A linear, time-varying system framework for noniterativediscrete-time band-limited signal extrapolation

A technique for the analysis and design of noniterative algorithms for discrete-time, band-limited signal extrapolation is described. The approach involves modeling the extrapolation process as a linear, time-varying (LTV) system, or filter. Together with a previously developed Fourier theory for LTV systems, this model provides a frequency-domain transfer function representation for the extrapolation system. This representation serves as a powerful tool for characterizing and comparing the reconstruction properties of several well-known least squares optimal algorithms for band-limited extrapolation. Moreover, the frequency-domain setting provides a conceptually attractive means for understanding the process of extrapolation itself. Additionally, a least squares approximation methodology for designing LTV filters for band-limited extrapolation is developed. The design technique is shown to unify a broad class of algorithms for extrapolating discrete-time data and, further, to provide a means for designing new and improved extrapolation algorithms     

Rain attenuation measurements over New Delhi with a microwave radiometer at 11 GHz

Rain attenuation measurements over New Delhi carried out with a microwave radiometer installed at the National Physical Laboratory (NPL), New Delhi and operating on 11 GHz for a period of more than three years are presented. For 0.01 percent of time for the period June 1977-April 1978, the attenuation exceeded for the monsoon period is 14.0 dB whereas for the whole year, it exceeds 10.4 dB. During the winter for the same percentage of time, the attenuation exceeded 1.5 dB, whereas for March-April it exceeds 0.5 dB. For the period May 1978-June 1980, it is observed that for 0.01 percent of time the attenuation for the whole year exceeds 9.0 dB. During the winter for the same percentage of time, the attenuation exceeds 1.4 dB whereas for March-April it exceeds 0.4 dB. A comparison of attenuation over New Delhi and those reported elsewhere are discussed. Yearly and worst month time ratio over New Delhi are given also as the values reported for the European region. Comparison of the attenuation distribution and the rate of surface rainfall measured with a rapid-response rain gauge are also given. The comparison shows that for the monsoon period and for 0.01 percent of time, the attenuation value exceeded for 14 dB corresponds to the surface rainfall rate of 140 mm/h. For the monsoon of 1978, 1979, comparison shows that for 0.1 percent of time, the attenuation value exceeded for 9.0 dB corresponds to the surface rainfall rate of 90 mm/h. Variation of attenuation and effective path length for various rainfall rates and elevation angles are also given.     

Design of wideband circularly polarized aperture-coupled microstripantennas

Two variations of a novel feeding technique for a wideband circularly polarized aperture-coupled microstrip antenna are described. Prototype designs for wideband linearly polarized elements are first presented, and then used for circularly polarized designs. Techniques used for design of the feed network are detailed, for both series feed and parallel feed versions. Experimental results are shown for each antenna, and results for the two designs are compared. The impedance and axial ratio bandwidths for these antennas are among the best yet achieved for microstrip antenna elements. Several design variations are also discussed     

Detection of Modulated Gaussian Signals in Noise

A method using Hermite polynomials is utilized for analyzing the outputs of νth-law devices for inputs of modulated Gaussian signals and zero-mean Gaussian noise. New results are developed for the output correlation functions, and techniques for obtaining closed-form expressions are pointed out. Output signal-to-noise ratios for various input carrier-to-noise-power ratios are calculated, and plots are shown for a single sinusoidal modulating signal. Results are derived to show the existence of a theoretical maximum for the output signal-to-noise ratio. The method can be directly applied for the case of general Fourier expandable signals modulating a Gaussian carrier.     

Final call: CPR's fall meeting in Boston on Oct. 25‐26

It's last call for three CPR doings: for the Fall Meeting in Boston later this month, for three trainings, and for nominations for the 2007 CPR Awards. Also, CPR member options for signing up for free electronic copies of Alternatives     

Crosstalk between microstrip transmission lines

Methods for prediction of crosstalk between microstrip transmission lines are reviewed and simplified for the weak-coupling case. Classical coupled transmission line theory is used for uniform lines, and potential and induced EMF methods are used for crosstalk between nonuniform lines. It is shown that the potential method is equivalent to classical coupled transmission line theory for the case of uniform lines. An experiment was performed for uniform coupled microstrip lines for frequencies from 50 MHz to 5 GHz, and good agreement between theory and measurement was obtained for both near- and far-end crosstalk     

