US1770497A - Method and arrangement for amplifying photoelectric currents - Google Patents

Method and arrangement for amplifying photoelectric currents Download PDF

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Publication number
US1770497A
US1770497A US266153A US26615328A US1770497A US 1770497 A US1770497 A US 1770497A US 266153 A US266153 A US 266153A US 26615328 A US26615328 A US 26615328A US 1770497 A US1770497 A US 1770497A
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United States
Prior art keywords
light
picture
cell
cells
photo
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Expired - Lifetime
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US266153A
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English (en)
Inventor
Schroter Fritz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DRAHTLOSE TELEGRAPHIE MBH
GESELLSCHAFT fur DRAHTLOSE TELEGRAPHIE M B H HALLESCHES
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DRAHTLOSE TELEGRAPHIE MBH
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Publication of US1770497A publication Critical patent/US1770497A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/30—Transforming light or analogous information into electric information

Definitions

  • the carrier is then further amplified and may be sent over the transmission line for wire work or may be arranged to control a wireless transmitter.
  • the carrier frequency is obtained by applying the alternating current potential (mostly conjointly with a constant direct current potential) directly as the suction or anode potential of the photoelectric cell which is exposed to the light variations incidental to exploration of the picture and (3).
  • the carrier frequency results through purely optical means by the rapid interruption ofth-e picture exploring light, for example, by means of a rapidly revolving disk with marginal holes.
  • the present invention discloses ways and means whereby direct positive recording at the receiver is made feasible also in the case of the two methods numbered (2) and (3), especially with the latter, even with such means as have before been mentioned, and without an additional reversin device between the photoelectric cell and the transmitter, comprising the rectifier tube in conjunction with another tone modulator of the radio or wire transmitter and controlled in the proper sense by the rectified potential.
  • the purpose of such a reversing device according to the present invention is attainable in a simpler manner by using the carrier frequency, produced by means ofa disk with marginal or peripheral perforations or suction alternating current potential at the photoelectric cell, itself for the modulation of thetransmitter.
  • the invention consists in that the action of the light upon the exploring photoelectric cell 'ation of a second is compensated by the irra hotoelectric cell with a correspondingly adjustableted luminous flux of constant, efi'ective value.
  • This luminous flux for exam 1e, may
  • audio frequency modulation of the transmitter oscillation or over thetransmission line occurs only w en changing to dark in the outgoing picture, and the receiver blackening upon the supply of current records directly a ositive image of the outgoing picture (5 ackening being broadly understood as the production of a dark picture tone).
  • Figs. 1 and 2 illustrate by wa of example embodiments incor orating the asic idea of the present invention, though the scheme is useful not only for picture transmission, but also forother purposes in which light variations are to be recorded b photoelectric cells, and where for the contro of the indicator or receiver similar conditions are present as with a: picture recorder giving a positive image the rays from-lens'3, 5 and 9 represent the exploring and compensating photoelectric cells, respectively, which are preferably placed to form a bridge arrangement, 6 i'sa mirror or reflector partly shifted into the path of the re s from lamp 1 for shunting or diverting a efinite quantity of light upon another deflection mirror 8 so arranged as to direct the diverted light upon the photoelectric cell 9, .10 is the direct current potential source for the hotoelectric current, 11 and 12 represent additional variable direct current potential sources for compensating differences in sensitiveness or characteristics of the photoelectric cells 5 and 9 13 and 14; are the resistance arms of the bridge arrangement, 15'and 16 are diagonal junction o
  • assage is a variable source of a negative grid bias-- 1 in tential for the am lifier 17.
  • the carrier frequency is produced by insertin in the trajectory of the rays the periphera row or circle of oles of a rapidly rotatin disk 7 which is arranged to interrupt the lig t from source'l at the desired frequency.
  • the carrier fretqluency is obtained by providing'in series wi the direct current potential source 10 an alternat current potential source 19 of any s.ui,t-' ab e frequency and value.
  • both arrangements are identical in o ration.
  • another arrangement for instance, an iris diaphragm, a y wedge cone or 'the like may be used.
  • the efiective quantiy of light which is caused to impinge upon the cell 9 is so balanced-that -in the presence of'the brightest shade occurring in the picture 4, no alternating current gtential or only a very small one, will tween points 15 and 16 of the bridge arrangement, and whatever remains can be rendered harmless by suitable-stopper means.
  • a system for amplifying varying electric current impulses produced by changes in light intensity a plurality of photo cells, a record to be transmitted, a light source, means for influencing one of said cells by light from said source varied in intensity in accordance with the variations in light and shade in said record, means for influencing the other of said cells directly from said light source, whereby said photo cells are subjected to equal light intensities and balanced during the light portions in said rec 0rd, an amplifier associated with said photo cells, means for impressing an alternating current frequency upon said cells, means for modulating said frequency in accordance with variations in light and shade reaching the first of said photo cells and means for applying said frequency to said amplifier during periods of unequal light intensities upon each of said photo cells.
  • a pair of photo cells each arranged to form one leg of a bridge structure, means for subjecting one of said cells to varying light intensities in proportion to the intensities of light and shade in a record to be transmitted, means for subjecting the other to a constant illumination whereby for highlights in said record said cells are balanced, means for introducing an alternating current frequency in said bridge diagonal ofsaid bridge structure, and means unbalanced condition in said bridge structure due to unequal light intenternating current frequency modulated in acsaid light intensities to said amplifier.
  • a pair of photo cells means for subjecting one of modulated alternating current "said cells to variations in light intensity in cells being connected bridge formation and arranged to each form one leg of said bridge structure, whereby forco-nditions of maximum light intensity reaching the first of said photo cells said bridge structure is substantially balanced, means provided in the legs of said bridge structure includhig said cells for compensating for differences in sensitiveness of said cells, means for introducing an alternating current frequency upon said bridge structure, means provided by varying light intensities reaching the first of said photo cells for modulating said alternating current frequency, an amplifier, and means provided by an unbalanced condition in said bridge structure for applying a modulate'd alternating current frequency input circuit of said amplifier.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Facsimile Scanning Arrangements (AREA)
US266153A 1927-03-26 1928-03-31 Method and arrangement for amplifying photoelectric currents Expired - Lifetime US1770497A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE287844X 1927-03-26

