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image of Volume 19, Issue 25-26
Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 19, Issue 25-26, 8 December 1983

Volumes & issues:

Volume 19, Issue 25

8 December 1983

Unique reflector arrangement with very wide field of view for multibeam antennas
  • Author(s): C. Dragone
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1061 –1062
  • DOI:  10.1049/el:19830720
  • Type: Article
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  • p. 1061 –1062 (2)
    We minimise the aberrations arising in a double reflector antenna when the feed is displaced from the focus. In a previous article, astigmatism and primary coma were reduced by slightly deforming the two reflecting surfaces and optimising the principal ray angles of incidence. Here we further reduce aberrations by determining the optimum subreflector magnification. The result is a new reflector arrangement, consisting of a deformed paraboloid combined with a deformed hyperboloid, having the widest possible field of view obtainable with two reflectors in a compact arrangement of short focal length.
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Low-pressure MOVPE growth of Sn-doped GaAs
Mobile radio propagation in Auckland at 76 MHz
  • Author(s): G.B. Rowe ; A.G. Williamson ; B. Egan
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1064 –1065
  • DOI:  10.1049/el:19830722
  • Type: Article
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  • p. 1064 –1065 (2)
    A series of field trials in Auckland at 76 MHz have confirmed that propagation path loss is normally distributed and may be characterised by a fourth-power-law distance dependency. The path loss standard deviation has been found to be dependent on the mobile terminal's environment and on frequency, but is essentially independent of base station antenna height and path length. The excess path loss over plane earth predictions and the standard deviation of path loss have been measured as 14.6, 5.0, 0.8 and 1.0 dB and 6.2, 5.2, 3.7 and 5.0 dB for urban, light urban, suburban and rural environments, respectively.
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Desktop computer appraisal of potential slow-wave propagation characteristics for Schottky coplanar lines
  • Author(s): C. Seguinot ; P. Kennis ; P. Pribetich
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1065 –1067
  • DOI:  10.1049/el:19830723
  • Type: Article
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  • p. 1065 –1067 (3)
    An original analytical model of the Schottky coplanar line is presented. Determination of the potential slowing factor is made with good accuracy. In its present form the model does not give the slow-wave mode frequency limitation. However, it can be useful to initialise computer analyses using FEM or SDA techniques, and to explain the effect of varying DC bias and geometrical parameters on propagation characteristics.
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Microbending loss in monomode fibres: solution of petermann's auxiliary function
Experimental investigation of stability properties for a semiconductor laser with optical feedback
  • Author(s): J.H. Osmundsen ; B. Tromborg ; H. Olesen
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1068 –1070
  • DOI:  10.1049/el:19830725
  • Type: Article
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  • p. 1068 –1070 (3)
    The stability limits for a semiconductor laser exposed to optical feedback have been measured as a function of the feedback level and the phase of the reflected field. The experimental results are in good agreement with a detailed theoretical analysis. They include a determination of the absolute feedback level in a practical set-up and of the R-parameter, which for the actual laser is found to be −3.0 ± 0.3.
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Integrating infra-red detector with electronically modulated response
  • Author(s): D.D. Coon ; S. Gunapala ; R.P.G. Karunasiri ; H.-M. Muehlhoff
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1070 –1071
  • DOI:  10.1049/el:19830726
  • Type: Article
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  • p. 1070 –1071 (2)
    A new integrating IR detector exhibits equivalent dark currents as low as 1.2 × 10−15 A/cm2. Signal integration takes place in the bulk of a semiconductor photosensitive element. The ultralow dark current permits very long integration and storage times. Integration times longer than 12 h are reported. IR response beyond the usual low field cutoff is observed and shown to depend strongly on the applied electric field. This allows voltage-controlled starting and stopping of in situ signal integration beyond the low field cutoff wavelength.
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Optoelectronic 10 Gbit/s code generation by a picosecond photoconductive device
Residual shrinkage of UV-cured acrylate-jacketed optical fibres
  • Author(s): N. Yoshizawa
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1073 –1074
  • DOI:  10.1049/el:19830728
  • Type: Article
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  • p. 1073 –1074 (2)
    UV-cured acrylate-jacketed optical fibres and nylon-jacketed optical fibres were heated up to 120°C and their changes in length measured. Experimental results show that residual strain of the acrylate-jacketed fibres is not caused by the temperature change of 20–120–20°C, while, for the nylon-jacketed fibres, compressive strain remains after the heat cycle. The strain is proportional to the cross-sectional area of the nylon layer.
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Phase-shift technique for the measurement of chromatic dispersion in single-mode optical fibres using LEDs
