North Eastern Regional Institute of Science and Technology

About: North Eastern Regional Institute of Science and Technology is a education organization based out in Itanagar, India. It is known for research contribution in the topics: Population & Raman spectroscopy. The organization has 813 authors who have published 1429 publications receiving 16122 citations.

Performance of M-MRC receivers over TWDP fading channels

Abstract: An expression of characteristic function of signal-to-noise ratio (SNR) for two waves with diffused power (TWDP) fading channel is derived. Using this expression, the expression for the probability density function (PDF) of the output SNR of maximal ratio combining (MRC) receiver is obtained. Expressions for the performance matrix of MRC receiver over TWDP fading channels are also deduced. PDF based approach is followed to derive expressions of outage probability and average symbol error rate for coherent and non-coherent m-ary modulation schemes. Effects of the number of branches M and the fading parameters K and Δ on the system performance are studied. The results obtained are verified by Monte Carlo simulation.

Behavior of collisional sheath in electronegative plasma with q-nonextensive electron distribution

Abstract: Electronegative plasma sheath is addressed in a collisional unmagnetized plasma consisting of q-nonextensive electrons, Boltzmann distributed negative ions and cold fluid positive ions. Considering the positive ion-neutral collisions and ignoring the effects of ionization and collisions between negative species and positive ions (neutrals), a modified Bohm sheath criterion and hence floating potential are derived by using multifluid model. Using the modified Bohm sheath criterion, the sheath characteristics such as spatial profiles of density, potential and net space charge density have been numerically investigated. It is found that increasing values of q-nonextensivity, electronegativity and collisionality lead to a decrease of the sheath thickness and an increase of the sheath potential and the net space charge density. With increasing values of the electron temperature to negative ion temperature ratio, the sheath thickness increases and the sheath potential as well as the net space charge density in ...

Multivariate Frequency Analysis of Meteorological Drought Using Copula

Abstract: The multivariate frequency analysis of droughts for Agartala (India) was carried out in the present study. The meteorological drought was modelled using Standardised Precipitation Index(SPI) at the time scale of 1, 3, 6 and 12 months. Three droughts variables i.e., duration, severity, interval were determined for SPI at the time scale of 1, 3, 6 and 12 months. For the construction of bivariate and trivariate joint distributions Archimedean and metaelliptical copulas were used. Upper tail dependence test was also carried out. The best copula was selected based on minimum value Akaike’s information criteria (AIC)) and Schwarz information criterion(SIC). The drought risk was estimated using joint probabilities and return period for the study area.

Ultra-low-power bulk-driven fully differential subthreshold OTAs with partial positive feedback for Gm-C filters

Abstract: This paper presents an ultra-low-power, bulk-driven, source-degenerated fully differential transconductor (FD-OTA), operating in subthreshold region. The source-degeneration (SD) and bulk-drive ensure linearity and rail-to-rail input swing. The flipped voltage follower and SD resistor perform V–I conversion in input core with power efficient class AB mode of operation. The reduction in open loop gain and gain bandwidth (GBW) of bulk-drive is compensated by applying partial positive feedback at diode connected MOSFET pair. The current gain from input core to output load side is set (1:1) in OTA1 and (1:4) in OTA2. The OTA2 offers increased transconductance and GBW whereas self-cascode load increases the output impedance and overall gain of the FD-OTAs. Both the input core and common source self-cascode load operate in class AB mode so these FD-OTAs provide enhanced slew rates. These OTAs have been employed to implement Biquadratic low-frequency Gm-C filter suitable for bio-signal applications. The proposed OTA2 has used dual supply voltage of ± 0.3 V and dissipates around 70 nW power and provides 62 dB FD-open loop gain with GBW of 7.73 kHz while driving the FD-load of 2 × 15 pF. The Cadence VIRTUOSO environment using UMC 0.18 µm CMOS process technology has been used to simulate the proposed circuit. The Simulation results verified fully differential total harmonic distortion of − 72 dB, for 1.2 Vp–p signal at 200 Hz frequency in unity gain configuration with resistive degeneration of 1 MΩ for OTA1.