Active-pull-down nonthreshold logic BiCMOS circuits for high-speedlow-power applications

A new active-pull-down nonthreshold logic (APD-NTL) BiCMOS circuit is presented and its performance has been evaluated and compared to that of standard NTL gate. The circuit utilizes an NMOS active-pull-down emitter-follower stage. A first-order analysis has been conducted to demonstrate the NMOS-APD concept. Simulation results based on 0.6 μm BiCMOS technology indicate that at a power consumption of 1 mW/gate, the APD-NTL circuit offers 4× improvement in the load driving capability and 3.4× improvement in the speed compared to conventional NTL circuits for a load of 1 pF/gate and a logic swing of 800 mV     

Low-power multi-threshold MCML: Analysis, design, and variability

The increasing demand on low-power applications is adding pressure on circuit designers to come out with new circuit styles that can decrease power dissipation while making use of the performance improvement of the new CMOS technologies. Multi-threshold MOS current mode logic (MTMCML) appears to be a solution to this problem by making use of the high-performance of MOS current mode circuits while minimizing power dissipation with the help of multi-threshold CMOS technologies. In this work, analytical formulations, based on the BSIM3v3 model, are proposed for MTMCML performance measures with an error within 10% compared to HSPICE. The formulation helps designers to efficiently design MTMCML circuits without undergoing the time-consuming HSPICE simulations. Furthermore, it provides design guidelines and aids for designers to fully understand the different tradeoffs in MTMCML design. In addition, the analysis is extended to study the impact of technology scaling and parameter variations on MTMCML. It is shown that the worst case variation in the minimum supply voltage of MTMCML is 1.16%, thus suggesting maximal power saving.     

A High-Performance MIMO-OFDM System with Walsh Block Coding

In this paper we present a multiple-input, multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) system that uses orthogonal Walsh sequences for block coding. Two configurations, space-time block coding (STBC) and the Vertical Bell Laboratories Layered Space-Time (V-BLAST) architecture, are considered for the proposed system. A least-squares channel estimation with the fast Fourier transform method is utilized in the system to replicate real-life scenarios. The idea of employing block coding based on orthogonal Walsh sequences is inspired by the IS-95 standard and is attempted for the first time in MIMO-OFDM systems. A simulation study is carried out by considering different antenna configurations, code sizes, and channel delays. Computer simulations show that the proposed system achieves a significant performance improvement compared to MIMO-OFDM systems that do not use the proposed block coding scheme. It is also shown that the new system is superior to some previous systems in computational complexity.     

Energy-efficient noise-tolerant dynamic styles for scaled-down CMOSand MTCMOS technologies

A new high-speed domino circuit, called HS-Domino has been developed. HS-Domino resolves the tradeoff between performance and reliability in conventional CD-domino logic while dissipating low dynamic power with minimal area overhead. HS-Domino, therefore, extends domino's operation in the deep submicron regime. A multithreshold implementation of HS-Domino is also devised to achieve substantially low leakage values during standby, while maintaining high performance and low power during the active mode. Furthermore, the generic multithreshold scheme is applied to differential cascode voltage switch (DDCVS) logic     

A new model for bipolar transistors at high current

A model for current gain and cutoff frequency falloff at high currents for bipolar transistors is proposed. The model is based on considering that the vertical and lateral base widening occur simultaneously for a typical bipolar transistor. The results of this model successfully fit Pisces-2B simulation results     

A validated HPLC method for separation and determination of promethazine enantiomers in pharmaceutical formulations

A simple, rapid, and validated method for separation and determination of promethazine enantiomers was developed. Promethazine was separated and quantitated on a Vancomycin Chirobiotic V column (250 x 4.6 mm), using a mixture of methanol, acetic acid, and triethylamine (100:0.1:0.1%, by volume) as a mobile phase at 20 degrees C and at a flow rate of 1 mL/min. The UV-detector was set to 254 nm. Acetyl salicylic acid (Aspirin) was used as an internal standard. The applied HPLC method allowed separation and quantification of promethazine enantiomers with good linearity (r > .999) in the studied range. The relative standard deviations (RSD) were 0.29 and 0.36 for the promethazine enantiomers with accuracy of 100.06 and 100.08. The limit of detection and limit of quantification of promethazine enantiomers were found to be 0.04 and 0.07 microg/mL, respectively. The method was validated through the parameters of linearity, accuracy, precision, and robustness. The HPLC method was applied for the quantitative determination of promethazine in pharmaceutical formulations.     

Understanding the advisor–advisee relationship via scholarly data analysis

Advisor–advisee relationship is important in academic networks due to its universality and necessity. Despite the increasing desire to analyze the career of newcomers, however, the outcomes of different collaboration patterns between advisors and advisees remain unknown. The purpose of this paper is to find out the correlation between advisors’ academic characteristics and advisees’ academic performance in Computer Science. Employing both quantitative and qualitative analysis, we find that with the increase of advisors’ academic age, advisees’ performance experiences an initial growth, follows a sustaining stage, and finally ends up with a declining trend. We also discover the phenomenon that accomplished advisors can bring up skilled advisees. We explore the conclusion from two aspects: (1) Advisees mentored by advisors with high academic level have better academic performance than the rest; (2) Advisors with high academic level can raise their advisees’ h-index ranking. This work provides new insights on promoting our understanding of the relationship between advisors’ academic characteristics and advisees’ performance, as well as on advisor choosing.     

PESO: Probabilistic evaluation of subspaces orthogonality for wideband DOA estimation

Multidimensional Systems and Signal Processing - This paper introduces a novel direction-of-arrival (DOA) estimation method for the closely related wideband sources. The new method estimates the...     

Design of a low-power ZigBee receiver front-end for wireless sensors

This paper describes the design of a low cost, low-power ZigBee receiver for wireless sensor networks. The receiver consists of a low-noise amplifier, a pair of down-conversion mixers, and a pair of variable-gain low-pass filters. The LNA has a single-ended input, eliminating the need for an off-chip balun, a differential output, allowing it to drive a double-balanced mixer, and it uses noise cancellation to improve its noise performance. The mixers are double-balanced passive mixers to improve the receiver linearity and decrease its power consumption and flicker noise. Finally, the filter is a third-order Butterworth G_m-C filter with a variable input transconductor to provide gain programmability for the receiver. The design is made using 130 nm CMOS technology with 1.2 V supply. Simulation results show that the receiver can achieve a sensitivity level of −97 dBm while consuming only 6 mA.     

Open-loop output characteristics of a current feedback operational amplifier

The output characteristics of the basic current feedback operational amplifier (CFOA) in the linear region, on open-loop, would not appear to have been treated in the literature. This is possibly because it is not straightforward to determine, the problem being that the output saturates without the closed-loop connection. This paper considers a theoretical discussion that explains the results of simulation.