WSEAS Transactions on Circuits and Systems

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Print ISSN: 1109-2734
E-ISSN: 2224-266X

Volume 13, 2014

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

Volume 13, 2014

Title of the Paper: Modelling of Ice-Melting Circuit under Influence of EMF Induced by the Currents of Overhead Lines

Authors: Nikolay V. Korovkin, Valeriy O. Goncharov, Nikolay V. Silin

Abstract: To prevent icing of TL (transmission lines) and GW (ground wires) during certain weather conditions the de-icing procedure is needed. The currents of operating TL influence on the de-icing process. A mathematical model was developed which makes possible the estimation of this influence. The main ice-melting diagrams are considered. The methodology of determination of induced EMF value in ice-melting loop is described. Ice-melting current curves under different conditions are compared and analyzed.

Keywords: Ice melting, ground wire, ice-melting circuit, induced EMF

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #51, pp. 476-484

Title of the Paper: Fractal Neural Vector - Machines, Tomography and Inheritance of Behaviour

Authors: Thomas Kromer

Abstract: Results of intensive studies of neural systems could not fully explain the astonishing performance of biological nervous systems in complex situations. Therefore alternative models of neural nets and their ways of pattern-processing might be of interest. Fractal neural nets offer interesting rich and flexible connectivity and biomorph aspects as hemispheres, lobes, gyri, sulci, decussatio of fibres, ventricular systems, thalamic structures and a high dynamism of processed patterns. Combining these fractal features with intracellular memory-strings to encode sequences of activities as engrams or vectors, to store, compare and reconstruct patterns of activities, a new tomographic form of information-processing seems to be achievable for such fractal neural vector- machines. Those memory-strings could, though completely hypothetically concerning their biological relevance, at least in principle allow the inheritance of behaviour. Though very preliminary, the results of a first small simulation may shed a light on the interplay of innate talents and learning experiences as well as on hypothetical mechanisms of genetic adjustments of organisms to the environment during evolution.

Keywords: three-dimensional fractal neural nets, vector-machines, memory-strings, engrams, tomography, inheritance of behaviour

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #50, pp. 464-475

Title of the Paper: Modelling and Design of a Small Scale Solar Tracking System; Application to a Green House Model

Authors: Ph. Dondon, L. Miron

Abstract: Power generation is one of the challenges in Sustainable Development. For example, well known sun tracking systems allows improvement of solar panel power ratio. In order to illustrate this concept, this paper presents a simplified and didactical small scale system for pedagogical application and sensitizing actions. Principle of tracking is described. A mixed SPICE modelling of the system, including geometrical, optical, electronic linear and non linear aspects is built. Simulations results are analyzed. Electronic analogue design is detailed, experimental test are presented before conclusion. This small scale solar tracking system is now installed in a green house model.

Keywords: Sun tracking, Mixed SPICE modelling, Analogue design, Sustainable development

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #49, pp. 454-463

Title of the Paper: Proposal of an ASIC CMOS for Sliding Mode Control of Switched Reluctance Aerogenerators

Authors: Bruno C. Dias, Evandro Bolzan, Jose A. Torrico Altuna, Alfeu J. Sguarezi Filho, Carlos E. Capovilla

Abstract: This paper proposes an ASIC CMOS for sliding mode control (direct power one) applied to switched reluctance aerogenerators. The topology of the circuit is designed in order to carry out, in the most optimal way, the mathematical function which processing directly the power error and supply the turn-off angle to the power system converter. The specifications and simulation performance are in close agreement, which validate the proposed compact design. The ASIC final layout is also presented.

Keywords: ASIC, CMOS, SRG, sliding mode control, wind energy

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #48, pp. 445-453

Title of the Paper: Characteristics of GaAs Concentrator Cells for High-Intensity Laser

Authors: Tiqiang Shan, Xinglin Qi

Abstract: High efficiency GaAs concentrator cells are useful for numerous applications requiring isolated power and voltage, or transmission of power without electromagnetic interference. This paper concerns the characteristics of GaAs concentrator cells illuminated by high-intensity laser beams. The objectives of this study are to identify and understand the mechanisms which limit the performance of GaAs concentrator cells for high-intensity laser. A modeling process is proposed to configure a computer simulation model based on the fundamental characteristics of photovoltaic (PV) cells, which is able to demonstrate the GaAs concentrator cell’s output features under the effects of series resistance and temperature. Both factors inevitably degrade the conversion efficiency of GaAs cells. The results indicate that the laser light intensity gets higher, the series resistance becomes smaller, while the effect of series resistance for the conversion efficiency becomes serious. In addition, the conversion efficiency also decreases as the temperature increases due to the temperature dependency of the open circuit voltage. For GaAs concentrator cells, there is a very good linearity between the open circuit voltage and the temperature, and at the same time, the conversion efficiency change rate is roughly proportional to the open circuit voltage change rate.

Keywords: GaAs concentrator cells, High-intensity laser, Series resistance, Temperature dependency

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #47, pp. 440-444

Title of the Paper: Low Space Complexity, High performance Unified and Scalable Word-Based Radix 4 Architecture for Montgomery Modular Multiplication in GF(P) and GF(2k)

Authors: Atef Ibrahim

Abstract: This paper presents a novel low space complexity and high performance (low power and high speed) unified and scalable word-based radix 4 architecture for Montgomery modular multiplication in GF(P) and GF(2k). In this architecture, the multiplicand and the modulus words are allocated to each processing element rather than pipelined between the processing elements as in the previous architectures extracted by L. Tawalbeh, and also the multiplier bits are fed serially to the first processing element of the processor array every odd clock cycle. To reduce multiplier area and accelerate its operation, the hardware architecture employs 3-to-2 carry save adders instead of 4-to-2 carry save adder, as used in conventional designs, to avoid carry propagation at each addition operation of the add-shift loop. To reduce power consumption, glitch blockers are employed at the outputs of some circuit modules to reduce the spurious transitions and the expected switching activities of high fan-out signals. Moreover, the architecture was modified to reduce more power by replacing the dual field conventional 3-to-2 carry save adder (CSA) by modified low power dual field 3-to-2 CSA that has internal logic structure with balanced delays in SUM and CARRY outputs to reduce the chance of glitches occurrence. An ASIC Implementation of the proposed architecture shows that it can perform 1024-bit modular multiplication (for word size w = 32) in about 4.81 μs. Also, the results show that it has smaller Area x Time values compared to existing competing designs by ratios ranging from 13.1% to 77.2% which makes it suitable for implementation where both area and performance are of concern. Also, it has higher throughput over them by ratios ranging from 2.6% to 82.9%. In addition, it achieves a decrease in power consumption compared to these designs by ratios ranging from 25.3% to 70.4%.

