US1849818A - Picture transmission - Google Patents

Picture transmission Download PDF

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Publication number
US1849818A
US1849818A US483033A US48303330A US1849818A US 1849818 A US1849818 A US 1849818A US 483033 A US483033 A US 483033A US 48303330 A US48303330 A US 48303330A US 1849818 A US1849818 A US 1849818A
Authority
US
United States
Prior art keywords
line
light
picture
scanning
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 - Lifetime
Application number
US483033A
Other languages
English (en)
Inventor
Alda V Bedford
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.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US483033A priority Critical patent/US1849818A/en
Priority to GB26187/31A priority patent/GB363979A/en
Priority to FR723018D priority patent/FR723018A/fr
Priority to DEI42621D priority patent/DE601114C/de
Application granted granted Critical
Publication of US1849818A publication Critical patent/US1849818A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H04N5/16—Circuitry for reinsertion of DC and slowly varying components of signal; Circuitry for preservation of black or white level
    • H04N5/165—Circuitry for reinsertion of DC and slowly varying components of signal; Circuitry for preservation of black or white level to maintain the black level constant

Definitions

  • My invention relates to the transmission of pictures and particularly to the transmis sion of moving pictures or to television.
  • One of the dificulties encountered in pres- 5 ent television systems is that of obtaining faithful amplification of the transmitted impulses, over the wide range in frequency of such impulses heretofore found necessary.
  • the lowest frequency which the amplifier should be able to handle with fidelity is that which corresponds to the transmission of a picture or view in which the upper half is light and the lower half is dark (or vice versa), the scanning being horizontal.
  • the scanning being horizontal.
  • the minimum frequency which must be amplified such as with a picture which is half light and half dark as described above is raised from the number of pictures per second to the number of scanned lines per second.
  • the minimum frequency which the amplifier must handle is raised from 20 to 1200 cycles per second.
  • I scan the object whose image is to be transmitted and produce impulses corresponding to the 40 shade variations in each line in the usual and well known manner.
  • the light areas and dark areas scanned in a single line will not total the same but the one or the other will predominate, the positive and negative values of the impulses due to the light and dark areas likewise predominating the one over the other.
  • Fig. 1 I have shown the scannin device of a well known form comprising't e disc lOhaving a spiral roll of holes 11 therein connected to be driven by the'motor 12- and the photoelectric cell 13 for receiving light reflected from the object being scanned.
  • a contactor-device comprising the rotatable arm 16- adapted successively to sweep over the long segment 17 and the two short segments 18 and 19. Arm 16 is rotated in synchronism with the scanning disc 10 being arranged to make one complete rotation for each scanning line.
  • the arm 16 connected by the shaft 20 with the shaft of the disc 10 through the gearing 21. It will be understood that the scan- 'ning mechanism illustrated is merely representative of any suitable scanning mechanism which may be connected in any desired manner with the contactor device 15.
  • the signal impulses produced by the photoelectric'cell 13 are amplified by the electron discharge amplifier 23 whose output circuit connects through a portion of battery 24 with the long segment 17 of the contactor 15.
  • Contact arm 16 connects throu h condenser 25 with the grid of electron disc arge amplifier 26 whose plate-circuit leads through condenser 27 tothe output circuit 28.
  • the impulses in this circuit may be transmitted to adistant receiving station by radio, wire line or any other suitable'means.
  • the signals received from,the photoelectric cell are in part further amplified by the thermionic amplifier 30 whose grid connects with the battery 24'and whose plate connects with battery 31-through the variable resistance 32.
  • the adjustable contact 33 of this resistance connects through resistance 34 with the'condenser 35 whereby the condenser-is charged to a level dependent upon the drop in potential. across that part of resistance 32 between the adjustable Contact 33 and battery 31.
  • Condenser 35 is shown shunted by the resistance 36 which controls the time constant of the condenser.
  • Battery 37 is connected between contactor segment 18 and that side of the condenser 35 which connects with the resist ance 34. Segment 19 of the contactor connects directly with the opposite side of the condenser.
  • the long segment. 17 of the contactor deviceis of such-a length that the arm 16- remains in contact there with during each scanning line and signal inipulses. are transmitted during that time in the usual manner.
  • the varging current flow in the plate circuit of ampli er 30 due to the varying lightand dark portionsof the line produce a corresponding charge in the condenser 35.
  • the condenser during such scanning being considered a negative storage;
  • the resulting voltage of condenser 35 is compared to that of battery. 37 If the two voltages happen to be equal, 3.
  • the auxiliary signal is such as to cause the amplifier system essentially to recover its equilibrium after its unbalanced condition resulting from any lack of equality of dark and light signals from each line.-
  • the distant receiver illumination of the recording light during the time of the auxiliary signal is not desired since it forms no part of the picture-and therefore should preferably be masked oflby a suitable screen or barrier placed along either the right 'or ture.
  • This light as far asthe received picture is concerned is superfluous and existssolely because of the apparatus for keeping the picture in balance.
  • the above described system I have accordin ly called the scrap pile border system. ince a lamp in the plate circuit of anyA. C. ampl bomb tends to supply a constant value of average light, whenever anyline of the picture has other than this avdrage amount of light, the difference either positive or negative issupplied by the scrap pile.
  • Fig. 2 I have shown a modified form of my invention in which the amplifiers 23 and are coupled not for the amplification of direct current but for a low frequency alternating current since it is desired that they handle the picture fregpency;
  • the C. component of the potential applied to segment 18 is adapted, to be manually controlled by the use of the adjustable resistance 40, I may, however, employ an auxiliary photoelectric cell to control this potential in accordance, with the general illumination of the picture.
  • the contactor 15 may employ a 'contactor having a greater number of contacts.
  • the number of contacts may be multiplied by ten whereby the speed at which the arm must rotate would be reduced to one tenth 0t that necessary when but three contactors are employed.
  • the method which comprises scanning line by line the object whose image is to be transmitted,-producing impulses during said scanning in accordance with the shade variations in .each line and producing an auxiliary impulse at the end of each line having-a value approximately proportional and opposite in sign to the average signal of that line.
  • the method which comprises scanning line by line the object whose image is to be transmitted, pro- 8t 3.
  • the method ducing positive and negative impulses in accordance with the light and dark areas in each line and producing anauxiliary impulse at the end of each line in accordance with any inequality in the light and dark areas of said ne. 4.
  • the method which comprises sc nning line by line the object whose image is to be transmitted, producing impulses during said scanning in accordance with the shade variations in each line, storingv energy during the -scanning of each line in accordance with the predominence of the light portions thereof and producing an auxiliary impulse at the end of each line substantially proportional to the stored energy.
  • Television transmission apparatus comprising means for scanning .the object whose image is to be transmitted, means for producing impulses in accordance with the shade variations in each scanning line, and means for producing an auxiliary impulse at the end of each line having a magnitude corresponding to the predominance of light or dark portions in said line.
  • Television transmission apparatus comprising means for scanning the object whose image is to be transmitted, means for producing impulses in accordance with the light and dark portions in each scanning line, and means for producing an auxiliary impulse at the end of each-line substantially proportional to any inequality in the impulses due to the light impulses and the dark impulses.
  • prising means forscanning the Object whose image is to be transmltte' 4 ducmg impulses in accordance with the h ht and dark portionsin e'ach'scanning line, and means for producing a corrective impulse at: the end. of each line comprising a condenser, 7

