Improvements in or relating to sound recording
Номер патента: GB390839A
Опубликовано: 10-04-1933
Автор(ы):
Принадлежит: Bell Telephone Laboratories Inc
Опубликовано: 10-04-1933
Автор(ы):
Принадлежит: Bell Telephone Laboratories Inc
Реферат: 390,839. Valve amplifying circuits. KEITH, C. R., 4, Arcade House, Finchley Road, London, ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadwav, New York, U.S.A., and WESTERN ELECTRIC CO., Ltd., Bush House, Aldwych, London.- (Bell Telephone Laboratories, Inc. ; 463, West Street, New York, U.S.A.) Oct. 10, 1931, Nos. 28202/31 and 10160/32. [Class 40 (v).] In recording sound on a film by a modulated light beam, wherein a part of the beam is deflected on to a light sensitive device connected with a monitoring telephone and with other means for facilitating adjustment of the recording apparatus, the light sensitive device 7 is connected in a circuit which may be regarded as a Wheatstone bridge, one arm comprising the primary 43 of a trans. former, for actuating a speaker connected at 49, an amplifier 42, a grid biasing resistance 44, the remaining arms comprising part of a potentiometer 46, the resistance 45, and the other part of the potentiometer 46 respectively. One diagonal of the bridge comprises the battery 40 for the device 7, which battery is connected to the adjustable connection 47 of the potentiometer 46, and the other diagonal includes a meter 48 which may read microamps or milliamps as required. The connection 47 may be adjusted so that when the device 7 is not illuminated the meter 48 reads zero, and the values of the resistances in the bridge may be chosen so that the meter reading will be approximately proportional to the illumination of the device. A telephone headset 50 may be applied in a branch circuit between the amplifier and the negative of the battery 40, which circuit also includes a condenser 51 and a variable resistance 52. Minor modifications of the circuit and values for the resistances therein are given.
Improvements in or relating to processes of sound recording
Номер патента: GB490843A. Автор: . Владелец: KLANGFILM GmbH. Дата публикации: 1938-08-17.