Keywords: Montgomery Modular Multiplier, Cryptography, Systolic Arrays, ASIC Design, Hardware Security

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #46, pp. 429-439

Title of the Paper: A Development of Class E Converter Circuit for Loosely Coupled Inductive Power Transfer System

Authors: Norezmi Jamal, Shakir Saat, Y. Yusmarnita

Abstract: This paper presents an Inductive Power Transfer (IPT) system design using a Class E converter circuit. The Class E converter is used to drive a nonlinear load and theoretically it offers 100% efficiency. To be specifically, the performance of IPT system at 1MHz operating frequency and 9V DC supply voltage is analyzed. Voltage doubler rectifier and Darlington circuit are proposed in this paper to maximize output power. Moreover, to ensure the resonant inductive coupling in IPT system,capacitor compensation is also proposed in this work. Based on the experimental results, the output power with the capacitor compensation circuit is 1.6W at 15 mm air gap distance is better than the circuit without a capacitor compensation.

Keywords: IPT system, Class E converter circuit, Voltage doubler and Darlington circuit

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #45, pp. 422-428

Title of the Paper: Online Data Stream Mining in Distributed Sensor Network

Authors: Iveta Zolotová, Tomáš Lojka

Abstract: Amount of end devices like sensors produce a much bigger amount of data. Collecting, transmitting and centrally processing amount of data from amount of devices is problematic. This paper deals with ways of reducing communication and distributed processing of data. With help of data mining and processing over real time stream of data we design an algorithm. This algorithm is based on data mining techniques, which we use to find important changes in the monitored environment. After finding interesting changes in the raw of data, the algorithm uses classification to create event in network which will share the new detected information. For communication we used Service Oriented architecture (SOA) and REST, which is described in designed architecture.

Keywords: Data mining, distributed network of sensors, entropy, monitoring system, sensor motes, Service Orientated Architecture (SOA)

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #44, pp. 412-421

Title of the Paper: A Double Closed-Loop Control Method for Quasi-Resonant Converter

Authors: Chun-Sen Tang, Hao Shen, Xiao Lv

Abstract: To achieve the soft-switching condition and stabilize the output voltage of quasi-resonant converters, the paper proposes a double closed-loop control method (DCCM). In the inner loop, soft-switching is guaranteed with the off-time of the switch determined by the zero-crossing signal of the switching voltage. In the outer loop, the output voltage is regulated to be constant against load variations by controlling the on-time of the switch according to the error between the output voltage and the reference voltage. The operation principle and implementation of the proposed method have been investigated in detail on an example BUCK zero-voltage-switching quasi-resonant converter. Both simulation and experiment results have verified the validation of the proposed method.

Keywords: soft-switching, zero-voltage quasi-resonant converter, double closed-loop control, proportional-integral (PI) controller

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #43, pp. 405-411

Title of the Paper: Adaptive Recurrent Functional-Link-Based Petri Fuzzy-Neural-Network Controller for a DSP-Based Induction Motor Servo Drive System

Authors: Fayez F. M. El-Sousy, Khaled A. Abuhasel

Abstract: In this paper, an intelligent adaptive control system (IACS) for induction motor (IM) servo drive to achieve high dynamic performance is proposed. The proposed IACS comprises a recurrent functional-link-based Petri fuzzy-neural-network (RFLPFNN) controller and a robust controller so that the developed adaptive control scheme has more robustness against parameters uncertainties and approximation errors. The RFLPFNN controller is used as the main tracking controller to mimic an ideal control law while the robust controller is proposed to compensate the difference between the ideal control law and the RFLPFNN controller. The proposed RFLPFNN model uses a functional-link neural network to the consequent part of the fuzzy rules. Thus, the consequent part of the proposed RFLPFNN model is a nonlinear combination of input variables. Moreover, the online structure and parameter-learning of the RFLPFNN are performed concurrently. The structure learning is based on the partition of input space and the parameter learning is derived based on the Lyapunov stability analysis and the back propagation method to guarantee the asymptotic stability of the IACS for the IM servo drive. In addition, to relax the requirement for the bound of minimum approximation error and Taylor higher-order terms, an adaptive control law is utilized to estimate the mentioned bounds. A computer simulation is developed and an experimental system is established to validate the effectiveness of the proposed IACS. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulation and experimental results confirm that the IACS grants robust performance and precise response regardless of load disturbances and IM parameters uncertainties. Furthermore, the superiority of the proposed IACS is indicated in comparison with the Petri fuzzy-neural-network control system and traditional PID controller.

Keywords: Functional-link neural-networks (FLNNs), intelligent control, indirect field-orientation control (IFOC), induction motor, Lyapunov satiability theorem, Petri net (PN), fuzzy-neural-network, robust control

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #42, pp. 381-404

Title of the Paper: Compact Computation of Tchebichef Moments for 3D Object Representation

Authors: Mostafa El Mallahi, Abderrahim Mesbah, Hakim El Fadili, Khalid Zenkouar, Hassan Qjidaa

Abstract: Discrete Tchebichef moments are widely used in the field of image processing application and pattern recognition. In this paper we propose a compact method of 3D Tchebichef moments computation. This new method based on Clenshaw’s recurrence formula and the symmetry property produces a drastic reduction in the complexity and computational time. The recursive algorithm is then developed for fast computation of inverse Tchebichef moments transform for image reconstruction. We also extract scale and translation 3D moment invariants using a proposed direct method. The validity of the proposed algorithm is proved by simulated experiments using 3D image/Object

Keywords: Digital image processing, Pattern analysis, Image reconstruction techniques, Three-dimensional image processing, Moment methods

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #41, pp. 368-380

Title of the Paper: Transient Analysis of VLSI Tree Interconnects Based on Matrix Pade Type Approximation

Authors: M. Kavicharan, N. S. Murthy, N. Bheema Rao

Abstract: This paper presents a novel, simple and accurate delay estimation model for single interconnect and tree interconnects, which is based on new matrix Pade-type approximant (MPTA). The proposed model provides a simpler rational function approximation for estimating delay and overshoot in lossy VLSI interconnects. Computational complexity is reduced by considering rational function denominator as scalar polynomial and avoiding matrix inversion. With the reduced order lossy interconnect transfer function, finite ramp responses are obtained and line delay and signal overshoot are estimated. The estimated delay and overshoot values are compared with the existing Pade model and HSPICE W-element model. Single interconnect 50% delay results are in good agreement with those of HSPICE within 0.5% error while the overshoot error is within 1% for a 1 mm long interconnects. For global lines of length more than 1 mm in SOC (system on chip) applications, the proposed model is found to be nearly two times more accurate than existing Pade model. Tree interconnects 50% delay values are also well agreeing with HSPICE and better than existing U-transform model. Furthermore the proposed model is computationally more efficient than HSPICE, Pade model and U-transform model.

Keywords: Delay, matrix rational model, ramp input, RLC interconnects, transient analysis, transfer function, Distributed tree interconnect, new MPTA approximant, U-transform

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #40, pp. 360-367

Title of the Paper: Thermoelectric Power Source for Building Sensors – Analysis and Measurement

Authors: Michal Oplustil, Martin Zalesak, Stanislav Sehnalek, Pavel Chrobak

Abstract: This paper deals with using of heat emitted from machinery parts, radiators for human for building automation needs. The most of devices and applications in environment produced some values of waste heat to vicinity. Mostly this heat goes to the surrounded area without any benefits for us and we lose valuable energy that can be still use. Especially aim of this paper is using of human waste heat as an electric energy source for building sensors and switches. As heat absorber were used the standard low-cost Peltier element. The limitations for this applications are small heat transfer area (human palm, human finger), small mechanical dimensions and low temperature difference. This temperature difference depends on actual temperature of the human skin and on temperature of heat dissipation side of Peltier element. Temperature difference during measurement was only approximately 11 °C.

