New Realization of Quadrature Oscillator using OTRA

In this paper a new, operational transresistance amplifier (OTRA) based, third order quadrature oscillator (QO) is presented. The proposed structure forms a closed loop using a high pass filter and differentiator. All the resistors employed in the circuit can be implemented using matched transistors operating in linear region thereby making the proposed structure fully integrated and electronically tunable. The effect of non-idealities of OTRA has been analyzed which suggests that for high frequency applications self-compensation can be used. Workability of the proposed QO is verified through SPICE simulations using 0.18μm AGILENT CMOS process parameters. Total harmonic distortion (THD) for the proposed QO is found to be less than 2.5%.The sensitivity, phasenoise analysis is also discussed for the proposed structure

A New Proposal for OFCC-based Instrumentation Amplifier

This contribution puts forward a new voltage mode instrumentation amplifier (VMIA) based on operational floating current conveyor (OFCC). It presents high impedance at input terminals and provides output at low impedance making the proposal ideal for voltage mode operation. The proposed VMIA architecture has two stages - the first stage comprises of two OFCCs to sense input voltages and coverts the voltage difference to current while the second stage has single OFCC that converts the current to voltage. In addition it employs two resistors to provide gain and imposes no condition on the values of resistors.  The behavior of the proposed structure is also analyzed for OFCC non idealities namely finite transimpedance and tracking error. The proposal is verified through SPICE simulations using CMOS based schematic of OFCC. Experimental results, by bread boarding it using commercially available IC AD844, are also included

Comparative study of medicinal plants on feeding behaviour of seven day old larvae of Tobacco caterpillar, Spodoptera litura (Fab.) and Bihar hairy caterpillar, Spilarctia obliqua (Walk.)

Eight medicinal plants viz., Sinduri, Bixa orellana (Bixaceae); Dalchini, Cinnamomum zelanicum (Lauraceae); Camphora, Cinnamomum camphora (Lauraceae); Gular, Ficus racemosa (Moraceae); Arjun, Terminalia arjuna (Combretaceae); Nagkesar, Messua ferrea (Calophyllaceae); Sarpgandha, Rauwolfia serpentina (Apocynaceae); Putranjeeva, Putranjeeva roxburghii (Euphorbiaceae) at 5% and 10 % concentrations were tested for the feeding against larvae of Spodoptera litura and Spilarctia obliqua. At 10% conc. C.camphora (hexane, diethyl ether, and acetone) was found extremely antifeedant against the larvae of both insects (S.litura and S.obliqua) while C.zeylanicum (hexane, diethyl ether, and acetone) and P.roxbughii (diethyl ether, and acetone), B.orellana (Acetone) showed extremely antifeedant activity only against the larvae of S.litura. At 5% concentration, the same plants were also effective against the larvae but their efficacy was less than at 10% concentration. The observation showed promising results with these plant extracts against the feeding and management of these two insect pests of agricultural importance

Operational transresistance amplifier based PID controller

This paper presents Operational transresistance amplifier (OTRA) based proportional-integral- derivative (PID) controller with independent electronic tuning of proportional, integral, and derivative constants. The configuration can be made fully integrated by implementing the resistors using matched transistors operating in the linear region. Theoretical propositions are verified through SPICE simulations using 0.18 µm process parameters from MOSIS (AGILENT). In order to demonstrate the workability of the proposed controller, its effect on step response of an OTRA based second order system is analyzed and presented

High Speed Power Efficient CMOS Inverter Based Current Comparator in UMC 90 nm Technology

A novel power-speed efficient current comparator is proposed in this paper. It comprises of only CMOS inverters in its structure, employing a simple biasing method. The structure offers simplicity of design. It posesses the very desirable features of high speed and low power dissipation, making this structure a highly desirable one for various current mode applications. The simulations have been performed using UMC 90 nm CMOS technology and the results demonstrate the propagation delay of about 3.1 ns and the average power consumption of 24.3 µW for 300 nA input current at supply voltage of 1V

Modelling and Design of Inverter Threshold Quantization based Current Comparator using Artificial Neural Networks

