Online ISSN
1350-911X
Print ISSN
0013-5194
Electronics Letters
Volume 34, Issue 2, 22 January 1998
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Volume 34, Issue 2
22 January 1998
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- Author(s): S.K. Satpathy ; K.P. Ray ; G. Kumar
- Source: Electronics Letters, Volume 34, Issue 2, p. 137 –138
- DOI: 10.1049/el:19980203
- Type: Article
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–138
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A circular microstrip antenna has been modified by shorting along the zero field to yield shorted semi-circular and 90° sectoral microstrip antennas. Experimental results on these antennas are presented. The shorted 90° sectoral antenna results in a size reduction of four times without any significant change in performance. The area is further reduced by partially shorting one of the edges of the 90° sectoral antenna. - Author(s): Chih-YuHuang ; Jian-YiWu ; Cheng-FuYang ; Kin-LuWong
- Source: Electronics Letters, Volume 34, Issue 2, p. 138 –139
- DOI: 10.1049/el:19980167
- Type: Article
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–139
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With the loading of a high-permittivity superstrate layer and a 1 Ω chip resistor, a compact rectangular microstrip antenna with enhanced gain and wider bandwidth can be implemented. With the antenna size reduced to be ~6% times that of a conventional patch antenna, the proposed structure can have an operating bandwidth of more than six times that of a conventional patch antenna, with an almost equal antenna gain level. Details of the experimental results are presented and discussed. - Author(s): Á. Serrano-Vaello and D. Sánchez-Hernández
- Source: Electronics Letters, Volume 34, Issue 2, p. 140 –141
- DOI: 10.1049/el:19980215
- Type: Article
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–141
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The recent developments of dual-band dual-mode D-AMPS/AMPS mobile handsets and radiostations has increased pressure on GSM service providers to follow similar technology breakthroughs as a first step towards IMT2000. A frequency-agile device accommodating both GSM standard frequency bands would serve more than 25 million GSM subscribers, with expectations as high as 100 million subscribers by the year 2000. Novel dual-band printed bow-tie antenna elements developed for dual-mode GSM/DCS 1800 handsets are described.
Compact shorted variations of circular microstrip antennas
Gain-enhanced compact broadband microstrip antenna
Printed antennas for dual-band GSM/DCS 1800 mobile handsets
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- Author(s): B. Al-Besher ; A. Bouridane ; A.S. Ashur ; D. Crookes
- Source: Electronics Letters, Volume 34, Issue 2, p. 141 –143
- DOI: 10.1049/el:19980093
- Type: Article
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A novel low latency, most significant digit-first, signed digit multiplier architecture is presented. The design of the multiplier is based on a new 2 bit adder cell. Judicious deployment of latches in the circuit ensures that the multiplier operates on two coefficients of the multiplicand at the same time and produces one 2n digit product every 2n+3 cycles with an initial delay (latency) of three cycles. Comparison with existing multipliers has shown a superior performance of the proposed architecture.
Hybrid low-latency serial-parallel multiplier architecture
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- Author(s): Chee HockNg and LirenZhang
- Source: Electronics Letters, Volume 34, Issue 2, p. 143 –144
- DOI: 10.1049/el:19980175
- Type: Article
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ATM25 is a 25.6 mbit/s ATM specifiction approved by the ATM Forum. The authors present a queueing solution for dimensioning the buffer cell loss requirement of an ATM25 switch which was implemented using field programmable gate arrays. - Author(s): Ing-JiunnSu and JingshownWu
- Source: Electronics Letters, Volume 34, Issue 2, p. 144 –145
- DOI: 10.1049/el:19980171
- Type: Article
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The capacity of binary frequency shift keying (BFSK) frequency-hopped multiple access (FHMA) systems with side information is derived. The use of erasure decision with ratio-threshold test (RTT) for generating side information in fading and non-fading channels is investigated. The authors demonstrate the benefits of using erasure decision, achievable maximum capacity, optimum threshold setting and the optimal number of users in order to maximise the capacity. - Author(s): F. Barceló and J. Jordán
- Source: Electronics Letters, Volume 34, Issue 2, p. 146 –147
- DOI: 10.1049/el:19980165
- Type: Article
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–147
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A simple procedure is presented for characterising the probability distribution function of the dwell time in a cellular telephony system. Other statistical figures related to mobility are also provided. - Author(s): S. Chen ; M.A. Beach ; J.P. McGeehan
- Source: Electronics Letters, Volume 34, Issue 2, p. 147 –148
- DOI: 10.1049/el:19980022
- Type: Article
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–148
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Division-free duplex is proposed for future wireless systems, thus providing simultaneous duplex radio transmission on a division-free basis. The required duplex isolation can be achieved by electronic interference cancellation operating at both RF and baseband, with results from an experimental RF system yielding some 72 dB duplex isolation at 1.8 GHz for 200 kHz channelisation. - Author(s): HongyiFu ; GuoanBi ; K. Arichandran
- Source: Electronics Letters, Volume 34, Issue 2, p. 149 –150
- DOI: 10.1049/el:19980178
- Type: Article
