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Electrical and Computer Engineering, Canadian Journal of

Issue 3/4 • Date July-Oct. 2003

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Displaying Results 1 - 13 of 13
  • [Front cover]

    Publication Year: 2003 , Page(s): c1 - c5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (206 KB)  

    Presents the front cover/table of contents for this issue of the periodical. View full abstract»

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  • Table of contents

    Publication Year: 2003 , Page(s): 6 - 7
    Save to Project icon | Request Permissions | PDF file iconPDF (146 KB)  
    Freely Available from IEEE
  • Message from the editors

    Publication Year: 2003 , Page(s): 98
    Save to Project icon | Request Permissions | PDF file iconPDF (138 KB)  
    Freely Available from IEEE
  • Corrugated copper membranes for use in reconfigurable ground plane antenna

    Publication Year: 2003 , Page(s): 99 - 104
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB)  

    Thin-film copper membranes on silicon substrates were constructed using micromachining techniques. Membranes possessed surface corrugations 10 ??m deep and ranged in size from 1.04 mm to 10.0 mm in diameter. Membranes were released using a combination of both KOH and xenon difluoride (XeF ) backside etching. Surface corrugations were made using KOH etching on the frontside of the wafer. The membranes were electrostatically actuated using a high-voltage dc supply, and flexibility was studied as a function of diameter. Measured data were compared to simulations of flat and corrugated membranes. Copper membranes were used as a reconfigurable ground plane under a microstrip transmission line. Actuation of the membranes induced phase shift in the transmitted signal. An array of five 4.3 mm diameter membranes was tested, as was a single 10.0 mm membrane, over frequencies ranging from 9.95 GHz to 35 GHz. A phase shift of 55.63??at 34.42 GHz was achieved for the array of five 4.3 mm membranes, and a phase shift of 57.93??at 35.0 GHz was achieved for the 10.0 mm membrane. View full abstract»

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  • Analogue integrated circuit sizing with several optimization runs using heuristics for setting initial points

    Publication Year: 2003 , Page(s): 105 - 111
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (465 KB)  

    Circuit sizing (i.e., determining MOSFET channel widths and lengths which result in the most appropriate and robust circuit) is an optimization process. When it is completed, there always remains a dilemma; namely, whether a better solution exists. With different starting points one can arrive at different local minima. A heuristic process, consisting of many optimization runs starting from different initial points, is proposed. It tries to find another local minimum of the cost function in every run and thus reveals some additional information about the circuit. The mathematical background of the algorithm used is described. Finally, the heuristic algorithm is tested on some real integrated operating amplifier designs. The results show that from the cost-function point of view surprisingly many equivalent solutions exist. View full abstract»

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  • A framework for UMTS air interface analysis

    Publication Year: 2003 , Page(s): 113 - 129
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (711 KB)  

    An integrated approach is presented for uplink and downlink air interface capacity evaluation and traffic analysis for the multiservice Universal Mobile Telecommunications System (UMTS). Within this framework the effects of both soft handoff (SHO) and fast power control (FPC) are considered. The canonical capacity of any given service, defined as the maximum number of concurrent users of that service, is derived; and the network total load is described as a function of this parameter and the number of concurrent users. The concept of virtual slots is defined within this integrated framework to obtain an accurate estimate for the blocking probability of each service type. A number of case studies are also presented to compare the results of utilizing the proposed framework with the results of network simulation. This comparison demonstrates the accuracy and usefulness of the proposed approach for network design and dimensioning. View full abstract»

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  • A reduced-complexity multistage detection algorithm for DS-CDMA systems in AWGN channels

    Publication Year: 2003 , Page(s): 131 - 137
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB)  

    In this paper a new, reduced-complexity algorithm for multistage detection of direct-sequence code division multiple access (DS-CDMA) signals in additive white Gaussian noise (AWGN) channels is presented. Bit error rate performance of the new algorithm is determined via Monte Carlo simulation, and it is shown that the new algorithm, although designed to reduce computational complexity, performs better than conventional multistage detection. View full abstract»

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  • A microprogrammable-processor teaching tool and its FPGA implementation

    Publication Year: 2003 , Page(s): 139 - 144
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (662 KB)  

    In this paper a microprogrammable-processor teaching tool and its FPGA implementation are presented. The processor is based on a classical Am2900 architecture and is implemented in the popular Xilinx Foundation" environment. The tool helps electrical and computer engineering students to become familiar with microprogramming through development of their own instruction sets and experiments with signal flow within a processor. In addition to simulation, the complete configuration can be run on a Xilinx 4010XL FPGA. In the paper a short description of the tool is provided. View full abstract»

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  • Power spectral density of a UWB signal with discrete quantized pulse positions

    Publication Year: 2003 , Page(s): 145 - 154
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1942 KB)  

