US1786812A - Facsimile-transmission system - Google Patents

Facsimile-transmission system Download PDF

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Publication number
US1786812A
US1786812A US349956A US34995629A US1786812A US 1786812 A US1786812 A US 1786812A US 349956 A US349956 A US 349956A US 34995629 A US34995629 A US 34995629A US 1786812 A US1786812 A US 1786812A
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US
United States
Prior art keywords
film
scanning operation
picture
mirror
distant
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
US349956A
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English (en)
Inventor
Vladimir K Zworykin
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
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
Priority to US19314D priority Critical patent/USRE19314E/en
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US349956A priority patent/US1786812A/en
Priority to DE1930582929D priority patent/DE582929C/de
Priority to FR692302D priority patent/FR692302A/fr
Priority to BE368861D priority patent/BE368861A/xx
Application granted granted Critical
Publication of US1786812A publication Critical patent/US1786812A/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
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/36—Scanning of motion picture films, e.g. for telecine
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T24/00—Buckles, buttons, clasps, etc.
    • Y10T24/14—Bale and package ties, hose clamps
    • Y10T24/1457—Metal bands
    • Y10T24/1482—Ratchet and tool tightened band clamp

Definitions

  • My invention relates to facsimile-transmitting systems and it has particular relation to systems especially adapted for the reproduction, at a distance, of moving-picture films.
  • One of the most troublesome problems connected with television systems and with systems for transmitting pictures and the like is that of securing motional synchronism between a scanning device at the sending station and an equivalent device at the receiving station.
  • the difiiculty of synchronization is increased by reason of the fact that the film, at the transmitting station, must be caused to pass in front of the scanning device at the same rate of speed that it traverses an ordinary moving-picture projector.
  • an object of my invention to provide an improved facsimile-transmission system wherein synchronism between a scanning device at a sending station and an analogous device at a receiving station is automaticall maintained.
  • Another 0 'ect of my invention is to provide a facsimi e-transmission system particularly adapted for the reproduction, at a distance, of moving-picture films.
  • a motion picture film to travel at a fixed rate of speed between an oscillating mirror and a photoelectric cell.
  • Light from a fixed source is directed against themirror, and, after reflection therefrom, is focused to a fine point that moves from side to side of the moving film.
  • the vertical component of the scanning motion is accordingly, provided for by the motion of the film, while the horizontal com onent is taken care of by the mirror-oscillatlons.
  • I provide a Braun tube having a plurality of cathode-ray controlling devices mounted therein.
  • One of the controlling devices functions in accordance with the output from the photoelectric cell at the sending station and serves to impose variations upon the amplitude of the ra another of the controlling devices causes t e ray to move horizontally to synchronism with the oscillating mirror at the sending station; while still another controlling device periodically deflects the ra vertically at a speed equal to the linear a Vance of the film at the sending station.
  • Figure 1 of the drawing is a diagrammatic view of a facsimile-transmission system comprising a preferred embodiment of my invention
  • a Fig. 2 is a diagram to which reference will hereinafter be made in describing the manner in which synchronism is secured.
  • the apparatus illustrated in the drawings comprises a film-storage reel 1 from which a motion-picture film 2 is withdrawn by a take-up reel 3.
  • a film-storage reel 1 from which a motion-picture film 2 is withdrawn by a take-up reel 3.
  • motive power for the storage reel nor various incidental ele- V ments of the device, such as a guiding tube through which the film passes, lens systems, etc., are illustrated.
  • Light from a fixed source 4 is reflected upon the film from an oscillatory mirror 5 that is so arranged as to periodically cause the reflected ray to pass from side to side of the film as indicated by the arrow A.
  • Any suitable means may be provided for causing the mirror to oscillate, such means being indicated by an inductor 6 energized from a source 7 of alternating current.
  • a photoelectric cell 8 is disposed immediately behind the film to receive the light which is reflected therethrough from the mirror 5.
  • the film travels in a downward direction, indicated by an arrow B, the ray of light reflected from the oscillatory mirror 5 I falls upon each frame of the film in a zigzag path, the longitudinal distance on the film between successive reversals of the path being a function of the speed of travel of the film and the rate of vibration of the mirror.
  • the light falling on the photoelectric cell is, at any instant, proportional to the transparency of the film, fluctuations in the output current from the cell, accordingly, being representative of the variations in density of the film where it is exposed to the scanmug-ray.
  • the scanning can, obviously, be accomplished by as fine a pencil of light as desired and the film can thus be transmitted with great fidelity.
  • the output current from the photo-cell is utilized to modulate a carrier-wave, in any well known manner, for either radio transmission to the distant receivers, or transmission thereto over metallic conductors.
  • a carrier-wave in any well known manner, for either radio transmission to the distant receivers, or transmission thereto over metallic conductors.
  • the miscellaneous apparatus incident to the amplification of the photo-cell current, the generation and modulation of the carrier-wave, the coupling devices for impressing the carrier current on the transmitting medium, etc., have been illustrated merely as a rectangular cabinet 9.
  • One of the output terminals of the transmitting apparatus 9 is connected to a distantly situated receiver 10 by a conductor 11 and the other terminal has a connection 12 to ground.
  • the receiver 10 preferably, comprises a pluralityofhigh-frequencyamplifyingstages, a demodulator, and an audio-frequency amplifying stage if the picture transmission is accomplished through the modulation of a carrier-wave.
  • the particular type of receiver constitutes specifically no part of the present invention, it being merely necessary to provide receiving apparatus of conventional type that will give an output proportional to such characteristic of the received signal that represents the varying translucence of the transmitted film.
