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image of Volume 18, Issue 25-26
Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 18, Issue 25-26, 9 December 1982

Volumes & issues:

Volume 18, Issue 25

9 December 1982

Semiconductor surface studies with SAW-oscillator structures
  • Author(s): R. Rademeyer ; B. Davari ; P. Das
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1065 –1066
  • DOI:  10.1049/el:19820729
  • Type: Article
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  • p. 1065 –1066 (2)
    A new method is described whereby the surface charge against surface potential of an oxidised semiconductor sample can be obtained by measuring the frequency shift of a SAW delay-line oscillator. In this method a direct voltage is applied across the semiconductor with different configurations. The SAW delay line is made on LiNbO3 and is designed to oscillate (at 100 MHz) with a wideband amplifier in a feedback configuration.
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Diode-laser-controlled millimetre-wave propagation in a silicon waveguide
Monte Carlo simulation of GaAs submicron n+-n-n+ diode with GaAlAs heterojunction cathode
Multidimensional bilinear transformations
Outage prediction of digital radio systems
  • Author(s): J.C. Campbell  and  R.P. Coutts
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1071 –1072
  • DOI:  10.1049/el:19820733
  • Type: Article
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  • p. 1071 –1072 (2)
    It is well established that the performance of digital radio systems is often limited by the amplitude and group delay distortions which accompany frequency selective fading, and the concept of the ‘system signature’ has been developed for predicting the outage probability of such systems. The letter presents a new outage prediction technique and introduces the concept of a ‘normalised system signature’ which enables comparisons of modulation schemes and equaliser implementations.
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Proposed use of rearrangement in multiexchange telecommunication networks
Analytical and simulation study of simple rearrangeable multiexchange networks
  • Author(s): A.K.M.M. Rahman Khan
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1073 –1075
  • DOI:  10.1049/el:19820735
  • Type: Article
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  • p. 1073 –1075 (3)
    Congestion probabilities for calls in simple three-exchange networks operated with and without rearrangements are determined analytically and by digital simulation. Load-loss curves are obtained, from which the gain in traffic capacity due to rearrangement and degradation due to overload can be found. It is concluded that routing control with rearrangements possesses a potential traffic-handling advantage over conventional automatic alternative routing.
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Changes in photovoltaic and dark electrical properties of hydrogenated amorphous silicon diodes induced by forward bias carrier injection
High-mobility selectively doped GaAs/GaAlAs structures grown by low-pressure OM-VPE
Electronic erasure of stored reference signals in a metal-ZnO-SiO2-Si induced junction storage correlator
Novel active-compensated variable-phase inverting integrator
  • Author(s): M.V. Popovich  and  O. Katić
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1080 –1081
  • DOI:  10.1049/el:19820739
  • Type: Article
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  • p. 1080 –1081 (2)
    A novel variable-phase inverting integrator is presented. Compared to some existing circuits, the circuit proposed has better high-frequency behaviour because it does not require the use of identical amplifiers. This integrator can considerably extend the useful frequency range of the two-integrator-loop and multiple-feedback active filters, reducing excess phase shift of the operational amplifiers.
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Pseudoheterodyne detection scheme for optical interferometers
Contact resistance of polysilicon silicon interconnections
  • Author(s): G.K. Reeves  and  H.B. Harrison
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1083 –1085
  • DOI:  10.1049/el:19820741
  • Type: Article
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  • p. 1083 –1085 (3)
    Electrical contacts to poly are an important part of current silicon technology. In this letter we present a method of calculating the electrical characteristics for a planar poly to silicon contact. An interesting and significant result that is derived and discussed is a minimum contact resistance that is a strong function not only of the specific contact resistance of the contact interface but also of the contact geometry.
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T-emitter bipolar power transistor with negative-temperature-gradient current gain
  • Author(s): N.D. Janković
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1085 –1087
  • DOI:  10.1049/el:19820742
  • Type: Article
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  • p. 1085 –1087 (3)
    A PNP epitaxial-base power transistor with double diffused emitter (T-emitter) which exhibits a negative temperature gradient for β is described. Qualitative analysis shows that a fall-off in β with increase in temperature is a consequence of both the T-emitter geometry and the boron double diffused emitter area. Measurements on realised transistors give a mean value of dβ/dt of −0.25 at temperatures ranging from 20°C to 110°C.