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A practical model is presented for analysing the multiple access interference due to all visible interfering users in CDMA-based multispot beam LEO satellite systems. The authors calculate the average bit error rate with perfect power control for different numbers of interfering users, showing that the amount of MAI has a substantial effect on the system capacity. - Author(s): M.S. Alencar
- Source: Electronics Letters, Volume 34, Issue 2, p. 150 –151
- DOI: 10.1049/el:19980170
- Type: Article
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The authors present a new bound on the estimation of the probability density function of random signals, using Woodward's theorem, correlation techniques and spectral analysis. The proposed method is based on the spectral analysis of the random process. - Author(s): SeongJoonBaek ; BumKiJeon ; DaeryongLee ; Koeng-MoSung
- Source: Electronics Letters, Volume 34, Issue 2, p. 151 –152
- DOI: 10.1049/el:19980217
- Type: Article
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A fast clustering algorithm is presented as an alternative to the K-means algorithm. By encoding training vectors selectively and changing the codebook updating step, the algorithm reduces the computation time. Simulations show that the algorithm outperforms the K-means algorithm in computation time and performance in terms of mean-squared-error. - Author(s): Woo-JuneKim and Byeong GiLee
- Source: Electronics Letters, Volume 34, Issue 2, p. 152 –154
- DOI: 10.1049/el:19980049
- Type: Article
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(3)
The authors present the FRED (fair random early detection) algorithm as a congestion control mechanism for TCP over ATM networks. The FRED algorithm enhances the RED gateway algorithm, by using the fact that TCP connections should be allocated buffer space in proportion to their bandwidth-delay products. Through simulation, the effectiveness of the proposed FRED algorithm is shown as compared with the drop-tail and the original RED algorithms. - Author(s): XiaodongWu ; YongmingLi ; HongyiChen
- Source: Electronics Letters, Volume 34, Issue 2, p. 154 –155
- DOI: 10.1049/el:19980143
- Type: Article
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The authors present a multi-domain speech compression method based on a wavelet packet transform. The signals are compressed in domains with different time-frequency resolutions according to their energy distribution in these domains. It is shown that this method is simple to implement and is effective at compressing speech and audio signals, even at bit rates as low as 2 kbit/s. - Author(s): M.S. Alencar
- Source: Electronics Letters, Volume 34, Issue 2, p. 155 –156
- DOI: 10.1049/el:19980169
- Type: Article
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The author presents a procedure for optimising the scalar quantiser, based on the power spectrum density of the quantisation noise. The input signal is assumed to be stationary in the wide sense, but no restriction is made concerning its probability density function. - Author(s): Seung HoChoi ; Hong KookKim ; Hwang SooLee ; R.M. Gray
- Source: Electronics Letters, Volume 34, Issue 2, p. 156 –157
- DOI: 10.1049/el:19980101
- Type: Article
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p.
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–157
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A low-complexity speech recognition method applicable to digital communication networks is proposed. A feature set suitable for speech recognition is obtained from quantised LSP parameters in CELP-type coders without reconstructing the speech signals. The authors present the effects of the speech coder on speaker-independent recognition performance, and show that the recognition accuracy of the proposed method is better than that of the recogniser using reconstructed speech signals. - Author(s): G.S. Taylor and G.M. Blair
- Source: Electronics Letters, Volume 34, Issue 2, p. 158 –159
- DOI: 10.1049/el:19980156
- Type: Article
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p.
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–159
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The two-dimensional micropipeline is introduced for data conversion between bit-parallel and bit-serial formats at a constant input data rate. By using micropipelines, the architecture has independent clock rates for the data input and output, and can be designed with level sensitive latches.
Buffer dimensioning of ATM25 switch
Capacity of a synchronous BFSK frequency-hopped multiple access system with RTT erasure decision
Channel holding time distribution in cellular telephony
Division-free duplex for wireless applications
Effect of multiple access interference on performance of multi-beam CDMA-based LEO satellite systems
Estimation of probability density function using spectral analysis
Fast clustering algorithm for vector quantisation
FRED - fair random early detection algorithm for TCP over ATM networks
Multi-domain speech compression based on wavelet packet transform
Optimisation of quantisers in the frequency domain
Speech recognition method using quantised LSP parameters in CELP-type coders
Two-dimensional micropipelines: for parallel-to-serial data conversion
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- Author(s): D.V. Poornaiah
- Source: Electronics Letters, Volume 34, Issue 2, p. 159 –160
- DOI: 10.1049/el:19980196
- Type: Article
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p.
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A new sign extension bit minimisation algorithm is presented to design efficient inner-product-processor cells with reduced area and computation time. Design examples are presented for the sake of illustration. - Author(s): S. Villareal ; M. Weichold ; J. Pineda
- Source: Electronics Letters, Volume 34, Issue 2, p. 161 –162
- DOI: 10.1049/el:19980174
- Type: Article
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p.
