GB428852A - Improvements in or relating to television and the transmission of pictures with sounds appropriate thereto - Google Patents

Abstract

428,852. Television. ELECTRIC & MUSICAL INDUSTRIES, Ltd., Blyth Road, Hayes, Middlesex, BROWNE, C. O., 29, Monks Drive, West Acton, London, and HARDWICK, J., 66, Drayton Gardens, West Drayton, Middlesex. Aug. 14, 1933, No. 22720. [Class 40 (iii)] In a film television system the signals are derived from a kinema film having an " intensity con. trast " substantially less than 1 : 8 which represents the intensity contrast of normally developed films. The object or scene may be photographed on a film which is treated to produce a negative with an " intensity contrast " considerably greater than unity and preparing from the negative a positive with a lower " intensity contrast " than the negative and employing the positive for transmission. At the receiver means are incorporated for reproducing the film with a higher " intensity contrast " than that transmitted, and when the signals are applied to a cathoderay tube the latter may be designed, in conjunction with the voltages applied to its electrodes, to effect the appropriate increase in the " intensity contrast " in the picture reproduced. A valve working from a point 1 on its curved characteristic, may precede the cathode-ray tube when the latter does not sufficiently increase the " intensity contrast " of the reproduced picture. When the receiving light-source is a Neon tube the " intensity contrast " may be increased by a valve operated as indicated in the Figure. The direct and lowfrequency components of the picture signals may be reinserted, if necessary, in the manner described in Specification 422,906. When the picture has a sound accompaniment, the picture and sound signals are transmitted with an effective " intensity contrast " of substantially unity and at the receiver the " intensity contrast " of the picture signals is increased whilst that of the sound signals is substantially not changed.