General coupling matrix synthesis methods for Chebyshev filteringfunctions

Methods are presented for the generation of the transfer polynomials, and then the direct synthesis of the corresponding canonical network coupling matrices for Chebyshev (i.e., prescribed-equiripple) filtering functions of the most general kind. A simple recursion technique is described for the generation of the polynomials for even- or odd-degree Chebyshev filtering functions with symmetrically or asymmetrically prescribed transmission zeros and/or group delay equalization zero pairs. The method for the synthesis of the coupling matrix for the corresponding single- or double-terminated network is then given. Finally, a novel direct technique, not involving optimization, for reconfiguring the matrix into a practical form suitable for realization with microwave resonator technology is introduced. These universal methods will be useful for the design of efficient high-performance microwave filters in a wide variety of technologies for application in space and terrestrial communication systems     

FSK With Limiter-Discriminator Detector in Nakagami Fading Channels With and Without Selection Combining

In this paper, an equation for the error probability of M-ary frequency shift keying with limiter-discriminator detection in Nakagami fading channels for arbitrary m is derived. The authors do the same for selection combining with L diversity channels for integer m and for switch and stay combining with two diversity channels for m=1 (Rayleigh fading). The error probability for various values of m, L, frequency deviation, and filter bandwidth is computed     

Backscattering for circular polarisation

Equations are given that express scattering for transmitting and receiving circularly polarised waves in terms of the characteristics for linear polarisation. Special cases are discussed, for which it is possible to estimate the radar cross-section for one polarisation based on data for other polarisations. Knowledge of polarisation characteristics is sometimes helpful for acquiring insight into the scattering mechanisms of complex surfaces.     

Image Processing of Biological Liquids Films for Medical Diagnostics

In this paper, the development of smart medical autonomous technology is considered. An example of a smart medical autonomous distributed system for diagnostics is also discussed. To develop this system for medical image analysis we review several processing methods. The use of the cuneiform dehydration method for medical diagnosis is considered. The experimental results obtained for blood serum dehydrated films are presented. The author proposes an algorithm for the primary identification of structures formed in the films and their use for automated detection of various structures for diagnostic purposes. The paper describes the first stage of image processing, i.e. the selection of filtering types for the correct identification of structural features and characteristics of the images. The results of filtering and some computational results of various types of structures in the films are presented.     

Information Model for Resource of ASON Control Plane

1　Introduction　Opticalnetworkshavebecomemorecomplicatedthanbefore ,andneednetworkmanagement.InASON ,theControlPlane (CP)isanewnetworkcomponent[1～ 3] ,inordertomanagethenewemergedresources ,anin formationmodelforCPisrequired .　TheReferenceModelofOpenDistributedProcessing(RM ODP) providesanobjectorientedframeworkfordistributedmanagementsystemsthatallowsuser sdif ferentrequirementsformanagementapplications[4 ] .RM ODPhasprovideduswithanetworkmanagementviewpoint,anditprovidesfiveview…     

CMOS circuit optimization

In this paper, optimization algorithms for CMOS circuits are described, from the propagation delay time viewpoint. The propagation delay time for a CMOS in erter is calculated for a step function input. A classical model of I–V characteristics for a MOSFET and the worst case Sah model for inter-electrode capacitances of a MOSFET are used for this deduction.     

Outage Capacity for Secondary Users Due to Bandwidth Fluctuations: Multicarrier Versus Single Carrier

In this work we study the channel capacity from the point of view of a secondary user that shares the bandwidth of the channel with a primary user using dynamic spectrum access in cognitive radio.The secondary user sees bandwidth fluctuations (i.e, at any given time the bandwidth can be available or not) that impact its channel capacity. We study the outage capacity for the secondary user considering two scenarios in which the secondary user uses either a single carrier modulation for the case in which bandwidth fluctuates over the complete transmission band, and a multicarrier modulation for the case in which bandwidth fluctuations are over various transmission subbands. We derive expressions for the outage capacity of the secondary user for both single carrier and multicarrier. Results show that: (1) The outage capacity for single carrier can be higher than for multicarrier, but with a higher outage probability for single carrier than for multicarrier. In fact, a low value of outage probability for single carrier requires a duty cycle for the secondary user close to one, but this has the problem that it leaves a very short duty cycle for the primary user. (2) Although for the secondary user the outage capacity for multicarrier is smaller than for single carrier, for multicarrier lower values of the outage probability can be achieved even for short values of the duty cycle of the secondary user, allowing larger duty cycle values of the primary user. (3) For multicarrier, the outage capacity is more sensitive to changes in the duty cycle than to changes in the outage probability. To obtain a larger outage capacity with low values of both the outage probability and the duty cycle, it requires the use of a large number of subbands.     