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–162
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The authors have applied a simple modelling approach for multiple resonant tunnelling transistors (mRTTs) which includes four resonant tunnelling diodes (RTDs) within the transistor structure. Unique features of this model, corresponding to device features compatible for integrated circuits, allow for tuning and matching the devices for optimum circuit performance. Two circuits are presented for analogue to quaternary conversion with analysis of their transfer characteristics; this analysis is consistent with the simulation results and implies that circuits of physical devices may be successfully implemented.
Sign extension bit minimisation algorithm for designing VLSI inner-product-processor cells for DSP applications
Simulation study of compact quantising circuits using multiple-resonant tunnelling transistors
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- Author(s): T. Isernia and G. Panariello
- Source: Electronics Letters, Volume 34, Issue 2, p. 162 –164
- DOI: 10.1049/el:19980212
- Type: Article
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The authors present a new approach for determining the excitations of a given set of sources that will produce a maximum field in a given direction subject to arbitrary sidelobe bounds. The approach guarantees attainment of the globally optimal solution for a large class of pencil beam synthesis problems, including possible near field constraints.
Optimal focusing of scalar fields subject to arbitrary upper bounds
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- Author(s): A.S. Korotkov
- Source: Electronics Letters, Volume 34, Issue 2, p. 164 –165
- DOI: 10.1049/el:19980182
- Type: Article
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p.
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–165
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It is well known that a doubly terminated lossless ladder network has zero sensitivity to each element at every frequency of maximum power transfer. The author shows that a singly terminated ladder network, with the same frequency response as a doubly terminated ladder network, has the same points of zero sensitivity to simultaneous changes in the values of the elements of the same type by an equal relative amount. This result has been extended to cover FDNR-based filters.
Sensitivity of singly and doubly terminated prototype circuits
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- Author(s): Jiann-DerLee
- Source: Electronics Letters, Volume 34, Issue 2, p. 165 –166
- DOI: 10.1049/el:19980146
- Type: Article
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p.
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–166
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A GA-based stereo matching algorithm is proposed for finding the correspondences among multi-polyhedron objects in a three-view system. An optimal camera configuration is used to reduce the feature searching area and a genetic algorithm is employed to refine the matching results. Experimental results show that the 3D multiple polyhedra in a complex scene can be successfully reconstructed. The proposed algorithm is fast, requires little memory, and is noise tolerant. - Author(s): E. Casilari ; M. Lorente ; A. Reyes ; A. Díaz Estrella ; F. Sandoval
- Source: Electronics Letters, Volume 34, Issue 2, p. 166 –168
- DOI: 10.1049/el:19980121
- Type: Article
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–168
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A new model for variable bit rate (VBR) video traffic is presented. The model, which could be used as a traffic generator, considers two time scales: scenes, for periods of several minutes, and groups of pictures (GOP), for periods of half a second. To model the scene changes, a Markov chain is used. For the GOP level, a modification for the projected autorregresive (PAR) model is proposed so that the fitting of the autocorrelation function is improved. The model is used to imitate two real MPEG video signals, showing that it is able to accurately capture the behaviour of the real traffic in a queue.
GA-based three-view matching algorithm for multi-polyhedron reconstruction
Scene oriented model for VBR video
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- Author(s): A.K. Khandani
- Source: Electronics Letters, Volume 34, Issue 2, p. 168 –169
- DOI: 10.1049/el:19980020
- Type: Article
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p.
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–169
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The author discusses the group property of turbo-codes when considered as a periodic linear system. It is shown that the interleaving procedure provides a homomorphism between different encoded sequences and thereby breaks the low weight sequences by a factor of, at most, 1/2r, where r is the constraint length of the code. - Author(s): C. Tellambura
- Source: Electronics Letters, Volume 34, Issue 2, p. 169 –170
- DOI: 10.1049/el:19980163
- Type: Article
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p.
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–170
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Recent research suggests combining partial transmit sequences (PTSs) to reduce the peak-to-average power ratio of orthogonal frequency division multiplexing (OFDM). The author presents a new optimisation criterion for PTS and estimates the resulting peak factor reduction. - Author(s): Lim LekHeng
- Source: Electronics Letters, Volume 34, Issue 2, p. 170 –172
- DOI: 10.1049/el:19980195
- Type: Article
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p.
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The author shows that the Cao-Li cryptosystem proposed in is not secure. Its private key can be reconstructed from its public key using elementary means such as LU-decomposition and the Euclidean algorithm.
Group structure of turbo-codes
Phase optimisation criterion for reducing peak-to-average power ratio in OFDM
Security of the Cao-Li public key cryptosystem
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- Author(s): Su Jin Ahn and Dae MannKim
- Source: Electronics Letters, Volume 34, Issue 2, p. 172 –173
- DOI: 10.1049/el:19980157
- Type: Article
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p.
