International Journal of Circuit Theory and Applications

Cover image for Vol. 41 Issue 1

January 2013

Volume 41, Issue 1

Pages 1–110

  1. Research Articles

    1. Top of page
    2. Research Articles
    3. Letter to the Editor
    1. A CCII-based wide frequency range square waveform generator (pages 1–13)

      Andrea De Marcellis, Claudia Di Carlo, Giuseppe Ferri and Vincenzo Stornelli

      Article first published online: 1 MAY 2011 | DOI: 10.1002/cta.781

      Thumbnail image of graphical abstract

      In this work, a novel currentmode square-wave generator is proposed. The circuit, whose working principle is based on a current differentiation instead of voltage integration, has been designed in a standard CMOS technology with low voltage (±1V) and low power (430µW) characteristics. Simulations and experimental measurements have confirmed the theoretical expectations showing a high linearity and a wide oscillation frequency range, which can independently be adjusted through either capacitive (in the range pF−µF) or resistive (in the range MΩ−GΩ) external passive components. Copyright © 2011 John Wiley & Sons, Ltd.

    2. Low-power, low-noise, active-RC band-pass filters using a ‘lossy’ LP–BP transformation (pages 15–32)

      Drazen Jurisic, Neven Mijat and George S. Moschytz

      Article first published online: 10 MAY 2011 | DOI: 10.1002/cta.782

      Thumbnail image of graphical abstract

      A new design procedure for single-opamp low-power, discrete-component, lowselectivity, low-sensitivity and low-noise active-RC band-pass filters. Considering all performance characteristics the advantages of the new design technique outweigh those of other design techniques, for example cascade of Biquads. Using a so-called ‘lossy’ LP-BP transformation, closed-form design equations for the design of secondto eighth-order, single-amplifier BP filters are presented. Copyright © 2011 John Wiley & Sons, Ltd.

    3. Low-power quadrature generators for body area network applications (pages 33–43)

      Jens Masuch and Manuel Delgado-Restituto

      Article first published online: 12 OCT 2011 | DOI: 10.1002/cta.783

      Thumbnail image of graphical abstract

      Two quadrature generation architectures, optimized for low power consumption in the 2.4 GHz frequency range, have been presented: a QVCO and a VCO with divider. Measurement results confirm that the QVCO achieves lower power consumption and better phase noise performance thanks to passive RC phase shifters in the coupling path.

    4. RC models of a constant phase element (pages 59–67)

      Juraj Valsa and Jiri Vlach

      Article first published online: 12 OCT 2011 | DOI: 10.1002/cta.785

      Thumbnail image of graphical abstract

      The described models consisting of several resistors and capacitors approximate an ideal constant phase element. Their input impedance phase is reasonably constant over several decades of frequency and can have any value between −90° and 0°. The models are much simpler and at the same time much more accurate than any other models of constant phase elements described so far.

    5. A complementary metal–oxide semiconductor digitally programmable current conveyor (pages 69–81)

      Hussain Alzaher, Noman Tasadduq, Osama Al-Ees and Fares Al-Ammari

      Article first published online: 12 OCT 2011 | DOI: 10.1002/cta.786

      Thumbnail image of graphical abstract

      A proposal for realizing a digitally programmable second-generation current conveyor (DPCC) is shown in the figure below. The proposed DPCC surmounts several drawbacks of the previous topologies through providing a more power and area efficient solution while exhibiting wider tuning range and bandwidth. Application examples including a variable gain amplifier and a second-order filter highlighting some of the attractive features of the proposed DPCC are given.

  2. Letter to the Editor

    1. Top of page
    2. Research Articles
    3. Letter to the Editor
    1. Formulating hybrid equations and state equations for nonlinear circuits using SPICE (pages 101–110)

      Kiyotaka Yamamura and Mitsuru Tonokura

      Article first published online: 12 OCT 2011 | DOI: 10.1002/cta.788

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      In this paper, a simple method is proposed for formulating hybrid equations and state equations for nonlinear circuits using SPICE. In this method, we only perform the transient analysis of SPICE on a linear circuit that is obtained through a small modification to the original circuit. With the proposed method, we can obtain hybrid equations and state equations easily using SPICE only.

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