Online ISSN
1350-911X
Print ISSN
0013-5194
Electronics Letters
Volume 23, Issue 9, 23 April 1987
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Volume 23, Issue 9
23 April 1987
New classes of complementary signals
- Author(s): B. Bartosiński and R. Zielonko
- Source: Electronics Letters, Volume 23, Issue 9, p. 433 –434
- DOI: 10.1049/el:19870312
- Type: Article
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New classes of so-called complementary signals (CSs)—power-type CSs and constant-amplitude CSs—useful for testing applications are proposed. Signal design relationships are derived. Preliminary investigations of the signals show that they may be applied to fast testing of linear circuits in the low or very low frequency region.
Noise performance of Gbit/s tuned optical receivers
- Author(s): J.X. Kan ; G. Jacobsen ; E. Bødtker
- Source: Electronics Letters, Volume 23, Issue 9, p. 434 –436
- DOI: 10.1049/el:19870313
- Type: Article
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We present design criteria for minimising the influence of f2 noise in broadband heterodyne optical receivers using a serial or parallel tuning inductor. The criteria are tested experimentally in a 2GHz-bandwidth front-end design. A 4dB receiver sensitivity improvement is demonstrated for a 400 Mbit/s ASK heterodyne application, and a 1 dB/2 dB sensitivity improvement is demonstrated for a 2 Gbit/s direct-detection/homodyne application.
New simple feed network for an array module of four microstrip elements
- Author(s): M.L. Oberhart ; Y.T. Lo ; R.Q.H. Lee
- Source: Electronics Letters, Volume 23, Issue 9, p. 436 –437
- DOI: 10.1049/el:19870314
- Type: Article
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A simple microstripline feed network for an array module comprising four microstrip elements is described. The advantages and disadvantages of the network are discussed as well as a theoretical explanation for the radiation characteristics of array modules using the network.
Spectral, phase noise and phase modulation characteristics of AM sideband injection-locked semiconductor lasers
- Author(s): K. Kikuchi and C.E. Zah
- Source: Electronics Letters, Volume 23, Issue 9, p. 437 –439
- DOI: 10.1049/el:19870315
- Type: Article
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AM sideband injection locking is demonstrated experimentally using 1.3μm DFB lasers. The slave laser is injection-locked to a 3 GHz AM sideband of the master laser. By controlling the injection power, a very stable injection-locked state of the slave laser can be achieved. The phase noise and phase modulation characteristics are also discussed.
Effect of residual doping on optimum structure of multiquantum-well optical modulators
- Author(s): D.J. Newson and A. Kurobe
- Source: Electronics Letters, Volume 23, Issue 9, p. 439 –440
- DOI: 10.1049/el:19870316
- Type: Article
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Using a variational method we have calculated the effect of residual doping on the optimum structure of multiquantum-well (MQW) optical modulators which utilise the quantum confined Stark effect. Residual doping gives a nonuniform electric field and a degraded modulation depth. For example, for a structure consisting of 100 Å GaAs wells and 100 Å Ga0.7A10.3As barriers, we calculate the optimum number of wells to be 20 for a doping of 5 × 1015 cm−3.
Novel fibre break locator for optical duplex transmission systems
- Author(s): P. Cochrane ; A.R. Hunwicks ; P.A. Rosher
- Source: Electronics Letters, Volume 23, Issue 9, p. 440 –442
- DOI: 10.1049/el:19870317
- Type: Article
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It is shown that duplex and diplex transmission systems inherently offer an accurate means of automatically detecting and locating fibre breaks. Theoretical and practical results from a 34 Mbit/s trial system are presented.
New systolic array for realising second-order recursive digital filters
- Author(s): H.K. Kwan
- Source: Electronics Letters, Volume 23, Issue 9, p. 442 –443
- DOI: 10.1049/el:19870318
- Type: Article
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A new systolic array for the realisation of a second-order recursive digital filter is presented. The systolic array is derived from a transformed digital transfer function. In so doing, a high throughput and regular systolic array consisting of only one type of basic cell can be derived.