New diffraction grating profiles in InP for DFB lasers and integrated optics
Performance of FH-MFSK cellular mobile radio in the presence of nonsynchronous users
Mode partition noise caused by wavelength-dependent attenuation in lightwave systems
  • Author(s): A. Tomita ; D.G. Duff ; N.K. Cheung
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1079 –1080
  • DOI:  10.1049/el:19830732
  • Type: Article
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  • p. 1079 –1080 (2)
    Power fluctuations among the longitudinal modes of laser diodes cause noise in the received signal after being filtered by a wavelength-dependent attenuation mechanism. We have developed a theoretical model to characterise this noise and studied degradation in lightwave system performance. Power penalties observed in a 432 Mbit/s wavelength division multiplexing system experiment agreed with theoretical predictions.
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Prediction of the ultimate performance of side-tunnel single-polarisation fibre
  • Author(s): T. Okoshi ; T. Aihara ; K. Kikuchi
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1080 –1082
  • DOI:  10.1049/el:19830733
  • Type: Article
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  • p. 1080 –1082 (3)
    As the result of recent progress in polarisation-maintaining optical waveguiding schemes, a basic question now arises: which of stress-induced type or geometrical type approach will finally offer better characteristics? The letter discusses the ultimate performance of a side-tunnel fibre which offers the strongest polarisation-maintaining capability among various geometrical-type ones. The result indicates that, if the structure is optimised, a relative bandwidth of truly single-polarisation characteristics of 0.21 and a normalised birefringence of 0.0045 can be achieved for a relative core-cladding index difference of 0.01. These values are comparable to or higher than the best data reported so far with stress-type ones.
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Low threshold current GaAs/GaAlAs GRIN-SCH stripe lasers grown by OMVPE
  • Author(s): M. Krakowski ; P. Hirtz ; R. Blondeau ; S.D. Hersee ; M. Baldy ; B. de Cremoux ; J.P. Duchemin
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1082 –1084
  • DOI:  10.1049/el:19830734
  • Type: Article
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  • p. 1082 –1084 (3)
    The letter describes the characteristics of stripe lasers formed in GaAs/GaAlAs single-quantum-well graded-composition separate-confinement heterostructures (GRIN-SCH) grown by low-pressure organometallic vapour phase epitaxy (LP-OMVPE). We show that the low threshold current density that has been achieved with the GRIN-SCH structure allows low threshold currents (38 mA) to be achieved in a simple gain-guided stripe-geometry laser. These low thresholds have been obtained without resorting to a complex nonplanar (lower yield) technology, and it is shown that the good uniformity offered by OMVPE is maintained through to the mounted device stage.
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High-power aging test on 1.3 μm DC-PBH lasers with reflective coated mirror
Group-type unidirectional SAW devices employing intra-transducer reflector banks
New technique for semiconductor device modelling
Technique for flexible multidimensional filter design
Predicted large-signal performance improvement by active compensation in microwave IMPATT amplifiers
Assessment of millimetre-wave Si IMPATT material
Determination of modal dispersion in monomode fibres from wavelength dependence of the mode spot size
Analysis of SC networks using continuous-time four-port equivalents
Subscriber line interface circuit LSI fabricated using high-voltage CMOS/SIMOX technology
  • Author(s): S. Nakashima  and  Y. Maeda
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1095 –1097
  • DOI:  10.1049/el:19830743
  • Type: Article
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  • p. 1095 –1097 (3)
    High-voltage buried-channel CMOS/SIMOX technology which is characterised with the existence of an electric-field-shielding layer formed by oxygen implanatation was applied to fabricate a BSH-LSI for a subscriber line interface circuit, providing three functions of battery feed, supervision and hybrid. In this CMOS BSH-LSI, a high breakdown voltage of higher than 60 V and a low breakdown voltage of 15 V were fabricated by the same process. This BSH-LSI showed a high level of performance during operation. The chip size and dissipation power of the BSH-LSI were reduced to approximately one-third and one-half, respectively, compared with a conventional BSH-LSI fabricated with bipolar technology.
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Minimised error criterion in recursive least-squares parameter estimation
Efficient algorithm for adaptive normalised lattice filters
  • Author(s): D.T. Nguyen
  • Source: Electronics Letters, Volume 19, Issue 25, p. 1098 –1099
  • DOI:  10.1049/el:19830745
  • Type: Article
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  • p. 1098 –1099 (2)
    The uniform norms of the observables in normalised lattice filters give the filters many stability and noise advantages over their 2-multiplier counterparts. Computational complexity due to the filter structure, however, has limited their use as adaptive filters. The letter presents a fast recursive algorithm for the generation of the gradients required in the steepest-descent adaptive filtering technique, using the normalised lattice structure.
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