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The DLL consists of two loops. The core loop is a first order DLL generating six edges evenly spaced by 30/spl deg/. The peripheral digital loop selects a pair of edges, /spl phi/ and /spl psi/, to interpolate. To cover the 360/spl deg/ desired range, the edges can be selectively inverted. The resulting edges, /spl phi/' and /spl psi/', drive a digitally-controlled interpolator that generates the main clock /spl Theta/. The interpolator quantization step is 2/spl deg/, i.e. 22ps for a 250MHz clock. This dual-loop architecture provides unlimited phase shift capability eliminating start-up issues and phase relationship constraints. The only requirement is that the DLL input clock and the reference clock are plesiochronous making this architecture suitable for clock-recovery applications.
Several technology independent rounding algorithms for multiplying normalized numbers are presented. The first is a simple rounding algorithm suitable for software simulation or moderate performance hardware multipliers. The next two algorithms are parallel addition schemes suitable for high-performance VLSI multipliers. One of them eliminates the carry produced by the lower-order bits from the critical path. Several methods for computing the sticky bit are also presented. Included is a new fast and efficient technique for computing the sticky bit directly from the carry-save form without undergoing the expense of a carry-propagate addition.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
All network devices must parse packet headers to decide how packets should be processed. A 64 × 10Gb/s Ethernet switch must parse one billion packets per second to extract fields used in forwarding decisions. Although a necessary part of all switch hardware, very little has been written on parser design and the trade-offs between different designs. Is it better to design one fast parser, or several slow parsers? What is the cost of making the parser reconfigurable in the field? What design decisions most impact power and area? In this paper, we describe trade-offs in parser design, identify design principles for switch and router designers, and describe a parser generator that outputs synthesizable Verilog that is available for download. We show that i) packet parsers today occupy about 1-2% of the chip, and ii) while future packet parsers will need to be programmable, this only doubles the (already small) area needed.
Trials from less developed countries in a few cases show significantly more favourable treatment effects than trials in more developed countries and, on average, treatment effects are more favourable in less developed countries. These discrepancies may reflect biases in reporting or study design as well as genuine differences in baseline risk or treatment implementation and should be considers when generalising evidence across different settings.
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Abstract Background China witnessed a surge of Omicron infections after abandoning ‘zero COVID’ strategies on 7 December 2022. The authorities report very sparse deaths based on very restricted criteria, but massive deaths are speculated. Methods We aimed to estimate the COVID‐19 fatalities in Mainland China until summer 2023 using the experiences of Hong Kong and of South Korea in 2022 as prototypes. Both these locations experienced massive Omicron waves after having had very few SARS‐CoV‐2 infections during 2020–2021. We estimated age‐stratified infection fatality rates (IFRs) in Hong Kong and South Korea during 2022 and extrapolated to the population age structure of Mainland China. We also accounted separately for deaths of residents in long‐term care facilities in both Hong Kong and South Korea. Results Infection fatality rate estimates in non‐elderly strata were modestly higher in Hong Kong than South Korea and projected 987,455 and 619,549 maximal COVID‐19 deaths respectively, if the entire China population were infected. Expected COVID‐19 deaths in Mainland China until summer 2023 ranged from 49,962 to 691,219 assuming 25–70% of the non‐elderly population being infected and variable protection of elderly (from none to three‐quarter reduction in fatalities). The main analysis (45% of non‐elderly population infected and fatality impact among elderly reduced by half) estimated 152,886–249,094 COVID‐19 deaths until summer 2023. Large uncertainties exist regarding potential changes in dominant variant, health system strain and impact on non‐COVID‐19 deaths. Conclusions The most critical factor that can affect total COVID‐19 fatalities in China is the extent to which the elderly can be protected.
A 14 bit digital-to-analog converter system based upon a dual-ramp technique has been fabricated in a standard monolithic bipolar process. The system features a precision sample-and-hold amplifier and postpackage trim for 0.003 percent linearity. The conversion time is 20 /spl mu/s.
This paper presents methods for efficient power minimization at circuit and micro-architectural levels. The potential energy savings are strongly related to the energy profile of a circuit. These savings are obtained by using gate sizing, supply voltage, and threshold voltage optimization, to minimize energy consumption subject to a delay constraint. The true power minimization is achieved when the energy reduction potentials of all tuning variables are balanced. We derive the sensitivity of energy to delay for each of the tuning variables, connecting its energy saving potential to the physical properties of the circuit. This helps to develop understanding of optimization performance and identify the most efficient techniques for energy reduction. The optimizations are applied to some examples that span typical circuit topologies including inverter chains, SRAM decoders, and adders. At a delay of 20% larger than the minimum, energy savings of 40% to 70% are possible, indicating that achieving peak performance is expensive in terms of energy. Energy savings of about 50% can be achieved without delay penalty with the balancing of sizes, supplies, and thresholds.
