Analogue switch for very low-voltage applications

A new analogue switch suitable for operation at very low-voltage supply in a standard CMOS technology is presented. The proposed switch is based on 'quasi-floating-gate' transistors and has a simple and compact structure. For illustrative purposes, two sample-and-hold circuits operating from a single supply voltage close to the threshold voltage of a transistor, and using the proposed technique, are presented. Experimental results obtained from prototypes in a 1.5 /spl mu/m CMOS technology are provided.     

Robust dual-quantisation multibit sigma-delta modulator

A new dual-quantisation sigma-delta modulator is proposed, which introduces an additional feedback path in the input of the second integrator. In this way, unlike other dual-quantisation architectures, larger signal-to-noise ratios can be obtained by means of aggressive noise-shaping, like in a conventional multibit modulator. The proposed modulator is also shown to be more robust against non-idealities than other dual-quantisation architectures.     

Low supply voltage high-performance CMOS current mirror with low input and output voltage requirements

This paper presents a scheme for the efficient implementation of a low supply voltage continuous-time high-performance CMOS current mirror with low input and output voltage requirements. This circuit combines a shunt input feedback and a regulated cascode output stage to achieve low input resistance and very high output resistance. It can be used as a high-precision current mirror in analog and mixed signal circuits with a power supply close to a transistor's threshold voltage. The proposed current mirror has been simulated and a bandwidth of 40 MHz has been obtained. An experimental chip prototype has been sent for fabrication and has been experimentally verified, obtaining 0.15-V input-output voltage requirements, 100-/spl Omega/ input resistance, and more than 200-M/spl Omega/ (G/spl Omega/ ideally) output resistance with a 1.2-V supply in a standard CMOS technology.     

80 million tiny images: a large data set for nonparametric object and scene recognition

With the advent of the Internet, billions of images are now freely available online and constitute a dense sampling of the visual world. Using a variety of non-parametric methods, we explore this world with the aid of a large dataset of 79,302,017 images collected from the Internet. Motivated by psychophysical results showing the remarkable tolerance of the human visual system to degradations in image resolution, the images in the dataset are stored as 32 x 32 color images. Each image is loosely labeled with one of the 75,062 non-abstract nouns in English, as listed in the Wordnet lexical database. Hence the image database gives a comprehensive coverage of all object categories and scenes. The semantic information from Wordnet can be used in conjunction with nearest-neighbor methods to perform object classification over a range of semantic levels minimizing the effects of labeling noise. For certain classes that are particularly prevalent in the dataset, such as people, we are able to demonstrate a recognition performance comparable to class-specific Viola-Jones style detectors.     

Speed control of induction motors using a novel fuzzy sliding-modestructure

This paper presents a new approach to indirect vector control of induction motors. Two nonlinear controllers, one of sliding mode type and the other PI-fuzzy logic-based, define a new control structure. Both controllers are combined by means of an expert system based on Takagi-Sugeno fuzzy reasoning. The sliding-mode controller acts mainly in a transient state while the PI-like fuzzy controller acts in the steady state. The new structure embodies the advantages that both nonlinear controllers offer: sliding-mode controllers increasing system stability limits, and PI-like fuzzy logic based controllers reducing the chattering in permanent state. The scheme has been implemented and experimentally validated     

Low Voltage Class AB Output Stage for CMOS Op-Amps Using Multiple Input Floating Gate Transistors

A new class AB output stage for CMOS op-amps is proposed with simple and accurate quiescent current control using floating gate transistors. The proposed stage can be operated with a supply voltage close to a transistor's threshold voltage. Experimental results are provided showing a 15 MHz gain-bandwidth product when it is used as the second stage of an op-amp with 1.5 V supply voltage in a standard 0.8 m CMOS technology.     

Effect of a binder system on the low-pressure powder injection moulding of water-soluble zircon feedstocks

Micronized natural zircon sand powders were used as a raw material to conduct low-pressure powder injection moulding (LPPIM) processes. PIM could lead to new technological applications for this mineral, which has very stable dimensional behaviour with changing temperature. Zircon powders that have unconventional attributes for PIM (in terms of size and morphology) were mixed with poly(ethylene glycol) (PEG) based binders. Combinations of this water-soluble substance with different polymers, including low-density polyethylene (LDPE) and several types of acetate butyrate celluloses (CAB), were investigated. The influence of acetyl, butyryl and hydroxyl groups on the behaviour of the created feedstocks at different process stages and on the final piece properties were studied. The higher affinity of CAB with PEG and zircon powders compared with LDPE could result in improved densification and properties, but the butyryl, acetyl and hydroxyls groups affect the processability of these feedstocks.     

Fabrication of bronze components by metal injection moulding using powders with different particle characteristics

The aim of this work is to fabricate bronze components by metal injection moulding (MIM) studying the possibility of changing partially or totally the gas atomised powder by water atomised ones that are cheaper than the former. In order to carry out this study, a bronze 90/10 gas atomised spherical powder (usual MIM powder <22 μm) and two water atomised irregular powders (particle size <35 μm and <140 μm) were mixed in different proportions. As received powders and their mixtures were used to fabricate feedstocks and processed by MIM to evaluate the influence of powder particle size and morphology on debinding and sintering stages. Finally, both mechanical properties hardness and maximum flexural stress were determined to characterize the sintered materials. The addition of irregular fine and coarse powders was found to affect the moulding process, although densities and mechanical properties close to values of gas atomised one were obtained after sintering. Therefore, the use of water atomised bronze powders could be a promising way to diminish production costs in this technology.     

Fuzzy models of language structures

Statistical distribution of language structures reflect important regularities controlling informational and psycho-physiological processes, which accompany the generation of verbal language or printed texts. In this paper, fuzzy quantitative models of language statistics are constructed. The suggested models are based on the assumption about a super-position of two kinds of uncertainties: probabilistic and possibilistic. The realization of this super-position in statistical distributions is achieved by the splitting procedure of the probability measure. In this way, the fuzzy versions of generalized binomial, Fucks', and Zipf-Mandelbrot's distributions are constructed describing the probabilistic and possibilistic organization of language at any level: morphological, syntactic, or phonological.