US2217831A - View transmission system - Google Patents

View transmission system Download PDF

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Publication number
US2217831A
US2217831A US181359A US18135937A US2217831A US 2217831 A US2217831 A US 2217831A US 181359 A US181359 A US 181359A US 18135937 A US18135937 A US 18135937A US 2217831 A US2217831 A US 2217831A
Authority
US
United States
Prior art keywords
cathode
tube
grid
circuit
current
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
US181359A
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English (en)
Inventor
Randall C Ballard
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.)
CBS Corp
Original Assignee
Westinghouse Electric and Manufacturing 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 BE386746D priority Critical patent/BE386746A/xx
Application filed by Westinghouse Electric and Manufacturing Co filed Critical Westinghouse Electric and Manufacturing Co
Priority to US181359A priority patent/US2217831A/en
Application granted granted Critical
Publication of US2217831A publication Critical patent/US2217831A/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

Definitions

  • the electron suitable means may bey provided fori'produ'oing Stream trarl'SlXl1Y ⁇ l1- a direction indicated by -z this.' oscillatory conditior1, such means being the arrowsffl, vand anotherl 'similar'inducta'nce .Y 'broadly indicated' ⁇ by-f ⁇ an inductor lil :energized 331.*positioned, atfright'angles to-'the inductance '-45 f 45* fr'omai'sourcecialternating currentl.
  • yTo provide means for producing the verticalscanning component at the receiving end of systems of the type described for the transmission and reception of motion pictures, it has been customary, according to the prior art, to
  • V electrostatic deflection produced distortion of the focus of the spot of'light striking the fluorescent screen.
  • the characteristics of the vertical scanning are entirely different from those of the horizontal scanning.
  • the velocity of travel of the cathode ray is substantially uniform in-both directions and it is a comparatively easy problem to cause the ray to oscillate at a uniform velocity by applying a sinusoidal voltage to the deecting coil.
  • the ray is caused to sweep acrossthe screen at one velocity and return to its starting place at a much higher velocity.
  • this invention comprises an improvement upon the scanning means of the prior art by providing electromagnetic means for producing the results obtained by the electrostatic means of the prior art, at the same time energizing the electromagnetic deflectors by voltages of substantially saw-tooth waveform in an eilicient manner, with the consequent result that the received pictures will more faithfully reproduce the details of the originals.
  • a toothed wheel 4I As the lm travels from the storage reel I to the take-up reel 5, it causes the rotation of a toothed wheel 4I, the teeth of which engage a series of marginal perfcrations in the film.
  • the toothed wheel is connected through a shaft to a disc 43 that is provided with a plurality of peripheral projections 45.
  • the free end of a contact member 4'I by reason of spring action is caused to ride upon the periphery of the disc 43 except at such times as the projections on the disc cause the contact member to be lifted from the periphery.
  • the electron stream in the cathode ray tube will be caused to oscillate from side to side in the direction of the arrows 3 I, at the same frequency that the ray of light is being caused to traverse the moving nlm.
  • One coordinate of the scanning operation at the receiving end is accordingly provided by reason of the fact that the same source of alternating current actuates both the mirror and the cathode-ray beam.
  • this coordinate was provided by the gradual building up of a ⁇ charge upon a condenser connected across a pair of deflecting plates.
  • the gradual building up of the charge caused the beam of electrons to sweep from one end of the screen to the other in the same time that it takes ⁇ one picture of the film to pass through the light beam reflecting upon it.
  • the electron beam be brought back to its initialposition before thelight beam reflected from the mirror 9 begins v to scan the succeeding picture.
  • the vertical vscanning *component is produced in accordance with this invention by a gradual building ⁇ up of the magneticeld, L'andtlfle return lated bythe movementcof'theimovingepicturelm Yf'irfrii'iiall fpostion is brought about'by -:.a ⁇ sud'denl *collapse-f off theaiield thus build-up.
  • the output fcircuit'fof the gnd- ⁇ gmwtubeflsa Y comprises a resistorlliB-.inv series'withajsource oi high, potential of 1 approximately .2000' volts;
  • the high-voltage .source potential may be the sameas thatrequirediorthe operation of ⁇ the fcathode-.ray:.tube',z so that-fno additional high-potential source: is rlrequired.- for the purpose.V Y .4 i
  • the ⁇ resistanceY capacity rcombination F65 ⁇ -and t3 in con-I vjunction With the mechanically triggered .g'ri'd glowr tube providingva ⁇ sudden discharge fpath, is vthe 'source' generating a-Voltage of .substantially saW-tooth Waveform. 'In order to apply the VVoltage so obtained jeciently tol the. deflecting i coil" 33, there is provided a coupling circuit' including a highimpe'dance coupling devicevinthe forni of a vacuumtube 61 of the'screenrgrid type.
  • Theinput --and output circuits, of-this tube are so arrangedfby properly chosennconstantsof ⁇ the .impedance -1 elements that the effect ofithe aanV ⁇ inductive reactancewof the-coil '33Will" not react f upon the voltagesource, or influencethe' linear 'characteristics of the output current.
  • the electrodes of thetube 61 are-connected :in .theaconventiona'l manner, VVthe-filament 15 beingenergized "by av suitablefjsourcev of fheatingfcurrent which in this case may be the transformerl employed 'for the Vfilament ofi the ygrid-glow tube53.y Operating potential 'for'the remaining electrodes arefshown schematically being obtained'iromtaps on a Voltage divider 83, which isconnected; across a source of approximately 600 l'volts D.'V C.v Taking,
  • the plate kcircuit 'in- V cludes the load" resistance lllz'andfa- ⁇ couplingconjdenser/85 of relatively-large capacityivaluaithe purpose of which is to isolate the-direct fcu'rrent component from the deflecting r coil 33 ⁇ which is enectively connected in parall'elfwith'the load' resistancelli
  • The' inputfcircuit includes the 4"grid "1I, the gridresistor18H-Which returnsto l'ajpoint more negativer'vvith respect to the cathode 15 on.
  • Ythe plate current of the screen-grid tube r6'! will gradually and uniformly build up.
  • the magnetic field in the laminated core will start ⁇ from a maximum value in one direction, decrease gradually, and uniformly pass through zero value and increase in the same manner to a maximum in the opposite direction.
  • the resistor 8'! across the condenser and coil is of such high value as not to delay the reversal of current or the reversal of the flux in the coil 33 during the periods when the reversals take place.
  • Resistor 86 2 megohms Resistor 81 50,000 ohms l Condenser 85 8 micro-farads
  • the operating voltages for the tube 61 were adjusted for linear response and the following conditions were found to give best results, with a plate potential source of approximately 600 volts, grid bias voltage approximately 4 volts negative, screen grid voltage 100V voltspositive with respect to the cathode '11. g
  • electromagnetic means arranged in proximity of said beam for controlling the transaxial movement thereof, an oscillator producing a voltage of substantially' saw-tooth wavev form, a transmission circuit coupling said oscillator with said means including a vacuum tube having at ⁇ least an anode, a control grid and a screen grid, means for energizing said screen grid, said vacuum tube having a plate-voltage, plate-current characteristic which is substantially at over the normal operating range of the plate current, an input circuit for said tube including said control grid and said cathode, said input circuit being energized by said oscillator, anoutput circuit between said anode and said cathode, said output circuit including said electromagnetic means.
  • electromagnetic means arranged in proximity of said beam for controlling the transaxial movement thereof, an oscillator producing a voltage of substantially saw-tooth wave form, a transmission circut 'coupling said oscillator with said means including a vacuum tube having at least an anode, a cathode, a control grid and a screen grid, means for energizing said screen grid, an input circuit for said tube including said control 'grid and said cathode, said'input circuit being energized by said oscillator, and an output circuit between said anode and said cathode, said output circuit comprising an impedence effectively in parallel with a capacitor and saidelectromagnetic means.
  • electromagnetic means arranged in proximity of said beam for controlling the transaxial movement thereof, an oscillator producing a voltage of substantially saw-tooth wave form, a transmission circuit coupling said oscillator Ywith said means including a vacuum tube having at least an anode,l a cathode, a control grid and a screen grid, means for energizing said screen grid, an inputl circuit for said tube including said control grid and said cathode, said input circuit being energized by said oscillator, and an output circuit between said anode and said cathode,v said output circuit comprising an-impedance eifectively in parallel with a capacitor and said electro-magnetic means, said impedance being of such magnitude and the operating characteristics of said tube so chosen as to produce a current in said output circuit which gradually and uniformly Vbuilds up to a maximum and then to quickly re- Verse.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US181359A 1937-12-23 1937-12-23 View transmission system Expired - Lifetime US2217831A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE386746D BE386746A (sv) 1937-12-23
US181359A US2217831A (en) 1937-12-23 1937-12-23 View transmission system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US181359A US2217831A (en) 1937-12-23 1937-12-23 View transmission system

