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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 25, Issue 15, 20 July 1989

Volumes & issues:

Volume 25, Issue 15

20 July 1989

Simulation model of sequential multichannel network and its throughput determination
  • Author(s): R.L. Brewster  and  A.M. Glass
  • Source: Electronics Letters, Volume 25, Issue 15, p. 941 –942
  • DOI:  10.1049/el:19890630
  • Type: Article
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  • p. 941 –942 (2)
    A sequential multichannel system has been simulated, based on resolving the allocation of channels in turn to the offered load packets using the CSMA/CA protocol for medium access. A set of throughput curves with different maxima have been obtained for different numbers of subchannels. The relatively low throughput of such a system is compensated for by other desirable features that have been included in the system especially for applications involving radio and mobile radio channels.
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Bearing estimation of coherent sources by spatial modulating and in-place reversal averaging technique
Wavelength dependence of 3×3 fibre couplers for gyro applications
Low-loss planar optical polarisation splitter with small dimensions
Losses in small-radius bends in single-mode fibres
Andrew's t-EC/AUED Codes
Modified CORDIC algorithm with reduced iterations
New RLL code for digital data storage
Experimental observation of spectral tuning in twin-segment double quantum well (DQW) AlGaAs diode laser
GaInAsP/InP mass transport laser monolithically integrated with photodetector using reactive ion etching
  • Author(s): T. Matsui ; H. Sugimoto ; K. Ohtsuka ; Y. Abe ; H. Ogata
  • Source: Electronics Letters, Volume 25, Issue 15, p. 954 –956
  • DOI:  10.1049/el:19890639
  • Type: Article
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  • p. 954 –956 (3)
    A l.5 μm GaInAsP/InP laser is monolithically integrated with a photodiode. The laser is isolated from the photodiode by an etched groove formed by reactive ion etching. Ethane and hydrogen gases are used as an etchant of reactive ion etching instead of chlorinated gas. The threshold current of the laser under CW operation and the sensitivity of the monitor photodiode are 57 mA and 0.24 A/W, respectively.
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900 MHz multipath propagation measurements in four United States cities
  • Author(s): T.S. Rappaport  and  S.Y. Seidel
  • Source: Electronics Letters, Volume 25, Issue 15, p. 956 –958
  • DOI:  10.1049/el:19890640
  • Type: Article
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  • p. 956 –958 (3)
    This letter describes multipath power delay profile measurements of 900 MHz mobile radio channels in four US cities. Preliminary data show that for over 98% of the measured locations, RMS delay spreads are less than 12 μs. In very rare instances, reflections from city skylines and mountains can cause RMS delay spreads which exceed 20 μs and excess delays which exceed 100 μs. Such large excess delays have not been previously reported in the literature.
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Surface-acoustic-wave unidirectional transducers using anodic oxidation technology and low-loss filters
  • Author(s): K. Yamanouchi ; T. Meguro ; K. Matsumoto
  • Source: Electronics Letters, Volume 25, Issue 15, p. 958 –960
  • DOI:  10.1049/el:19890641
  • Type: Article
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  • p. 958 –960 (3)
    A new surface-acoustic-wave interdigital transducer (IDT) and unidirectional transducer (UDT) are described. Using a lift-off anodic oxidation method, controllable gaps between electrodes with good insulation can be obtained. Experimental results show good characteristics at 2nd-harmonic operation for a new floating electrode type unidirectional transducer (NG-FEUDT). Also, a low-loss filter of 3.46dB with side-lobe suppression of 40dB at 893 MHz is obtained using the above techniques.
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Frame synchronisation with errors and erasures
  • Author(s): P.F. Driessen
  • Source: Electronics Letters, Volume 25, Issue 15, p. 960 –961
  • DOI:  10.1049/el:19890642
  • Type: Article
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  • p. 960 –961 (2)
    The probability of successful frame synchronisation in the presence of jamming or interference may be increased by using bit erasure information without also increasing the total probability of simulated alignment Pt,sim in an incorrect position in the overlap region. An expression for Pt,sim is obtained as a function of the bit error and erasure probability, the specified frame alignment pattern, the amount of overlap and the number of bit errors and erasures which are tolerated in the frame sync word.
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Pipelined logical convolvers for binary picture processing
  • Author(s): A.D. Hall
  • Source: Electronics Letters, Volume 25, Issue 15, p. 961 –963
  • DOI:  10.1049/el:19890643
  • Type: Article
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  • p. 961 –963 (3)
    Pipelined logical convolvers (PLCs) are well suited to document facsimile processing as they can simply be inserted into the video data stream of scanners, etc. Their introduction has no effect on throughput and they require only a partial picture memory. A method is described for designing and implementing PLCs, using a structured approach that encourages experimentation and produces a cost efficient circuit. An example PLC is presented which performs image smoothing.
