GB417644A - Improvements in or relating to recording sounds - Google Patents

Abstract

417,644. Recording and reproducing sound. SOC. RECHERCHE INDUSTRIELLE FRANCAISE (R.I.F.) SOC. D'ETUDES POUR L'EXPLOITATION DES BREVETS NUBLAT, 5, Rue GalilÚe, Paris. March 29, 1933, No. 23462/34. Convention date, March 31, 1932. Divided out of 417,597. [Class 40 (ii).] In recording sound by the removal, by means of a vibrating cutter, of a strip of constant width from an opaque layer covering a transparent film, the recording is supervised by reproducing the sound, immediately after recording, by means of a photo-electric system arranged adjacent to the point where the cutter operates. As shown, the film support 3 is apertured at 7, close to the recording tool 4, to allow the passage of a light beam transmitted from a lamp 9 by an optical system 10 through the film to a photo-electric cell 11, whereby reproduction is effected. The optical system may embody a fine slit, an image of which is projected in appropriate position on the sound track, as described in Specification 417,597. After a record has thus been made, the recording device 4, 12 may be moved transversely, so as to produce a second sound trace on the film, the cutter being actuated in this case by currents derived photo-electrically from the first trace, using the device 9, 10, 11. The amplifier employed to transmit the photo-electric currents to the mechanical recorder may be such that the higher frequencies are emphasized. Further, the second recording may be made with the film travelling at a reduced speed.