Keywords: Heat transfer, Peltier cell, Seebeck effect, step-up DC/DC converter, voltage, current

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #39, pp. 353-359

Title of the Paper: A 1.8V 22mW 10 bit 165 MSPS Pipelined ADC for Video Applications

Authors: D. S. Shylu, D. Jackuline Moni

Abstract: In analog to digital converter, power consumption is considered as a major challenge to improve the performance. In this paper double sampling MDAC and amplifier sharing techniques are used to reduce power consumption for video applications.Since the requirements of high frame rate video capturing instruments and other video systems are successfully matched with that of the presented pipelined data converter, it is suitable for such applications. Use of dynamic comparators in the 1.5 bit stage architecture causes further reduction in power consumption.A 10 bit 165 MSPS Pipelined ADC which consumes 22mW of power was designed. The ADC was designed in a 0.18μm CMOS process and achieves 64 dB SFDR,56.1 dB SNDR, 9.02 ENOB and 0.25PJ/step FOM for a 1-V differential input signal and 9 MHz Input frequency from a 1 .8V supply voltage. From the results it was observed that this 10 bit Pipelined ADC was suitable for Video applications.

Keywords: Pipelined ADC, Low power, Video application, Dynamic Comparator, Amplifier sharing, Sample-and-Hold

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #38, pp. 343-352

Title of the Paper: Simulation Analysis for Controllable Reactor of Transformer Type with Multifold Magnetic Materials Integration

Authors: Jianning Yin, Mingxing Tian

Abstract: This paper presents a construction of a controllable reactor of transformer type (CRT) with multifold magnetic materials, and the construction based on the magnetic-integration techniques is used to weaken the magnetic coupling effect among control windings and eliminate requirement of series current limiting reactance. At last, based on the proposed equivalent circuit of integrated magnetic structure, a simulation model is fabricated by MATLAB/SIMULINK. Simulation analysis of winding current and control characteristic show that this construction meets the design requirements of “high impedance and weak coupling”, the harmonic content of the work winding is small, also the construction can realize the smooth reactive power regulation and react with a high speed. The validity of the construction and the correctness of the simulation model are proved by the results of simulation. This multifold magnetic materials integration method offers a reference to the integration of complex electromagnetic equipment.

Keywords: Controllable Reactor of Transformer Type, Magnetic Integration, Magnetic Coupling, Equivalent Circuit, Simulation Model, Simulation Analysis

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #37, pp. 336-342

Title of the Paper: SVPWM Control Based Bridgeless PFC Cuk Converter for PMSM under Dynamic Conditions

Authors: R. Sankarganesh, S. Thangavel

Abstract: The widely used converter models in most of the power electronics and power system applications are the DC-DC converter models. Increase in switching losses has been observed in Conventional Diode Bridge Rectifier (DBR) and hence the researchers are more focused towards bridgeless converters. The design of a novel bridgeless cuk converter model with buck mode operation is focused in this work. In this converter model, four different modes of operations with two modes in positive cycle (switch ON and OFF condition) and two modes in negative cycles with (switch ON and OFF condition) were analyzed. The design of cuk converter with outer voltage control and inner current control integrated with the Power Factor Correction (PFC) analysis is also dealt in this study. Integration of Permanent Magnet Synchronous Motor (PMSM) load and Sensorless Space Vector Pulse Width Modulation (SVPWM) vector with this design is also proposed to control the PMSM. The performance is analyzed for load varying and speed varying conditions using MATLAB and the results are simulated. The results showed that the proposed system provides significant results with cost effective components utilities.

Keywords: Cuk Converter, Power Factor Correction, Permanent Magnet Synchronous Motor, Space Vector Pulse Width Modulation, Total Harmonic Distortion (THD)

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #36, pp. 319-335

Title of the Paper: Ant Colony Optimization for Optimal Low-Pass Butterworth Filter Design

Authors: Bachir Benhala

Abstract: Performance analog filters depend strongly values of discrete components (Resistors and capacitors) which are selected from the series following constant values chosen. Exhaustive search on all possible combinations of value choices for an optimized design is not feasible. The metaheuristics have proved a capacity to treat such problem effectively. In this paper, we present an optimization algorithm based on the Ant Colony Optimization (ACO) technique for dealing with the active filter design. The ACO algorithm is applied to the Low-Pass Butterworth Filter Design realized with components selected from different manufactured series. SPICE simulations are used to validate the obtained result/performances. A comparison with published works is highlighted.

Keywords: Metaheuristic, Ant Colony Optimization, Low-pass Butterworth Filter

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #35, pp. 313-318

Title of the Paper: A Digitally Assisted Telescopic AmplifierWith Improved ICMR and Programmable Unity Gain Frequency

Authors: Rishi Todani, Ashis Kumar Mal

Abstract: Telescopic amplifiers are often preferred for their large DC gain, low power dissipation and low flicker noise. On the other side, they suffer from serious problems like poor input common mode range and output swing. In this work, a simple technique to improve the input common mode range of telescopic structure is presented. To achieve this, two telescopic amplifiers using complementary differential pairs are utilized. The proposed design incorporates a digital switching technique which enables to maintain a flat response throughout the extended input common mode range. It also provides a facility to elevate the performance of the circuit over a predefined range of input common mode level, at the cost of extra power. The entire design is verified using UMC 180 nm CMOS technology and the simulation results are presented.

Keywords: Analog design, CMOS; operational amplifier, telescopic amplifier, input common mode range, complementary amplifier

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #34, pp. 301-312

Title of the Paper: Diagnosis of Resistive-Open Defects Using IDDT in Digital CMOS Circuits

Authors: Changgeng Yu, Guixiong Liu, Liping Lai

Abstract: A resistive-open defect is an imperfect circuit connection that can be modeled as a defect resistor between two circuit nodes that should be connected. Resistive-open defects will not cause function fault immediately, but it will cause the delay fault, and cannot use the method of voltage to survey. In this paper, we propose a test method of transient power supply current (IDDT) for resistive open faults, and use wavelet analysis to location the fault. The experimental results show that the effectiveness of IDDT methods uses the RMS values of the wavelet transforms of the transient power supply or ground currents. The delay faults test process to be very effective in all cases.