Performance of a MOS based circuit is highly influenced by the transistor dimensions chosen for that circuit. Thus, proper dimensioning of the transistors plays a key role in determining its overall performance.  While choosing the dimension is critical, it is equally difficult, primarily due to complex mathematical formulations that come into play when moving into the submicron level. The drain current is the most affected parameter which in turn affects all other parameters. Thus, there is a constant quest to come up with techniques and procedure to simplify the dimensioning process while still keeping the parameters under check. This study presents one such novel technique to estimate the transistor dimensions for a current comparator structure, using the artificial neural networks approach. The approach uses Multilayer perceptrons as the artificial neural network architectures. The technique involves a two step process. In the first step, training and test data are obtained by doing SPICE simulations of modelled circuit using 0.18μm TSMC CMOS technology parameters. In the second step, this training and test data is applied to the developed neural network architecture using MATLAB R2007b

COMPARISON OF COMMERCIALLY AVAILABLE DRUGS FOR TYPE 2 DIABETES WITH NATURAL MOLECULE FROM TINOSPORA

Objective: Efficacy of natural molecule from Tinospora cordifolia versus commercially available drugs to control diabetes 2.Methods: Twelve different drug molecules were selected to study drug properties, bioactivity and detailed mode of action. A comparative study was carried out among the drugs and plant metabolite to understand the putative mechanism of metabolite action and its potential to be developed as an herbal drug. PharmaGist Server was used to carry out pharmacophore modeling. The sequence of the target molecule (Q09428) was retrieved from UniProtKB/SwissProt, and structure prediction was carried out using ITASSER. The best model generated was further refined by energy minimization using Deep View. Validation of the structure was performed by Ramachandran plot analysis using PDBSum. Interaction analysis of the docked complex was done using LigPlot+.Results: The potential of natural plant metabolite to target ATP-binding cassette sub-family C member 8 seems probable based on docking and interaction analysis results. The natural molecule showed comparable binding energy (-5.57) in four out of seven drugs.Conclusion: Natural molecule from Tinospora cordifolia may serve as a potential lead drug molecule after modification and optimization for enhanced interaction.Keywords: Diabetes mellitus, Natural molecule, Tinospora, Type 2 diabete

Differential Difference Current Conveyor Transconductance Amplifier: A New Analog Building Block for Signal Processing

A new active building block for analog signal processing, namely, differential difference current conveyor transconductance amplifier (DDCCTA), is presented, and performance is checked through PSPICE simulations which show the usability of the proposed element is up to 201 MHz. The proposed block is implemented using 0.25 μm TSMC CMOS technology. Some of the applications are presented using the proposed DDCCTA, namely, a voltage mode multifunction filter, a current mode universal filter, an oscillator, current and voltage amplifiers, and grounded inductor simulator. The feasibility of DDCCTA and its applications is confirmed via PSPICE simulations

VM and CM Universal Filters Based on Single DVCCTA

A universal voltage-mode filter (VM) and a current-mode filter (CM) based on recently proposed active building block, namely, differential voltage current conveyor transconductance amplifier (DVCCTA) are proposed. Both the circuits use a single DVCCTA, two capacitors, and a single resistor. The filters enjoy low-sensitivity performance and low component spread and exhibit electronic tunability of filter parameters via bias currents of DVCCTA. SPICE simulation using 0.25 μm TSMC CMOS technology parameters is included to show the workability of the proposed circuits

A Class of Differentiator-Based Multifunction Biquad Filters Using OTRAs

This paper presents Signal Flow Graph (SFG) approach-based realization of Single Input Multiple Output (SIMO) filter topologies. A differentiator is placed as basic building block. A total of sixteen variants are derived from the proposed differentiator-based SFG. The Operational Trans-Resistance Amplifier (OTRA), an active block having low parasitics at input terminals, is used to validate the proposed methodology. All the derived filter structures use three OTRAs, six resistors and two capacitors. The filter performance parameters can be adjusted independently. The functional verification of the proposed method is done via SPICE simulations using 0.18 μm CMOS technology parameters from MOSIS