The history of television, from the earliest impractical notions to the commercial success of the new medium, comprises three distinct periods, namely: the period of speculation (c. 1877 to c. 1925); the period of low-definition television broadcasts (c. 1926 to c. 1933); and the period of high-definition television broadcasts (1936 to date). This chapter presents the life and works of John Logie Baird in the development of low-definition colour television.

Electric and Musical Industries Ltd (EMI) was formed in 1931 to acquire the ownership of the Gramophone Company Limited (sometimes known as HMV after the company's His Master's Voice records) and the Columbia Graphophone Company Limited. The research groups of the two companies were merged. Previously HMV (in which RCA had a financial interest) had demonstrated in January 1931 a mechanical multi-zone television system, operating on 150 lines per picture, based on the use of cine film as the source of the televised images. Following the merger, EMI's directors agreed that HMV's television development effort should continue to be an item of the new company's R&D programme. One of the first questions that had to be tackled was whether this work should proceed on mechanical or electronic lines. Mechanical scanners had the advantage that they had been made successfully, whereas electronic scanners were still in the development phase. On the other hand, electronic scanning had many potential advantages for high-definition television.

On 27 August 1940. CBS. using its experimental television station in New York, broadcast colour television pictures for the first time. A private test of CBS's system was given the following day to the FCC's chairman. J.L. Fly, and some of his staff Fly seems to have been impressed and stated 'that if we can start television off as a colour proposition, instead of a black and white show, it will have a greater acceptance with the public'. CBS claimed that colour television was capable of being accommodated in a 6 MHz channel and that 'existing receivers need not suffer radical changes to adapt them to three colours instead of mere black and white'. The FCC representatives were quite excited by the test, although they were concerned that the method could only work with film. But soon CBS was able to adopt a new camera tube, the orthicon, to its colour system, thereby providing a direct pick-up capability.

The accomplishment of a compatible color television system within a 6 MHz bandwidth is a tribute to the skill and ingenuity of the electronics industry. The proposed color television signal specifications produce a reasonably satisfactory picture with a good overall picture quality. The quality of the picture is not appreciably marred by such defects as misregistration, line crawl, jitter or unduly prominent dot structure. The picture is sufficiently bright to permit a satisfactory contrast range under favourable ambient light and is capable of being viewed in the home without objectionable flicker. Color pictures can be transmitted satisfactorily over existing inter-city relay facilities and improvements in inter-city relay facilities may be reasonably anticipated.

On the day, 17 December 1953, the Federal Communications Commission approved the NTSC's compatible colour television standards, the National Broadcasting Company commenced to broadcast colour television programmes on its entire television network. This historic occasion was followed almost immediately by many more colour 'firsts' for the NBC.

Mention has been made in an earlier chapter to the genesis of RCA's camera tube the iconoscope and the independently developed, but similar, camera tube - the emitron - of EMI. The merits of these tubes led to the growth of high-definition television in the UK, the USA and elsewhere, though they were not ideal and suffered from a number of defects.

This article discusses the development of colour television.

The color picture signal shall correspond to a luminance (brightness) component transmitted as amplitude modulation of the picture carrier and as a simultaneous pair of chrominance (coloring) components transmitted as the amplitude modulation sidebands of a pair of suppressed sub-carriers in quadrature having the common frequency relative to the picture carrier of +3.579545 [MHz] +/- 0.0003 per cent with a maximum rate of change not to exceed 1/10 cycle per sec per sec.