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–173
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An analogue-to-digital conversion scheme based on the e-periodic transfer characteristics of an SET inverter is proposed. The authors demonstrate the 4 bit analogue-to-digital converter performance using Monte-Carlo simulation in which an SET inverter implements a binary quantiser and encoder for one significant bit. This scheme can be easily extended to higher order bits. - Author(s): G. Stochino
- Source: Electronics Letters, Volume 34, Issue 2, p. 173 –174
- DOI: 10.1049/el:19980159
- Type: Article
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p.
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–174
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A new wide dynamic range, class AB, bipolar differential voltage-to-current converter (DVCC), which features a virtually constant transconductance (gm) over the useful dynamic range and is suitable for monolithic IC fabrication, is described. The new DVCC, which additionally provides fairly good DC-AC performance, is mainly intended for precision, high-speed analogue signal conditioning and processing applications and building blocks, such as fast settling operational amplifiers, fast settling front ends for analogue to digital converters and digital to analogue converters. Some SPICE simulation results are also reported, which demonstrate the effectiveness of the proposed technique. - Author(s): J. Mahattanakul and C. Toumazou
- Source: Electronics Letters, Volume 34, Issue 2, p. 175 –176
- DOI: 10.1049/el:19980172
- Type: Article
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p.
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–176
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A linear BiCMOS transconductance amplifier based on a MOS transistor operated in the linear region is presented. The circuit uses regulated cascode techniques to restrict the variation of the drain-source voltage of the MOS device and hence enhance the linearity of the V-I conversion. Simulation results confirm that the proposed circuits have superior linearity compared with other transconductance amplifiers operating in the linear region.
Asynchronous analogue-to-digital converter for single-electron circuits
Class AB wide dynamic range bipolar differential voltage-to-current converter with constant transconductance
Tunable low-distortion BiCMOS transconductance amplifiers
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- Author(s): K. Takada ; Y. Hida ; S. Mitachi
- Source: Electronics Letters, Volume 34, Issue 2, p. 176 –178
- DOI: 10.1049/el:19980134
- Type: Article
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The authors report the length dependence of polarisation crosstalk for a 10 m long silica-based waveguide in which the total polarisation crosstalk is 8.9 × 10–3. This is achieved by numerically integrating the coupling strength obtained by using low coherence interference between excited and orthogonally coupled light waves along the length of the waveguide. A comparison of the measured and theoretical crosstalk curves leads to confirmation that the bends in the waveguide are the main origin of the crosstalk. The polarisation crosstalk per bent section is 4.7 × 10–5. - Author(s): B. Madhavan and A.F.J. Levi
- Source: Electronics Letters, Volume 34, Issue 2, p. 178 –179
- DOI: 10.1049/el:19981476
- Type: Article
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0.5 µm CMOS technology is used to drive oxide-confined low-threshold current vertical cavity surface emitting laser diodes at 2.5 Gbit/s. The 7 mW power consumption for the optoelectronic transmitter is twenty times less than a 3.6 V electronic positive emitter coupled logic transmit circuit and four times less than a 3.6 V electronic low voltage differential signal transmit circuit.
Growth of polarisation crosstalk along a silica-based optical waveguide
Low-power 2.5 Gbit/s VCSEL driver in 0.5 µm CMOS technology
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- Author(s): H. Shi ; G.A. Alphonse ; J.C. Connolly ; P.J. Delfyett
- Source: Electronics Letters, Volume 34, Issue 2, p. 179 –181
- DOI: 10.1049/el:19980155
- Type: Article
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A 20 wavelength optical WDM transmitter capable of transmitting 12 ps pulses at 5 Gbit/s for an aggregate rate of 100 Gbit/s has been experimentally demonstrated, based on a modelocked semiconductor laser. Temporal synchronisation and wideband spectral correlation between the multiwavelength pulses are also achieved. - Author(s): A.V. Naumenko ; N.A. Loiko ; S.I. Turovets ; P.S. Spencer ; K.A. Shore
- Source: Electronics Letters, Volume 34, Issue 2, p. 181 –182
- DOI: 10.1049/el:19980214
- Type: Article
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The authors demonstrate that nonlinear and chaotic dynamics in external cavity laser diodes can be controlled by the use of optimised impulsive delayed feedback applied via the laser drive current. Attention is given to practical constraints arising from technical delay in application of the control signal. The rapid convergence to a targetted dynamical state of the laser is graphically shown by the diminishing amplitude of the required control pulses. - Author(s): Min-YongJeon ; Hak KyuLee ; Joon TaeAhn ; Dong SungLim ; Ho YoungKim ; Kying HonKim ; El-HangLee
- Source: Electronics Letters, Volume 34, Issue 2, p. 182 –184
- DOI: 10.1049/el:19980139
- Type: Article
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p.
