The specification and testing of television wire-broadcasting systems

In view of the continued growth of the wire broadcasting of sound programmes, attention has been given to the possibilities of the wire broadcasting of television programmes since the television service first commenced in 1936. The first licence for commercial operation of a television wire-broadcasting system was issued by the Post Office in the autumn of 1950 and four systems were in operation before the summer of 1951. These licences are issued subject to certain technical conditions and are accompanied by recommended standards of performance similar in scope to those which have for some years been associated with the licence agreements for the wire broadcasting of sound programmes. The main purpose of the paper is to describe and discuss the technical conditions and recommended standards of performance specified for television wire-broadcasting systems, and the methods of testing used to check whether the systems conform to the conditions and standards. Mention is made (with reference to more detailed accounts which have been published elsewhere) of some aspects of the history and development of wire broadcasting, to show the extent of its present and possible future use and to introduce the considerations which have been taken into account in drafting the conditions and the performance specification. The main features of a number of experimental or working systems are tabulated. Special features of these are discussed and results are given of tests made on four systems.