects favouring current saturating cathodes are predicted. View full abstract»

• ### Alternating beam method (ABM) in photothermal microscopy (PTM) and photoacoustic microscopy (PAM)

Publication Year: 1981, Page(s):540 - 541
Cited by:  Papers (1)
| | PDF (257 KB)

In measuring thermal properties of nearly uniform surfaces, it is often difficult to resolve small differences in the surfaces. The letter reports a differential method to measure small variations with the detector operating as a null detector. This method is applied to measure the thickness of plasma-sprayed coatings. View full abstract»

• ### Picosecond pulse generation by lateral mode switching of (GaAl)As-heterostructure stripe lasers

Publication Year: 1981, Page(s):541 - 543
| | PDF (421 KB)

The presence of kinksÂ¿ in the light/current characteristics of (GaAl)As injection lasers is investigated by applying large amplitude electrical RF modulation. It is suggested that the 20 ps pulses which have been observed may be produced through mechanisms associated with these kinks. View full abstract»

• ### Reliability of a new method for measurements of modal power distribution in optical fibres with application to mode scrambler testing

Publication Year: 1981, Page(s):543 - 545
Cited by:  Papers (3)
| | PDF (439 KB)

An experimental investigation about the reliability of an attractive method recently proposed for modal power distribution measurements in multimode fibres is performed. The method is shown to work also in some common cases when the hypotheses of validity are not rigorously fulfilled. Finally, an illustrative application to the testing of mode scramblers is presented. View full abstract»

• ### Field dependence of mobility in Al0.2Ga0.8As/GaAs heterojunctions at very low fields

Publication Year: 1981, Page(s):545 - 547
Cited by:  Papers (7)
| | PDF (427 KB)

Multiple-period (Al, Ga)As/GaAs modulation doped heterojunction structures have been grown with molecular beam epitaxy. Electron mobilities of about 200 000 cm2/Vs at 10 K and 90000 cm2/Vs at 77 K with associated sheet carrier concentrations of about 2Ã1012 cmÂ¿2 have been observed. The current parallel to the interfaces for low electric fields was examined as a function of lattice temperature. T... View full abstract»

• ### Fast biased polynomial transforms for two-dimensional convolutions

Publication Year: 1981, Page(s):547 - 548
Cited by:  Papers (1)
| | PDF (241 KB)

The fast biased polynomial transforms are defined directly on the ZNÂ¿1 ring instead of a conventional cyclotomic polynomial ring. Such biased polynomial transforms may be combined with very efficient fast FFT algorithms. Two-dimensional convolutions may be carried out without using the complicated Chinese remainder theorem, complex mapping and column-row reordering processes. View full abstract»

• ### Retiming 2.24 Gbit/s and demultiplexing 2.24 to 1.12 Gbit/s in an optical transmission system by means of a single-gate field-effect transistor

Publication Year: 1981, Page(s):548 - 549
Cited by:  Papers (2)
| | PDF (512 KB)

In the letter a circuit is presented which can be used for retiming and demultiplexing in Gbit/s applications. Taking advantage of the three-port properties of a field-effect transistor only one transistor is needed. 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
Head of Photonics Research
University of Cambridge, UK