Methods for the connection of signalling units to switching networks
- Author(s): A. Jajszczyk and W. Kabaciński
- Source: Electronics Letters, Volume 23, Issue 9, p. 443 –444
- DOI: 10.1049/el:19870319
- Type: Article
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Two methods for the connection of signalling units to digital switching networks are presented. The proposed methods make it possible to connect singalling units without affecting the traffic characteristics of networks.
Analysis of the stability of the highest-order supermode in semiconductor laser arrays
- Author(s): G.H.B. Thompson and J.E.A. Whiteaway
- Source: Electronics Letters, Volume 23, Issue 9, p. 444 –446
- DOI: 10.1049/el:19870320
- Type: Article
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Uniform evanescently coupled laser arrays tend to oscillate in the highest-order supermode. We show by modelling that this supermode is much more stable with increasing output power than the zero-order supermode.
Surface-acoustic-wave device incorporating conducting Langmuir-Blodgett films
- Author(s): B. Holcroft ; G.G. Roberts ; A. Barraud ; J. Richard
- Source: Electronics Letters, Volume 23, Issue 9, p. 446 –447
- DOI: 10.1049/el:19870321
- Type: Article
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Surface-acoustic-wave (SAW) devices incorporating conducting Langmuir-Blodgett (LB) films are reported for the first time. Excellent characteristics have been obtained using a mixed valence charge tranfer salt of a substituted pyridinium tetracyanoquinodimethane. The control afforded by the deposition technique has enabled the fractional change in surface wave velocity due to the electrical effects to be distinguished from those due to mass loading. The resistivity of the organic surface layer is measured to be 2Ωcm.
Dual-gate silicon permeable-base transistors built on LPVPE-grown material
- Author(s): A. Gruhle ; L. Vescan ; H. Beneking
- Source: Electronics Letters, Volume 23, Issue 9, p. 447 –449
- DOI: 10.1049/el:19870322
- Type: Article
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Permeable-base transistors have been fabricated on epitaxial silicon layers grown by low-pressure vapour-phase epitaxy. Reactive ion etching is used to form the grooved-etched transistors with 0.5-2 μm-wide channels. The emitter geometry permits self-aligned formation of two separate base electrodes which can be useful in mixer applications. Measured gm values of 62 mS/mm are the highest yet reported for Si PBTs.
Single-mode-fibre passive components made in the fused-head-end technique
- Author(s): P.J. Severin
- Source: Electronics Letters, Volume 23, Issue 9, p. 449 –450
- DOI: 10.1049/el:19870323
- Type: Article
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The fused-head-end technique, used successfully until now for producing passive fibre components in multimode fibre, can also be applied to produce single-mode fibre couplers and splitters. The device is based on evanescent mode coupling and has no pigtail problem. The first experimental results are presented, together with the theoretical interpretation. Some expected system applications and further improvements are indicated.
Role of Petermann's K-factor in semiconductor laser oscillators—a further note
- Author(s): J. Arnaud
- Source: Electronics Letters, Volume 23, Issue 9, p. 450 –451
- DOI: 10.1049/el:19870324
- Type: Article
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The classical Schawlow–Townes formula for the linewidth of a laser should be multiplied by a factor K' = (1+αA2)K/2. In this formula, αA, is the ratio of changes in the real and imaginary parts of the compl resonant frequency resulting from a change in carrier density, and K is Petermann's factor. It is shown here that this factor is identical to a result reported in 1971 by other authors in connection with impact oscillators.
Very low-loss GaInAs/InP optical waveguides for the 10.6μm wavelength
- Author(s): D. Delacourt ; M. Papuchon ; M.A. Di Forte-Poission ; M. Razeghi
- Source: Electronics Letters, Volume 23, Issue 9, p. 451 –453
- DOI: 10.1049/el:19870325
- Type: Article
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Optical waveguides for the 10.6μm wavelength have been fabricated using the MOCVD technique in the InP/GaInAs system. First, the indices of refraction of the relevant materials are determined using integrated-optic techniques. Then, high-optical-quality optical waveguides are reported with propagation losses as low as 0.7 dB/cm. These structures are the basis of more sophisticated electrically controlled devices for 10.6 μm.
