General solution of a monopole loaded by a dielectric hemisphere for efficient computation

A simple result for the general solution of a monopole loaded by a dielectric hemisphere is presented. The result can be calculated without the need for any numerical integration and, thus, it is computationally very efficient. In addition, the result is very easy to implement and should be useful to the design engineer.     

A simple approximation for calculating impurity profiles for a two-step diffusion process

An accurate approximation for calculating two-step diffusion profiles is given. The result valid for the field-free case has the same form as the Gaussian profile resulting from the conventional delta function approximation. The result is simple enough to be useful for first-order analytic evaluation of device fabrication parameters.     

An asymptotic result for the diffraction of plane waves propagating along a cylindrically truncated flat surface

An asymptotic result is obtained for evaluating the diffraction of a plane wave incident along a perfectly conducting fiat surface toward a drop in this surface. This drop is formed with a convex cylinder smoothly joined to the fiat section, thus creating a discontinuity in curvature at the join. The asymptotic result is also useful for analyzing the radiation of a source mounted on the fiat section of the conducting surface. Unlike a previously available solution which still requires a fair amount of numerical evaluation using a hybrid approach combining the moment method with the geometrical theory of diffraction, the computation of this asymptotic result is simple and efficient. Since this result is expressed in the simple format of the geometrical theory of diffraction, it is easily applied to solving more complicated diffraction problems. An application is found in the aperture-matched horn designs.     

Differential amplifier input impedance

The analysis of a simple differential amplifier excited by two separate voltage sources reveals that the input impedance which loads the voltage source at the inverting input is not a constant but rather is a function of the characteristics of each voltage source. An expression is derived for the input impedance and the result is illustrated in a simple example.     

Sequential Prediction of Unbounded Stationary Time Series

A simple on-line procedure is considered for the prediction of a real-valued sequence. The algorithm is based on a combination of several simple predictors. If the sequence is a realization of an unbounded stationary and ergodic random process then the average of squared errors converges, almost surely, to that of the optimum, given by the Bayes predictor. An analog result is offered for the classification of binary processes     

Multiple local optima in vector quantizers (Corresp.)

Two results are presented on vector quantizers meeting necessary conditions for optimality. First a simple generalization of well-known centroid and moment properties of the squared-error distortion measure to a weighted quadratic distortion measure with an input dependent weighting is presented. The second result is an application of the squared-error special case of the first result to a simulation study of the design of1bit per sample two- and three-dimensional quantizers for a memoryless Gaussian source using the generalized Lloyd technique. The existence of multiple distinct local optima is demonstrated, thereby showing that sufficient conditions for unique local optima do not exist for this simple common case. It is also shown that at least three dimensions are required for a vector quantizer to outperform a scalar quantizer for this source.     

The collision channel with recovery

We consider a simple conceptual model of random accessing to a receiver deploying multiuser detection techniques. The model is a simple extension of Massey and Mathys' collision channel without feedback in which a certain probability of recovery from collision is introduced. As the main result, we derive the slot-synchronized capacity region of this recovery channel and show that for sufficiently powerful multiuser detectors, maximal performance is achieved without any sophisticated transmission protocols. We also explore the effect of a simple fading model.     

A note on cross-Grammians for symmetric realizations

A recent result [1] concerning cross-Grammians for SISO systems is generalized to symmetric realizations of MIMO systems and a simple proof is provided. A counterexample demonstrates that the SISO result does not extend to general MIMO systems.     