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
  • Tests Of Electric Status Of Batteries (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • Secondary Cells (AREA)
US483033A 1930-09-19 1930-09-19 Picture transmission Expired - Lifetime US1849818A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US483033A US1849818A (en) 1930-09-19 1930-09-19 Picture transmission
GB26187/31A GB363979A (en) 1930-09-19 1931-09-18 Improvements relating to the electrical transmission of pictures
FR723018D FR723018A (fr) 1930-09-19 1931-09-19 Perfectionnements aux systèmes de transmission d'images et plus particulièrement à leurs amplificateurs
DEI42621D DE601114C (de) 1930-09-19 1931-09-19 UEbertragungsverfahren fuer die Bildtelegraphie und das Fernsehen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US483033A US1849818A (en) 1930-09-19 1930-09-19 Picture transmission

Publications (1)

Publication Number Publication Date
US1849818A true US1849818A (en) 1932-03-15

Family

ID=23918370

Family Applications (1)

Application Number Title Priority Date Filing Date
US483033A Expired - Lifetime US1849818A (en) 1930-09-19 1930-09-19 Picture transmission

Country Status (4)

Country Link
US (1) US1849818A (fr)
DE (1) DE601114C (fr)
FR (1) FR723018A (fr)
GB (1) GB363979A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2592308A (en) * 1948-09-01 1952-04-08 Bell Telephone Labor Inc Nonlinear pulse code modulation system

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE401713A (fr) * 1933-02-28
GB472980A (en) * 1936-04-02 1937-10-04 Baird Television Ltd Improvements in or relating to television and like systems
DE741785C (de) * 1937-11-29 1943-11-17 Fernseh Gmbh Verfahren zur UEbertragung von Fernsehbildern, deren Helligkeitsumfang geringer ist als der zur Verfuegung stehende Modulationsbereich
DE757149C (de) * 1938-08-17 1954-03-08 Fernseh Gmbh Verfahren zur Einfuehrung eines festen Schwarzwertes bei der UEber-tragung von Negativbildern, -filmen bei Fernsehuebertragungsanlagen
US5302476A (en) * 1990-12-03 1994-04-12 Globe-Union Inc. High performance positive electrode for a lead-acid battery
KR100828275B1 (ko) 2003-10-21 2008-05-07 존슨 컨트롤스 테크놀러지 컴퍼니 배터리 페이스트 물질 및 방법
US7011805B2 (en) 2004-03-19 2006-03-14 Ges Technologies Ip Gmbh Production of tetrabasic lead sulfate from solid state reactions for the preparation of active plates to be used in lead-acid batteries

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2592308A (en) * 1948-09-01 1952-04-08 Bell Telephone Labor Inc Nonlinear pulse code modulation system

Also Published As

Publication number Publication date
GB363979A (en) 1931-12-31
DE601114C (de) 1934-08-08
FR723018A (fr) 1932-04-01

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