    The FCC specification for ultra-wideband (UWB) emissions states that the effective isotropic radiated power (EIRP) cannot exceed 41.3 dBm per 1 MHz bandwidth in the frequency region of 3.1 to 10.6 GHz. Hence, to achieve adequate transmit power in a UWB data link it is necessary to use a wide-bandwidth modulation scheme. This requirement presents a pair of technical challenges which are addressed in this paper. The first challenge is to realize a wide-bandwidth radiated transmitter pulse shape which adequately covers the UWB band from 3.1 to 10.6 GHz. The second challenge is to structure the modulation such that the discrete line component of the power spectral density (PSD) of the transmitted signal is minimized. This is necessary as the discrete spectral components are essentially wasted power and limit the output transmitted power due to the FCC EIRP mask. In this paper the radiated EIRP of a UWB signal based on pulse position modulation (PPM) is explored. Previous researchers have derived the PSD under the supposition that the PPM pulse delay is continuous. However, simpler and more insightful expressions are possible for the PPM PSD if the pulse delays are restricted to quantized steps, as is assumed in this paper. A network-analysis approach for determining the EIRP of the unmodulated radiated pulses is given based on spectral measurements of an experimental UWB transceiver pair. These EIRP characteristics are applied to the derived equations for the continuous and discrete portions of the PSD of the UWB signal. From this, insights emerge into optimum PPM transmitter implementation that maximizes transmit power and minimizes power losses due to the discrete spectral lines. As demonstrated in this paper, such optimization necessitates the joint design of the UWB transmitter radiated pulse shape and PPM structure. View full abstract»

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  • An endoscopic force-position sensor grasper with minimum sensors

    Publication Year: 2003 , Page(s): 155 - 161
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (918 KB)  

    This study reports on the design, fabrication, testing, and mathematical modelling of a semiconductor microstrain-gauge endoscopic tactile sensor. The sensor can measure, with reasonable accuracy, the magnitude and the position of an applied load on a grasper. The designed assembly consists of two semiconductor microstrain-gauge sensors, which are positioned at the back face of a prototype endoscopic grasper. The intensity of the applied force can be seen on a light emitting diode (LED) device. Altogether, 20 different force magnitudes for seven different locations on the endoscopic grasper are tested experimentally. The magnitudes of force vary from 0.5 to 10 N with an increment of 0.5 N. The in-house electrical amplification system for the microstrain gauges is also designed, fabricated, and tested. The sensor is insulated and can operate safely in wet environments. It exhibits high force sensitivity, good linearity, and large dynamic range. To predict the behaviour of the designed system under various loading conditions, three-dimensional finite element modelling (FEM) is used. There is a good correlation between the computed theoretical results for the force magnitudes together with their points of application and the experimental results. The miniaturized electronic device could be integrated with an endoscopic grasper. View full abstract»

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  • A simple method for calculating the sinr in DS-CDMA systems with despreading sequences weighted by stepping chip waveforms

    Publication Year: 2003 , Page(s): 163 - 167
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    This article presents a simple method for calculating the signal toi nterference-plus-noise ratio in direct sequence code division multiple access systems with despreading sequences weighted by stepping chip waveforms. The method is based on a simple equality, which gives a relation among the number of occurrences of various chip patterns belonging to random spreading sequences. It is found that there is no need to scrutinize all the chips of a random spreading sequence to determine the number of transitions that occur between two consecutive chips. Several numerical examples and computation times are provided to demonstrate the validity and significance of this method. View full abstract»

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  • A simple and fast algorithm for determining asymptotic stability of linear autonomous systems

    Publication Year: 2003 , Page(s): 169 - 172
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    The method introduced here determines explicitly whether a given system has only eigenvalues with negative real parts, without determining these eigenvalues, but rather by determining the eigenvalues of a related symmetric matrix which are always real and hence easy to calculate. The new method is similarly applied to linear autonomous discrete systems where all the eigenvalues of the system matrix are required to be positioned within the unit circle in the z-plane. View full abstract»

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  • Uniform asymptotic stability of linear non-autonomous systems

    Publication Year: 2003 , Page(s): 173 - 176
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB)  

    In this paper a new method is developed for obtaining necessary and sufficient conditions which, when satisfied, guarantee that a linear non-autonomous system will be uniformly asymptotically stable. The method is essentially an extension of two earlier theorems on the asymptotic stability of linear autonomous systems; these theorems, developed by the same author, are here extended to non-autonomous systems. Basically, the method consists of ascertaining whether a certain matrix is positive definite. In general, it is shown that this knowledge is necessary and sufficient to determine whether a linear non-autonomous system is exponentially stable and hence uniformly asymptotically stable. View full abstract»

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Aims & Scope

The role of the Canadian Journal of Electrical and Computer Engineering is to provide scientific and professional activity for its members in Canada, the CJECE complements international journals and will be of particular interest to anyone involved in research and development activities in the field of electrical and computer engineering.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dr. Shahram Yousefi
Dept. of Electrical and Computer
     Engineering
Queen's University