Power estimation in adiabatic circuits: a simple and accurate model

A simple procedure to evaluate the energy consumption of adiabatic gate circuits is proposed and validated. The proposed strategy is based on a linearization of the circuit and simplifying the analytical result obtained on the equivalent network. The approach leads to simple relationships which can be used for a pencil-and-paper evaluation or implemented on software. The accuracy of the results is validated by means of Spice simulations on an adiabatic full adder designed with a 0.8 μm technology     

利用光电流效应测定选支CO激光器的输出谱线波长

本文介绍了一种利用激光光电流效应测定选支CO激光器输出波长的简便方法。测量结果和用光谱仪测得的相符合。     

Very fast accurate square-root algorithm for use with gradient edge operators

Commonly used gradient edge operators such as the Sobel, Prewitt and Roberts operators all required a square root operation; this is, however, computationally intensive and, consequently, simple but very inaccurate approximations are often used instead. The author describes a new square root algorithm specifically designed for use with these edge operators. The result is a very simple, fast and extremely accurate algorithm.<>     

A simple derivation of Lloyd's classical result for the optimum scalar quantizer (Corresp.)

The classical result of Lloyd for the optimum scalar quantizer in the asymptotic case of fine quantization is derived from first principles. The derivation is offered as a simple alternative to Lloyd's original and elegant piece of analysis, and the result is used to derive the optimum compander. We then show why a compander that presents uniformly distributed random variables to the quantizer is not a good idea.     

Device Failures During Equipment Life for Lognormal Distributions

A simple graph is presented showing the total fraction of devices which will fail over any given time for lognormal failure distributions. The result is a function of the median life and the geometric dispersion.     

IQ误差自适应校准在OFDM解调器的应用

研究了正交解调器IQ误差对OFDM解调器的影响,提出了一种简单易行的IQ误差自适应校准方法。仿真结果表明,WLAN802.11a通信系统中单纯的采用基带AGC不能消除IQ误差,使用该方法校准后的OFDM解调器性能得到了很大改善。研究结果为研制OFDM宽带接收机提供了参考。     

Shifting of the peak generation rate in double-drift silicon IMPATT diodes

In double-drift (DD) silicon IMPATT diodes, it is observed that the peak generation rates of both carriers (electrons and holes) lie within the n side. The shifting is due to the unequal ionization rates for electrons and holes in silicon. By neglecting the reverse saturation current, a simple analytical expression for the location where the peak generation occurs is derived. This simple result may be useful for the design of double-drift as well as complementary single-drift IMPATT diodes.     

基于Proteus和Keil的单片机演奏乐曲的仿真

针对乐曲演奏在单片机实践教学中实现的不足,介绍了基于Proteus和Keil联调的单片机演奏乐曲的设计方法,通过对乐谱的音符和节拍进行编码,实现了乐曲演奏的功能。仿真结果表明：该方法电路简单、调试方便,只需简单的修改程序就可实现其它歌曲的演奏。     

A note on minimal repair

The cumulative function for the number of failures for a unit which is subjected to minimal repair after each failure is a nonstationary Poisson process. In this note, a simple method for obtaining this result is presented. A conditional probability approach is used for the derivation     

On the optimum average distortion attainable by fixed-rate coding of a nonergodic source

A simple proof is given for the Gray-Davisson result on the ergodic decomposition of the optimum average distortion attainable by fixed-rate coding of a nonergodic source, for the special ease of a bounded distortion measure. A second proof is given for a more general class of distortion measures using a result of Ziv.     

Design for testability and DC test of switched-capacitor circuits

The authors present a design for testability (DFT) technique for switched-capacitor circuits. The principle is to reconfigure the SC circuit so that it realises a cascade of DC voltage amplifiers in which all capacitors are represented in a simple form. Then, the transfer function becomes a product of the ratio of two capacitors and the sensibility of the DC gain to each capacitor is close to unity. Consequently, a simple test with partial diagnosis is realised with some DC voltage stimuli and gives an accurate test result at the output of the last voltage amplifier     

A stochastic invariant imbedding approach to avalanche noise in semiconductors

The multiplication statistics in an avalanche region in semiconductors by impact ionization are treated stochasticly by means of the invariant imbedding technique. An explicit result is obtained for the variance of the process for arbitrary ionization coefficients. A simple formula is derived for the determination of the spectral density of the fluctuations, caused by multiplication statistics. Formulae will be given for the mean and the variance of both electrons and holes. An exact result is obtained for a linear spatial dependency of the ionization coefficients.