Keywords: Resistive-open defects, Transient power supply current (IDDT), Digital circuit, Wavelet analysis

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #33, pp. 296-300

Title of the Paper: The Design of Self Starting Regulator Using Step-Up Converter Topology for WSN Application

Authors: Haslinah Binti Mohd Nasir, Mai Mariam Binti Aminuddin

Abstract: Continuous monitoring is very important for chronic patient, elderly or who was under supervision for recovery from an acute event or surgical. For this Wireless Sensor Network give a solution for continuous health monitoring and able to wirelessly monitoring patient conditions at any time. It is able to generate early warning if received unwanted signal from the patient as well. As known, Wireless Sensor Network is only consumes a little power to turn it on and energy harvesting is able to power up this devices without using the batteries. Continuous monitoring needs a continuous and uninterruptable power source. Hence, energy harvesting is one of the options of the solutions. However, up till now the energy harvesting still develop a low output voltage which is not enough to power on the wireless sensor network . Therefore, this paper proposed a new technique called a self starting DC to DC converter which is able to boost up the input voltage as low as 0.4V to the output voltage of 5.1V. The circuit efficiency is up to 92% which is verified by simulation using LTspice tools. Hardware implementation will be done in future work.

Keywords: Continuous monitoring, Wireless Sensor Network, energy harvesting, low output, DC to DC converter, LTspice tool

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #32, pp. 291-295

Title of the Paper: Magnitude Approximation of IIR Digital Filter Using Greedy Search Method

Authors: Ranjit Kaur, Damanpreet Singh

Abstract: The paper presents a greedy search method based on binary successive approximation-evolutionary search (BSA-ES) strategy to design stable infinite impulse response (IIR) digital filter using L1 optimality criterion. The stability constraints are well taken care of during the design procedure. The filter designed based on L1-approximation error possesses flat pass-bands and stop-bands to that of the least square design. A comparison has been made with other design techniques, demonstrating that BSA-ES obtains better results for designing digital IIR filters than the existing genetic algorithm (GA) based methods.

Keywords: Digital infinite impulse response (IIR) filters, Greedy algorithms, Stability, Magnitude response

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #31, pp. 284-290

Title of the Paper: Genetic Algorithm Particle Swarm Optimization Based Hardware Evolution Strategy

Authors: Zhang Junbin, Cai Jinyan, Meng Yafeng, Meng Tianzhen

Abstract: There are many problems exist in the Evolutionary Algorithm (EA) using Genetic Algorithm (GA), such as slow convergence speed, being easy to fall into the partial optimum ,etc. Particle Swarm Optimization (PSO) can accelerate the space searching and reduce the number of convergences and iterations. The proposed characteristics of Genetic Algorithm Particle Swarm Optimization (GAPSO) are proved by many examples, when the GA, PSO and GAPSO are adopted under the same conditions, GAPSO can get the least iteration numbers and the highest evolvable success rate. It also can reduce the number of convergence iteration and raise the accuracy of searching. And the performance of PSO is inferior to the performance of GAPSO, while the GA has the worst searching performance. It also can be found that the number of initializing particles will affect the number of convergences and iterations. The larger the number of the initializing particles is, the less the number of iterations will be.

Keywords: Hardware Evolution, Evolutionary Algorithm, GAPSO, Fault Self-repair

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #30, pp. 274-283

Title of the Paper: A Software of Generating a Symbolic Circuit Model with Computers for Wireless Power Transmission System

Authors: Takuya Hirata, Yuta Yamamoto, Kazuya Yamaguchi, Ichijo Hodaka

Abstract: Conventional researches onWireless Power Transmission systems use experimental or numerical method to analyze the systems. However, the situation will be better if symbolic method is available. This paper develops a software which generates a state equation directly from schematics. The software helps engineers that design circuits and obtain characteristics of circuits to analyze the behavior of circuits with circuit parameters by symbolic computing. Our software also provides various perspectives of the system with circuit parameters.

Keywords: symbolic circuit analysis, modelling, power transfer

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #29, pp. 266-273

Title of the Paper: A Low-Voltage Three-Phase AC Generator Built from Analogue Blocks

Authors: Francisco Llopis, Jacobo González, Mario Jakas

Abstract: A circuit capable of delivering three 40Vpp 50Hz AC voltage outputs with 120º phase separation between them has been built. It uses standard, low-cost electronic components and, unlike other previous similar power supplies [1-3], the present circuit is entirely based on analogue electronics. This power supply was purposely built for educational purposes, where low-voltage is necessary in order to prevent students from suffering electrical shocks. Its design, simple and robust, makes this circuit be an interesting project for undergraduate students, either as part of a regular electronics laboratory course or as a final degree project in electronic and electrical engineering.

Keywords: DC-to-3-phase AC converters, Negative feedback, Phase-shift oscillator, Output stages

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #28, pp. 262-265

Title of the Paper: Handling Carbon Fiber Fabric in Agile Manufacturing Cells

Authors: Rezia Molfino, Matteo Zoppi, Francesco Cepolina, Jack Yousef, Emanuela Elisa Cepolina

Abstract: The paper addresses the design of agile cells for manufacturing low volume aircraft sub-assemblies and focuses on the problem of robust grasping and handling carbon fiber fabric. The difficulty of the manufacturing task is faced equipping the cell with two cooperative robots. Both robots use purposely developed. The paper presents in detail the adaptive end-effectors purposely developed like robotic hands following the approach of multi point grasping technology and the design of some alternative picking modules that can be used at the robotic hands fingertips.

Keywords: Flexible Manufacturing Cell, Dexterous Handling, Soft Material, Carbon Fiber Fabric, Robotics, Mechatronic Design

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #27, pp. 253-261

Title of the Paper: Fast Flashover Identification Methodology on Brushed DC Machines

Authors: Márcio Zamboti Fortes, Carlos Henriques Reis Dos Santos, Ramsés Fellini Oliveira, Bruno Soares Moreira Cesar Borba

Abstract: Direct current machines are applied in several industry sectors, such as steel, paper industry, mining, among others. However, the maintenance of this type of machine is quite complicated. For instance, brush sparking and flashing over can occur after a maintenance period, if interpole windings are connected in the reverse way. Since the commutator and brush assembly are high-wear parts of DC machines, a fast and simple maintenance methodology is necessary to ensure the proper commutation process and augmented equipment performance. This paper presents a research review about DC machines sparking and flashover causes and an experimental analysis with simple, fast and low cost test that can ensure that the interpole connections have been made correctly. This methodology can also be inserted into training protocols and service standards of the maintainers of DC machines.

Keywords: Maintenance, availability, field maintenance, test machines, electric machines

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #26, pp. 246-252

Title of the Paper: Feedback Effect for Wireless High-Power Transmission

Authors: Yuta Yamamoto, Kazuya Yamaguchi, Takuya Hirata, Ichijo Hodaka

Abstract: Wireless power transmission is based on electromagnetical phenomenon between two separate coils. In order to transfer power from one to the other, we have to cause a time-varying current along one coil. Many of conventional wireless power transmission systems suppose a sinusoidal current of the coil. One reason for it could be the convenience that we have a sinusoidal power source as the industry standard. If we can use a power source which generates many types of wave form, we do not necessarily use the sinusoidal wave. In this study, we propose to add a feedback signal on a sinusoidal signal, that is, we propose to utilize a non-sinusoidal input. We will evaluate the sinusoidal wave and non-sinusoidal wave from the viewpoint of transmission power and efficiency to secondary side.