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High-Q SC biquad with a minimum capacitor spread
Novel technique for antenna gain measurement in satellite Earth stations
  • Author(s): P. Daly  and  D. Tits
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1089 –1090
  • DOI:  10.1049/el:19820744
  • Type: Article
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  • p. 1089 –1090 (2)
    A novel technique is proposed for the measurement of the gain of antennas used in Earth stations involved in satellite communications. In principle the technique requires a standard-gain reference antenna, automatic level control over a satellite loop, and narrowband detection techniques. Advantages over conventional techniques (line-of-sight or radio star measurement) are claimed including stable received flux, measurement in situ at operational elevation, accurate crosscalibration with other earth-station antennas, and removal of the influence of propagation on the signal level.
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Formation of shallow photodiodes by implantation of boron into mercury cadmium telluride
  • Author(s): P.G. Pitcher ; P.L.F. Hemment ; Q.V. Davis
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1090 –1092
  • DOI:  10.1049/el:19820745
  • Type: Article
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  • p. 1090 –1092 (3)
    Hall-effect measurements on p-type MCT implanted with 1 × 1014 B+/cm2 at 150 keV show that an abrupt junction is formed at a depth of 0.6 ± 0.12 μm after annealing at 230° for 7 min with a ZnS cap. Prior to the anneal the carrier profile was graded and extended to a depth of 5.0 ± 1.0 μm. Photodiodes have been formed by a dual implant of 5 × 1014 B+/cm2 at 100 keV and 50 keV, and after annealing a five-fold improvement in RoA has been measured to give a value of 1.2 Ωcm2.
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Simple spectral control technique for external cavity laser transmitters
Evidence of detrimental surface effects on GaAs power MESFETs
Low-threshold single quantum well (60 Å) GaAlAs lasers grown by MO-CVD with Mg as p-type dopant
  • Author(s): R.D. Burnham ; W. Streifer ; D.R. Scifres ; C. Lindström ; T.L. Paoli ; N. Holonyak
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1095 –1097
  • DOI:  10.1049/el:19820748
  • Type: Article
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  • p. 1095 –1097 (3)
    The letter reports low-threshold MO-CVD GaAlAs DH (∼7730 Å) lasers containing Mg as the p-type dopant. The structure consists of symmetric stepped index cladding layers on both sides of a thin single quantum well (∼60 Å) active region. Broad-area threshold current densities of 460 A cm−2 and 270 A cm−2 are achieved for cavity lengths of 250 and 500 μm, respectively. Broad-area room-temperature lasers without facet coatings emit in excess of 400 mW/facet CW output power.
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High-efficiency GaAs power MESFETs prepared by ion implantation
  • Author(s): M. Feng ; H. Kanber ; V.K. Eu ; M. Siracusa
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1097 –1099
  • DOI:  10.1049/el:19820749
  • Type: Article
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  • p. 1097 –1099 (3)
    GaAs power MESFETs have been fabricated using ion implantation to form channel layers. A 1 μm gate length by 2400 μm gate width device has demonstrated an output power of 1.63 W with 6.9 dB associated gain, 35% power-added efficiency and 9.7 dB linear gain at 10 GHz. The transconductance of this device is 280 mS, which corresponds to 117 mS/mm. This result demonstrates that excellent GaAs power MESFETs can be made by ion implantation, and is comparable to average results demonstrated by devices made by AsCl3 vapour phase epitaxy.
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Analogue-to-digital conversion using integrated electro-optic interferometers
Novel architecture for a time division switch
Exact design of switched-capacitor bandpass ladder filters
First measurement of a superconducting microstrip-line attenuation constant at 10 GHz
Novel leaky-wave antenna for millimetre waves based on groove guide
New form of liquid crystal touch switch
Measurement of radiative recombination coefficient and carrier leakage in 1.3 μm InGaAsP lasers with lightly doped active layers
Effects of broadband noise in radio-frequency six-port scattering-parameter measurements
  • Author(s): R.N. Clarke  and  D.A. Granville-George
  • Source: Electronics Letters, Volume 18, Issue 25, p. 1110 –1112
  • DOI:  10.1049/el:19820757
  • Type: Article
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  • p. 1110 –1112 (3)
    Significant errors can arise in six-port metrology if broadband noise is present on the source signal. In order to describe noise effects, six-port analysis has been extended to include junction parameters which allow for noise correlations. The effects are demonstrated by means of a theoretical example and by reference to white-noise excitation of a six-port reflectometer operating at 10 MHz–1 GHz. Errors of the order of 0.2% in a reflectivity of 1.0 may result if an unfiltered broadband source such as a synthesiser is used.
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Phase-shift keying: symbol error rate in presence of random fluctuation noise—an elementary treatment

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