Improvements in or relating to television transmission or the transmission of images

摘要

487,240. Television transmitters. RADIOAKT.-GES. D. S. LOEWE. Dec. 16, 1936, No. 34577. Convention date, Dec. 16, 1935. [Class 40 (iii)] Light from the subject 5 is so automatically attenuated that the range of fluctuation of the mean light intensity is reduced electro-optically. A Kerr cell, crystal or similar light valve 11 is in the path of the light and is controlled by - currents from a photo-electric cell 9 on which the subject is projected simultaneously with the projection on the transmitting cell 1. Alternatively, a controlling current, dependent on the intensity of the image, is obtained from the amplifier 4 by a circuit of the kind used for volume control in wireless, Fig. 2 (not shown). The controlling current is also used to shift the mean value of the signalling currents prior to, or simultaneously with, the modulation of a carrier. When using storing-electrode transmitting tubes, the controlling current also so regulates the scanning light or electrons that photo-electric charges are always compensated or removed. The apparatus may be used in conjunction with that described in Specification 486,896. Specification 404,020 also is referred to.