GB549076A - Improvements in or relating to facsimile signalling systems - Google Patents
Improvements in or relating to facsimile signalling systemsInfo
- Publication number
- GB549076A GB549076A GB968/41A GB96841A GB549076A GB 549076 A GB549076 A GB 549076A GB 968/41 A GB968/41 A GB 968/41A GB 96841 A GB96841 A GB 96841A GB 549076 A GB549076 A GB 549076A
- Authority
- GB
- United Kingdom
- Prior art keywords
- black
- scanning
- slit
- holes
- copy
- 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
- 230000011664 signaling Effects 0.000 title abstract 2
- 230000004048 modification Effects 0.000 abstract 1
- 238000012986 modification Methods 0.000 abstract 1
- 230000010349 pulsation Effects 0.000 abstract 1
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
- H04N1/23—Reproducing arrangements
-
- 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
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/029—Heads optically focused on only one picture element at a time
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Facsimile Scanning Arrangements (AREA)
- Facsimile Heads (AREA)
Abstract
549,076. Facsimile signalling systems ; photoelectric scanning. CREED & CO., Ltd., and MASON, F. P. Jan. 24, 1941, No. 968. [Class 40 (iii)] A photo-electric scanning system for a facsimile telegraph transmitter is so arranged that invariable " black" elements are sighted by a single photo-electric cell alternately with the black or white elements of the copy, so that a black element produces steady unidirectional potential which is not transmitted by the amplifier whereas a white element produces a pulsation which is transmitted by the amplifier. This increases the ratio of white to black signal, enabling the effective signal to be maintained at a more uniform level. In one arrangement, Figs. 1, 2, 3, light from a lamp 1 is directed by a lens 2 to a slit block 4 against the copy 3, and reflected light collected by a lens 5 is directed to a photoelectric cell 7 through a scanning disc 6 having a spiral set of holes, as described in Specification 543,023. According to the present invention, the slit in the block 4 is half closed by a thin strip 4a, the surface of which exposed to the light is made to correspond to the blackness of the " black" elements on the copy 3, the effective width of the slit being of the same size as the scanning holes in the disc 6 and the space between these holes. The surface of the block 4 itself is fully black. By this arrangement, reflections from the strip 4a are interposed between the reflections from the copy 3. In another arrangement, instead of a strip 4a in the slit block, an additional set of scanning holes are provided in the scanning disc 6, Fig. 7, this additional set being in a circle and in opposite phase to the scanning holes proper and being covered by an adjustable filter to produce the intermediate invariable "black" spots thrown on the cell. In a modification of this, the adjustable filter is provided in a second light beam thrown on the slit by means of separate lenses and a mirror. Specifications 332;318, [Class 40 (iii)], and 547,704 also are referred to.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB289554X | 1941-01-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB549076A true GB549076A (en) | 1942-11-05 |
Family
ID=10283897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB968/41A Expired GB549076A (en) | 1941-01-24 | 1941-01-24 | Improvements in or relating to facsimile signalling systems |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US2368369A (en) |
| BE (1) | BE469518A (en) |
| CH (1) | CH289554A (en) |
| FR (1) | FR930637A (en) |
| GB (1) | GB549076A (en) |
-
0
- BE BE469518D patent/BE469518A/xx unknown
-
1941
- 1941-01-24 GB GB968/41A patent/GB549076A/en not_active Expired
-
1942
- 1942-01-06 US US425714A patent/US2368369A/en not_active Expired - Lifetime
-
1946
- 1946-07-13 FR FR930637D patent/FR930637A/en not_active Expired
-
1947
- 1947-02-25 CH CH289554D patent/CH289554A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BE469518A (en) | |
| US2368369A (en) | 1945-01-30 |
| FR930637A (en) | 1948-01-30 |
| CH289554A (en) | 1953-03-15 |
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