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Fast measuring frequency-to-voltage convertor with DC output
High-speed switching characteristics of integrated 4×4 InP optical switch array
Frequency-locked loop circuit providing large pull-in range
  • Author(s): B. Glance  and  R.W. Wilson
  • Source: Electronics Letters, Volume 25, Issue 15, p. 965 –967
  • DOI:  10.1049/el:19890646
  • Type: Article
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  • p. 965 –967 (3)
    The letter presents a frequency-locking circuit that provides a larger pull-in bandwidth than that of a conventional automatic frequency control (AFC) circuit. In addition, the proposed circuit has a stable mode of operation over the full frequency response of the frequency discriminator, and locks the oscillator at exactly the centre frequency of this discriminator. The frequency offset and the unstable mode of operation presented by the conventional circuit outside its pull-in range can thus be eliminated.
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Planar-junction, top-illuminated GainAs/InP pin photodiode with bandwidth of 25 GHz
Multipurpose single-mode fibre-optic coupling substrate, made with silicon etch and polish technique
Effects of annealing on electrical properties of Se-implanted GaAs
10 watt CW, 5000 h lifetime monolithic AlGaAs laser diode arrays
Intensity modulation at 1.06μm wavelength using ultranarrow GaInAsP quantum wells
Threshold voltage of submicron Ga0.47In0.53As HIGFETs
  • Author(s): M.D. Feuer ; S.C. Shunk ; J.M. Kuo ; D.M. Tennant ; B. Tell
  • Source: Electronics Letters, Volume 25, Issue 15, p. 975 –976
  • DOI:  10.1049/el:19890652
  • Type: Article
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  • p. 975 –976 (2)
    We present threshold voltage data for Al0.48In0.52As/Ga0.47In0.53As/InP heterostructure insulated gate FETs (HIGFETs) with gate lengths from 1.2μm to 0.4μm. The refractory-gate, self-aligned fabrication process was applied to MBE-grown structures with 300Å Ga0.47In0.53As channels and semi-insulating superlattice buffers, to achieve sharp pinchoff with excellent threshold uniformity. HIGFETs with L = l.2μm showed a threshold voltage of −0.076 ± 0.019V, making them well-suited to application in direct-coupled FET logic (DCFL) circuits.
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External feedback effects on I/L characteristics of laser diode
Electron pulse generation at 64 GHz in scanning electron microscope
  • Author(s): J.T.L. Thong ; B.C. Breton ; W.C. Nixon
  • Source: Electronics Letters, Volume 25, Issue 15, p. 978 –979
  • DOI:  10.1049/el:19890654
  • Type: Article
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  • p. 978 –979 (2)
    An electron beam chopping technique has been developed which enables the generation of electron pulses at tens of GHz in an SEM. This is effected by deflecting the beam in a circle and chopping it with a multislot aperture. Electron pulses have been produced at 64 GHz and measured, and a waveform measurement at 18 GHz demonstrates its potential application to electron beam characterisation of very high speed devices and MMICS.
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2.5 W, C-band, GaAs/AlGaAs heterojunction bipolar power transistor
  • Author(s): A.P. Long ; I.H. Goodridge ; J.P. King ; A.J. Holden ; J.G. Metcalfe ; R.C. Hayes ; R. Nicklin ; R.C. Goodfellow
  • Source: Electronics Letters, Volume 25, Issue 15, p. 979 –981
  • DOI:  10.1049/el:19890655
  • Type: Article
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  • p. 979 –981 (3)
    A high-power GaAs/AlGaAs microwave heterojunction bipolar transistor (HBT) with a total emitter periphery of 1.2mm has been designed and fabricated. At 4 GHz an output power at idB gain compression of 1W with 5dB gain and 30% peak power added efficiency was obtained in CW class A. Under pulse bias operation the output power increased to 2.54 W with 6.4 dB gain and 37% peak power added efficiency. This represents a significant increase in power handling over previous power HBTs and demonstrates the potential of these devices as building blocks in power amplifier modules. A large-signal model has been developed to run on SPICE to predict the power performance for the device and the optimum load impedances.
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Integrated optic 1×4 splitter in SiO2/GeO2
Alternative implementation of systolic recursive digital filters
Low-voltage multiple quantum well reflection modulator with on:off ratio > 100:1
  • Author(s): M. Whitehead ; A. Rivers ; G. Parry ; J.S. Roberts ; C. Button
  • Source: Electronics Letters, Volume 25, Issue 15, p. 984 –985
  • DOI:  10.1049/el:19890658
  • Type: Article
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  • p. 984 –985 (2)
    We report the demonstration of a high-contrast (> 100:1), low-voltage multiple quantum well reflection modulator. The performance is achieved by using resonantly-enhanced electroabsorption in GaAs quantum wells embedded in the spacer region of an asymmetric Fabry-Pérot cavity, which is at the same time a pin diode. Optimum contrast is observed at ≃860nm with only 9 V bias and ≈3.5dB insertion loss.
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Ion-implanted Nd:YAG planar waveguide laser
Twin-ridge laser amplifier crosspoint switch
Very narrow spectral linewidth of GaInAs MQW-DFB-PPIBH laser diodes
