Banlue Srisuchinwong

Fully balanced current-tunable sinusoidal quadrature oscillator

An integrable current-tunable sinusoidal quadrature oscillator is presented. A current-tunable all-pass filter using a signal-differencing technique is realized as the frequency-selective network. The implementation is fully balanced so as to enable accurate quadrature signals with symmetry. The oscillation frequency is current-tunable over a wide-frequency sweep range of approximately three orders of magnitude. The quadrature signals possess the amplitude matching and the quadrature phase matching of better than 0.004dB and 0.15°, respectively. The maximum useful frequency of oscillation is in excess of 8MHz. Total harmonic distortions are less than 0.5%.

A current-tunable sinusoidal oscillator

A high-performance integrable current-tunable sinusoidal oscillator is proposed and experimentally investigated. A current-tunable bandpass filter is used as the frequency-determining network. Practical frequency-sweep ranges of approximately three orders of magnitude have been obtained. The maximum useful frequency of oscillation is in excess of 20 mHz, and the total harmonic distortions can be adjusted easily to be less than 0.5%. The measured temperature coefficient of the oscillation frequency is less than -30 p.p.m./°C. The circuit technique is simple enough for use in the construction of practical instrumental oscillators using only a few off-the-shelf integrated circuit packages.

REALIZATION OF A LAMBERT W-FUNCTION FOR A CHAOTIC CIRCUIT

A new chaotic circuit is practically realized, for the first time, using a Lambert W-function. The circuit consists of three main parts. The first part employs a well-known Wilson current mirror, whereas the second part is a simple resistor at the two connected emitters of the current mirror. Both parts form a new circuit for a Lambert W-function by enabling a term of an emitter current to be simultaneously appeared on both sides of an exponential equation. Such a nonlinear equation is particularly well suited for realization of a Lambert W-function. The third part exploits a capacitor–inductor–capacitor (CLC) network and a resistor, which are connected to the nonlinear circuit of the Lambert W-function to allow for chaotic oscillations. The new circuit is capable of both a Lambert W-function and a current-tunable chaotic oscillator.

Highly Complex Chaotic System with Piecewise Linear Nonlinearity and Compound Structures

A new chaotic system is presented using a single parameter for a two-scroll attractor with high complexity, high chaoticity and widely chaotic range. The system employs two quadratic nonlinearities and two piecewise-linear nonlinearities. The high chaoticity is measured by the the maximum Lyapunov Exponent of 0.429 and the high complexity is measured by the Kaplan-Yorke dimension of 2.3004. Dynamic properties are described in terms of symmetry, a dissipative system, an existence of attractor, equilibria, Jacobian matrices, bifurcations, Poincaroe maps, chaotic waveforms, chaotic spectrum, and forming mechanisms of compound structures .

A Chua’s chaotic oscillator based on a coarsely cubic-like CMOS Resistor

An implementation of a Chuas chaotic oscillator is proposed based on a coarsely cubic-like CMOS resistor. A simple current mirror and a single-ended differential pair form a grounded nonlinear CMOS resistor. Such nonlinearity resembles a coarse version of cubic-like voltage-current characteristics. Simulated trajectories of the single-scroll and the double-scroll chaotic attractors are demonstrated.

A heart-sound-like chaotic attractor and its synchronization

A heart-sound-like chaotic attractor is presented with some basic properties in terms of equilibria, eigenvalues of the Jacobian matrices, a dissipative system or an existence of the attractor and Lyapunov exponents. In the time domain, the appearance of the proposed chaotic signals resembles the conventional heart sound signals. As an example, synchronization between the new system and the well-known Rossler attractor is demonstrated using active control.

A new Lorenz-Like chaotic attractor and its synchronization

A new Lorenz-Like chaotic attractor is presented with some basic properties in terms of equilibria, eigenvalues of the Jacobian matrices, generalized Lorenz system (GLS), existence of the attractor, Lyapunov exponents and compound structures. Although the differential equations of the new system are quite different from those of the Lorenz system, and although they are not topological equivalent, the appearance of the chaotic attractor of the new system resembles that of the Lorenz system. As an example, synchronization between the new system and the well-known Rossler attractor is demonstrated using active control.

High Frequency Implementation of Sprott's Chaotic Oscillators Using Current-Feedback Op Amps

High frequency implementation of Sprotts chaotic oscillators based on current-feedback op amps (CFOAs) is proposed. A Sprotts jerk function and four different types of nonlinear components are implemented using the attractively high-frequency features of the CFOAs operating in both voltage and current modes. Four trajectories of the chaotic attractors are demonstrated. The chaotic spectrums are easily scaled and extended to higher frequencies by a factor of 277 to 380.

A symmetric cipher using autonomous and non-autonomous cellular automata

Ciphers are applied to provide security for communications and data storage systems. A new, cellular automata-based, symmetric cipher and its architecture are described. Using 16 bit words through non-autonomous cellular automata (CA), the cipher can provide data rates of 320 Mbits per second at a clock rate of 20 MHz. By employing involutions, unidirectional data flow is maintained through the cipher. A 96-bit autonomous CA is used to store the secret key and this evolves as data are introduced into the cipher. Such CA techniques are conducive to VLSI implementation due to modularity, parallelism and local communications.

A high-frequency low-power all-NMOS all-current-mirror sinusoidal quadrature oscillator

A high-frequency low-power sinusoidal quadrature oscillator is presented through the use of only current mirrors where the small-signal paths are realized through all NMOS transistors. The technique is relatively simple based on (i) inherent time constants of current mirrors, i.e. the internal capacitances and the transconductance of a diode-connected NMOS, (ii) a negative resistance formed by a transconductance of a diode-connected NMOS load of a current mirror. No external passive components are required. As a particular example, a 2.83-GHz, 0.374-f/sub T/, 0.38-mW sinusoidal quadrature oscillator is demonstrated. Total harmonic distortions (THD) are less than 0.8 %. The oscillation frequency is current-tunable over a range of 640 MHz or 22.62 %. The amplitude matching and the quadrature phase matching are better than 0.04 dB and 0.17/spl deg/, respectively. A figure of merit called CNR/sub norm/ is 158.23 dBc/Hz at the 2 MHz offset from 2.83 GHz.