Recent Submissions

Now showing 1 - 5 of 22
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    CFOA-Based Lossless and Lossy Inductance Simulators
    (Společnost pro radioelektronické inženýrství, 2011-09) Kacar, Firat; Kuntman, Hakan
    Inductance simulator is a useful component in the circuit synthesis theory especially for analog signal processing applications such as filter, chaotic oscillator design, analog phase shifters and cancellation of parasitic element. In this study, new four inductance simulator topologies employing a single current feedback operational amplifier are presented. The presented topologies require few passive components. The first topology is intended for negative inductance simulation, the second topology is for lossy series inductance, the third one is for lossy parallel inductance and the fourth topology is for negative parallel (-R) (-L) (-C) simulation. The performance of the proposed CFOA based inductance simulators is demonstrated on both a second-order low-pass filter and inductance cancellation circuit. PSPICE simulations are given to verify the theoretical analysis.
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    Single-Input Five-Output Electronically Tunable Current-Mode Biquad Consisting of Only ZC-CFTAs and Grounded Capacitors
    (Společnost pro radioelektronické inženýrství, 2011-09) Satansup, Jetsdaporn; Tangsrirat, Worapong
    This paper presents an electronically tunable current-mode biquadratic filter constructing with four Z-copy current follower transconductance amplifiers (ZC-CFTAs) and only two grounded capacitors. The presented filter can realize all the five standard biquadratic functions simultaneously without requiring any component matching conditions and connecting any relevant output currents. The circuit has one low-impedance input and five high-impedance outputs, resulting in easy cascadability in current-mode. Also, the developed circuit exhibits the advantage of non-interactive electronic control of the natural angular frequency and the quality factor Q along with low incremental active and passive sensitivities. Computer simulation results using PSPICE program are given to confirm the validity of the theoretical prediction and to point out the attractive performance of the circuit.
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    Supplementary Inductance Simulator Topologies Employing Single DXCCII
    (Společnost pro radioelektronické inženýrství, 2011-09) Metin, Bilgin
    In this study, six grounded inductance simulator circuits are presented including additional useful features in comparison to previous dual-X current conveyor (DXCCII) based implementations. To demonstrate the performance and usefulness of the presented circuits, one of them is used to construct a fifth order Butterworth high-pass filter and a current-mode multifunction filter as application examples. Simulation results are given to confirm the theoretical analysis. The derived DXCCII and its applications are simulated using CMOS 0.35 μm technology.
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    Exploiting Temporal Context in High-Resolution Movement-Related EEG Classification
    (Společnost pro radioelektronické inženýrství, 2011-09) Dolezal, Jaromir; Stastny, Jakub; Sovka, Pavel
    The contribution presents an application of a movement-related EEG temporal development classification which improves the classification score of voluntary movements controlled by closely localized regions of the brain. A dynamic Hidden Markov Model-based (HMM) classifier specifically designed to capture EEG temporal behavior was used. Surprisingly, HMM classifiers are rarely used for BCI design despite of their advantages. Because of this we also experimented with Learning Vector Quantization, Perceptron, and Support Vector Machine classifiers using a feature space which captures the temporal dynamics of the data. The results presented in this work show that HMM achieves the best performance due to an a priori information on physiological behavior of EEG inserted to the HMM classifier. Feature extraction process and problems with classification were analyzed as well. Classification scores of 66.7% – 94.7% were achieved in our experiments.
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    A Novel QAM Technique for High Order QAM Signaling
    (Společnost pro radioelektronické inženýrství, 2011-09) Ozen, Ali
    The paper proposes a novel spread quadrature amplitude modulation (S-QAM) technique with high SNR improvement for high-order QAM channels. Simulated and experimental bit error rate (BER) performance analyses of the proposed technique in blind and non-blind equalizers are obtained by using single carrier (SC) WiMAX (IEEE 802.16-2004) radio. Instead of using any one particular type of channel profile, this study concentrates on true frequency selective Rayleigh fading channels in the real-time WiMAX radio environment around 3.5 GHz. The Constant Modulus Algorithm (CMA) blind equalizer has been compared with the popular non-blind equalizers, Recursive Least Squares (RLS) and Least Mean Squares (LMS) algorithm, as benchmarks. It has been proven in experimental and simulated channels that CMA blind equalizer, using the proposed technique, can be considered as a low complexity, spectrum efficient and high performance time domain equalizations to be embedded in a transceiver for the next generation communications. Furthermore the proposed technique has also reduced approximately till 5 dB and 7.5 dB performance differences between non-blind and blind equalizers for 16-QAM and 64-QAM, respectively. The simulation results have demonstrated that the simulated and experimental studies of the proposed technique are compatible with each other and extremely satisfying.