Keywords: Wireless Power Transmission, Non-Sinusoidal Input, Feedback

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #25, pp. 241-245

Title of the Paper: Time-Scale Analysis of Magnetic Field Intensity Produced by High Voltage Powerlines

Authors: Luigi Maxmilian Caligiuri, Francesco Lamonaca, Alfonso Nastro, Domenica Giordano

Abstract: High voltage powerlines represent one of the most important source of exposition to ELF electrical and magnetic fields for population and environment. The time and frequency analysis of fields produced by such sources is fundamental in order to properly characterize them and correctly evaluate the relative exposition. This is particularly important for fields characterized by different spectral components, for which the exposure limits are specified in function of frequency as stated by the ICNIRP guidelines for limiting exposure to time – varying electric, magnetic, and electromagnetic fields. If the frequency composition of such fields is non – stationary during the measurement time interval, the “traditional” frequency analysis techniques based on simple Fourier transform cannot be applied, but time -frequency and /or time –scale analysis techniques, assuming the signal stationary during a sufficiently small time interval, must be performed. Among these, a great importance have those based on different versions of multiresolution algorithms. The aim of this work is to analyse, by means of such techniques, the time – frequency features of magnetic ELF fields produced by typical high voltage (150 and 220kV) powerlines in their neighbourhood. To such purpose, a set of magnetic broadband field measurements has been performed at specific points placed at difference distances from high voltage wires during a “typical” day (that’s to say during normal operative conditions). Discrete wavelet transform and Daubechies multiresolution algorithms has been applied to the measured fields time history, showing the results obtained respectively using various base atoms system (Gabor, Gauss, Morlet and Franklin atoms in particular) and different Daubechies parameters number. It will be shown how a properly use of these transforms can help us to characterise sources emission especially in order to evaluate human and environmental exposition to ELF magnetic fields.

Keywords: Magnetic Field, ELF, Time – Frequency Analysis, Multiresolution, Wavelet, High – Voltage Powerlines, Human Exposition

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #24, pp. 233-240

Title of the Paper: A Novel Structure of Embryonics Electronic Cell Array

Authors: Sai Zhu, Jinyan Cai, Yafeng Meng, Danyang Li, Junbin Zhang, Tianzhen Meng

Abstract: Based on the classic embryonics electronic cell array structure, a novel structure of embryonic electronic cell array is proposed. The connections between cells are subdivided into local connection mode and remote connection mode. Cell is directly connected to its eight surrounding neighbor electronic cells in local connection mode. In remote connection mode, the signal between nonadjacent electronic cells transmits via the cooperation of switch boxes in electronic cells. By extending the connections between the electronic cells, the width of the switch box in each electronic cell is reduced and the length of gene configured connection is shorted with the ensuring connectivity between electronic cells. The self-repair ability of the proposed embryonics electronic cell array is verified through the simulation realization of a circuit.

Keywords: Embryonics Electronic Cell Array, Local Connection Mode, Remote Connection Mode, Electronic Cell Structure

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #23, pp. 224-232

Title of the Paper: Resonance and Efficiency in Wireless Power Transfer System

Authors: Kazuya Yamaguchi, Takuya Hirata, Yuta Yamamoto, Ichijo Hodaka

Abstract: Many papers about wireless power transfer use resonant phenomena. In general if input frequency is adjusted to the resonant frequency, the amplitude of current or voltage will be maximal. Since the power of resistive load is determined by its current or voltage, the power will be maximal at the resonance. As for wireless power transfer, it is one of significant specifications to transfer power as much as possible. Then it is natural to try to maximize transmitted power with resonant phenomena. On the other hand, efficiency is another significant specification on wireless power transfer. However efficiency is defined as a ratio with two different powers, and it cannot be concluded that efficiency is always maximal when either power is maximal. Therefore efficiency has no straightforward relation with resonance in contrast with the relation between resonance and power. In this paper, we show an example which cannot realize the maximal efficiency, although resonant phenomena are caused and discuss why the situation is caused. An analytical method for wireless power transfer is clarified and how to choose an optimal frequency is scrutinized. The power of transmitting and receiving sides and efficiency are calculated by using mathematical models, e.g. a state equation, a transfer function.

Keywords: Wireless Power Transfer, Highly Efficient Power Transmission, Electromagnetic Resonance

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #22, pp. 218-223

Title of the Paper: Analysis of Lyapunov Function Features for Some Strategies of the Network Optimization Problem

Authors: Alexander Zemliak, Alexandra Bychkovska

Abstract: General methodology for system design was elaborated by means of the optimal control theory approach. The problem of analog system design can be formulated in this case as a classical problem of the optimal control for some functional minimization. In this context the aim of the optimal control is to result to minimum point a cost function of the design process and to minimize the total computer time. The minimal time system design algorithm was defined as the problem of functional minimization. By this definition the aim of the system design process with minimal computer time is presented as a transition process of some dynamic system that has the minimal transition time. The optimal sequence of the control vector switch points was determined as a principal characteristic of the minimal-time system design algorithm. The conception of the Lyapunov function was proposed to analyze the behavior of design process. The special function that is a combination of the Lyapunov function and its time derivative was proposed to predict the design time of any strategy by means of the initial time interval analysis.

Keywords: Minimal-Time System Design, Control Theory Application, Lyapunov Function

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #21, pp. 208-217

Title of the Paper: Design and Analysis of UWB Down-Conversion Mixer with Linearization Techniques

Authors: D. Selvathi, M. Pown, S. Manjula

Abstract: Frequency translation which converts the original signal to a much lower baseband frequency signal is a vital role in the RF receiver design. In this work, a high linear down-conversion Gilbert cell mixer at 100MHz is designed using TSMC 0.18μm RF CMOS process. Linearity is an important performance measure in RF circuits particularly in mixer design. In this paper, the two types of linearization techniques called Cross Coupled Post Distortion (CCPD) and Multiple Gated Transistor (MGTR) are performed on wideband CMOS mixer and their performances are analysed. The mixer covers the frequency band of 3.1-9.5 GHz. The mixer with CCPD provides the conversion gain of 7.96dB with a noise figure of 14.66dB at 100MHz IF. The mixer with MGTR provides the conversion gain of 6.12dB with a noise figure of 14dB. The third order intercept point for these techniques is 3.33dBm and -1.365 dBm respectively. From this analysis, CCPD technique gives the high gain and high linearity for this UWB mixer. The circuit operates at the supply voltage of 1.8 V and the power consumption is 6.93mW.

Keywords: CCPD, down-conversion mixer, Linearization techniques, MGTR, UWB mixer

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #20, pp. 202-207

Title of the Paper: Practical Swarm Intelligent Control Brushless DC Motor Drive System Using GSM Technology

Authors: Ehab H. E. Bayoumi, Zaid A. Salmeen

Abstract: Sending written text messages are extremely popular among mobile phone users. Instant messaging allows quick transmission of short messages that allow an individual to share ideas, opinions and other relevant information. In this paper the same concept to design a system that acts a platform to receive messages is used. The designed control system which is based on the GSM technology allows control from a remote area to the desired location. The mathematical model and the design of PID speed controller for the brushless DC motor drive system are presented. A Practical Swarm Optimisation (PSO) algorithm is employed in order to obtain the controller parameters assuring enhanced step response performance criterion. Simulation results of the designed controllers are compared with that of classical controllers whose parameters are adjusted using Ziegler-Nichols technique. Results signify the superiority of the proposed technique over the classical method. The overall system is implemented and tested. The experimental results illustrate that the proposed system allows a greater degree of freedom to control and monitor the electric drive systems of a certain location is eliminated.

