Unity of measurements and its maintenance. Fundamental concepts

We consider the group of fundamental concepts involved in the unity of measurements and its maintenance.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 15–17, October, 1994.     

A multi-purpose CMOS sensor interface for low-power applications

A dedicated low-power CMOS transponder microchip is presented as part of a novel telemetry implant for biomedical applications. This mixed analog-digital circuit contains an identification code and collects information on physiological parameters, i.e., body temperature and physical activity, and on the status of the battery. To minimize the amount of data to be transmitted, a dedicated signal processing algorithm is embedded within its circuitry. All telemetry functions (encoding, modulation, generation of the carrier) are implemented on the integrated circuit. Emphasis is on a high degree of flexibility towards sensor inputs and internal data management, extreme miniaturization, and low-power consumption to allow a long implantation lifetime     

Shunting neural network photodetector arrays in analog CMOS

This paper describes a custom analog CMOS photodetector array IC that exploits nonlinear lateral inhibition to achieve dynamic range compression, edge enhancement, and adaptation to mean input intensity. The neural net array architecture, characterized by nearest-neighbor connections and multiplicative cell interaction, is modeled after biological vision systems. The fabricated IC successfully implements a portion of the compact and powerful nonlinear signal processing performed in the outer layers of the vertebrate retina. Measured results are presented for an optical input intensity range of nearly six decades. A scanning architecture that allows for preferential directional sensitivity is also demonstrated. Measured data agree well with models created using a spreadsheet program     

Optimum degeneration for minimum mismatch in bipolar currentsources

Statistical analysis of mismatch in bipolar degenerated current sources reveals the existence of an optimum degeneration for minimum mismatch. Extra degeneration does not improve matching but degrades it and forces unnecessary DC restrictions on the circuit     

Achievement of pencil-beam radiation from a TM01 modecircular waveguide source

A method employing appropriately placed parallel-metallic plates in the aperture of a TM₀₁ mode circular waveguide source so as to have it produce pencil-beam radiation is described and analyzed. Programmed computations, with experimental verification, are given for the case of a C-Band TM₀₁ source flared out to a conical horn so as to produce moderate (22 dBi) gain. Means of extending the method to achieve higher gains (40 dBi to 60 dBi) and to modify the plate arrangement so as to produce the same effect with a TE₀₁ mode are briefly outlined     

Modeling pentode-like characteristics of recessed-gate staticinduction transistor

A new analytical model is described for the pentode-like region of the characteristics of recessed-gate SIT structures. The model allows one to investigate the transition from saturating characteristics of long channel JFET's to nonsaturating behavior of SIT devices, taking into account realistic device geometry     

Overgrown silicon PBT's: calculations and measurements

The device parameters of overgrown silicon permeable base transistors (PBT's) have been systematically investigated by two dimensional drift diffusion simulations and analytical calculations. Hence some design rules arise for optimizing the high frequency performance of PBT's. The calculations indicate the source-drain distance as the essential PBT parameter, which should be kept below 200 nm in order to expect unity-current-gain frequencies f_T over 50 GHZ. In addition, PBT's with buried monocrystalline CoSi₂-gates have been fabricated by high dose cobalt ion implantation through a grid-like mask into MOS-compatible n-type Si(100). Measurements revealed a transconductance of 70 mS/mm and a f _T value of 6 GHz. The comparison between measured and simulated output characteristics shows good agreement     

Measuring efficiency of power plants in Israel by data envelopmentanalysis

An application of data envelopment analysis (DEA) for measuring and evaluating the operating efficiency of power plants in the Israeli Electric Corporation (IEC) is presented. Emphasis is placed on the process of screening the list of potential input and output factors and determining the most relevant ones. Special attention is given to the qualitative factor concerning air pollution, which is treated as a categorical variable. The incorporation of `standard data' is examined and the results are analyzed     

On the posterior-probability estimate of the error rate ofnonparametric classification rules

The posterior-probability estimate of the classification error rate of some nonparametric classification rules is studied. The variance of the estimator is shown to have same remarkable distribution-free properties for the k-nearest neighbor, kernel, and histogram rules. We also investigate the bias of the estimate and establish its consistency and upper bounds. The version of the estimate calculated from an independent set of unclassified patterns is also considered     

Dielectric measurements using a rational function model

A recently proposed rational function model for the aperture admittance of 50 ohm Teflon filled coaxial lines in contact with a homogeneous dielectric is experimentally validated. A calibration technique of the automatic network analyzer utilizing standard terminations and time domain gating is used. Uncertainties in the dielectric properties of reference liquids do not enter the calibration procedure. Experimental results for water and methanol are compared with estimated values. A model expression for the sensitivity of the probe is validated. The sensitivities of two coaxial line probes for the measurements made are determined. Results obtained using the new model are compared with those of other workers