US1849839A - Transmission of pictures - Google Patents

Transmission of pictures Download PDF

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Publication number
US1849839A
US1849839A US407762A US40776229A US1849839A US 1849839 A US1849839 A US 1849839A US 407762 A US407762 A US 407762A US 40776229 A US40776229 A US 40776229A US 1849839 A US1849839 A US 1849839A
Authority
US
United States
Prior art keywords
picture
synchronizing
frequency
frequencies
signal
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
US407762A
Other languages
English (en)
Inventor
Ray D Kell
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
Priority to BE368046D priority Critical patent/BE368046A/xx
Priority to BE371955D priority patent/BE371955A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US407762A priority patent/US1849839A/en
Priority to FR39590D priority patent/FR39590E/fr
Priority to GB34620/30A priority patent/GB350371A/en
Priority to FR39593D priority patent/FR39593E/fr
Priority to BE374986D priority patent/BE374986A/fr
Application granted granted Critical
Publication of US1849839A publication Critical patent/US1849839A/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
    • H04N5/04—Synchronising
    • H04N5/12—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising
    • H04N5/123—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising whereby the synchronisation signal directly commands a frequency generator
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/07—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on electro-optical liquids exhibiting Kerr effect
    • 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
    • H04N3/02—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only
    • H04N3/04—Scanning details of television systems; Combination thereof with generation of supply voltages by optical-mechanical means only having a moving aperture also apertures covered by lenses
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H04N5/067—Arrangements or circuits at the transmitter end
    • H04N5/073—Arrangements or circuits at the transmitter end for mutually locking plural sources of synchronising signals, e.g. studios or relay stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/08—Separation of synchronising signals from picture signals