Ultrafast optical multi/demultiplexer utilising optical kerb effect in polarisation-maintaining single-mode fibres
- Author(s): T. Morioka ; M. Saruwatari ; A. Takada
- Source: Electronics Letters, Volume 23, Issue 9, p. 453 –454
- DOI: 10.1049/el:19870326
- Type: Article
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An ultrafast time-domain optical multi/demultiplexer utilising the optical Kerr effect in two birefringent fibres concatenated with each fast axis crossed is proposed. Stable demultiplexing of an ultrashort 30 ps optical pulse train at 1.97 GHz from a gain-switched DFB LD has been successfully demonstrated using CW mode-locked Nd:YAG laser control pulses.
New proposal for a multigigabit/s clock recovery IC based on a standard silicon bipolar technology
- Author(s): Z. Wang and U. Langmann
- Source: Electronics Letters, Volume 23, Issue 9, p. 454 –456
- DOI: 10.1049/el:19870327
- Type: Article
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A clock recovery IC for optical fibre communication at multigigabit/s is proposed. The clock frequency extracted corresponds to half the bit rate. The 2:1 frequency division is carried out by a double balanced mixer and the frequency selection by an SAW filter. Circuit simulations are based on a standard 2 μm silicon bipolar technology. The circuit was optimisd at 3.4 Gbit/s for a power consumption of 220 mW with a 1.7 GHz SAW filter (Q = 340). The dynamic clock phase jitter, estimated from circuit simulations, is less than 0.5°. Circuit simulations predict that the operating bit rate may be exended up to 4.5 Gbit/s.
Cooling characteristics of diamond-shaped interrupted cooling fin for high-power LSI devices
- Author(s): T. Kishimoto and S. Saski
- Source: Electronics Letters, Volume 23, Issue 9, p. 456 –457
- DOI: 10.1049/el:19870328
- Type: Article
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We propose a diamond-shaped interrupted microgrooved cooling fin to decrease the junction temperature variation across the chip. The analytical result indicates that the junction temperature variation decreses to less than 25% compared with a conventional paralles-plate-shaped cooling fins. This cooling structure is sufficient to cool high-power-consumption silicon chips.
Comment: Thermal model of laser diode arrays
- Author(s): D.J. Dean
- Source: Electronics Letters, Volume 23, Issue 9, page: 457 –457
- DOI: 10.1049/el:19870329
- Type: Article
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Reply: Thermal model of laser diode arrays
- Author(s): W. Nakwaski
- Source: Electronics Letters, Volume 23, Issue 9, page: 458 –458
- DOI: 10.1049/el:19870330
- Type: Article
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CMOS logic cell switching speed thermal characterisation
- Author(s): F.S. Shoucair
- Source: Electronics Letters, Volume 23, Issue 9, p. 458 –460
- DOI: 10.1049/el:19870331
- Type: Article
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A study of the switching speed performance of basic CMOS logic cells in the (junction) temperature range 25–250°C is reported. Experimental measurements for capacitively loaded inverters and NAND gates of two standard 4 μm CMOS processes are compared to theory and to SPICE2G. 6 simulations. It is found that, to a good approximation, a simple delineation factor (lying between 0.004 and 0.006/deg C in this study), applied to the average gate delay at a given temperature, correctly predicts this parameter. Logic cells are thereby typically found to be up to 65% slower at 250°C than they are at room temperature.
Modified bit-level systolic inner product/convolver architecture with increased throughput
- Author(s): R.A. Evans and R. Eames
- Source: Electronics Letters, Volume 23, Issue 9, p. 460 –461
- DOI: 10.1049/el:19870332
- Type: Article
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We show how the architecture of a recently proposed bit-level systolic convolver/inner product array can be modified to provide a significantly improved word throughput rate. The approach is particularly beneficial to applications involving large numbers of low-resoultion products, and in some cases a 100% improvement in throughput can be achieved.
