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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 25, Issue 8, 13 April 1989

Volumes & issues:

Volume 25, Issue 8

13 April 1989

Analysis of combined priority and bit-rate compression traffic access control strategy for integrated services networks
  • Author(s): K.C. Chua  and  D.T. Nguyen
  • Source: Electronics Letters, Volume 25, Issue 8, p. 489 –490
  • DOI:  10.1049/el:19890335
  • Type: Article
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  • p. 489 –490 (2)
    A performance analysis of a combined pre-emptive priority and bit-rate compression access control strategy for multiplexing a blockable wide-band and a queueable narrow-band traffic type onto a common broad-band channel is presented. It is shown that contrary to intuitive expectation this scheme does not always yield the optimum performance compared to its component strategies, the pre-emptive priority and bitrate compression strategies, for all values of narrow-band offered load. Rather, it is observed that its performance may be hampered by high arrival rates of wide-band traffic, in which case it is out-performed by the bit-rate compression scheme at low narrow-band loads.
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Mode-locking of diode laser-pumped Nd:YAG laser at 1.3μm
Experimental confirmation of laser amplifier intermodulation model
Mode field diameter measurement conditions in single-mode fibres
565 Mbit/s FSK direct detection system operating with four cascaded photonic amplifiers
Calculation of error probabilities for distance-invariant nonlinear error control codes
Photorefractive gratings in single-mode optical fibres
Improved sensitivity of 60 video channel FM-SCM receiver with semiconductor optical preamplifier
Partial response quadrature differential phase shift keying (PR-QDPSK): spectrally efficient linear modulation for personal communications
Influence of intensity-dependent fields on nonlinear couplers
94 GHz low-noise HEMT
Radome crosspolarisation on Intelsat standard ‘A’ communication satellite antennas
  • Author(s): S. Rwabona-Katashaya  and  B.G. Evans
  • Source: Electronics Letters, Volume 25, Issue 8, p. 506 –507
  • DOI:  10.1049/el:19890346
  • Type: Article
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  • p. 506 –507 (2)
    The reduction in size of Intelsat standard ‘A’ satellite communication antennas from 30.5 m to 15 m in diameter has necessitated the computation of depolarisation effects when the smaller antennas employ metal and dielectric space frame radomes for hardening and protection. Using the standard 15 m antennas enclosed by appropriately scaled-down metal and dielectric space frame radomes, the crosspolar discrimination (XPD) and the borcsight shift (BS) have been computed close to antenna axis at 4 and 6 GHz. Comparisons with the larger 30.5 m antennas enclosed by 45 m radomes have been made. It is reported that within 0.1° of antenna boresight, the XPD introduced by the radomes does not exceed 33.0 dB as the worst case at 4 GHz. In particular, the Intelsat specification of 30.7 dB for the XPD within the antenna's tracking beamwidth in clear weather conditions for frequency re-use satellite communication systems is satisfied. The BS is negligibly low.
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Random access optical heterodyne receiver for coherent FDM broadcasting systems
  • Author(s): S. Yamazaki ; M. Shibutani ; N. Shimosaka ; S. Murata ; M. Shikada
  • Source: Electronics Letters, Volume 25, Issue 8, p. 507 –508
  • DOI:  10.1049/el:19890347
  • Type: Article
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  • p. 507 –508 (2)
    A random access optical heterodyne receiver for a coherent FDM broadcasting system has been developed, using a wavelength tunable local DBR LD, polarisation diversity technique and a random access automatic frequency controller. In a 10-channel FDM experimental system, 114 GHz capture range, 80 GHz lock range and arbitrary channel selection within less than 1 ms were realised.
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Comparison of sinusoidal and pulse modulation techniques for generating optical frequency reference combs
Minimum Euclidean distances of partial response multi-h phase-coded modulations with asymmetric modulation indices
0.15 μm GaAs MESFETs applied to ultrahigh-speed static frequency dividers
  • Author(s): T. Enoki ; S. Sugitani ; Y. Yamane
  • Source: Electronics Letters, Volume 25, Issue 8, p. 512 –513
  • DOI:  10.1049/el:19890350