一种基于CCD的非接触尺寸测量系统

设计了一种基于CCD的非接触尺寸测量系统.运用亚像素边缘检测法对圆环进行边缘检测,完成对圆环的非接触尺寸测量.利用数据库实现对测量数据的存储管理及网络传输.通过实验证明:对圆环测量精度外径误差0.005 mm,内径误差0.001 mm,壁厚误差0.015 mm,整体绝对误差小于0.02 mm,相对误差小于0.07％,满足了工程高精度测量要求.本系统适合有危害性的工业现场环境,数据的存储管理功能也给实际应用带来很大便利.     

An efficient method for terminal and multiterminal pathset enumeration

The literature is abundant with algorithms for determining separately the paths for the single terminal pair, paths for multiterminal pairs and cuts for a specified terminal pair of any network, from knowledge of the reliability logic diagram (RLD). However, very few methods are available as efficient algorithms for enumerating simultaneously the paths between any single terminal pair, paths for multiterminal pairs and cuts for the specified terminal pair.The present paper provides a conceptually simple and computationally efficient algorithm to obtain simultaneously the paths between any single pair of terminals, paths for multiterminal pairs and the cuts for the specified terminal pair of interest of any complex network. The algorithm is easy and computationally economical and also applicable to graphs having both nodes and branches of finite non-zero failure probability.An illustrative example is provided to demonstrate the effectiveness of the proposed algorithm.     

Volterra series representation of a forward-biased p-i-n diode

A nonlinear model is proposed for a forward-biased p-in diode controlled by an ac signal consisting of a group of sinusoidal signals. The model is applicable to these phases of diode operation where linearized basic physical equations are valid. Current-voltage relations have been obtained for junctions and the "i" region in the form of a Taylor series with frequency-dependent coefficients. The new model is valid for signal levels considerably exceeding those admissible for the known linear model [3], [4]. A new form of signal limiting condition, suitable for measurement verification and calculations, has been obtained. The Volterra series for the equations representing the diode has been found which correspond to the Taylor series obtained. The convergency condition for this series is identical to that for thel Taylor series. The conformability of measurement and calculation results fully testifies to the usefulness of the proposed model for nonlinear distortion analysis.     

Uniform Quantizers for Noisy Channels

We consider optimum uniform data quantization for noisy channels. We present a general formulation for natural encoding that results in simple expressions for the mean-square error. Specifically, we show that the optimum location of the center of the quantizer is at the mean of the distribution for all error rates. The optimum levels for quantization and the corresponding mean-square error are presented for Gaussian and uniform data. For the latter the width of the optimum quantizer for noisy channels is shown to be smaller than the entire range of probability distribution.     

显示用透明导电氧化物

人们还在继续寻求一种用于平板显示器的具有成本效益的氧化铟锡(ITO)替代品。本文介绍了一种实用的形成氟掺二氧化锡(FTO)高精确度图案的解决方案,使得FTO在PDP中成为一种很具吸引力的ITO替代品。     

低密度纠删码度分布序列的研究

本文对低密度纠删码的度分布序列进行了研究,提出了低密度纠删码度分布序列可达信道容量的充分必要条件,给出了Heavy-Tail/Poisson和右边正则的两种度分布序列的性质,证明了低密度纠删码达信道容量度分布序列的一个分析性质.这些分析性质对低密纠删码达信道容量度分布序列的设计有着重要的理论指导意义.     

Reflections, diffractions, and surface waves for an interiorimpedance wedge of arbitrary angle

The asymptotic-impedance wedge solution for plane-wave illumination at normal incidence is examined for interior wedge diffraction. An efficient method for calculating the diffraction coefficient for arbitrary wedge angle is presented, as previous calculations were very difficult except for three specific wedge angles for the uniform geometrical theory of diffraction (UTD) expansion. The asymptotic solution isolates the incident, singly reflected, multiply reflected, diffracted, surface wave, and associated surface wave transition fields. Multiply reflected fields of any order are considered. The multiply reflected fields from the exact solution arise as ratios of auxiliary Maliuzhinets functions; however, by using properties of the Maliuzhinets functions, this representation can be reduced to products of reflection coefficients which are much more efficient for calculation. A surface-wave transition field is added to the surface wave boundaries. Computations are presented for interior wedge diffractions although the formulation is equally valid for both exterior and interior wedges with uniform but different impedances on each face for both soft and hard polarizations. In addition, the accuracy of the high-frequency asymptotic expansion is examined for small diffraction distances by direct comparison of the exact and asymptotic solutions