Role of source N+N- structure in parasitic bipolar action of lightly doped short-channel MOSFETs
- Author(s): N.D. Janković
- Source: Electronics Letters, Volume 23, Issue 9, p. 461 –463
- DOI: 10.1049/el:19870333
- Type: Article
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Theoretical and experimental evidence of the influence of N+N- source structures, encountered in state-of-the-art short-channel NMOSTs, on the value of the breakdown sustaining voltage is presented. It appears that, by increasing the distance between the high-low diffusion junction and the N-P metallurgical junction, one decreases the emitter (source) efficiency and also the current gain of the parasitic bipolar transistor. Taking this effect into account, the same value of breakdown sustaining voltage with a lower series source and drain resistivity may be achieved. This is shown experimentally.
Optical-fibre Fabry–Perot frequency discriminator for communications applications
- Author(s): L.J. Cimini ; J. Stone ; L.L. Buhl
- Source: Electronics Letters, Volume 23, Issue 9, p. 463 –464
- DOI: 10.1049/el:19870334
- Type: Article
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We demonstrate the use of a fibre Fabry–Perot interferometer as an optical frequency discriminator for communications applications. The operation of this device has been characterised for sinusoidally phase-modulated signals. Distortion results are presented for several modulation frequencies and modulation depths. It is observed that distortion is acceptably low for modulation frequencies up to nearly the spectral width of the Fabry–Perot bandpass.
Narrow-bandwidth optical waveguide transmission filters
- Author(s): K.O. Hill ; D.C. Johnson ; F. Bilodeau ; S. Faucher
- Source: Electronics Letters, Volume 23, Issue 9, p. 465 –466
- DOI: 10.1049/el:19870335
- Type: Article
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A general method for fabricating narrowband transmission filters at optical frequencies is proposed. For fibre- or integrated-optic applications the method consists of forming a waveguide loop by connecting the output ports of a 3dB coupler to each other. A Bragg reflection grating in the loop determines the filters frequency response.
Fast computation of discrete Hartley transform via Walsh–Hadamard transform
- Author(s): Chau-Yun Hsu and Ja-Ling Wu
- Source: Electronics Letters, Volume 23, Issue 9, p. 466 –468
- DOI: 10.1049/el:19870336
- Type: Article
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A new fast algorithm is proposed to compute the discrete Hartley transform (DHT) via the Walsh–Hadamard transform (WHT). The processing is carried out on an interframe basis in (N × N) data blocks, where N is an integer power of two. The WHT coefficients are obtained directly, and then used to obtain the DHT coefficients. This is achieved by a transform matrix, the H-transform matrix, which is ortho-normal and has a block-diagonal structure. A complete derivation of the block-diagonal structure for the H-transform matrix is given.
Gate current in 0.75μm N-channel MOSFETs with doubly diffused drain
- Author(s): R.K. Watts ; L. Manchanda ; R.L. Johnston
- Source: Electronics Letters, Volume 23, Issue 9, p. 468 –469
- DOI: 10.1049/el:19870337
- Type: Article
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The MOSFET with doubly diffused drain has been proposed as a solution to the problem of degradation in small MOSFETs. We find good agreement between measured gate current and values calculated assuming that the gate current is due to hot channel electrons thermionically emitted into the gate oxide.
Switching characteristics of a piezoelectrical actuated evanescent-wave directional coupler
- Author(s): H. Berthou and L. Falco
- Source: Electronics Letters, Volume 23, Issue 9, p. 469 –471
- DOI: 10.1049/el:19870338
- Type: Article
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A single-mode-fibre evanescent-wave coupler can be used as an optical switch. The fabrication and technical features of such a device are described. Extension of this switch to wavelength multiplexing is presented.
Stable pulsations of semiconductor lasers by optoelectronic feedback with avalanche photodiodes
- Author(s): P. Paulus ; R. Langenhorst ; D. Jäger
- Source: Electronics Letters, Volume 23, Issue 9, p. 471 –472
- DOI: 10.1049/el:19870339
- Type: Article
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Experimentally, stable pulsations of semiconductor lasers are achieved by using optoelectronic feedback via an avalanche photodiode and a coaxial delay line. The observed micro-wave spectrum yields a linewidth (–3 dB) down to 90 kHz at 1.7 GHz. The pulse width is determined to be 130 ps.