Keywords: GSM Technology, Brushless DC Motor, PID control, Practical Swarm Optimisation (PSO)

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #19, pp. 188-201

Title of the Paper: Transient Modeling of Z-Source Chopper with and without ESR Used for Control of Capacitor Voltage

Authors: Byamakesh Nayak, Saswati Swapna Dash

Abstract: The newly proposed Z-source chopper with two controlled switches is used to stabilize the duty cycle above 0.5 is presented. The device has boost capability without polarity reversal in the range of duty cycle 0 to 0.5 and buck-boost capability with polarity reversal of output voltage in the range of duty cycle 0.5 to 1. The above capabilities of the topology are studied through simulation. This paper also presents transient modeling of the proposed Z-source chopper with and without ESR (equivalent series resistance). The effects of ESR are studied in depth and based upon the transient modeling; the dc-link voltage is controlled by direct measurement of capacitor voltage and inductor current. The presence of RHP (right-half-plane) zero in developed average control-to-output model reveal that the output decreases initially before rising toward its new steady-state value when a step increase in control input is applied. The non-minimum-phase transient response can be reduced by proper feed-back control technique. Compensator for both voltage mode and current mode control are designed using classical control technique through small-signal-analysis. Hysteresis band modulator is used for finding out the switching function of switches. Performance of control method of the compensated Z-source chopper is verified by simulation.

Keywords: Z-source chopper, Current mode control (CMC), Hysteresis band modulator, Buck-Boost capabilities, Non–minimum–phase transient response, ESR (Equivalent series resistance), RHP (Right-halfplane)

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #18, pp. 175-187

Title of the Paper: Circuits Design of Memory Accessing System based on AXI Interface

Authors: Bing Li, Xiaoling Wang, Yong Liu

Abstract: This paper proposes a method for designing the DDR3 SDRAM (Double Data Rate3 Synchronous Dynamic Random Access Memory) memory accessing system based on AXI (Advanced eXtensible Interface) interface, which can achieve data transmission between SoC (System on-Chip) and off-chip SDRAM through AXI interface complying with AXI protocol. The whole design has been accomplished by using Verilog hardware description language, and the functional simulation has been done in Modelsim10.0a software tool. Three different parameters, including bandwidth, delay and the size of buffer FIFO (First In First Out) have been analysed in the proposed system. Through FPGA (Field Programmable Gate Array) on-board verification, this DDR3 memory accessing system can operate at 200MHz well.

Keywords: AXI; DDR3 SDRAM; memory accessing system; Packets; memory performance; SoC

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #17, pp. 165-174

Title of the Paper: Study of Structure of Control Vector for the Problem of Analog Circuit Optimization

Authors: Alexander Zemliak, Jose Salinas, Fernando Reyes, Sergio Vergara, Tatiana Markina

Abstract: The generalized methodology for electronic networks optimization was elaborated by means of the optimal control theory approach. A special control vector is defined to redistribute the compute expense between a network analysis and a parametric optimization. In this case the problem of the electronic system optimization is formulated as a classical problem of functional minimization of the optimal control theory. The optimization algorithm with a minimal computer time was defined as a controllable dynamic process with an optimal control vector. By this methodology the aim of the optimization process with a minimal computer time is presented as a transition process of some dynamic system that has the minimal transition time. The optimal position of the control vector switch points was determined as a principal characteristic of the algorithm with a minimal computer time for network optimization. The conception of the Lyapunov function of dynamic controllable system is used to analyze the principal characteristics of the process of network optimization. The special function that is a combination of Lyapunov function of the design process and its time derivative was proposed to predict the optimal control vector to construct the best algorithm for circuit optimization.

Keywords: Time-Optimal Design Algorithm, Circuit Optimization, Control Theory Formulation, Lyapunov Function, Switch Points

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #16, pp. 153-164

Title of the Paper: Grounded Resistance/Capacitance-Controlled Sinusoidal Oscillators Using Operational Transresistance Amplifier

Authors: Srinivasulu Avireni, Chandra Shaker Pittala

Abstract: This paper represents, five sinusoidal oscillators based on the Operational Transresistance Amplifier (OTRA). The proposed circuits require single OTRA and a few passive components to generate oscillations. The condition of oscillation and frequency of oscillation of the first proposed circuit is controlled by a single grounded resistor. And the remaining circuits depend on independent control of condition of oscillation and frequency of oscillation. In all these proposed circuits the grounded resistor can be replaced by a grounded capacitor, which is important so far on integration point of view. The performance of the proposed circuits is examined using SPICE models. The proposed circuits were built using commercially available current feedback operational amplifier (AD844 AN) on a laboratory bread board and passive components used externally and tested for waveform generation. Theoretical analyses of the proposed circuits are verified by the experimental results carried out with the prototype circuits.

Keywords: Oscillators, Operational Transresistance Amplifier, Analog Integrated Circuit Design, Current-Mode Oscillators, Sinusoidal Oscillators

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #15, pp. 145-152

Title of the Paper: Elliptic Curve Cryptoprocessor with Hierarchical Security

Authors: Alaaeldin Amin, Turki F. Al-Somani

Abstract: This paper describes an elliptic curve scalar multiplication method which is resistant to power analysis attacks. The proposed method confuses both the private key bit values and positions. Even with correct leaked information on the type of operations performed, associating that with a particular key bit value or position is almost impossible. Resistance to side channel attacks is provided at several levels. At the top level, the secret key is segmented into a number of randomly sized segments processed in random order. At the segment level, each segment is encoded randomly using NAF or binary encodings. Further, at the segment level, the inspection direction of segment bits for binary-encoded segments is randomly assigned either in MSB-to-LSB or LSB-to-MSB. Furthermore, at the individual segment bit level, zero bits can randomly trigger a dummy PADD operation. In addition to improved security, this results in an average saving of 50% over the number of dummy PADDs in the Double-and-Add-Always algorithm. Such hierarchical multi-level scheme causes the relation between the private key and possible leaked information to be quite confused resulting in a higher system security with minimal overhead for both speed and area.

Keywords: Elliptic Curve Cryptosystems, Side Channel Attacks, Normal Basis, Non Adjacent Form, Public Key Cryptography

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #14, pp. 135-144

Title of the Paper: A 12-bit CMOS Dual-Ladder Resistor String D/A Converter Integrated with Self-adjusted Reference Circuit

Authors: Feng Yang, Chaoqun An, Liang Xie, Xiangliang Jin

Abstract: This paper presents a 12 bit dual-ladder resistor string digital to analog converter (DAC) with the power supply of ±5V which adopts a self-adjusted reference circuit and a class-AB output buffer. A selfadjusted reference circuit is used to provide differential reference voltages for obtaining better accuracy and symmetry. The DAC reuses the resistors of the differential reference voltages circuit as the dual-ladder resistor string, which saves a considerable chip area. Class-AB output stage is employed to reduce the setup time and enhance the load-driving capability. The 12 bit DAC is fabricated in a standard 0.5μm CMOS process. The measured results show that the integral non-linearity (INL) and differential non-linearity (DNL) are less than 2 LSB and 0.25 LSB, respectively. The proposed DAC features the characteristics of high precision, good monotonicity and excellent symmetry.

