DOI:10.1049/piee.1969.0001

出版商:IEE    

年代:1969

数据来源: IET

DOI:10.1049/piee.1969.0002

出版商:IEE    

年代:1969

数据来源: IET

摘要:

The paper considers the development, design and test procedures for a range of random-pulse generators which exploit the properties of chaincodes. While the generators were developed for simulation of road-traffic situations, they have wide applications in the simulation of the central processors of digital computers and the testing of digital control systems. The generators operate at high speed in a parallel fashion. They require only a very limited number of logical elements, and output-pulse patterns may be repeated starting at any point.

DOI:10.1049/piee.1969.0003

出版商:IEE    

年代:1969

数据来源: IET

摘要:

The objective of this paper is to contrast random generators built by Redshaw and Robinson with simpler generators devised by the author. The test procedures laid down in an earlier paper are followed. Both types of random generator were designed for the simulation of random arrivals of vehicles at road-traffic intersections. There is, however, a wide variety of other applications for such generators. These include message-switching simulation, and the simulation of the operation of the central processor of a multiprogram computer. The tests performed indicated that both classes of generator satisfied criteria for randomness, provided that care was exercised at the design stage.

DOI:10.1049/piee.1969.0004

出版商:IEE    

年代:1969

数据来源: IET

摘要:

A method is described for stabilising a single-loop negative-feedback transistor amplifier based on measurements of a chosen short-circuit-stable closed-loop driving-point admittance between two terminals within the amplifier. A correcting network is synthetised, the admittance of which, when added to the measured admittance, prevents zero encirclement by the locus of the total admittance by an adequate margin. Formulas are given enabling margins against zero encirclement to be interpreted in terms of movements of corner frequencies associated with a frequently used internal amplifier configuration. The method is demonstrated to be straightforward for an amplifier requiring measurements up to 20MHz, and the admittance margins obtained are compared with margins obtained from loop-gain measurements.

DOI:10.1049/piee.1969.0005

出版商:IEE    

年代:1969

数据来源: IET

摘要:

The mean-square value of the phase error in the phase-lock loop is determined from the linear differential equation. Conditions are then derived, for its minimisation, with an integral plus proportional filter in the loop, for an input consisting of an f.m. f.d.m. carrier plus thermal noise. The statistics of the phase error are then deduced using the Fokker-Planck technique for an arbitrary loop filter. From the statistics, the loss of lock rate is derived and each loss of lock is assumed to produce an inpulse in the baseband. The well known result of Rice is used to determine the output signal/noise ratio, and the point of threshold arising from the loss of lock is shown.

DOI:10.1049/piee.1969.0006

出版商:IEE    

年代:1969

数据来源: IET

摘要:

The paper describes the synthesis of arithmetically symmetrical, broadbandLCfilters having prescribed amplitude response and nearly constant group delay, with particular reference to i.f. filters for radio-relay systems. These filters must suppress unwanted signals, particularly the adjacent carrier frequencies, without significantly distorting the required signal. For low distortion, the filters must have both flat amplitude and constant group-delay responses over the passband centre. Filters synthetised for 1800- and 960-channel systems have satisfied these requirements, the transfer-function design and measured characteristics of the filter for the 960-channel system being given as an example. The filters have the advantages that they can be inserted in the i.f. chain without the need for further phase equalisation, and that they give improved amplitude responses compared with conventional filter and equaliser combinations.

DOI:10.1049/piee.1969.0007

出版商:IEE    

年代:1969

数据来源: IET

摘要:

A transformation procedure is described for determining a set of nonautonomic distributions which are complementary to previously described general classes of lines. A table of these distributions is presented, together with the conditions necessary for their evaluation. In particular, for the Gaussian distributedRCline, which is inherent, for example, in some diffused-semiconductor realisations, a solution is obtained in terms of a convergent confluent hypergeometric series which is equivalent to an earlier solution in terms of Hermite polynomials. Finally, its performance is evaluated and experimentally compared with a well known distribution.

DOI:10.1049/piee.1969.0008

出版商:IEE    

年代:1969

数据来源: IET

摘要:

Necessary and sufficient conditions for the synthesis of a driving-point function using any two kinds of one-port impedances are presented, and the result is used to develop a procedure for synthetising a driving-point function using tapered lines. The result also provides a short proof for O'Shea's necessary and sufficient conditions for the realisation of a driving-point function using symmetric structures. It is shown that any impedance which can be realised using symmetric lines may always be realised using the one-port impedances of the nonuniform transmission lines used in the construction of the symmetric lines. It is shown that all the existing synthesis procedures for the realisation of a driving-point function using any two one-port impedances are special cases of the general procedure advanced in this paper. Necessary and sufficient conditions for realising a driving-point function as a cascade of symmetric structures have been advanced. These are shown to be equivalent to those for realising the same driving-point function using the open- and short-circuit impedances of a symmetric structure. A procedure for such a cascade synthesis is advanced. If the structure is a uniform line, it provides a simple alternative to Wyndrum's cascade-synthesis procedure. An illustrative example is also included. By using known transformations, all the results may be applied to other types of lines such as lossless lines.

DOI:10.1049/piee.1969.0009

出版商:IEE    

年代:1969

数据来源: IET

摘要:

Asymptotic and other formulas are derivedab initiofor the field diffracted by a perfectly conducting wedge when illuminated by a line source. In the transition zone between lit and shadowed regions, the field is decomposed into image and diffraction terms which enable the formulas to be used throughout the region for self-consistent field analyses. The wedge-diffraction functions are finding a growing application in the investigation of electromagnetic problems in which the dimensions are too large for waveguide-mode analysis, but too small for geometric optics to apply. Various formulas are scattered throughout the literature. In this paper, they are derived from first principles and presented in a form in which the areas of use are indicated, and the important transition zone near a shadow boundary is explained in some detail.

DOI:10.1049/piee.1969.0010

出版商:IEE    

年代:1969

数据来源: IET