  • Type: Article
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  • p. 512 –513 (2)
    0.15 μm gate-length FETs fabricated by SAINT using photolithography are applied to ultrahigh-speed static frequency dividers. Short channel effects are suppressed by a buried p-layer and shallow active layers formed by low energy implantations and rapid thermal annealing. The maximum cutoff frequency of the 0.15 μm gate-length FETs was 80.6 GHz. The maximum toggle frequency of the LSCFL one-quarter frequency divider is 26.8 GHz with a power dissipation of 263 mW.
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15 GHz static frequency-divider IC in silicon bipolar technology
Finite element/finite difference propagation algorithm for integrated optical device
GaInAs/AlGaInAs DH and MQW lasers with 1.5–1.7 μm lasing wavelengths grown by atmospheric pressure MOVPE
  • Author(s): R. Gessner ; M. Druminski ; M. Beschorner
  • Source: Electronics Letters, Volume 25, Issue 8, p. 516 –517
  • DOI:  10.1049/el:19890353
  • Type: Article
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  • p. 516 –517 (2)
    The first successful growth and fabrication of long wavelength (1.5–1.7 μm) DH and MQW lasers by atmospheric pressure MOVPE in a ‘phosphorus-free’ material system is reported. The GaInAs/AlGaInAs DH and MQW lasers were grown on InP substrates. DH lasers emitting at around 1690 nm exhibit threshold current densities down to 2.8 kA/cm2 at 25°C; the characteristic temperature is 50 K in the 15–55°C range. First MQW lasers with 1565 nm emission wavelength have threshold current densities around 3.2 kA/cm2.
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Resistive element using depletion mode MOSFETs
  • Author(s): P.A. Shoemaker ; M. Stewart ; R. Shimabukuro
  • Source: Electronics Letters, Volume 25, Issue 8, p. 518 –519
  • DOI:  10.1049/el:19890354
  • Type: Article
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  • p. 518 –519 (2)
    A two-terminal resistive element consisting of depletion-mode MOSFETs is described. This circuit can provide a combination of large resistance and extended range of linearity when compared with individual depletion-mode loads. A small-signal AC analysis has been performed to relate the frequency response of the element to the electrical parameters of the transistors and to the operating point. The circuit has been fabricated in thin-film silicon-on-sapphire and its operation demonstrated.
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Near-field far-field predictions from single-intensity-planar-scan phase retrieval
Median LMS algorithm
Monolithic integration of fully ion-implanted lateral GaInAs pin detector/InP JFET amplifier for 1.3–1.55 μm optical receivers
  • Author(s): W.S. Lee ; S.A. Kitching ; S.W. Bland
  • Source: Electronics Letters, Volume 25, Issue 8, p. 522 –523
  • DOI:  10.1049/el:19890357
  • Type: Article
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  • p. 522 –523 (2)
    An optical receiver front-end consisting of a lateral interdigitated GaInAs pin detector integrated with an InP JFET amplifier has been fabricated. This lateral detector structure simplifies the GaInAs material growth requirement to a single layer and provides low capacitance. A quasiplanar approach has been developed in conjunction with a two-level metallisation interconnect scheme. An optical sensitivity of −29 dBm was measured at 560 Mbit/s and 1.3 μm wavelength.
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Absorption and dispersion of low-loss dielectrics measured with microwave transient radiation
Novel content addressable memory
Adaptive nonlinear prediction of TV image sequences
Robust approximation of time series with Walsh functions
Harmonic balance model of laser diode
Digital circuit on x = 0.35 Hg1−xCdxTe
Learning by diffusion for multilayer perceptron
New CFE for system approximation
Fibre gyro experiment using fibre laser source
  • Author(s): K.A. Fesler ; B.Y. Kim ; H.J. Shaw
  • Source: Electronics Letters, Volume 25, Issue 8, p. 534 –536
  • DOI:  10.1049/el:19890366
  • Type: Article
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  • p. 534 –536 (3)
    Fibre lasers using Nd: glass fibre as the lasing medium have been shown earlier to be capable of broad emission bandwidth together with good temperature stability and high output power, which makes them attractive alternative sources for fibre gyros. We describe here initial experiments on an Nd: glass fibre laser source coupled to a fibre gyro. We find that the laser has high sensitivity to modulated optical feedback from the gyro, resulting in large rotation rate errors, and we show that low-frequency phase modulation within the laser cavity is a promising approach to suppression of this effect.
