摘要:

Details concerning fast and accurate electrostatic field calculation techniques based on the 3-dimensional surface charge simulation method by means of Fourier-type charges are presented. The techniques range over (a) the direct potential and field coefficient formulas, (b) a computation of Legendre function of the second kind with half integer degree—toroidal functionQm−½(x), (c) a high-speed integral and (d) an introduction of the associated toroidal functionSm−½(x). As an example for application, a tilted hemispherically tipped cylindrical rod electrode with a spherical dielectric is analysed and the results are demonstrated.

DOI:10.1049/ip-a-1.1986.0011

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The electrostatic field associated with a conducting spherical protrusion on a smooth plane can be obtained by utilising a finite number of image charges, if the angle of intersection is restricted to a submultiple of π. The essential steps in obtaining the solution are presented, and general expressions for the system of image charges are derived.

DOI:10.1049/ip-a-1.1986.0012

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The stability characteristics of the Xi-core at constant airgap is examined by experimental and theoretical methods. The 2-dimensional field is solved numerically using the finite difference technique. It is shown that the stability characteristics can be deduced from stored field energy variations.

DOI:10.1049/ip-a-1.1986.0014

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The design of a multichannel discrete STAT analyser is described. The machine design incorporates a event-driven multitasking microprocessor with the capability of concurrent control of eight analytical modules. The microprocessor controller introduces flexibility and versatility to the system by replacing electro-mechanical and/or discrete logic components, and hence simplifies system modification and future expansion. As an added advantage, other machine functions, such as sequential control, signal acquisition and processing and data management, are performed by the microprocessor.

DOI:10.1049/ip-a-1.1986.0015

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The hoarseness of 28 subjects with laryngeal complaints of widely differing severity has been automatically evaluated by using the simple Chebychev norm to compare a 3-component vector representing the subject's voice with a normal template. A second procedure used the absolute values of the parameters without comparison with a standard. The three components of the characteristic vectors were extracted from recorded utterances of the Spanish vowel ‘a’, for which it was necessary to determine the approximate tone period of the signals. Two methods of pitch extraction were used, one based on the autocorrelation function and the other on a SIFT algorithm.

DOI:10.1049/ip-a-1.1986.0016

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Flowmeters which utilise the Doppler principle at ultrasonic frequencies can be tested by means of a single-sideband generator which adds or subtracts the Doppler frequency and the ultrasound frequency. The design and performance of a generator is described.

DOI:10.1049/ip-a-1.1986.0017

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The original background to the discovery of electromagnetic waves is described. It is shown that many of the extremely high-frequency techniques, which have been used in modern times, can be traced back to Heinrich Hertz himself. The influence which Hertz's work had on the invention of the cavity magnetron by Randall and Boot is described in somewhat more detail than has hitherto been published.

DOI:10.1049/ip-a-1.1986.0020

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The paper describes the development of the electricity grid in the United Kingdom from its establishment in 1935. It originally allowed a pooling of the generating capability of many undertakings, and then led quickly to lower overall costs. After the second world war there was vast expansion of demand. In the 1950s and 1960s the 275 kV and 400 kV grids were built, and the present network, with relatively modest extensions and regular refurbishment, appears strong enough to serve beyond the turn of the century.

DOI:10.1049/ip-a-1.1986.0021

出版商:IEE    

年代:1986

数据来源: IET

摘要:

The author, who first joined the IEE 60 years ago, traces how the early craft of instrument making first met the needs of the new telegraph and power industries for control and portable test meters. Several firms were located in the Clerkenwell area, the home of clock and scientific instrument making: histories are briefly sketched of Elliott Brothers (from 1800), Nalder Bros. & Thompson, Evershed & Vignoles, Everett Edgcumbe (who, in 1910, built an aeroplane), Ferranti, and Record Electrical. The subsequent changes in the industry are outlined, as a transition from being instrument makers to instrument manufacturing. The contribution of the annual Conversazione and Exhibition of the Physical Society is mentioned, and the advent of electronics can be traced through the annual catalogues of this exhibition.

DOI:10.1049/ip-a-1.1986.0022

出版商:IEE    

年代:1986

数据来源: IET