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Cascadable Voltage-Mode Multifunction Biquad Employing Single OTRA

Abstract – A voltage-mode (VM), multi-input single-output (MISO) type multifunction biquad is proposed. It uses only one operational transresistance amplifier (OTRA) as the active element, while previously reported VM multifunction filters require more OTRAs. Proposed MISO type biquad configuration can realize all five different filter transfer functions. Theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA.

Cascadable allpass and notch filters employing single operational transresistance amplifier

A new voltage-mode filter configuration is proposed. The presented topology uses single operational transresistance amplifier (OTRA) and can realize first-order allpass, second-order allpass and notch filtering functions. The proposed circuits are insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. Low output impedance of the configuration enables the circuits to be cascaded without additional buffers. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA. Experimental work is also carried out. The feasibility of the proposed first-order allpass filter is illustrated on the design of a quadrature oscillator.

Catalogue of Variable Frequency and Single-Resistance-Controlled Oscillators Employing A Single Differential Difference Complementary Current Conveyor

A set of fourteen current-mode sinusoidal oscillators employing a single differential difference complementary current conveyor (DDCCC) is proposed. This is the largest catalogue of sinusoidal oscillators with single resistor frequency control, that use only a single active building block (ABB) and minimum number of passive components. The proposed topologies were automatically designed by a genetic algorithm rather than by a human designer. Some of the synthesized networks have very attractive topological features. PSPICE simulation results and non-ideal analysis of the oscillators has been included. Index Terms – sinusoidal oscillators, current conveyors, genetic algorithms

Operational transresistance amplifier based first-order allpass filter with an application example

A new voltage-mode filter configuration is proposed. The presented topology uses single operational transresistance amplifier (OTRA) and can realize first-order allpass, second-order allpass and notch filtering functions. The proposed circuits are insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. Low output impedance of the configuration enables the circuits to be cascaded without additional buffers. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA. The feasibility of the proposed first-order allpass filter is illustrated on the design of a quadrature oscillator.

MULTISCROLL CHAOTIC ATTRACTORS FROM A HYSTERESIS BASED TIME-DELAY DIFFERENTIAL EQUATION

In this paper, the generation of multiscroll chaotic attractors derived from a time-delay differential equation is presented. The proposed system is represented by only one first-order differential equation including time-delayed state variable, and employs hysteresis function as the nonlinear characteristic. The generalization of the introduced system is based on adding multihysteresis nonlinear characteristic which leads to n-scroll chaotic attractors. The circuit implementation of the proposed system and some experimental results referring to two-, three-, four-, and five-scroll chaotic attractors are reported.

Nonlinear modeling and analysis of resonant inverter tuning loops with voltage-pump phase-frequency detector

In this paper, a nonlinear model for large signal analysis of resonant inverter (RI) tuning loops with voltage-pump phase-frequency detector is presented. The proposed model employs the resistance multiplication approach, applicable for the circuits containing periodically operated switch. The generic model is valid for both positive and negative phase error values with slight differences. Transient and stability analysis of an RI tuning loop is carried out by employing the presented model. Time-domain expressions for any initial condition are derived as the result of transient analysis. On the other hand, stability analysis reveals the conditions that make the overall system stable. Experimental results, which confirm the theoretical study, are obtained.

A CMOS realization of double-scroll chaotic circuit and its application to random number generation

A new chaotic oscillator which can be implemented on standard CMOS process is presented. The circuit generates double-scroll chaotic attractor and is suitable for high-frequency operation. As a possible application, the use of the circuit as the core of a random number generator (RNG) is illustrated. The quality of the RNG is investigated using standard statistical tests (according to FIPS-140-1 and NIST 800-22) and it is shown that the generated binary sequences have good statistical properties.

Current differencing buffered amplifier (CDBA) based current-mode filters

A new current-mode second-order filter configuration is proposed. Using the presented configuration, lowpass, highpass, bandpass and notch filters can be realized employing only a single current differencing buffered amplifier (CDBA), two capacitors and two resistors which are minimum in number. The high output impedance of the proposed filter configuration enables the circuits to be cascaded without requiring additional buffers. All passive sensitivities are no more than one half in magnitude. The theoretical results are verified with PSPICE simulations using a CMOS realization of CDBA.

Realization of allpass filters using operational transresistance amplifier (OTRA)

A new voltage-mode allpass filter configuration is proposed. The presented circuit uses a single operational transresistance amplifier (OTRA) and can realize both first- and second-order allpass filtering functions. The proposed circuit is insensitive to parasitic input capacitances and input resistances due to internally grounded input terminals of the OTRA. It provides an alternative solution to the realization of phase equalizer; quadrature oscillator and high-Q bandpass filter for analog signal processing applications. The theoretical results are verified with PSPICE simulations using a CMOS realization of the OTRA. The feasibility of the proposed allpass filter is illustrated by the design of a quadrature oscillator.

Second Order Analog Filter Design Using a Single OTRA Suitable for Integration

A configuration for the realization of voltage-mode second-order filters employing a single operational transresistance amplifier as the active element is presented. This topology can synthesize lowpass, highpass, bandpass, notch and allpass filtering functions. Theoretical analysis is verified with SPICE simulation results.