  • the amplitude of the output must be suflicient to control the magnitude of an electron stream in a Braun tube 13 and, consequently, the brilliancy of the fluorescence where the cathode stream therein strikes a screen at the end of the tube.
  • the Braun tube is preferably of the type having a thermionic cathode 14, a control element 15, an anode 16, a plurality of plates 17 and 18 for deflecting the electron stream in a direction indicated by the arrows A-B, and a plurality of plates 19 and 20 for defleeting the electron stream in a direction C-D at right angles to the direction A.B
  • the control electrode 15 of the Braun tube is connected to the cathode thereof through a source 21 of biasing potential and the secondiry winding 22 of a transformer.
  • the primary winding included in the output circuit of the receiver 23 of the transformer is 10.
  • the potential radient between the control electrode and t e cathode comprises two com onents, a direct-current biasing potential rom the source 21, and an alternatin potential representative of the picture-m ulation of the incoming signal.
  • the magnitude of the electron stream between the cathode 14 and the anode 16 is a function of the potential between the control-electrode and the cathode and, since the fluorescence of the screen at the end of the tube is a function of the magnitude of the electron stream or cathode ray, passing through the anode, the brilliance of the said fluorescence is, at any instant, proportional to the picture-modulation.
  • the deflecting plate 18 is connected to ground, and the opposite deflecting plate 17 is connected, by a conductor 24, to one of the terminals of the alternating-current source 7 that causes the mirror to oscillate.
  • terminal of the alternating-current source is connected to ground through the actuating winding 6 of the oscillatory mirror.
  • the plate 20 of the pair of plates in the Braun tube that control the deflection of the' electron stream in the direction of the arrows CD is connected to ground, and the opposite plate 19 is connected, by a metallic conductor 25, to a fixed contact member 26 that is normally disconnected from a movable grounded contact 27.
  • the film As the film travels from the storage reel to the take-up reel, it is driven by a toothed wheel 28, the projections 29 of which engage a series of marginal perforations 30 in the film.
  • the toothed wheel is connected, through a shaft 31, to a disc 32 that is provided with a plurality of peripheral projections 33. The free end of the contact member.
  • the plates 19 and 20, in the Braun tube, are connected across a condenser 35 having a Vernier condenser 36 disposed in'shunt thereto.
  • the condenser 35 is so disposed as to be charged from a source 37 of constant current, a rectitfying device 38, operating at or near saturation, preferably being utilized for placing the charge on the said condenser.
  • the film in its travel between the store e and take-up reels, is exposed to a beam 0 light from the oscillating mirror that moves from side to side across it at a frequency corresponding to that of the alternating-current source.
  • This coordinate is provided by the gradual building up, from the rectifying device, of a charge upon the condenser connected across the pair of deflecting plates 19 and 20.
  • the size of the condenser and the potential of the source are so chosen that the charge upon the condenser plates will build from zero 'to the desired maximum during the time required for the film at the transmitter to travel a distance corresponding to the distance between the centers of the spaces bounding a single picture-frame of the film.
  • the charge upon the defleeting plates 19 and 20 is zero or substantially zero, the successive portions of the path traced by the scanning light on the film will be represented by successive shifts of the electron stream in the Braun tube in the direction of the arrows 0-1), the rate of shift being determined by the rate at which the condenser charges and being made equivalent to the film-speed.
  • the peripheral projections iipon the disc are so chosen and spaced that the contact 26 is connected to ground, by reason of the engagement therewith of the contact member 27, at each instant when the light ray ffom the oscillating mirror strikes a point midway between successive frames of the moving film.
  • the periodic charge and discharge of the condenser is illustrated graphically in Fig. 2, wherein distances on the Y-axis represent potentials existing across the pair of deflecting plates 19 and 20, and distances along the X-axis are representative of time. From an inspection of Fig. 2, it will be noted that the potential across the condenser is indicated as rising gradually from zero to its maximum in a period of 1/20th of a second and then dropping quickly to zero.
  • the charging period chosen corresponds to a film speed of substantially 20 pictures per second, which speed is ample for. the satisfactory transmission of pictures.
  • the film speed may be increased and the condenser may be reduced in capacity, proportionally, in order that it shall acquire its charge in a shorter space of time.
  • electromagnetic means for causing a local scanning operation in synchronism with a distant scanning operation and electrostatic means for causing repetitions of said local scanning operation in accordance with a movement of an object subjected to said distant scanning operation.
  • electromagnetic means for causing a local scanning operation in syhchronism witha distant scanning operation, electrostatic means for causing repetitions of said local scanning operations and means whereby the influence of said electrostatic means on said scanning operation is controlled-in accordance with a movement of an object subjected to said distant scanning operation.
  • receiving apparatus including a ray-receptive screen, means for generating a ray, means for causing said ray to traverse said screen in one dimension in accordance with a distant scanning operation and means for causing said my to repeatedly traverse said screen in accordance with a movement of an object subjected to said distant scanning o eration.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
US349956A 1929-03-26 1929-03-26 Facsimile-transmission system Expired - Lifetime US1786812A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US19314D USRE19314E (en) 1929-03-26 Facsimile-transmission
US349956A US1786812A (en) 1929-03-26 1929-03-26 Facsimile-transmission system
DE1930582929D DE582929C (de) 1929-03-26 1930-03-15 Verfahren zum Fernsehempfang kontinuierlich bewegter Filmbilder mittels Kathodenstrahlroehren
FR692302D FR692302A (fr) 1929-03-26 1930-03-19 Système de transmission d'images
BE368861D BE368861A (enrdf_load_stackoverflow) 1929-03-26 1930-03-24