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The authors have obtained, for the first time to their knowledge, pulse amplitude equalisation in a high repetition rate (up to 22.6 GHz) pulse train, which is generated from rational harmonic modelocking of an Er-doped fibre ring laser, by using an equalising fibre laser. The equalising fibre laser is based on a passively modelocked laser with an NALM (nonlinear amplifying loop mirror) and a Faraday rotating mirror. - Author(s): S. O'Brien ; H. Zhao ; R.J. Lang
- Source: Electronics Letters, Volume 34, Issue 2, p. 184 –186
- DOI: 10.1049/el:19980095
- Type: Article
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–186
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Wide aperture lasers are fabricated which produce record maximum powers of 11.3 and 16.5 W CW at 870 nm from 100 and 200 µm wide apertures, respectively. These powers are approximately two-fold higher than those previously reported in this wavelength regime and are also the highest reported CW powers from wide aperture lasers at any wavelength. - Author(s): Chia-ChienLin ; Kuo-ShungLiu ; Meng-ChyiWu ; Hung-PinShiao
- Source: Electronics Letters, Volume 34, Issue 2, p. 186 –187
- DOI: 10.1049/el:19980211
- Type: Article
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Highly uniform characteristic 12-element monolithic AlGaInAs/InP 1.5 µm strain-compensated multiquantum well ridge laser arrays with low threshold current and high characteristic temperature have been achieved. The array element exhibits a threshold current of 5.4 mA and a characteristic temperature of 90 K. Excellent uniformity, with standard deviations of 0.14 mA, 0.007 W/A, and 1.13 nm for threshold current, slope efficiency and lasing wavelength, respectively, were obtained. - Author(s): P. Schnitzer ; M. Grabherr ; R. Jäger ; C. Jung ; K.J. Ebeling
- Source: Electronics Letters, Volume 34, Issue 2, p. 187 –189
- DOI: 10.1049/el:19980179
- Type: Article
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–189
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Linear 1 × 8 arrays of laterally oxidised, polyimide passivated singlemode, single-polarisation GaAs VCSELs are investigated for parallel optical interconnection. The authors demonstrate 24 Gbit/s (8 × 3 Gbit/s) data transmission with 231 – 1 PRBS signals over 500 m of graded index multimode fibre at a bit-error rate of 10–11. - Author(s): S.Y. Hu ; E.R. Hegblom ; L.A. Coldren
- Source: Electronics Letters, Volume 34, Issue 2, p. 189 –190
- DOI: 10.1049/el:19980162
- Type: Article
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Multiple-wavelength photonic integrated emitter arrays are demonstrated for low cost direct-coupled wavelength-division multiplexing applications. Each array consists of eight pie-shaped top-emitting vertical-cavity lasers with a manufacturable planar structure. The achieved linear channel spacing and total lasing wavelength span are 4.0 and 28.8 nm, respectively.
20 × 5 Gbit/s optical WDM transmitter using single-stripe multiwavelength modelocked semiconductor laser
Bias current impulsive feedback control of nonlinear dynamics in external cavity laser diodes
External fibre laser based pulse amplitude equalisation scheme for rational harmonic modelocking in a ring-type fibre laser
High power wide aperture AlGaAs-based lasers at 870 nm
Highly uniform characteristics 12-element 1.5 µm strain-compensated AlGaInAs/InP laser arrays with low threshold current and high characteristic temperature
Linear 1 × 8 GaAs VCSEL arrays for 24 Gbit/s data rate transmission
Multiple-wavelength top-emitting vertical-cavity photonic integrated emitter arrays for direct-coupled wavelength-division multiplexing applications
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- Author(s): T. Kuroiwa ; T. Yasuda ; F. Matsukura ; A. Shen ; Y. Ohno ; Y. Segawa ; H. Ohno
- Source: Electronics Letters, Volume 34, Issue 2, p. 190 –192
- DOI: 10.1049/el:19980128
- Type: Article
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Faraday rotation of (Ga, Mn)As, with an Mn composition of 0.043, is presented. The measurements were performed in the fundamental absorption edge region (1.24–1.8 eV) at 10 K (ferromagnetic phase) and at room temperature (paramagnetic phase). The magnetic behaviour of (Ga, Mn)As manifests itself in the magnetic field dependence of Faraday rotation, which was found to be proportional to the magnetisation of the sample. A large Faraday rotation of 6 × 104 deg/cm (at 0.1 T, 1.55 eV) at 10 K is observed. The Verdet constant at room temperature is 8 × 10–2 deg/G·cm (1.49 eV).
