Browsing by Author "Tan, M. A."

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Open Access
Analog CMOS implementation of cellular neural networks
(IEEE, 1993) Baktır, I. A.; Tan, M. A.
The analog CMOS circuit realization of cellular neural networks with transconductance elements is presented. This realization can be easily adapted to various types of applications in image processing just by choosing the appropriate transconductance parameters according to the predetermined coefficients. The effectiveness of the designed circuits for connected component detection is shown by HSPICE simulations. For “fixed function” cellular neural network circuits the number of transistors are reduced further by using multi-input transconductance elements.
Open Access
Application of asymptotic waveform evaluation for time-domain analysis of nonlinear circuits
(Taylor & Francis, 1997) Topçu, S.; Atalar, Abdullah; Tan, M. A.
A method is described to exploit asymptotic waveform evaluation (AWE) in the time-domain analysis of nonlinear circuits by using SPICE models for nonlinear devices such as diodes, transistors, etc. Although AWE has been used for linearized circuits only, the aim is to enhance the accuracy of the simulation while preserving the computational efficiency obtained with AWE and to eliminate the piecewise-linear modelling problem. Practical examples are given to illustrate significant improvements in accuracy. For circuits containing weakly nonlinear devices, it is demonstrated that this method is typically at least one order of magnitude faster than SPICE.
Open Access
Biquadratic transconductance switched-capacitor filters
(IEEE, 1993-04) Tan, M. A.
Switched-capacitor (SC) filters yield efficient implementations in integrated form. However, they employ op-amps, each of which must be designed for a given filter separately. Furthermore, SC filters are not tunable. This work presents a new type of sampled data filters consisting of transconductance elements, switches and capacitors, called transconductor switched capacitor (TSC) filters. Transconductance elements do not degrade their performance within a wide frequency range and tunable ones are available.
Open Access
Current-mode tunable integrator for low voltage applications
(IEEE, 1995-08-31) Karşilayan, A. İ.; Tan, M. A.
The Letter presents a damped integrator for the design of lowvoltage (3V) tunable current-mode filters. The circuit is analysed and the tuning characteristics are discussed.
Open Access
Design of all-pole low-pass ladder filters using current-mode damped integrators
(IEEE, 1996) Oralkan, Ömer; Karşılayan, Aydın İlker; Tan, M. A.
A method for operational simulation of all-pole low-pass LC ladders filters by using current-mode damped integrators is introduced. The circuits obtained by this method need only current mirrors and capacitors and are convenient for realization in CMOS technology as well as can be used in other technologies.
Open Access
A new method for nonlinear circuit simulation in time domain: NOWE
(Institute of Electrical and Electronics Engineers, 1996-03) Ocalı, O.; Tan, M. A.; Atalar, Abdullah
A new method for the time-domain solution of general nonlinear dynamic circuits is presented. In this method, the solutions of the state variables are computed by using their time derivatives up to some order at the initial time instant. The computation of the higher order derivatives is equivalent to solving the same linear circuit for various sets of dc excitations. Once the time derivatives of the state variables are obtained, an approximation to the solution can be found as a polynomial rational function of time. The time derivatives of the approximation at the initial time instant are matched to those of the exact solution. This method is promising in terms of execution speed, since it can achieve the same accuracy as the trapezoidal approximation with much smaller number of matrix inversions.
Open Access
A new method for the steady-state analysis of periodically excited nonlinear circuits
(Institute of Electrical and Electronics Engineers, 1996-12) Celik, M.; Atalar, Abdullah; Tan, M. A.
We propose a new method for the steady state analysis of periodically excited nonlinear microwave circuits. It is a modified and more efficient form of Newton-Raphson iteration based harmonic balance (HB) technique. It solves the convergence problems of the HB technique at high drive levels. The proposed method makes use of the parametric dependence of the circuit responses on the excitation level. It first computes the derivatives of the complex amplitudes of the harmonics with respect to the excitation level efficiently and then finds the Pade approximants for the amplitudes of the harmonics using these derivatives.
Open Access
A novel algorithm for DC analysis of piecewise-linear circuits: popcorn
(IEEE, 1994) Topçu, S.; Ocalı, O.; Atalar, Abdullah; Tan, M. A.
A fast and convergent iteration method for piecewise-linear analysis of nonlinear resistive circuits is presented. Most of the existing algorithms are applicable only to a limited class of circuits. In general, they are either not convergent or too slow for large circuits. The new algorithm presented in the paper is much more efficient than the existing ones and can be applied to any piecewise-linear circuit. It is based on the piecewise-linear version of the Newton-Raphson algorithm. As opposed to the Newton-Raphson method, the new algorithm is globally convergent from an arbitrary starting point. It is simple to understand and it can be easily programmed. Some numerical examples are given in order to demonstrate the effectiveness of the proposed algorithm in terms of the amount of computation. © 1994 IEEE
Open Access
Pole-zero computation in microwave circuits using multipoint Padé approximation
(Institute of Electrical and Electronics Engineers, 1995-01) Celik, M.; Ocali, O.; Tan, M. A.; Atalar, Abdullah
A new method is proposed for dominant pole- zero (or pole-residue) analysis of large linear microwave circuits containing both lumped and distributed elements. The method is based on a multipoint Padé approximation. It finds a reduced-order rational s-domain transfer function using a data set obtained by solving the circuit at only a few frequency points. We propose two techniques in order to obtain the coefficients of the transfer function from the data set. The proposed method provides a more efficient computation of both transient and frequency domain responses than conventional simulators and more accurate results than the techniques based on single-point Padé approximation such as asymptotic waveform evaluation.
Open Access
Transient analysis of nonlinear circuits by combining asymptotic waveform evaluation with volterra series
(Institute of Electrical and Electronics Engineers, 1995-08) Celik, M.; Atalar, Abdullah; Tan, M. A.
A new method is proposed for the transient analysis of circuits with large number of linear lumped elements and lossy coupled transmission lines, and with few mildly nonlinear terminations. The method combines the Volterra-series technique with Asymptotic Waveform Evaluation approach and corresponds to recursive analysis of a linear equivalent circuit.