Keywords: digital-to-analog converter, DAC, dual-ladder, class-AB, INL, DNL, self-adjusted reference circuit

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #13, pp. 129-134

Title of the Paper: Dynamic Self Controllable Surfing for Differential On-Chip Wave-Pipelined Serial Interconnect

Authors: Bhaskar M., Srinivas Gantasala, Venkataramani B.

Abstract: In the literature, surfing technique has been proposed for differential wave-pipelined serial interconnects with uniform repeaters (UR) and non-uniform repeaters (NUR) to increase the data transfer rate. In this paper, a new surfing circuit called „Dynamic self controllable inverter pair‟ is proposed for differential wave-pipelined serial interconnects with UR and NUR to increase the data transfer rate further. The method of logical effort is used for the design of surfing circuits both UR and NUR. To evaluate the efficiency of these techniques, 40 mm metal 4 interconnects using the proposed surfing techniques are implemented along with transmitter, receiver and delay locked loop(DLL) in UMC 180nm technology and their performances are studied through post layout simulations. From this study, it is observed that the proposed surfing technique using UR and NUR achieve 3.53 times and 3.76 times higher data transfer rates respectively compared to the single ended scheme. The proposed scheme using UR and NUR has 1.18 times and 1.25 times higher data transfer rates respectively compared to differential scheme.

Keywords: Controllable Inverter Pair, Differential Interconnect, Method Of Logical Effort, Repeater Insertion, Self Controllable, Serial Link, Surfing, Wave-Pipelining

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #12, pp. 117-128

Title of the Paper: Generalized Thévenin/Helmholtz and Norton/Mayer Theorems of Electric Circuits with Variable Resistances

Authors: Penin Alexandr

Abstract: The generalized equivalent circuits, which develop the known theorems, are formulated. It appears that the load straight line at various values of a changeable element (resistor) of an active twopole passes into a bunch of these lines. The bunch centre coordinates do not depend on this changeable element. It is proposed to use as the parameters of the generalized equivalent generator such a load current and voltage, which proved the current across this element equal to zero. The application of projective coordinates instead of resistance values allows obtaining suitable formulas of the recalculation of the load current, to define the scales for the load and variable element.

Keywords: Equivalent Circuit, Active Two-Pole, Load Straight Line, Projective Geometry, Geometric Circuit Theory

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #11, pp. 104-116

Title of the Paper: Design of a Passive Millimeter-Wave Imager Used for Concealed Weapon Detection BHU-2D-U

Authors: Bao-Hua Yang, Zhi-Ping Li, Cheng Zheng, Jin Zhang, Xian-Xun Yao, An-Yong Hu, Jun-Gang Miao

Abstract: A passive millimeter-wave imager BHU-2D-U is introduced for detecting concealed weapons on human body. It is a subsequent model of BHU-2D. The improvements of BHU-2D-U over BHU-2D are introduced. Firstly, the field of view (FOV) of the new imager is enlarged and an U type antenna of array is adopted for whole body scan. Secondly, the enlarged FOV requires smaller antenna spacing and compact receiver arrays. The I/Q demodulators operating in double side band mode is proved for no mirror-image. In order to avoid the image-reject filter between front end and IF module, this structure mode is adopted. Thirdly, the front-end circuit and IF circuit are introduced, the good consistency and the orthogonal error are obtained. Fourthly, compared with the BHU-2D, the quantity of the receiving elements is increased to 48 unites. To cope with the increase of the correlator quantity, a multiplexing technique is used in the FPGA internal layout of the correlator array unit. Finally, the design and image reconstruction algorithms are verified based on the imaging experiments on a person with concealed weapon. The initial results of BHU-2D-U have showed the effectiveness improvements.

Keywords: Concealed Weapon Detection, Front End, Passive Microwave Radiometry, Receiver, Synthetic Aperture Imaging

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #10, pp. 94-103

Title of the Paper: An Improved Recycling Folded Cascode OTA with Positive Feedback

Authors: S. Kumaravel, B. Venkataramani

Abstract: In the literature, Improved Recycling Folded Cascode (IRFC) Operational Transconductance Amplifier (OTA) is proposed for enhancing the DC gain and the Unity Gain Bandwidth (UGB) of the Recycling Folded Cascode (RFC) OTA. In this paper, an enhanced IRFC (EIRFC) OTA which uses positive feedback at the cascode node is proposed for enhancing the differential mode (DM) gain without changing the unity gain bandwidth (UGB), and lowering the Common mode (CM) gain. For the purpose of comparison, IRFC and EIRFC OTAs are implemented using UMC 90 nm CMOS technology and studied through simulation. From the simulation, it is found that the DM gain and CM gain of EIRFC OTA is higher by 6dB and lower by 39 dB respectively, compared to that of IRFC OTA for the same power and area. The slew rate of EIRFC OTA is also higher by a factor of 1.5.

Keywords: Cascode Amplifier, CMRR, gm/ID Methodology, Recycling, Slew Rate, Common-mode

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #9, pp. 85-93

Title of the Paper: The Design of DSP/FPGA based Maneuvering Target Tracking System

Authors: Pan-Long Wu, Lian-Zheng Zhang, Xin-Yu Zhang

Abstract: Debiased converted measurement Kalman filter based IMM (IMM-DCMKF) algorithm is a commonly used maneuvering target tracking algorithm, which is combined with the interacting multiple model (IMM) and the debiased converted measurements Kalman filter (DCMKF). However, the computation complexity of this algorithm is large and the traditional realization of this algorithm using software can’t meet the real-time needs in actual application. This paper presents the hardware design of IMM-DCMKF algorithm based on DSP/FPGA. In this tracking system, the FPGA is used as a floating point co-processor of the fixed point DSP, and the large amount of calculation of IMM-DCMKF algorithm is realized in FPGA. DSP is in charge of the scheduling of the total tracking algorithm and the control of the data stream, which resolves the problem of the concurrency and real time in the realization of the single DSP scheme. The simulations of results which show the hardware design scheme of IMM-DCMKF algorithm can meet the real-time requirement and simultaneously ensure the accuracy of the data processing.

