Ground bounce in digital VLSI circuits

This paper is concerned with the analysis and optimization of the ground bounce in digital CMOS circuits. First, an analytical method for calculating the ground bounce is presented. The proposed method relies on accurate models of the short-channel MOS device and the chip-package interface parasitics. Next the effect of ground bounce on the propagation delay and the optimum tapering factor of a multistage buffer is discussed and a mathematical relationship for total propagation delay in the presence of the ground bounce is obtained. Effect of an on-chip decoupling capacitor on the ground bounce waveform and circuit speed is analyzed next and a closed form expression for the peak value of the differential-mode component of the ground bounce in terms of the on-chip decoupling capacitor is provided. Finally, a design methodology for controlling the switching times of the output drivers to minimize the ground bounce is presented.     

Energy-efficient video streaming over Bluetooth using rateless coding

Energy-efficient error control for IEEE 802.15.1 (Bluetooth) video communication is proposed. The scheme is based on block-oriented incremental redundancy provided by rateless coding and receiver feedback. Results are presented for time-sensitive video streaming applications under a Markovian channel model. When the proposed algorithm is compared to variations of Bluetooth forward error control, there are improvements of around 3 dB in received video quality and of over 10% in energy efficiency.     

Study of the morphology and mechanical properties of polypropylene composites with silica or rice‐husk

The mechanical, morphological behavior and water absorption characteristics of polypropylene (PP) and silica, or PP and rice‐husk, composites have been studied. The silica used in this study as filler was a commercial type produced from soluble glass or rice husks. The compatibilizing effect of PP grafted with monomethyl itaconate (PP‐g‐MMI) and/or with vinyltriethoxysilane (PP‐g‐VTES) as polar monomers on the mechanical properties and water absorption was also investigated. In general, a high loading of the studied fillers in the polymer matrix increases the stiffness and the water absorption capacity. This effect is more noticeable in the tensile modulus of the PP/silica composite with PP‐g‐VTES as compatibilizer. However, the increase of the rice‐husk charge as a natural filler in the PP matrix decreases the stiffness, and in the presence of PP‐g‐MMI as compatibilizer in PP/rice‐husk, the tensile modulus and water absorption of the composite were improved. The better adhesion and phase continuity in the PP/silica and PP/rice‐husk composites with different compatibilizers was confirmed by the morphological study. Copyright © 2004 Society of Chemical Industry     

A 2.5-Gb/s 15-mW clock recovery circuit

This paper describes the design of a 2.5-Gb/s 15-mW clock recovery circuit based on the quadricorrelator architecture. Employing both phase and frequency detection, the circuit combines high-speed operations such as differentiation, full-wave rectification, and mixing in one stage to lower the power dissipation. In addition, a two-stage voltage-controlled oscillator is utilized that incorporates both phase shift elements to provide a wide tuning range and isolation techniques to suppress the feedthrough due to input data transitions. Fabricated in a 20-GHz 1-μm BiCMOS technology, the circuit exhibits an rms jitter of 9.5 ps and a capture range of 300 MHz     

Statistical analysis of fiber-optic CDMA communication systems. I. Device modeling

In this paper, we present a new methodology for analysis of all-optical fiber-optic code-division multiple-access (FO-CDMA) networks. In this analysis, we propose statistical models, based on photon-counting techniques, for some basic elements of the network, such as splitters, combiners, star couplers, and FO-CDMA passive encoders/decoders. By following the statistical variation of the photon-count of the string of pulses that constitutes the address sequence in an FO-CDMA network, we will be able to reveal the quantum-limited optical signal-to-noise ratio (OSNR) required at the transmitter output to meet the performance limits. Moreover, considering receiver thermal noise and source extinction ratio, we explore the role of using an optical preamplifier before the detector and the dependence of the performance on the transmitted power and the weight of the employed optical orthogonal codes (OOCs).     

Architectures for Silicon Nanoelectronics and Beyond

Although nanoelectronics won't replace CMOS for some time, research is needed now to develop the architectures, methods, and tools to maximally leverage nanoscale devices and terascale capacity. Addressing the complementary architectural and system issues involved requires greater collaboration at all levels. The effective use of nanotechnology calls for total system solutions     

A 6 GHz 68 mW BiCMOS phase-locked loop

The design of a 6 GHz fully monolithic phase-locked loop fabricated in a 1 μm, 20 GHz BiCMOS technology is described. The circuit incorporates a voltage-controlled oscillator that senses and combines the transitions in a ring oscillator to achieve a period equal to two ECL gate delays. A mixer topology is also used that exhibits full symmetry with respect to its inputs and operates with supply voltages as low as 1.5 V. Dissipating 60 mW from a 2 V supply, the circuit has a tracking range of 300 MHz, an rms jitter of 3.1 ps, and phase noise of -75 dBc/Hz at 1 kHz offset     

Superior vena cava syndrome after heart transplantation: percutaneous treatment of a complication of bicaval anastomoses

The aims of this study were to establish a working rabbit heart model of regional myocardial ischaemia in which electrophysiologic parameters and arrhythmogenesis could be correlated and to explore the mechanisms underlying the antiarrhythmic activity of lignocaine. Monophasic action-potential duration (MAPD90), effective refractory period (ERP), and conduction delay were measured at three ventricular sites in isolated hearts paced at 3.3 Hz. The hearts were treated before and throughout 30 min of ischaemia and 15 min of reperfusion with a vehicle or 20 microM lignocaine. In both groups, ischaemia produced a similar shortening in MAPD90. Lignocaine decreased ERP shortening during ischaemia from -56+/-4 to -32+/-6 ms. An ischaemia-induced increase in conduction delay was greater in the lignocaine than the control group (49+/-7 vs. 11+/-2 ms). Ischaemia-induced dispersion of repolarisation was reduced by lignocaine from 66+/-4 to 32+/-7 ms, and dispersion of refractoriness was decreased from 57+/-6 to 16+/-3 ms. Lignocaine decreased inducibility of ventricular fibrillation (VF) during ischaemia from 86 to 25%. We conclude that, in this model, the antiarrhythmic activity of lignocaine during regional ischaemia is associated with an increase in ischaemia-induced conduction delay and reduced dispersion of repolarisation and refractoriness.     

A 200-MHz 15-mW BiCMOS sample-and-hold amplifier with 3 V supply

A sample-and-hold amplifier designed for the front end of high-speed low-power analog-to-digital converters employs a BiCMOS sampling switch and a low-voltage amplifier to achieve a sampling rate of 200 MHz while allowing input/output voltage swings of 1.5 V with a 3-V supply. The circuit also incorporates a cancellation technique to relax the trade-off between the hold-mode feedthrough and the sampling speed. Fabricated in a 20-GHz 1-μm BiCMOS technology, an experimental prototype exhibits a harmonic distortion of -65 dB with a 10-MHz analog input and occupies an area of 220×150 μm². The measured feedthrough is -52 dB for a 50-MHz analog input and the droop rate is 40 μV/ns     

Segregation Neutralised Steels: Microstructural Banding Elimination from Dual-Phase Steel Through Alloy Design Accounting for Inherent Segregation

Metallurgical and Materials Transactions A - Banding in commercial dual-phase steels, such as banded ferrite and pearlite or ferrite and martensite microstructures, is inherited from segregation...