DOI:10.1049/pi-3a.1952.0002

出版商:IEE    

年代:1952

数据来源: IET

摘要:

Although the word “television” has come to be associated in the public mind with the broadcasting of entertainment by means of radio, such a limitation seems unacceptable and illogical in dealing with the history of the subject. The authors have therefore interpreted their task as one involving a broad historical review of the various methods whereby visual phenomena may be reproduced at a distance but without regard to the method of transmission or to the time occupied in transmission. In consequence of this interpretation, the earlier part of the paper deals with a number of proposals which aimed at providing a reproduction on paper of the original image in a form which, to-day, we should associate more with the practice of phototelegraphy than with modern television. Since all practical systems of either photo-telegraphy or television involve some form of scanning, it will be realized that both arts have a common ancestry.

DOI:10.1049/pi-3a.1952.0005

出版商:IEE    

年代:1952

数据来源: IET

摘要:

This survey paper has been written with the object of presenting information about the development in Great Britain of the engineering technique associated with the origination of the B.B.C. television programmes. In any developing art a decision made at a certain time depends upon previous experience. In order to present an understandable account of television engineering methods as at present practised, it is desirable to trace their origins back to the beginning.The paper starts by considering very briefly the development of the pre-war B.B.C. television service and refers, for further information, to other papers published during that period. The paper then records the results of post-war planning for expansion and discusses the origin of the White City scheme, the Lime Grove studio building and lastly the marked development in television outside broadcasts which has been such a feature of the period from 1946 to 1951.Up to this point the paper is concerned with the broader basis of planning and not with technical detail. Section 4 discusses the several types of camera equipment which have been used in this country for studio or outside-broadcast purposes. The technique of television engineering operations is closely concerned with the properties of camera tubes and their associated circuits, so that this subject has been treated in some detail. Brief mention is also made of the associated sound equipment.Certain points of interest in the design of control and apparatus rooms are treated next. This is followed by a discussion of the purposes and technique of presentation as opposed to production, presentation being an aspect of television activity which has assumed considerable importance in recent years. It is acknowledged that the televising of film has been brought to a high standard of perfection in this country. Some account is given of the development of telecine and telefilm recording. In addition to such matters as camera channels, telecine apparatus, studios and control rooms, a television system requires a number of other mechanical and electrical aids to production. Some of these are of special interest and are surveyed in Section 10.Section 11 discusses the standards of circuit performance which it has been found both desirable and practicable to ask the manufacturer to meet in designing his apparatus.The paper is written largely from the standpoint of the user, but not, it is hoped, without some sympathy for the problems of the designer. However, several supporting papers have been contributed by designers, so that the complete series should present a comprehensive picture.

DOI:10.1049/pi-3a.1952.0008

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The paper outlines the more important duties of, and the problems confronting, a present-day television producer in Great Britain, and it goes on to deal with the planning stage of a production, camera technique, the fundamentals of lighting and the basic rules of cutting.In a Section on planning the layout, details are given of an actual production. Subsequent Sections are devoted to the requirements of the television camera, the functions of the control room and telecine equipment, aids to production and sound-equipment considerations. Finally, there is a Section concerning the quality of the picture.

DOI:10.1049/pi-3a.1952.0009

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The problems of camera design are reviewed as affected primarily by tube characteristics.The most important data on the latter are collected in a Figure, which shows the transfer characteristics and operating points for the principal types of camera tube and corresponding data for photographic film.The principal features of current camera designs are tabulated.

DOI:10.1049/pi-3a.1952.0010

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The results of an attempt to scale down a high-velocity scanning tube of the Super-Emitron type, without loss of sensitivity, is described.The pick-up tube so constructed has a performance superior to that of its predecessor and is about two or three times more sensitive. The superiority is due to increased mosaic storage, which reduces the shading signal but increases the picture lag. This is unnoticeable, except for very rapidly moving objects. The tonal gradation of the picture which the tube produces is satisfactory when viewed on modern cathode-ray tubes.

DOI:10.1049/pi-3a.1952.0011

出版商:IEE    

年代:1952

数据来源: IET

摘要:

Features of motion-picture film reproduction by the medium of television are considered, and an explanation is given of the continuous-motion flying-spot system. The methods adopted to overcome particular problems are analysed, and the development of special facilities, both mechanical and electrical, are described, including the mechanical filter system, film-shrink compensation, and negative film reproduction.In the main, the description is that of a 35-mm channel, but mention is also made of the 16-mm film and the reproduction of lantern slides.

DOI:10.1049/pi-3a.1952.0012

出版商:IEE    

年代:1952

数据来源: IET

DOI:10.1049/pi-3a.1952.0013

出版商:IEE    

年代:1952

数据来源: IET

摘要:

The object of the paper is to outline briefly the design and performance features of lighting equipment used in television studios. Almost all the lighting equipment, together with the appropriate optical and electrical accessories as used to-day, is the result of considerable development over a number of years in film studios, which may be likened to television studios in so far as lighting requirements are concerned. This does not mean, however, that the similarity of lighting-equipment requirements, convenient as it is, will continue, and indeed there are several original pieces of equipment designed to satisfy the peculiar needs of television lighting.

DOI:10.1049/pi-3a.1952.0014

出版商:IEE    

年代:1952

数据来源: IET

摘要:

Various means of recording vision-frequency signals are considered. For high-definition television, it is concluded that the information must be recorded transversely to the direction of movement of the recording medium, and that the transverse movement must be achieved electrically. Photographic recording appears to be the only practicable method.The film may be moved at constant velocity or intermittently, and some known systems are classified under these headings and described with their advantages and disadvantages, particular attention being given to the two methods now in use by the B.B.C.Various factors affecting the performance of television-recording cameras are then discussed, such as picture joins, interlacing, loss of definition on movement, optical efficiency, film stability, emulsion pil-up, and spot-position modulation.A suitable arrangement of the vision-frequency equipment is dealt with, and the necessary electrical corrections are described. The factors governing the choice of a cathode-ray tube for recording purposes are discussed, while some possible improvements are indicated.The various transfer characteristics concerned have been measured, and the possibility of contrast correction is discussed, together with possible ways of improving the overall performance, such as highgamma recording. The conditions for making satisfactory positive prints direct from negative television pictures are stated.Some conclusions based on operating experience of continuous and intermittent systems are then given.

DOI:10.1049/pi-3a.1952.0015

出版商:IEE    

年代:1952

数据来源: IET