A high-performance,low-power ∑△ ADC for digital audio applications

A high-performance low-powerΣΔanalog-to-digital converter(ADC) for digital audio applications is described.It consists of a 2-1 cascadedΣΔmodulator and a decimation filter.Various design optimizations are implemented in the system design,circuit implementation and layout design,including a high-overload-level coefficient-optimized modulator architecture,a power-efficient class A/AB operational transconductance amplifier,as well as a multi-stage decimation filter conserving area and power consumption.The ...     

一个18位高性能音频Σ-Δ数模转换器

本文介绍了一个采用多比特量化的高性能音频Σ-Δ数模转换器。相对于单比特量化的Σ-Δ DAC来说,多比特量化具有调制器环路设计简单、时钟频率低、杂波小等优点;而由多比特量化引入的失配误差,可以采用DWA误差整形算法,将其转换为高频段噪声外推到信号带外,使带内的噪底降低到单比特量化的水平。为减弱数模串扰,进行了对每个模拟元件都加上保护环的创新尝试。采用上述技术在0.18μm混合信号CMOS工艺上实现了一个18位DAC,芯片面积1.86 mm2。测试结果表明,数模转换器的信噪失真比(SNDR)和动态范围（DR）分别达到88dB和96dB。     

A high-performance,low-power ∑Δ ADC for digital audio applications

A high-performance low-power ∑Δ analog-to-digital converter (ADC) for digital audio applications is described.It consists of a 2-1 cascaded ∑Δ modulator and a decimation filter.Various design optimizations are implemented in the system design,circuit implementation and layout design,including a high-overload-level coefficientoptimized modulator architecture,a power-efficient class A/AB operational transconductance amplifier,as well as a multi-stage decimation filter conserving area and power consumption.The ADC is implemented in the SMIC 0.18-μm CMOS mixed-signal process.The experimental chip achieves a peak signal-to-noise-plus-distortion ratio of 90 dB and a dynamic range of 94 dB over 22.05-kHz audio band and occupies 2.1 mm2,which dissipates only 2.1 mA quiescent current in the analog circuits.     

Effects of Bed Structure on Erosion of Cohesive Sediments

Data from two recent papers are used to illustrate the effects of change of structure of fine sediment on erosion rates. The paper by Roberts et al. presents erosion rates as functions of bed bulk density and shear stress. Ranges of densities were obtained by allowing various times for consolidation, and the erosion tests were made where the density was nearly constant with depth. A marked change in the linear relation between erosion rate and density is presented that is attributed to a change of bed structure. The paper by Zreik et al. presents erosion rate data for a thin layer near the surface of a bed formed by sedimentation. The linear relation between amount of overburden removed and bed strength also has a marked change that can be attributed to a change of bed structure. The initial structures are described as aggregates of aggregates, and the changes are shown to be progressive collapse of the larger to smaller interaggregate pores due to thermal motion, biased by overburden pressure, to a nearly homogeneous primary aggregate structure. Small increases of bed stress above that necessary to initiate erosion of this structure have large effects.     

Inclusion filters: a class of self-dual connected operators.

In this paper, we define a connected operator that either fills or retains the holes of the connected sets depending on application-specific criteria that are increasing in the set theoretic sense. We refer to this class of connected operators as inclusion filters, which are shown to be increasing, idempotent, and self dual (gray-level inversion invariance). We demonstrate self duality for 8-adjacency on a discrete Cartesian grid. Inclusion filters are defined first for binary-valued images, and then the definition is extended to grayscale imagery. It is also shown that inclusion filters are levelings, a larger class of connected operators. Several important applications of inclusion filters are demonstrated-automatic segmentation of the lung cavities from magnetic resonance imagery, user interactive shape delineation in content-based image retrieval, registration of intravital microscopic video sequences, and detection and tracking of cells from these sequences. The numerical performance measures on 100-cell tracking experiments show that the use of inclusion filter improves the total number of frames successfully tracked by five times and provides a threefold reduction in the overall position error.     

The discriminative validity of a phallometric test for pedophilic interests among adolescent sex offenders against children.

The authors examined the responses of adolescent sex offenders against children on a phallometric test of pedophilic interests. Participants were 40 adolescent sex offenders against children, 75 young adult sex offenders against children, and 39 young adult comparison participants. The responses of adolescents with female victims resembled those of comparison participants; adolescents with any male victims had larger relative responses to child stimuli than comparison participants. Young adult offenders, regardless of victim sex, had larger relative responses to child stimuli than comparison participants. Using a cut score of 0 (indicating equal or greater arousal to children than to adults), sensitivity was 42% for adolescents with any male victims, and specificity was 92% for the comparison participants. Results suggest phallometric testing can identify pedophilic interests among these adolescent sex offenders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontology mapping for the interoperability problem in network management

Interoperability between different network management domains, heterogeneous devices, and various management systems is one of the main requirements for managing complex enterprise services. While substantial advances have been made in low-level device and data interoperability using common data formats and specifications such as simple network management protocol's (SNMP's) SMI and TMF's SID, various interoperability issues including semantic interoperability offer interesting research challenges. While semantic interoperability is a difficult problem in its own right, the semantic web that incorporates intelligent agents necessitates an interoperability solution requiring agents to communicate unambiguously and reason intelligently to perform cooperative management tasks. Agents need a formal representation of knowledge; an ontology is capable of modeling the rich semantics of the managed environment (and especially, relationships between managed entities) so that agents can act on them. This paper presents an ontology-driven approach for solving the semantic interoperability problem in the management of enterprise services, illustrated here with a router configuration management application.     

Comparative study of bio-ethanol production from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae cells immobilized in agar agar and Ca-alginate matrices

Batch fermentation of mahula (Madhuca latifolia L., a tree commonly found in tropical rain forest) flowers was carried out using immobilized cells (in agar agar and calcium alginate) and free cells of Saccharomyces cerevisiae. The ethanol yields were 151.2, 154.5 and 149.1 g kg⁻¹ flowers using immobilized (in agar agar and calcium alginate) and free cells, respectively. Cell entrapment in calcium alginate was found to be marginally superior to those in agar agar (2.2% more) as well as over free cell (3.5% more) as regard to ethanol yield from mahula flowers is concerned. Further, the immobilized cells were physiologically active at least for three cycles [150.6, 148.5 and 146.5 g kg⁻¹ (agar agar) and 152.8, 151.5 and 149.5 g kg⁻¹ flowers (calcium alginate) for first, second and third cycle, respectively] of ethanol fermentation without apparently lowering the productivity. Mahula flowers, a renewable, non-food-grade cheap carbohydrate substrate from non-agricultural environment such as forest can serve as an alternative to food grade sugar/starchy crops such as maize, sugarcane for bio-ethanol production.