Developments of Television

Editor’s Note

In a theatre in the West End of London on 20 March 1934, Nature reports here, shareholders of Baird Television Ltd. saw and heard the chairman address them from a studio at the Crystal Palace eight miles away. The feat relied on the a newly developed large cathode-ray oscilloscope, as well as high-quality photo-cells and amplifiers capable of processing signals over a wide frequency range. Transmissions from the Crystal Palace location could broadcast television signals to the whole of Greater London. The report notes that another demonstration is planned of a method reported earlier in Nature by which television images of topical events might be displayed on cinema screens and home receivers within only a few seconds of having happened.　　中文

AN application of science has enabled a chairman of a company to become a historic figure. At the annual general meeting of Baird Television, Ltd., held in a theatre in the west end of London on March 20, the shareholders heard and saw distinctly the chairman address them from a studio at the Crystal Palace, nearly eight miles distant. To the shareholders, and afterwards to representatives of the Press, the Baird Company arranged a programme of transmissions by radio from the Crystal Palace to enable the audience to see persons talking on various subjects, a cartoonist sketching at his easel, excerpts from popular films and “still” pictures. All these items were reproduced in the receiver with sufficient detail for an audience of more than a hundred persons to “look in”, although the receiver was devised for use in the home rather than a theatre. The success of these demonstrations is attributed to the state of perfection of the large cathode ray oscillographs made exclusively for the Baird Co. by the research staff of a British industrial concern, the excellence of the photoelectric cells in use at the transmitting end, and the construction of amplifiers which are capable of dealing without phase distortion with a range of frequencies from 25 to 1,000,000 cycles per second. The subject matter to be televised is divided up into 180 lines (or strips) corresponding to 24 times the definition obtainable with the old 30-line apparatus. Vision is being transmitted from a dipole aerial on a wave-length of 6.0 metres, and sound on 6.25 metres.　　中文

Judging from the demonstrations given last week, the Baird Company’s engineers have successfully overcome interference effects due to motors, lifts and other electro-magnetic disturbances met with at these short wave-lengths. A series of experiments have been carried out to ascertain the effective range of reception, as a result of which it is claimed that the Crystal Palace transmitting station can provide an ultra-short wave high definition television service for the whole of the Greater London area, which includes a population of about eight millions. Capt. A. G. D. West, who joined the board of the Baird Company last June to direct its technical development, is to be warmly congratulated on his achievement; and the Company on the first public demonstration of the broadcasting possibilities of high-definition television. We understand that a demonstration will shortly be given of the intermediate film-method, described by Major A. G. Church in Nature of September 30, 1933, by means of which televised images of topical events will be thrown on screens in cinema theatres as well as on home-receivers within a few seconds of their occurrence. Another series of experiments on a new system of “scanning” invented by Mr. Baird is nearing completion. These experiments aim at securing sufficient illumination in a studio to enable “crowd” scenes to be televised directly with detailed fidelity.　　中文

(133, 488-489; 1934)