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US349956A US1786812A (en) 1929-03-26 1929-03-26 Facsimile-transmission system

Publications (1)

Publication Number Publication Date
US1786812A true US1786812A (en) 1930-12-30

Family

ID=23374686

Family Applications (2)

Application Number Title Priority Date Filing Date
US19314D Expired USRE19314E (en) 1929-03-26 Facsimile-transmission
US349956A Expired - Lifetime US1786812A (en) 1929-03-26 1929-03-26 Facsimile-transmission system

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US19314D Expired USRE19314E (en) 1929-03-26 Facsimile-transmission

Country Status (4)

Country Link
US (2) US1786812A (enrdf_load_stackoverflow)
BE (1) BE368861A (enrdf_load_stackoverflow)
DE (1) DE582929C (enrdf_load_stackoverflow)
FR (1) FR692302A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547987A (en) * 1945-11-16 1951-04-10 Jr Edwin C Vestal Sawtooth voltage generator
US2703150A (en) * 1949-09-29 1955-03-01 Lu Garda Rieber Geophysical display system
US2757234A (en) * 1950-03-29 1956-07-31 Gen Precision Lab Inc Television shutter
US3177287A (en) * 1958-10-24 1965-04-06 Leslie Farrer Brown System for reproduction of record images

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2547987A (en) * 1945-11-16 1951-04-10 Jr Edwin C Vestal Sawtooth voltage generator
US2703150A (en) * 1949-09-29 1955-03-01 Lu Garda Rieber Geophysical display system
US2757234A (en) * 1950-03-29 1956-07-31 Gen Precision Lab Inc Television shutter
US3177287A (en) * 1958-10-24 1965-04-06 Leslie Farrer Brown System for reproduction of record images

Also Published As

Publication number Publication date
FR692302A (fr) 1930-11-04
USRE19314E (en) 1934-09-11
DE582929C (de) 1933-08-25
BE368861A (enrdf_load_stackoverflow) 1930-04-30

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