Tunable, narrow-linewidth and high-power λ/4-shifted DFB laser
One-dimensional ballistic resistor in hot-electron regime: nonlinear and negative differential resistance to 10 THz
  • Author(s): M.J. Kelly ; R.J. Brown ; C.G. Smith ; D.A. Wharam ; M. Pepper ; H. Ahmed ; D.G. Hasko ; D.C. Peacock ; J.E.F. Frost ; R. Newbury ; D.A. Ritchie ; G.A.C. Jones
  • Source: Electronics Letters, Volume 25, Issue 15, p. 992 –993
  • DOI:  10.1049/el:19890663
  • Type: Article
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  • p. 992 –993 (2)
    We extend into the high field regime the usual (very low field) treatment of the one-dimensional (ID) ballistic resistor that leads to quantised resistance. We find nonlinear resistance and eventually negative differential resistance (NDR) with a high-frequency cutoff above 10 THz. We outline preliminary experimental evidence in support.
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AlGaAs/GaInAs strained-base pnp heterojunction bipolar transistors
GaAs/AlGaAs multiple quantum well optical modulator using multilayer reflector stack grown on Si substrate
Polarisation diversity optical receiver using novel combining method
GaInAs/InP I2L ring oscillators
4 Gbit/s, 188 km optical fibre transmission experiment using three packaged laser amplifiers
  • Author(s): H. Taga ; S. Yamamoto ; K. Mochizuki ; H. Wakabayashi
  • Source: Electronics Letters, Volume 25, Issue 15, p. 999 –1000
  • DOI:  10.1049/el:19890668
  • Type: Article
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  • p. 999 –1000 (2)
    We report on 4 Gbit/s optical fibre transmission experiments using three packaged laser amplifiers as linear optical repeaters. With total amplifier gain 32 dBm, a directly modulated 1.518 μm DFB laser signal was transmitted over 188 km fibres, consisting of dispersion shifted fibres and conventional fibres for dispersion compensation. The overall system penalty was only 0.9 dB.
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Combined space/time diversity technique for narrowband TDMA mobile radio systems
New scheme for digital multisignatures
  • Author(s): L. Harn  and  T. Kiesler
  • Source: Electronics Letters, Volume 25, Issue 15, p. 1002 –1003
  • DOI:  10.1049/el:19890670
  • Type: Article
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  • p. 1002 –1003 (2)
    When two individual users wish to carry on a secure conversation, they can use the well-known RSA public key cryptosystem in doing so. This cryptosystem provides to these users both data secrecy and digital signature in a very efficient manner. However, in many applications, multiple users need to sign a document. In this letter, we propose a modified scheme, based on the RSA scheme, which will allow any number of users to sign a document and send it secretly to the receiver. The length of ciphertext remains constant, no matter how great the number of signatories. The trade-off is that the processing times required for generating the multisignature, and for verifying multisignatures, depend on the number of signatories.
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3 GHz optical soliton propagation using all laser diodes
New algorithm for 2-D linear system eigenstructure assignment
  • Author(s): Z. Geng  and  R.L. Carroll
  • Source: Electronics Letters, Volume 25, Issue 15, p. 1005 –1006
  • DOI:  10.1049/el:19890672
  • Type: Article
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  • p. 1005 –1006 (2)
    An algorithm for eigenstructure assignment of twodimensional linear systems is proposed, which reveals the degrees of freedom in selecting the feedback gain matrix of 2-D systems. Sufficient conditions for the existence of a linear state feedback gain matrix are given. By using the freedom which may be offered by these algorithms an output feedback controller can be designed to achieve the desired eigenstructure.
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Finite-difference time-domain (FD-TD) analysis of discontinuities in homogeneous, dispersive waveguides
Algorithms for converting convolutional codes from feedback to feedforward form and vice versa
High-quality dual-gate PMOS devices in local overgrowth (LOG)
  • Author(s): R.P. Zingg ; B. Höfflinger ; G.W. Neudeck
  • Source: Electronics Letters, Volume 25, Issue 15, p. 1009 –1010
  • DOI:  10.1049/el:19890675
  • Type: Article
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  • p. 1009 –1010 (2)
    A new SOI technology is introduced with enhanced device performance and small geometries. The low-impurity crystalline SOI film is produced by local overgrowth (LOG) over an oxide, an important alternative to recrystallised silicon films for 3D-CMOS and SOI circuits. This technology was developed from epitaxial lateral overgrowth (ELO), to allow the use of the substrate as an interconnect layer and to enable access to submerged gates. Surface-channel mobilities are measured to be 165cm2/V s for PMOS devices built on top of the overgrowth and 160cm2/V s for devices with a submerged gate. The structures produced by LOG arc planar and allow for further stacking of devices.
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Versatile polycrystalline silicon transistor/switching structure
Polarisation diversity receiver for coherent optical FSK communications using active weight controller
New two-way, 3 dB, equiphase, impedance-transforming power divider suitable for high-power applications
Erratum: Improved Rabin's scheme with high efficiency

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