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Novel silicon-on-insulator MOSFET for high-voltage integrated circuits
MOCVD growth of GaAs/AlGaAs wavelength resonant periodic gain vertical cavity surface-emitting laser
  • Author(s): C.F. Schaus ; H.E. Schaus ; S. Sun ; M.Y.A. Raja ; S.R.J. Brueck
  • Source: Electronics Letters, Volume 25, Issue 8, p. 538 –539
  • DOI:  10.1049/el:19890368
  • Type: Article
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  • p. 538 –539 (2)
    The first all-semiconductor GaAs/AlGaAs vertical cavity laser incorporating wavelength resonant periodic gain layers grown by metalorganic chemical vapour deposition is reported. The optically pumped structure exhibits a threshold of 0.5 nJ at 852 nm for 720 nm pulsed excitation and energy conversion efficiencies up to ̃6%. The output linewidth is ≤0.4 nm FWHM with single longitudinal mode oscillation. An output of 0.43 nJ (~60 mW) is demonstrated at 300 K.
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Novel polarisation-frequency conversion-type polarisation diversity optical receiver
Improved wideband −3 dB nonuniform directional coupler
  • Author(s): S. Uysal  and  A.H. Aghvami
  • Source: Electronics Letters, Volume 25, Issue 8, p. 541 –542
  • DOI:  10.1049/el:19890370
  • Type: Article
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  • p. 541 –542 (2)
    A 2–20 GHz, −3 dB 90-degree directional coupler is designed and built on alumina substrate. The overall area occupied by the coupler is reduced by selecting a nonzero value for the initial coupling coefficient. A considerable improvement in the coupler performance is also achieved due to the reduced slopes of the wiggly coupled lines. Coupler design parameters and measured performance are presented.
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Power added efficiency optimisation of microwave transistor amplifier
  • Author(s): A. Algani ; H. Wang ; A. Konczykowska
  • Source: Electronics Letters, Volume 25, Issue 8, p. 542 –543
  • DOI:  10.1049/el:19890371
  • Type: Article
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  • p. 542 –543 (2)
    A high-efficiency microwave amplifier design routine which optimises the power added efficiency of any class (A, AB, B, C, D, E, …) of amplifier is reported. It has the advantage of a reduced variable number, and easy synthesis for input–output circuits. A heterojunction bipolar transistor amplifier at 1 GHz for mobile telephone applications has been optimised using this routine. The simulation result shows 71% of power added efficiency under class C operation.
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New intra-gate-offset high-voltage thin-film transistor with misalignment immunity
  • Author(s): T.-Y. Huang ; A.G. Lewis ; I.-W. Wu ; A. Chiang ; R.H. Bruce
  • Source: Electronics Letters, Volume 25, Issue 8, p. 544 –545
  • DOI:  10.1049/el:19890372
  • Type: Article
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  • p. 544 –545 (2)
    A new high-voltage thin-film transistor (HVTFT) which, for the first time, eliminates misalignment errors in the drain offset length is described. Unlike previous HVTFTs where the drain offset length is determined by the alignment of two masking layers, it is set in the new device by the separation of two gates defined with the same mask, and is therefore immune to alignment errors. The new intra-gate-offset (ITGO) scheme introduces no extra processing compared to conventional HVTFTs, and improves device uniformity and reproducibility, allowing a relaxed alignment tolerance on the normally critical n+ implant mask.
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Sensitivity degradation of conventional and balanced 3×3 port phase diversity DPSK receivers due to thermal and local oscillator intensity noise
Effects of energy relaxation time on performance of AlGaAs/GaAs heterojunction bipolar transistor
Narrow linewidth tunable operation of Er3+-doped single-mode fibre laser
Nonlinear quantisation of spectral shape in sub-band coding
Acquisition problem of class of second-order digital phase-locked loops
Erratum: Throughput of nonpersistent inhibit sense multiple access with capture
Erratum: On the CNET: a rearrangeably nonblocking optical interconnection network

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