Guided-wave multi/demultiplexers with high stopband rejection
- Author(s): K. Imoto ; H. Sano ; M. Miyazaki ; Y. Takasaki
- Source: Electronics Letters, Volume 23, Issue 9, p. 472 –473
- DOI: 10.1049/el:19870340
- Type: Article
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A new guided-wave multi/demultiplexer with high stopband rejection is realised using high-silica embedded channel waveguides. This consists of three directional couplers of the same structure. That is, the second and third directional couplers are connected with two output waveguides of the first directional coupler. This multi/demultiplexer is fabricated using chemical vapour deposition, lithography and reactiveion-etching processes. Its structure is convenient for applying a stand-by module to improve reliability and for accommodating a two-way repeater transmission module using wavelength division multiplexing, as well as for other various uses.
Performance of LMS algorithm as a function of input signal pole loci
- Author(s): G.J. Freij and B.M.G. Cheetham
- Source: Electronics Letters, Volume 23, Issue 9, p. 474 –475
- DOI: 10.1049/el:19870341
- Type: Article
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The degree to which the performance of the adaptive LMS transversal filter depends on the ratio of the extreme eigen-values of the input autocorrelation matrix is investigated. Subsequently, performance is related to the spectral properties of the input signal via a study of the relationship between the eigenvalues and the loci of the poles characterising the input signal.
Low-noise D-band IMPATT oscillators
- Author(s): J. Wenger and S. Huber
- Source: Electronics Letters, Volume 23, Issue 9, p. 475 –476
- DOI: 10.1049/el:19870342
- Type: Article
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The single-sideband FM noise characteristics of IMPATT diode oscillators for D-band frequencies have been measured by means of a direct-detection system with a high-Q quasi-optical resonator. For an n-type silicon single-drift IMPATT diode a Δfrms of 11 Hz/√Hz and a noise measure of 37 dB at 137.5 GHz and 26 mW output power was determined.
Bist structure using multi-input shift register with initial value
- Author(s): A. Hlawiczka
- Source: Electronics Letters, Volume 23, Issue 9, p. 476 –478
- DOI: 10.1049/el:19870343
- Type: Article
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Parallel signature analysers are very useful for compression of test response data for VLSI. In the letter the compression result is obtained from a signature of zeros alone or ones alone from a nonzero initial state, rather than from the traditional method of obtaining a nonzero signature from a zeroed MISR register. An algebraic description of such a signature analysis is given, realised by means of the external exclusive-OR-type MISR.
Optical receiver with optical feedback
- Author(s): G.S. Forsberg
- Source: Electronics Letters, Volume 23, Issue 9, p. 478 –480
- DOI: 10.1049/el:19870344
- Type: Article
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A new optical receiver with optical feedback is described. The optical feedback is implemented by feeding back a fraction of the light from an optical source which is connected to the output of the receiver, to an extra photodiode. The proposed theoretical model was found to be in good agreement with measurement results on a 5 MHz optical receiver.
Erratum: Wavelength dependence of optical oxidation of silicon
- Author(s): I.W. Boyd and F. Micheli
- Source: Electronics Letters, Volume 23, Issue 9, page: 480 –480
- DOI: 10.1049/el:19870345
- Type: Article
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Erratum: Taylor series approach to functional approximation for inversion of Laplace transforms
- Author(s): Hung-Yuan Chung and York-Yih Sun
- Source: Electronics Letters, Volume 23, Issue 9, page: 480 –480
- DOI: 10.1049/el:19870346
- Type: Article
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Erratum: Narrowband digital voice communications over a meteor burst channel
- Author(s): J.R. Herman ; C.C. Duggan ; W.I. Thompson ; R.A. Costa ; D.M. Deluca
- Source: Electronics Letters, Volume 23, Issue 9, page: 480 –480
- DOI: 10.1049/el:19870347
- Type: Article
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Addendum: Missing boundary conditions of electromagnetics
- Author(s): K.A. Michalski
- Source: Electronics Letters, Volume 23, Issue 9, page: 480 –480
- DOI: 10.1049/el:19870348
- Type: Article
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