Keywords: DSP, DCMKF, IMM-DCMKF, FPGA, Maneuvering target tracking

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #8, pp.75-84

Title of the Paper: Sampling Clock Imperfection Analysis for Synthetic Aperture Interferometric Radiometer

Authors: Jin Zhang, Zhiping Li, Cheng Zheng, Xianxun Yao, Baohua Yang, Xiaozhoushang

Abstract: In this paper, a nontrivial sampling clock imperfection analysis is presented for Synthetic Aperture Interferometric Radiometers (SAIR). Sampling clock determines the edges at which analog radiometric demodulated signal are digitized for digital correlation, and its jitter and skew could lead to SAIR performance degradations. Firstly, the jitter and skew contributions to visibility uncertainty degradation is analyzed by SAIR correlation principles. Secondly, clock jitter effects on Analog-to-Digital Converter (ADC) SNR is demonstrated, and this effect is quantitatively evaluated by Time Interval Error (TIE) jitter. The jitter simulation method by Phase Noise Integration (PNI) is also proposed. Thirdly, the Phase Synchronization Method (PCM) is presented to decrease the clock skews between correlation channel pairs to improve decorrelation effects. The experimental verifications for clock jitter and skews are conducted on the BHU-2D-U SAIR instrument, and the contributions of this paper are concluded. This paper has proposed nontrivial imperfection analysis for SAIR sampling clock, and the conclusions could be used for SAIR and polarimetric radiometer digital correlation designs.

Keywords: Samping Clock, Jitter, Skew, SAIR, Visibility Uncertainty, SNR, TIE Jitter

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #7, pp.68-74

Title of the Paper: Circuit Design of PCI Express Retry Mechanisms

Authors: Bing Li, Yan Ding, Yong Liu

Abstract: TLP retry mechanism is an effective measure of PCI Express to ensure data reliable transmissions. The paper theoretically analyzes reasons for retransmission, operating rules of retransmission and factors affecting the size of retry buffer. On this basis, proposes a circuit structure of implementing TLP retry mechanisms, describing the implementation process of retry management, and conducts functional verification based on VMM verification platform, using VCS simulation tool. Verification results show that this method not only implements the function of the retry mechanisms, but also guarantee data transmission normally and orderly. What’s more, it would save the storage space of retry buffer and improve the efficiency of the link transmission.

Keywords: PCI Express, TLP retry mechanism, Retry buffer, VMM

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #6, pp.62-67

Title of the Paper: An Interleaved Boost Converter with Coupled Inductor for PV Energy Conversion

Authors: Sheng-Yu Tseng, Chien-Chih Chen, Ching-Ting Huang

Abstract: This paper presents an interleaved boost converter with coupled inductors for photovoltaic (PV) energy conversion. The proposed soft-switching boost converter uses an interleaved method to increase its power density and coupled-inductor technology to extend its step-up voltage ratio. To reduce switching losses of active switches, the proposed interleaved boost converter incorporates a synchronous switching technology to obtain a wider soft-switching range. Thus, the conversion efficiency can be further improved. In order to draw the maximum power from the PV energy, a perturbation-and-observation method and a microchip are associated to implement maximum power point tracking (MPPT) algorithm and power regulating scheme. Finally, a prototype soft-switching interleaved boost converter with coupled inductors has been built and implemented. Experimental results have been proposed to verify the performances and feasibility of the proposed soft-switching interleaved boost converter for PV energy conversion.

Keywords: photovoltaic, soft-switching, coupled- inductor, perturbation-and-observation, MPPT

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #5, pp.47-61

Title of the Paper: Comparative Design and Modeling Study of Single Sided Linear Planner Switched Reluctance Motor

Authors: Zaafrane Wajdi, Khediri Jalel, Rehaoulia Habib

Abstract: This paper presents the comparison study between two design method of a single sided Linear Planner Switched Reluctance Motor (LPSRM) with an a translator and a passive stator .The work presents a LSRM complete design by 2-D Finite Element Analysis method (2-D FEA) and rotary to linear conversion method design . A detailed analysis of the influence of various geometrical parameters on the force developed by the actuator mainly gives in particular tooth size influence on fixed and mobile parts. A model of the actuator is performed neglecting magnetic saturation. The proposed actuator can be used in positioning task for high precision application.

Keywords: Linear switched reluctance motor, single sided planner actuator, Rotary to linear switched reluctance motor conversion, optimal design, 2D finite element analysis, LSRM modeling

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #4, pp.37-46

Title of the Paper: Induction Motor Drive's Parameters Identification Using Extended Kalman Filter Algorithms

Authors: Moulay Rachid Douiri, Mohamed Cherkaoui

Abstract: This paper presents a detailed study of the extended Kalman filter (EKF) for estimating the rotor resistance and rotor speed of an induction motor drive. The overall structure of the EKF is reviewed and the various system vectors and matrices are defined. By including the rotor resistance and rotor speed as a state variables, the EKF equations are established from a discrete two-axis model of the three-phase induction motor. The investigations show that the EKF is capable of estimating the rotor resistance and capable of tracking the actual rotor speed provided that the elements of the covariance matrices are properly selected. Moreover, the performance of the EKF is satisfactory even in the presence of noise or when there are variations in the induction machine parameters.

Keywords: extended Kalman filter, parameters estimation, induction motor

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #3, pp.29-36

Title of the Paper: Simulator Based Device Sizing Technique for Operational Amplifiers

Authors: Rishi Todani, Ashis Kumar Mal

Abstract: In this work, design of CMOS operational amplifiers (opamps) is discussed using a new technique of transistor sizing, called as Potential Distribution Method (PDM). PDM is a technique proposed to simplify analog design and is primarily based on voltage and current distribution at different nodes of a circuit. Apart from being technology independent, PDM is also free from complex mathematical expressions governing the devices and the circuit. Instead of relying on traditional analytical methods, PDM directly uses the simulator as a device sizing tool to meet the desired performance from the circuit. This is achieved by first designing the circuit with moderate performance by logically allocating node voltages and currents, and then modifying the potentials and currents (dc operating points) to meet the target specifications. A fully differential folded cascode opamp is thus designed to illustrate the design methodology. The effect of node voltages and branch currents on response of the opamp is also examined. Thereafter, using these dependencies, the guidelines for tuning the performance parameters to achieve the target specifications are discussed. The methodology demonstration is carried out using UMC 180 nm CMOS technology at 1.8 V supply and the simulation results are presented.

Keywords: Analog design, CMOS, operational amplifier, transistor sizing, simulation, fully differential folded cascode

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #2, pp.11-28

Title of the Paper: Role of the Threshold Voltage and Transconductance Parameters of NMOS Transistors in NMOS Inverter Performance for Static and Switching Conditions of Operation

Authors: Milaim Zabeli, Nebi Caka, Myzafere Limani, Qamil Kabashi

Abstract: The aim of this paper is to show the influence of the threshold voltage and transconductance parameters that characterize the NMOS transistors on the behavior of NMOS inverters in static and switching conditions of operation, as well as set directive that should be followed during the design phase of NMOS inverters that enable designers to design NMOS inverters with the best possible performance, depending on operation conditions. Designing the NMOS inverters with controlled parameters that characterize NMOS transistors in NMOS inverters also enables designers to design the logic circuits based in NMOS inverters (NMOS logic) with the best possible performance, according to the operation conditions and designers’ requirements.

Keywords: NMOS inverter, NMOS transistor, VTC characteristics, threshold voltage, critical voltages, noise margins, NMOS transconductance parameter, propagation delay times

WSEAS Transactions on Circuits and Systems, ISSN / E-ISSN: 1109-2734 / 2224-266X, Volume 13, 2014, Art. #1, pp.1-10