Serdar Ozoguz

A new versatile building block : current differencing buffered amplifier suitable for analog signal-processing filters

A new multi-terminal active component with two inputs and two outputs, namely current differencing buffered amplifier (CDBA) is proposed. It is derived from current feedback amplifier (CFA) which is commercially available as AD844. It has been shown by realising high-order voltage transfer function that it is beneficial to use this element as a building block to realize analog signal-processing filters.

Current-mode all-pass filters using current differencing buffered amplifier and a new high-Q bandpass filter configuration

A new configuration realizing first-order canonical current processing all-pass filters based on current differencing buffered amplifier, a recently introduced active element, is proposed. Using this configuration, two types of first-order current-mode all-pass filters are derived. They employ only a single active element and a bare minimum number of passive components. No component-matching constrains are required. Because of the high performance of the current differencing buffered amplifier, they are suitable for wideband applications. The derived filters are cascadable because of their high output impedances and they use fewer active and/or passive components compared to their previously reported counterparts. As an application of the proposed first-order all-pass networks, a new current-mode high-Q bandpass filter, which offers a number of advantages over its counterparts, is also given.

Creation of a complex butterfly attractor using a novel Lorenz-Type system

A novel Lorenz-type system of nonlinear differential equations is proposed. Unlike the original Lorenz system, where the chaotic dynamics remain confined to the positive half-space with respect to the Z state variable due to a limiting threshold effect, the proposed system enables bipolar swing of this state variable. In addition, the classical set of parameters (a, b, c) controlling the behavior of the Lorenz system are reduced to a single parameter, namely a. Two possible modes of operation are admitted by the system; switching between these two modes results in the creation of a complex butterfly chaotic attractor. Numerical simulations and results from an experimental setup are presented.

Insensitive current-mode universal filter using dual output current conveyors

A new current-mode universal filter with single input and three outputs employing only three dual output current conveyors and five grounded passive elements is presented. The proposed filter realizes three filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive and active sensitivities are low. Furthermore, the filter can also realize the notch and all-pass responses. Orthogonal control of the natural angular frequency and the quality factor is achieved.

Multiscroll Chaotic Oscillators: The Nonautonomous Approach

A novel technique for designing chaotic oscillators capable of producing multiscrolls is presented. The technique is based on multilevel-logic pulse-excitation. A modified forced Van der Pol oscillator, a forced active tank resonator, and a forced cross-coupled oscillator are given as design examples

n-scroll chaotic attractors from a first-order time-delay differential equation.

In this paper, a novel first-order delay differential equation capable of generating n-scroll chaotic attractor is presented. Hopf bifurcation of the introduced n-scroll chaotic system is analytically and numerically determined. The bifurcation diagram and Lyapunov spectrum of the system are calculated and the results show that the system has a chaotic regime in a wider parameter range. Furthermore, period-3 behavior has been observed on the system. Circuit realizations of two-, three-, four-, and five-scroll chaotic attractors are also presented.

New current-mode universal filters using only four (CCII+)s

Two new single-input three-output current-mode (CM) universal filters using only four CCIIs of plus-type were presented. It was shown that both filters have simpler implementations compared to the current conveyor-based universal current filters already known in the literature. Experimental results verifying theoretical analyses are also included.

On the realization of circuit-independent nonautonomous pulse-excited chaotic oscillator circuits

The aim of this paper is to present a simple circuit design method for realizing a nonautonomous chaotic oscillator given a second-order sinusoidal oscillator with two capacitors. The proposed method relies on applying a periodic pulse train, as an exciting source, and the addition of a signum-type nonlinear transconductor to the given sinusoidal oscillator. Experimental results of designed circuits are shown.

On the Realization of MOS-Only Allpass Filters

The objective of this paper is to present a simple filter topology, which can be used to implement first- and second-order MOS-only allpass filters. The resulting filters realize the allpass functions without using any external passive components; hence these occupy very small chip area and are capable of operating at high frequencies. Cadence Spectre simulation and experimental results verifying the main advantages of the filters are provided.

An integrated circuit chaotic oscillator and its application for high speed random bit generation

An integrated continuous-time chaotic oscillator capable of operating at very high frequencies is presented and its application to a high-speed random bit generator is described. Numerical and experimental results show that the generated binary streams pass standard statistical tests. Simulation using CADENCE tools also verifies that the circuit operates in the GHz range.