US1951781A - System for electrical transmission and reception of pictures, documents, and the like - Google Patents
System for electrical transmission and reception of pictures, documents, and the like Download PDFInfo
- Publication number
- US1951781A US1951781A US524094A US52409431A US1951781A US 1951781 A US1951781 A US 1951781A US 524094 A US524094 A US 524094A US 52409431 A US52409431 A US 52409431A US 1951781 A US1951781 A US 1951781A
- Authority
- US
- United States
- Prior art keywords
- circuit
- variations
- phenomenon
- current
- pictures
- 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 - Lifetime
Links
- 230000005540 biological transmission Effects 0.000 title description 3
- 230000000694 effects Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 4
- 230000001131 transforming effect Effects 0.000 description 4
- 230000010287 polarization Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/14—Picture signal circuitry for video frequency region
- H04N5/20—Circuitry for controlling amplitude response
- H04N5/202—Gamma control
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
- H03F1/33—Modifications of amplifiers to reduce non-linear distortion in discharge-tube amplifiers
Definitions
- My invention relates to devices for identically reproducing a phenomenon A, through intermediary steps B, C, D, etc.
- step B a phenomenon permitting to transform varia tions of current into luminous variations
- step D a phenomenon permitting to transform varia tions of current into luminous variations
- the object of my invention is to provide means through which certain of these laws can be acted upon in order to compensate for the deformations introduced by other ones.
- the photoelectric currents that correspond to the black portions of the document are exceedingly feeble and the differences between such currents for very dark portions are very small.
- the differences are very important between currents corresponding to light shades.
- the variation of the photoelectric current as a function of half tints is very different from a linear function.
- the shades of the original may be accurately reproduced by means of an apparatus transforming electric variations into luminous variations.
- I amplify the incoming current from the emitting photoelectric amplifier by means of two or more circuits having different characteristics and I provide means for subsequently detecting said current in different manners in each of these circuits.
- FIG. 1 is a diagrammatic view of an electric arrangement adapted to be used in connection with the above mentioned application.
- Figs. 2 and 3 are diagrammatic representations of the operation of the tubes by reference to the characteristic curves of the same.
- the incoming current is sent into transformer T, then amplified and detected by two separate circuits.
- the first one includes T1, T1, T1", and R and will be called circuit 1.
- the second one includes T2, T2, T2, and will be called circuit 2.
- the two circuits are connected together in Z and in the common circuit (or in another one coupled therewith) is located apparatus E, which serves to transform electric variations into luminous variations.
- the circuits located before the detecting tubes of each circuit 1 and 2 are arranged in such manner that the alternating amplitude applied to the detectors of circuit 1 may be adjustable and higher than that applied to the detectors of circuit 2.
- That difference of amplitude may be obtained for example, by using either an input transformer having several different terminals on its secondary (see the figure) or amplifying tubes having different characteristic or still a supplementary stage of amplification on one of the branches and so on.
- the detector or detectors (T1', T1") of circuit 1 on the grids of which is applied a great alternating amplitude are but little polarized.
- the low value of this polarization makes it possible by operating in the higher portion of the charicteristic, to block the amplifier when the alternating amplitude exceeds a certain value.
- the detectors of circuit 2 are normally polar- 1266. and the alternating amplitude applied to their grids is smaller than in circuit 1.
- a resistance R having suitable value inserted in the plate circuit of the detectors of circuit 1 makes it possible to regulate the relative action of the two detections of circuit 1 and 2 respectively.
- the example shown is but a particular type of application.
- This method of modifying the law of detection may be adapted to any other kinds of application for obtaining the best result from the effects received at the input end in order to have them produce at the output end an sheet which is correct with respect to the cause of the effects received at the input end.
- an arrangement comprising an apparatus for transform" ing variations of an electic current back into variations of the phenomenon to be reproduced two circuits connected in parallel to apparatus, an amplifying tube and a detecting tube in each circuit, the detecting tube of the first circuit being less polarized than that of the second circuit, means for feeding the electric current whose variations correspond to those of the original phenomenon to be reproduced to the grids of the above mentioned amplifying tubes, and means for causing the amplitude of the current fed to the amplifying tube of the first circuit to be greater than that of the current fed to the amplifying tube of the second circuit.
- an arrangement comprising an apparatus for transforming variations of an electric current back into variations of the phenomenon to be reproduced, two circuits connected in parallel to said apparatus, an amplifying tube and two detecting tubes in each circuit, the detecting tubes of the first circuit being less polarized than those of the second circuit, a transformer for feeding the electric current whose variations correspond to those of the original phenomenon to be reproduced to the grids of the above mentioned amplifying tubes, a plurality of terminals on the secondary of said transformer connected to the amplifying tubes of the two circuits in such manner that the amplitude of the current fed to the first circuit is greater than that of "he current fed to the second circuit.
- An arrangement accor to claim 1 further comprising a resistance inserted in the plate circuit of the detecting tube of one of the above named circuits for regulating the relative action of these two circuits on the apparatus for converting variations of the electric circuit into variations of the phenomenon to be reproduced.
- An arrangement according to claim 2 further characterized in the plates of the two detecting tubes of circuit are connected in parallel to the above named apparatus, and comprising a resistance insered between the plates of the detecting tubes of one circuit and said apparatus for regulating the combined action of the two circuits on said apparatus.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR606435X | 1930-03-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US1951781A true US1951781A (en) | 1934-03-20 |
Family
ID=8974672
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US524094A Expired - Lifetime US1951781A (en) | 1930-03-29 | 1931-03-20 | System for electrical transmission and reception of pictures, documents, and the like |
Country Status (3)
Country | Link |
---|---|
US (1) | US1951781A (de) |
DE (1) | DE606435C (de) |
FR (1) | FR708107A (de) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2887576A (en) * | 1954-11-10 | 1959-05-19 | Harmuth Henning | Electronic squaring circuit |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE887209C (de) * | 1937-06-19 | 1953-08-20 | Siemens Ag | Optische Steuereinrichtung mit Lichthahn fuer Bildtelegraphenempfaenger |
GB702321A (en) * | 1949-07-21 | 1954-01-13 | Emi Ltd | Improvements relating to non-linear electrical control circuits |
-
1930
- 1930-03-29 FR FR708107D patent/FR708107A/fr not_active Expired
- 1930-05-04 DE DE1930606435D patent/DE606435C/de not_active Expired
-
1931
- 1931-03-20 US US524094A patent/US1951781A/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2887576A (en) * | 1954-11-10 | 1959-05-19 | Harmuth Henning | Electronic squaring circuit |
Also Published As
Publication number | Publication date |
---|---|
DE606435C (de) | 1934-12-01 |
FR708107A (fr) | 1931-07-20 |
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