2012/4
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- ItemTunable Versatile High Input Impedance Voltage-Mode Universal Biquadratic Filter Based on DDCCs(Společnost pro radioelektronické inženýrství, 2012-12) Horng, Jiun-Wei; Chiu, To-Yao; Jhao, Zih-YangA high input impedance voltage-mode universal biquadratic filter with three input terminals and seven output terminals is presented. The proposed circuit uses three differential difference current conveyors (DDCCs), four resistors and two grounded capacitors. The proposed circuit can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass, simultaneously. The proposed circuit offers the features of high input impedance, using only grounded capacitors, and orthogonal controllability of resonance angular frequency and quality factor.
- ItemModified Level Restorers Using Current Sink and Current Source Inverter Structures for BBL-PT Full Adder(Společnost pro radioelektronické inženýrství, 2012-12) Tirumalasetty, Venkata Rao; Avireni, SrinivasuluFull adder is an essential component for the design and development of all types of processors like digital signal processors (DSP), microprocessors etc. In most of these systems adder lies in the critical path that affects the overall speed of the system. So enhancing the performance of the 1-bit full adder cell is a significant goal. In this paper, we proposed two modified level restorers using current sink and current source inverter structures for branch-based logic and pass-transistor (BBL-PT) full adder [1]. In BBL-PT full adder, there lies a drawback i.e. voltage step existence that could be eliminated in the proposed logics by using the current sink inverter and current source inverter structures. The proposed full adders are compared with the two standard and well-known logic styles, i.e. conventional static CMOS logic and Complementary Pass transistor Logic (CPL), demonstrated the good delay performance. The implementation of 8-bit ripple carry adder based on proposed full adders are finally demonstrated. The CPL 8-bit RCA and as well as the proposed ones is having better delay performance than the static CMOS and BBL-PT 8-bit RCA. The performance of the proposed BBL-PT cell with current sink & current source inverter structures are examined using PSPICE and the model parameters of a 0.13 µm CMOS process.
- ItemEvolutionary Synthesis of Fractional Capacitor Using Simulated Annealing Method(Společnost pro radioelektronické inženýrství, 2012-12) Slezak, Josef; Goetthans, Tomas; Drinovsky, JiriSynthesis of fractional capacitor using classical analog circuit synthesis method was described in [6]. The work presented in this paper is focused on synthesis of the same problem by means of evolutionary method simulated annealing. Based on given desired characteristic function as input impedance or transfer function, the proposed method is able to synthesize topology and values of the components of the desired analog circuit. Comparison of the results given in [6] and results obtained by the proposed method will be given and discussed.
- ItemA Non-blind Color Image Watermarking Scheme Resistent Against Geometric Attacks(Společnost pro radioelektronické inženýrství, 2012-12) Ghafoor, Abdul; Imran, MuhammadA non-blind color image watermarking scheme using principle component analysis, discrete wavelet transform and singular value decomposition is proposed. The color components are uncorrelated using principle component analysis. The watermark is embedded into the singular values of discrete wavelet transformed sub-band associated with principle component containing most of the color information. The scheme was tested against various attacks (including histogram equalization, rotation, Gaussian noise, scaling, cropping, Y-shearing, X-shearing, median filtering, affine transformation, translation, salt & pepper, sharpening), to check robustness. The results of proposed scheme are compared with state-of-the-art existing color watermarking schemes using normalized correlation coefficient and peak signal to noise ratio. The simulation results show that proposed scheme is robust and imperceptible.
- ItemCurrent-Mode Universal Filters Employing Single FDCCII(Společnost pro radioelektronické inženýrství, 2012-12) Kacar, Firat; Yesil, Abdullah; Kuntman, HakanIn this study, to realize current-mode multifunction filters, three new circuit configurations are presented. The circuits include fully differential current conveyor (FDCCII) and four passive components. First proposed circuit is a universal filter with single-input and three-outputs, which can simultaneously realize current mode low-pass, band-pass and high-pass filter responses employing all grounded passive components. The last two proposed are universal filters with three-inputs single-output, which can realize current mode low-pass, band-pass, high-pass, band-stop and all-pass filter responses employing single FDCCII. Furthermore, each of the proposed circuits still enjoys realization using a minimum number of active and passive components. First and last of the proposed circuits have no requirement with the component choice conditions to realize specific filtering functions. No parameter matching condition is required. Active and passive sensitivities of filters are investigated and calculated 5 percentage hangings. Simulation results are found in close agreement with the theoretical results.