GB405227A - Improvements in or relating to facsimile transmission systems - Google Patents
Improvements in or relating to facsimile transmission systemsInfo
- Publication number
- GB405227A GB405227A GB27101/33A GB2710133A GB405227A GB 405227 A GB405227 A GB 405227A GB 27101/33 A GB27101/33 A GB 27101/33A GB 2710133 A GB2710133 A GB 2710133A GB 405227 A GB405227 A GB 405227A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- point
- brightness
- bridge
- condenser
- 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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/40—Picture signal circuits
- H04N1/409—Edge or detail enhancement; Noise or error suppression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/40—Picture signal circuits
- H04N1/403—Discrimination between the two tones in the picture signal of a two-tone original
Abstract
405,227. Copying-telegraphy. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.- (Assignees of Ellis, S. G. ; 878, Worthington Street, Springfield, Massachusetts, U.S.A.) Oct. 2, 1933, No. 27101. Convention date, Sept. 30, 1932. [Classes 40 (iii) and 40 (v).] A transmitter is keyed by a potential corresponding to the difference between the average brightness of the object and the brightness of the elemental area being transmitted. Chopped light from the object is incident on a photoelectric cell 2, and the photoelectric current is applied through rectifiers 6 to a point 8 on a bridge circuit. The arm between the point 8 and a lead 11 to the grid of a valve 13 comprises a condenser 30 and resistance in parallel and has a time constant of several seconds. The other arm from the point 8 comprises a condenser 31 and resistance with a time constant equal to one or two periods of the chopping frequency. The bridge is thus balanced under steady conditions and the valve 13 is conducting, but on abrupt change of brightness the bridge is unbalanced and the valve is blocked.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US635522A US1977380A (en) | 1932-09-30 | 1932-09-30 | High speed keyer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB405227A true GB405227A (en) | 1934-02-01 |
Family
ID=24548127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB27101/33A Expired GB405227A (en) | 1932-09-30 | 1933-10-02 | Improvements in or relating to facsimile transmission systems |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US1977380A (en) |
| DE (1) | DE640741C (en) |
| FR (1) | FR762226A (en) |
| GB (1) | GB405227A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2477307A (en) * | 1946-11-09 | 1949-07-26 | Mackta Leo | Combined x-ray and fluoroscopic apparatus |
-
1932
- 1932-09-30 US US635522A patent/US1977380A/en not_active Expired - Lifetime
-
1933
- 1933-09-30 FR FR762226D patent/FR762226A/en not_active Expired
- 1933-09-30 DE DEW92760D patent/DE640741C/en not_active Expired
- 1933-10-02 GB GB27101/33A patent/GB405227A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE640741C (en) | 1937-01-11 |
| FR762226A (en) | 1934-04-07 |
| US1977380A (en) | 1934-10-16 |
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