Faraday rotation of ferromagnetic (Ga, Mn)As
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- Author(s): A.I. Fisun
- Source: Electronics Letters, Volume 34, Issue 2, p. 192 –193
- DOI: 10.1049/el:19980144
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An efficient analysis, based on the waveguide performance of the quasioptical resonator, is used on an open resonator with step-like deformation of mirrors. The spectrum and field topologies of the corner-echelette open resonator are provided as an example. This method is promising for other complicated quasioptical structures. - Author(s): G. Hanington ; Y.M. Hsin ; Q.Z. Liu ; P.M. Asbeck ; S.S. Lau ; M. Asif Khan ; J.W. Yang ; Q. Chen
- Source: Electronics Letters, Volume 34, Issue 2, p. 193 –195
- DOI: 10.1049/el:19980091
- Type: Article
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A novel process for the isolation of AlGaN/GaN HFETs is reported, utilising co-implantation of phosphorus and He ions. After implantation the material sheet resistance is > 108 Ω/□, even at temperatures as high as 200°C. The high resistance is maintained for high temperature anneals > 700°C. HFETs fabricated with this procedure exhibit good characteristics. - Author(s): J.G. Hartnett ; M.E. Tobar ; A.G. Mann ; J. Krupka ; E.N. Ivanov
- Source: Electronics Letters, Volume 34, Issue 2, p. 195 –196
- DOI: 10.1049/el:19980177
- Type: Article
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A new method of compensating the frequency-temperature dependence of high-Q sapphire dielectric resonators near liquid nitrogen temperature is presented. This is achieved by doping monocrystalline sapphire with Ti3+ ions. This technique offers significant advantages over other methods.
Method for analysis of open resonators with step-like deformation of mirrors
P/He ion implant isolation technology for AlGaN/GaN HFETs
Temperature dependence of Ti3+ doped sapphire whispering gallery mode resonator
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- Author(s): A. Leyk and E. Kubalek
- Source: Electronics Letters, Volume 34, Issue 2, p. 196 –198
- DOI: 10.1049/el:19980185
- Type: Article
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A recently developed high frequency electric force microscope (HF-EFM) test system combines both high spatial and temporal resolution, and enables functional probing and failure analysis of monolithic microwave- and millimetre-wave integrated circuits (MMICs) on wafer. It has previously been shown that this test system is capable of detecting pulse shaped signals up to 100 GHz on a 1 µm transistor gate, by using nonlinear transmission lines as signal generators. For realising the possibility of testing MMIC-internal devices in normal working conditions, this test system is improved by using millimetre-wave generators as signal sources in order to allow the system to measure sinusoidal signals. For the first time, the test system was used for measurements of sinusoidal milliwave-wave signals on different MMICS at frequencies up to 110 GHz, simultaneously achieving a spatial resolution better than 2 µm.
High spatially resolved MMIC-internal millimetre-wave measurements of sinusoidal signals by high frequency electric force microscope-testing
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- Author(s): A. Hirano ; H. Kobayashi ; H. Tsuda ; R. Takahashi ; M. Asobe ; K. Sato ; K. Hagimoto
- Source: Electronics Letters, Volume 34, Issue 2, p. 198 –199
- DOI: 10.1049/el:19980154
- Type: Article
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The switching energy of a saturable absorber optical gate is reduced by optimisation of its MQW (multiple quantum well) thickness. Using the refined optical gate, the repetition frequency of switching is improved, and successful error-free 10 Gbit/s all-optical discrimination is demonstrated. - Author(s): O. Leclerc ; P. Brindel ; S. Bigo ; E. Brun-Maunand ; E. Desurvire
- Source: Electronics Letters, Volume 34, Issue 2, p. 199 –201
- DOI: 10.1049/el:19980047
- Type: Article
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Regeneration through Kerr fibre phase modulation is proposed and applied for the first time to wavelength-multiplexed soliton signals. Periodic regeneration by Kerr fibre modulators without the use of guiding filters and dispersion management is shown to increase the error-free distance in 2 × 20 Gbit/s WDM soliton transmission up to 3500 km. - Author(s): F. Favre ; D. Le Guen ; T. Georges
- Source: Electronics Letters, Volume 34, Issue 2, p. 201 –202
- DOI: 10.1049/el:19980168
- Type: Article
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Soliton transmission at 20 Gbit/s, with a BER < 10–9, was achieved over 5200 km of non-zero-dispersion-shifted fibre (NZ-DSF). The 106.7 km long span of NZ-DSF was partially compensated by using 2.4 km of dispersion-compensating fibre (DCF). - Author(s): E. Ciaramella
- Source: Electronics Letters, Volume 34, Issue 2, p. 202 –204
- DOI: 10.1049/el:19980220
- Type: Article
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The probability distribution function of the system penalty is numerically evaluated considering the four wave mixing effect in a realistic fibre network. Owing to chromatic dispersion nonuniformity, Monte Carlo simulations predict a remarkable statistical reduction in the impairments, with respect to the worst case for the uniform fibre. Frequency translation of the channels can provide a slight improvement. - Author(s): W.D. Cornwell ; N. Wada ; K.-I. Kitayama ; I. Andonovic
- Source: Electronics Letters, Volume 34, Issue 2, p. 204 –205
- DOI: 10.1049/el:19980221
- Type: Article
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To date, approaches to coherent optical coding have used fibre-based devices for the coding/decoding operation: placing practical limitations on the ultimate system throughput. Here, a photonic integrated lightwave circuit, based on the imbalanced interferometer in tandem with a modelocked laser diode, is used to demonstrate optical phase encoding/decoding of a 10 GHz pulse stream. - Author(s): C.C. Lee ; Y.K. Chen ; S.K. Liaw
- Source: Electronics Letters, Volume 34, Issue 2, p. 205 –206
- DOI: 10.1049/el:19980065
- Type: Article
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A simple tunable and selective wavelength converter using degenerate fibre four-wave mixing based on pump wavelength and pump polarisation controls is proposed and demonstrated. Both single- and multichannel tunability/selectivity of conversion can be realised. This converter may enable wavelength division multiplexing networks to have improved efficiency and operational flexibility.
