GB477253A - Improvements in or relating to television and like transmitters - Google Patents

Abstract

477,253. Automatic control systems. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. May 13, 1937, No. 13564. Convention date, May 13, 1936. [Class 38 (iv)] [Also in Group XL] The output of a television iconoscope transmitter contains disturbing signals producing unwanted variations in the intensity of the received picture. Compensating signals for individual areas of the object are derived from the disturbing signals produced in the individual areas and are added to the output signals. The object 14, Fig. 1, is imaged on the iconoscope screen 11 and on a bank of cells 16. The output from the iconoscope is applied over MS to a monitor receiver 17 whose reconstituted image is projected onto a bank of cells 19. The currents in corresponding cells of the two banks 16, 19 are compared and a signal proportional to the difference is derived at VA, applied to ZS to develop a correcting signal which is mixed with the picture signals at MS. Each pair of corresponding cells 20, 21, Fig. 2, is associated with one electrode of a bank 27 ... 31 in a cathode-ray tube. The electrodes 27 ... 31 are scanned in synchronism with the scanning of the original object to produce a current in resistance 33 proportional to the difference in current between corresponding cells of the two banks 16, 19. This current is amplified at 34 and mixed with the picture signal from the iconoscope screen 11. The signal to be transmitted is taken from HS, Fig. 1.