GB360898A - Improvements in and relating to sound reproducing apparatus - Google Patents
Improvements in and relating to sound reproducing apparatusInfo
- Publication number
- GB360898A GB360898A GB2404730A GB2404730A GB360898A GB 360898 A GB360898 A GB 360898A GB 2404730 A GB2404730 A GB 2404730A GB 2404730 A GB2404730 A GB 2404730A GB 360898 A GB360898 A GB 360898A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- sound
- cell
- auxiliary
- sound track
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
360,898. Optical sound-reproducing apparatus. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London, COCKE, K. J. R., 46, Dale Street, and EADE, S. R., 14, Laughton Road, Paddox Delivery, both in Rugby. Aug. 11, 1930, No. 24047. [Class 40 (ii).] Means for eliminating hum when the light source in optical sound-reproducing apparatus is fed with alternating current, comprises an auxiliary light - sensitive cell which is connected in circuit so that the current impulses therefrom are in opposition to those from the main cell. A beam of light from the source 1 is directed by an optical system 2 on to the film 3 and thence to a light-sensitive cell 4. Light from the source 1 also falls on an auxiliary light-sensitive cell 5 through an adjustable shutter 6. The cells 4, 5 are connected in opposition as shown in Fig. 2, in which 8, 9 are output impedances and 10 the leads to the amplifier. In an alternative arrangement, the auxiliary cell may receive light from a separate lamp the light from which fluctuates in phase with that of the sound-reproducing lamp. In a further modification, an optical system may be used to cause the light falling on the auxiliary cell to pass through the sound track as a wide beam, so that it is unaffected by the modulation of the sound track but is proportional to the mean density of the sound track, to make the hum-neutralizing means independent of the mean density of the sound track.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2404730A GB360898A (en) | 1930-08-11 | 1930-08-11 | Improvements in and relating to sound reproducing apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2404730A GB360898A (en) | 1930-08-11 | 1930-08-11 | Improvements in and relating to sound reproducing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB360898A true GB360898A (en) | 1931-11-11 |
Family
ID=10205530
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2404730A Expired GB360898A (en) | 1930-08-11 | 1930-08-11 | Improvements in and relating to sound reproducing apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB360898A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE742170C (en) * | 1935-11-19 | 1943-11-24 | Zeiss Ikon Ag | Circuit for the coupling of photocells working in push-pull mode to an optical sound reproduction amplifier |
-
1930
- 1930-08-11 GB GB2404730A patent/GB360898A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE742170C (en) * | 1935-11-19 | 1943-11-24 | Zeiss Ikon Ag | Circuit for the coupling of photocells working in push-pull mode to an optical sound reproduction amplifier |
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