10 Gbit/s RZ all-optical discrimination using refined saturable absorber optical gate
2 × 20 Gbit/s, 3500 km regenerated WDM soliton transmission with all-optical Kerr fibre modulation
20 Gbit/s soliton transmission over 5200 km of non-zero-dispersion-shifted fibre with 106 km dispersion-compensated span
Effect of non-uniform chromatic dispersion of fibre link in determining system limitations due to four wave mixing
Experimental demonstration of coherent coding of picosecond pulses
Tunable and selective wavelength converter using degenerate fibre four-wave mixing with pump wavelength and polarisation controls
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- Author(s): M. Hoffmann ; P. Kopka ; T. Groß ; E. Voges
- Source: Electronics Letters, Volume 34, Issue 2, p. 207 –208
- DOI: 10.1049/el:19980145
- Type: Article
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A fibre optical 1 × 2 switch based on Si-micromechanics for singlemode fibres is presented. For bistable operation, the input fibre is switched and fixed in a V-groove clamp using thermal actuators. The power consumption during switching is 1.5 W for several 10 ms, the insertion loss achieved so far is 5 dB and the cross talk is below –60 dB. - Author(s): J.A. Croucher ; L. Gomez-Rojas ; S. Kanellopoulos ; V.A. Handerek
- Source: Electronics Letters, Volume 34, Issue 2, p. 208 –209
- DOI: 10.1049/el:19980028
- Type: Article
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Rocking filters have been successfully fabricated in side-hole fibre by exposure to UV light and the filters have been tested for pressure sensitivity. Sensitivities up to 20000 times higher than those reported previously using Bragg gratings were obtained. - Author(s): J.L. Corral ; J. Martí ; J.M. Fuster ; R.I. Laming
- Source: Electronics Letters, Volume 34, Issue 2, p. 209 –211
- DOI: 10.1049/el:19980164
- Type: Article
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The electrical bandwidth limitation of continuous variable time delay units based on chirped fibre gratings is studied. The radiofrequency response of a linearly chirped fibre grating with an optical bandwidth of 4 nm and a dispersion of nearly 850 ps/nm has shown a –3 dB bandwidth of 6.4 GHz. To overcome this limitation, the use of a single-sideband plus carrier generator employing a dual-drive electro-optical modulator is experimentally demonstrated. - Author(s): V. Hagemann ; M.N. Trutzel ; L. Staudigel ; M. Rothhardt ; H.-R. Müller ; O. Krumpholz
- Source: Electronics Letters, Volume 34, Issue 2, p. 211 –212
- DOI: 10.1049/el:19980136
- Type: Article
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Fibre strength measurements according to IEC 793-1-3 were performed on draw-tower fibre Bragg gratings (FBGs), including an evaluation of the stress corrosion susceptibility parameter. The FBGs suffer nearly no loss of strength, even though we wrote gratings with an index modulation more than three times higher than published recently.
All-silicon bistable micromechanical fibre switches
Approach to highly sensitive pressure measurements using side-hole fibre
Dispersion-induced bandwidth limitation of variable true time delay lines based on linearly chirped fibre gratings
Mechanical resistance of draw-tower-Bragg-grating sensors
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- Author(s): Chih-WeiHsu ; S.D. Huang ; D.W. Huang ; C.C. Yang
- Source: Electronics Letters, Volume 34, Issue 2, p. 212 –214
- DOI: 10.1049/el:19980183
- Type: Article
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The authors report experimental results of the retracing behaviours in a BBO optical parametric oscillator pumped by the second harmonic of a Q-switched Nd:YAG laser. Two sets of signal-idler could be observed in their noncolinear type-I phase-matching configuration in a certain tuning range. Particularly, near the turning point of phase-matching angle, they have implemented simultaneous phase matching for a broad wavelength range. In this situation, the spectral width of the signal output can be as large as 160 nm (740 – 900 nm), and that of the idler is 590 nm (1.3 – 1.89 µm). With a tuning setup, such as a grating, broadly tunable coherent sources can be obtained in the above wavelength ranges without a complicated tuning mechanism.
