摘要:

The present position in the development and use of printed circuits is discussed and some schemes for depositing resistors as part of a printed wiring process are mentioned. A description is given of a pilot-production process used for digital-computor circuits. The subdivision of the size of units by circuit functions is suggested to have an optimum value lying between two uneconomic extremes. Characteristics of potting resins are discussed, the results of experimental work on loaded resins are tabulated and the results of measurements made on printed and potted coils are given. The application of potted-circuit techniques to a telemetering unit and an experimental radar equipment is shown. Possible future automatic assembly techniques are discussed and illustrated by means of a flow diagram.

DOI:10.1049/pi-3.1953.0038

出版商:IEE    

年代:1953

数据来源: IET

摘要:

An analysis is made of a large number of cases in which communication has been effected on frequencies 1–6 Mc/s in excess of the monthly mean values predicted from normal-incidence ionospheric data. The analysis indicates that during the winter period, and particularly at the equinox periods March and September, the variability in F2-region characteristics will explain many of the apparent anomalies. The remaining cases show no marked disagreement with the conclusion that reflections from the abnormal E-region are responsible for the received signals.An analysis of observations on 30-Mc/s signals made in Japan over the four-year period 1935–39 indicates conclusively that single-hop transmissions on frequencies considerably in excess of F2-region maximum usable frequencies are due to reflections from the abnormal E-region.

DOI:10.1049/pi-3.1953.0041

出版商:IEE    

年代:1953

数据来源: IET

摘要:

Part 1 of the paper describes a theoretical analysis of the effective permittivity of arrays of perfectly conducting elements of simple geometric shapes—e.g. cylindrical rods, thin strips, spheres and discs— and the results of a supporting experimental investigation on arrays of metallic elements of these shapes at a frequency of 1 000 c/s. Dielectric media of this type are being used for the construction of centimetre-wave lenses. It is shown that representation of the elements as simple dipoles is inadequate at high concentrations and that account must then be taken of higher-order multi-pole interaction between them. Where evaluation of the latter has proved practicable, the experimental and theoretical permittivity values are found to be in close agreement over the whole range of concentration investigated.Part 2 describes an experimental investigation of the permittivity and dielectric-loss characteristics over the frequency range 400–10 000 c/s of a cubical array of spherical elements composed of imperfectly conducting material as a function of the concentration of these elements, and discusses the results in terms of the theoretical analysis given in Part 1. This investigation is an extension of earlier studies of the behaviour of composite dielectric materials.

DOI:10.1049/pi-3.1953.0042

出版商:IEE    

年代:1953

数据来源: IET

摘要:

Measurements of the attenuations produced by air-filled silver-plated waveguides have been made at a frequency of 9 375 Mc/s before and after corrosion. The results suggest that plated surfaces are generally rougher than drawn ones. A detailed study has therefore been made of the surface roughness of various sizes of waveguide tubing when electroplated internally. The relative merits of several different types of electroplate, and the effects of variations in plating thickness and current density in the plating bath, have been determined.Although silver plating of waveguide components seems to be standard practice it is concluded that plating may not give the improvement in attenuation expected and is probably not worth while for many applications.

DOI:10.1049/pi-3.1953.0043

出版商:IEE    

年代:1953

数据来源: IET

摘要:

The paper sets out an analysis, in terms of geometrical optics, of the Buchmann-Meyer, or light, pattern which is formed by reflection from the modulated grooves of a recorded tone-disc. The pattern is considered as lying in the focal plane of the circular groove walls and not on the disc surface, as is usually assumed. A new apparatus for measuring the width of the patterns is described and the errors in disc-surface and focal-plane measurements found when using it are compared. The latter results are shown to possess the higher degree of consistency and their correctness is confirmed by an examination of the pattern formation in terms of physical optics. The origin of two sets of interference fringes which are visible in the patterns is also described. The decrease of luminous intensity which occurs at the edge of the patterns is then computed and it is shown that the new method of measurement described should give a higher degree of accuracy than hitherto available, even under some practical conditions when the edge of the pattern is not sharply defined.

DOI:10.1049/pi-3.1953.0044

出版商:IEE    

年代:1953

数据来源: IET

摘要:

During the war there accumulated a considerable knowledge of valve circuits used for waveform generation and associated operations. Arising out of this, a fairly general circuit technique was developed which laid down some general principles of circuit design. One of the main objectives was the ability to design circuits that would operate with valves having characteristics which varied within fairly wide tolerances without component adjustments being necessary when valves were changed. The paper outlines a similar technique for use with point-contact transistors. It is written from the point of view of one familiar with the valve-circuit technique, and draws heavily on the analogy between the characteristics of transistors and pentodes. Much of the terminology and many of the ideas are carried over into the new field.Some basic circuits are described, such as 2-state devices, timing circuits, counters and relaxation oscillators. The application of these in digital computers is then considered and more complex arrangements are described.It is concluded that, using the methods described, circuits can be designed that will operate with the transistors currently available without the adjustment of components, or over-rigid selection of transistors.

DOI:10.1049/pi-3.1953.0045

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-3.1953.0048

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-3.1953.0049

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-3.1953.0050

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-3.1953.0051

出版商:IEE    

年代:1953

数据来源: IET