Patent GB-297078-A (GB)
Title: Improvements in or relating to television systems
IPC: H04N5/84
Filed: 1928-03-19
Abstract: 297,078. Electrical Research Products, Inc., (Assignees of Hartley, R. V. L., and Ives, H. E.). Sept. 14, 1927, [Convention date]. Television of back-ground details is improved, and increased illumination is obtained, by taking a kinematograph film of the scene to be transmitted and causing the film to control the television signals, these processes being cor.ducted in a continuous train. In addition or alternatively a photographic process is interposed at the television receiving station. The picture signals may be accompanied by signals derived from a phonographic film. In the transmitting apparatus, Fig. 2, the film 99 passes from a spool 103 through (a) a kinematograph camera 101, in which its movement is intermittent. (b) A sound recording device 110, in which its movement is continuous ; this comprises a source of light 113, a lens system 114, 115, and a light-valve 111 controlled by the microphone currents. (c) Developing and fixing tanks 121, 122; washing and drying arrangements may also be included in the apparatus if desired. (d) A kinematographic projector 130 providing intermittent movement; light parses from a source 136 through optical systems 137, 138, through the film 99 while still wet, and through a scanning disc 155 to a light sensitive cell 160 which controls the outgoing television signals. (e) A transmitter 140 for phonographic signals; light passes from a source 143 through an optical system 144 and the phonographic record on the film 99 to a light sensitive cell 170 which controls the out-going phonographic signals. (f) A storage spool 180 or other means for for disposing of the film. The receiving apparatus (Fig. 3, not shown) is generally similar to the transmitting apparatus and comprises means for passing a film through (a) a television receiver of known type adapted to project the signalled picture on to the film. (b) A sound recorder similar to the apparatus 110 for projecting the signalled sound-record on to the same film. (c) Developing and fixing tanks. (d) A kinematograph projector of known type for throwing the picture on to a screen visible to an audience. (e) Phonographic, apparatus similar to that shown at 140 for controlling a loud-speaker, and (f) Means for storing or otherwise disposing of the film. The receiving apparatus may also comprise (right-hand side of Fig. 1, not shown) switching arrangements whereby the television, phonographic and synchronizing currents can be diverted from the photographic receiver just described and applied to a television receiver of the known type which comprises a bank of lamps adapted to be successively illuminated under the control of a rotary distributer, and to an associated loud-speaker. The phonographic and kinematographic records may alternatively be impreseed on different films. In cases where the television signals but not the phonographic signals are subjected to the delay involved in developing the film, means are provided for delaying the reproduction of the sound. These may comprise (a) a telegraphone having an endless wire on which the sound record is continuously impressed, the record being erased after reproduction; or (b) a phonograph record of the disc type associated with recording and reproducing styli (Fig. 4, not shown). In cases where the photographic process is used at the transmitter only, the distortion which occurs may be corrected by the use of an amplifier having a suitable characteristic.