Retracing behaviours of a BBO optical parametric oscillator pumped with 532 nm laser
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- Author(s): Y. Miyamoto ; M. Yoneyama ; K. Hagimoto ; T. Ishibashi ; N. Shimizu
- Source: Electronics Letters, Volume 34, Issue 2, p. 214 –215
- DOI: 10.1049/el:19980131
- Type: Article
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The authors demonstrate a 40 Gbit/s simple optical receiver that uses a uni-travelling-carrier photodiode as a decision IC driver. The photodiode drives the decision circuit directly with 1 Vp-p without any electrical amplifier. Receiver sensitivity of –27.8 dBm was obtained at 40 Gbit/s. - Author(s): K. Sano ; K. Murata ; T. Akeyoshi ; N. Shimizu ; T. Otsuji ; M. Yamamoto ; T. Ishibashi ; E. Sano
- Source: Electronics Letters, Volume 34, Issue 2, p. 215 –217
- DOI: 10.1049/el:19980202
- Type: Article
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An ultra-fast optoelectronic circuit, using resonant tunnelling diodes (RTDs) and a uni-travelling-carrier photodiode (UTC-PD) is proposed. At extremely low power consumption, the circuit can demulitiplex an ultra-fast optical data signal into an electrical data signal with a lower bit rate. The monolithically fabricated circuit demultiplexed an 80 Gbit/s optical signal into a 40 Gbit/s electrical signal at 7.75 mW.
40 Gbit/s high sensitivity optical receiver with uni-travelling-carrier photodiode acting as decision IC driver
Ultra-fast optoelectronic circuit using resonant tunnelling diodes and uni-travelling-carrier photodiode
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- Author(s): Chih-TangSah ; A. Neugroschel ; K.M. Han
- Source: Electronics Letters, Volume 34, Issue 2, p. 217 –219
- DOI: 10.1049/el:19980194
- Type: Article
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A channel hot carrier current and the failure rate of n- and p-channel MOS transistors are both increased by one to two orders of magnitude by forward biasing the substrate or source p/n junction. Correlations with the hydrogen-bond-breaking theory give a threshold kinetic energy of 3.06 ± 0.05 eV for interface trap generation by hot carriers. - Author(s): X.Y. Chen ; M.J. Deen ; Z.X. Yan ; M. Schroter
- Source: Electronics Letters, Volume 34, Issue 2, p. 219 –220
- DOI: 10.1049/el:19980173
- Type: Article
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Low frequency (LF) noise of self-aligned double-polysilicon bipolar process featuring high-speed transistors has been studied. In all BJTs, the LF noise is dominated by 1/f noise due to fluctuations in the number of carriers. The location of the LF noise sources is determined by a scaling technique. - Author(s): T. Suemitsu ; T. Enoki ; H. Yokoyama ; Y. Umeda ; Y. Ishii
- Source: Electronics Letters, Volume 34, Issue 2, p. 220 –222
- DOI: 10.1049/el:19980166
- Type: Article
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The RF performance of InP-based lattice-matched high electron mobility transistors (HEMTs) is improved by using a two-step-recess process. 0.07 µm gate HEMTs show a cutoff frequency (fT) of 300 GHz, a value previously achievable only with a gate length of 0.05 µm in the conventional gate structure, and a maximum frequency of oscillation fmax of 400 GHz. The high fT indicates that the effective gate length is successfully suppressed by the two-step-recessed gate structure. Moreover, owing to the selective etching property, this gate recess process provides high uniformity of the threshold voltage and the cutoff frequency of the HEMTs on a 3 in wafer. - Author(s): Gao Min ; D.M. Rowe ; F. Volklein
- Source: Electronics Letters, Volume 34, Issue 2, p. 222 –223
- DOI: 10.1049/el:19980148
- Type: Article
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The possibility of fabricating thermoelectric coolers using thin film deposition and micromachining is investigated. The processing sequences described facilitate fabrication of the thermoelectric cooler and electronic components, such as laser diodes, CCD and infrared detectors, as elements of an integrated circuit. Theoretical calculations based on the proposed thin film thermoelectric cooler indicate that a maximum temperature difference of ~40–50 K can be obtained with a maximum pumping capacity of around a few milliwatts.
Current-accelerated channel hot carrier stress of MOS transistors
Effects of emitter dimensions on low-frequency noise in double-polysilicon BJTs
Impact of two-step-recessed gate structure on RF performance of InP-based HEMTs
Integrated thin film thermoelectric cooler
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- Author(s): C. Urdiales ; A. Bandera ; F. Arrebola ; F. Sandoval
- Source: Electronics Letters, Volume 34, Issue 2, p. 223 –224
- DOI: 10.1049/el:19980204
- Type: Article
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The authors present a complete path-planning method for sensor-based navigation in an autonomous mobile robot. The environment is described by probabilistic maps processed with a new obstacle enhancement algorithm. The novelty of the approach consists of using a pyramid structure as a preprocessing module to classical path planning algorithms. This stage enhances the performance of the system, minimising the computational cost by operating in an optimal resolution level. Thus, the system is allowed to work with huge environments with a very fine-coarse descomposition in real time.
Multi-level path planning algorithm for autonomous robots
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