Publications (1)

Publication Number Publication Date
US1770497A true US1770497A (en) 1930-07-15

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ID=6059390

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US266153A Expired - Lifetime US1770497A (en) 1927-03-26 1928-03-31 Method and arrangement for amplifying photoelectric currents

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US (1) US1770497A (en)van)
FR (1) FR651051A (en)van)
GB (1) GB287844A (en)van)
NL (1) NL23519C (en)van)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2531951A (en) * 1944-08-02 1950-11-28 W I Westervelt Interference reducing method of secret communication
US2721275A (en) * 1935-02-21 1955-10-18 Albert M Jackson Method of and means for detecting aircraft
US3014135A (en) * 1957-03-04 1961-12-19 Hewlett Packard Co Direct current amplifier and modulator therefor
US3197643A (en) * 1960-12-30 1965-07-27 Ibm Electro-optical plane aligning apparatus
US3566135A (en) * 1967-12-11 1971-02-23 Comp Generale Electricite Optical calibrating device for objects of different heights

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721275A (en) * 1935-02-21 1955-10-18 Albert M Jackson Method of and means for detecting aircraft
US2531951A (en) * 1944-08-02 1950-11-28 W I Westervelt Interference reducing method of secret communication
US3014135A (en) * 1957-03-04 1961-12-19 Hewlett Packard Co Direct current amplifier and modulator therefor
US3197643A (en) * 1960-12-30 1965-07-27 Ibm Electro-optical plane aligning apparatus
US3566135A (en) * 1967-12-11 1971-02-23 Comp Generale Electricite Optical calibrating device for objects of different heights

Also Published As

Publication number Publication date
FR651051A (fr) 1929-02-14
NL23519C (en)van)
GB287844A (en) 1928-06-28

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