Publications (1)

Publication Number Publication Date
US2217831A true US2217831A (en) 1940-10-15

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US181359A Expired - Lifetime US2217831A (en) 1937-12-23 1937-12-23 View transmission system

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BE (1) BE386746A (sv)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2533010A (en) * 1945-06-07 1950-12-05 Joseph E Henabery Method and apparatus for visually determining unknown vibration characteristics
US2559316A (en) * 1948-03-22 1951-07-03 Louis W Parker Sweep circuit for television receivers
US2563487A (en) * 1951-08-07 Television receiver synchronizing
US2571824A (en) * 1949-08-25 1951-10-16 Rca Corp Gaseous discharge circuit
US2660721A (en) * 1942-04-09 1953-11-24 Robert M Page Radio echo ranging apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563487A (en) * 1951-08-07 Television receiver synchronizing
US2660721A (en) * 1942-04-09 1953-11-24 Robert M Page Radio echo ranging apparatus
US2533010A (en) * 1945-06-07 1950-12-05 Joseph E Henabery Method and apparatus for visually determining unknown vibration characteristics
US2559316A (en) * 1948-03-22 1951-07-03 Louis W Parker Sweep circuit for television receivers
US2571824A (en) * 1949-08-25 1951-10-16 Rca Corp Gaseous discharge circuit

Also Published As

Publication number Publication date
BE386746A (sv)

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