Definitions

  • My invention relates to the transmission of pictures, and has for its principal object the provision of an improved apparatus and method of, operation whereby synchronism :s' is readily maintained between the moving parts of the picture transmitting and receiving apparatus.
  • a television or picturetransmitting signal consists of a complex wave containing frequencies distributed between the picture frequency and the frequency produced by the maximum resolving power of the scanning elements such, for example,.as twenty cycles for twenty pictures per second, and twenty-three thousand cycles for twenty threepicture elements. Due to the fact that the picture is composed of such a wide band of frequencies, a small part of the frequencies may be eliminated from the transmitted signal without a perceptible change in the quality of the picture. In accordance with my invention a narrow band (about one percent) of the frequencies is transmitted signal, and
  • a synchronizing frequency is introduced into the gap thus produced.
  • This synchronizing frequency may be supplied from any suitable source such as an alternator driven by' the same motor that moves the scanning eleparatuswherein light from 'ning disc 13. Under ment.
  • the signals containingthe picture and synchronizing frequencies are passed through suitable filters so that the pic- I ture frequencies are utilized to build up the picture while the synchronizing frequency is utilized to maintain synchronism between the movable parts of the transmitter and receiver.
  • Figs. 1 and 2 show picture transmitting and. receiving apparatus wherein my inventionhas been embodied
  • Figs. 3 to 6 are explanatory diagrams relating to the operation of the apparatus.
  • Fig. 1 illustrates a picture-transmitting apa suitable source 10 is applied to a picture 11 through a lens 12, a scanning disc 13, and a lens 14.
  • the output circuit of the amplifier 16 is connected to a radio transmitter 17 through a filter 18 which functions to eliminate a narrow band of frequencies corresponding to the selected synchronizing frequency.
  • the radio transmitter 17 is also connected to an alternator 19 mounted'on the shaft of a motor 20, which drives the scanthese conditions potential of synchronizing and, together with the picture signal frequencies, is transmitted to the receivlng apparatus.
  • the scanning .disc 13 is provided with a plurality of spifrequency is applied to the input circuit of the radio transmitter 17 11 is recelved by a light sensiis connected-to a neon lamp 22 or the like through an amplifier'23.
  • Theradio receiver 21 is also connected to an alternating current motor 24 which is coupled to a scanning disc 26 interposed betweenthe modulated light source 22 and the receiving screen 27.
  • the connections between the receiver 21 and the motor 24 include a pair of electric discharge and 31.
  • the device 29 is provided with an input circuit, whlch includes a resistor 32 and a reactor 33, and with an output circuit. which ncludes a reactor 34, a capacitor connected in shunt to the reactor 34, and a suitable plate current source 36.
  • a capacitor 37 and the primary winding of the transformer 31 are also connected to the output circuit of the device 29.
  • the input circuit of the device 28 is connected to a bias potential source 38 through the secondary circuit of the transformer 31, and the output circuit of this device is connected to the motor 24 through a plate battery 29 and the transformer 30.
  • the picture and synchronizing. signals are applied to the resistor 32, which controls the potential of the input circuit of the device 29.
  • the inductances. 33 and 34 are coupled together, and the reactor 34 and. the capacitor 35 are so designed as to form -a circuit which is resonant to the synchronizing frequency.
  • the resistance in the tuned circuit formed by the reactor 34 and the capacitor 35 limits the selectivity of the tuned circuit.
  • the coupling between the reactors 33 and 34 is so adjusted that the effective resistance of the resonant circuit approaches zero at resonance, thus increasing the selectivity of the circuit and at the same time amplifying the synchronizing signal in the device 29, from which it is supplied to the amplifying device 28 and to themotor 24.
  • the synchronizing frequency may be mixed with the picture di-' rectly. at the transmitter, the synchronizing frequency current is amplified sufliciently to frequency being of such small amplitude that it is not noticeable on the receiving screen.
  • the synchronizing drive the disc 26 in synchronism with the disc 13 by means of the motor 24.
  • the de-. scribed circuit it has beenfound possible toselect a 600-cycle frequency from the picture signal. mixed with a'GOO-cycle synchronizing frequency the magnitude of the synchronizing frequency to the picture frequencies being of the order of 1 to 100 as received.
  • Figs. 3,4, 5,and 6 wherein the curve of Fig. 3 represents thepicture signal, Fig. 4 represents the picture signal with a gap produced by the filter 18, Fig. 5 represents the combined picture and synchronizing signals, and Fig. 6 represents the synchronizing signal.
  • nal having a frequency lying in said portion with the remainder of said picture signal.
  • means including a movable element for scanning a icture, means for producing picture signals ependent on the shade of the picture, means for eliminating a predetermined intermediate band of frequencies of said signal, means operable in accordance with the motion of said movable member for combining a synchronizing signal having a frequency lying in said band with the remainder of said picture .signal, and a picture-receiving apparatus including means for separating said picture and synchronizing, signals, a light source modulated in accordance with said picture signal, a movable scanning member, and means arranged to cause said scanning memher to be moved in accordance with said synchronizing signal.
  • a relaroducing a rent varied in accordance with said scanningray as modified by said object said current including a wide band of frequencies, means for suppressing one of the frequencies of said band, a-source of alternating current having a frequency within said band, a carrier current, means for modulatin said carrier current by the unsuppressed requencies of said band, and-means for modulatmg said carrier current by the output of said source.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Closed-Circuit Television Systems (AREA)
  • Optical Communication System (AREA)
US407762A 1928-05-29 1929-11-16 Transmission of pictures Expired - Lifetime US1849839A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE368046D BE368046A (enrdf_load_stackoverflow) 1929-11-16
BE371955D BE371955A (enrdf_load_stackoverflow) 1929-11-16
US407762A US1849839A (en) 1929-11-16 1929-11-16 Transmission of pictures
FR39590D FR39590E (fr) 1928-05-29 1930-11-15 Perfectionnements aux systèmes de télévision
GB34620/30A GB350371A (en) 1929-11-16 1930-11-17 Improvements in and relating to the transmission of pictures
FR39593D FR39593E (fr) 1928-05-29 1930-11-19 Perfectionnements aux systèmes de télévision
BE374986D BE374986A (enrdf_load_stackoverflow) 1929-11-16 1930-11-29

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US407762A US1849839A (en) 1929-11-16 1929-11-16 Transmission of pictures

Publications (1)

Publication Number Publication Date
US1849839A true US1849839A (en) 1932-03-15

Family

ID=23613422

Family Applications (1)

Application Number Title Priority Date Filing Date
US407762A Expired - Lifetime US1849839A (en) 1928-05-29 1929-11-16 Transmission of pictures

Country Status (3)

Country Link
US (1) US1849839A (enrdf_load_stackoverflow)
BE (2) BE368046A (enrdf_load_stackoverflow)
GB (1) GB350371A (enrdf_load_stackoverflow)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE403568A (enrdf_load_stackoverflow) * 1933-01-28

Also Published As

Publication number Publication date
BE368046A (enrdf_load_stackoverflow)
BE371955A (enrdf_load_stackoverflow)
GB350371A (en) 1931-06-11

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