US2047533A - Television method - Google Patents

Television method Download PDF

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Publication number
US2047533A
US2047533A US635406A US63540632A US2047533A US 2047533 A US2047533 A US 2047533A US 635406 A US635406 A US 635406A US 63540632 A US63540632 A US 63540632A US 2047533 A US2047533 A US 2047533A
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United States
Prior art keywords
image
potential
frequency
line
producing
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Expired - Lifetime
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US635406A
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English (en)
Inventor
Ardenne Manfred Von
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Loewe Opta GmbH
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Loewe Opta GmbH
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Filing date
Publication date
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Publication of US2047533A publication Critical patent/US2047533A/en
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    • 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
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/30—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical otherwise than with constant velocity or otherwise than in pattern formed by unidirectional, straight, substantially horizontal or vertical lines
    • H04N3/32—Velocity varied in dependence upon picture information

Definitions

  • a controlling potential is generated by a photoelectric cell.
  • This controlling potential varied by the light intensity of the picture, controls at the receiver the intensity of a light source.
  • two pairs of deflecting plates are provided, controlled by two defleeting voltages, one for scanning the image of the picture in a line direction, the other one for scanning the picture transversely to the line direction.
  • the light intensity of the picture points during the composition is controlled by varying the intensity of cathode rays (for instance by means of cutting off parts of the cathode ray beam by a shutter).
  • Both deflecting voltages line changing frequency and picture changing frequency
  • the line control method used in the present case a constant intensity of the cathode ray is used and the line potential is varied with the light intensity of the picture. Therefore in this method the intensity of the cathode ray is not varied.
  • the scanning in a line direction does not occur with uniform speed, but may be varied spot by spot by the light intensity of the picture.
  • a cathode ray of constant intensity is scanning at certain places with either slow or quick speed and therefore causing bright or dark parts of the picture.
  • the interval for line-scanning is not constant for each line but depends upon the mean value of the light intensity of the line. If the scanning in the picture direction (transverse to the line direction) is controlled by an oscillation of straight line wave form of constant steepness, the lines could not appear in equal distances to each other. The lines being quickly scanned (dark lines) would appear in close proximity to each other, while the lines being scanned slowly (bright lines) would appear far apart. Therefore distortion in picture transmission would occur.
  • This distortion of picture may be removed by using an oscillation for scanning transversely to the line direction, having not a constant steepness, but a slope varied by the mean value of the light intensity of the lines.
  • an oscillation for scanning transversely to the line direction having not a constant steepness, but a slope varied by the mean value of the light intensity of the lines.
  • the lines are equally spaced.
  • the frequencies situated below the image frequency are withheld from the elements modulating the straight line wave form.
  • Fig. 1 shows a part of an arragement in order to explain the modulation of the image-and line- 0 voltages.
  • Fig. 2 shows a television device according to the invention using the arrangement illustrated in Fig'. 1.
  • Fig. 3 shows a modification of the arrangement 15 illustrated in Fig. 2.
  • Fig. 1 there is shown a supply transformer 20, which furnishes the heating potentials necessary for the modulating valves I5 and I6 and the rectifier valve 2
  • the winding 22 of this transformer supplies the alternating potential to be rectified, necessary for generation of the plate potential, which alternating potential, rectified, is smoothed by the system 23, which is composed of condensers and resistances.
  • the condensers suitably possess a size of 4M5 and shall be able to bear voltages up to at least 3000 volts.
  • the resistances suitably possess a size of 3.10 ohms.
  • the rectified plate potential now feeds a generator for producing an oscillation of straight line wave form, comprising the condensers 26 (e. g. 0.08aF) and 21 (e.
  • connection systems comprising the resistances 38 (e. g. 5.10 ohms) and 39 (e. g. 5.10 --10 ohms) and the condenser 40' (e. g. 2,uF) permit of the adjustment of a suitable constant bias for the pairs of 50 deflecting plates of the Braun tube.
  • 42 and 43 are the connections for the deflecting potentials.
  • 44 is the connection for the photo-cell potential.
  • a resistance 46 e. g.
  • l is the Braun tube having the pairs of deflecting plates 2 and 3, the Wehnelt cylinder 4, the cathode 5, the anode 6 and the fluorescent screen I.
  • a special screening ring 8 which preferably is taken to earth.
  • 9 is the network connection apparatus, which supplies heating potential, the Wehnelt cylinder potential, initial potential and plate potential.
  • the rectangle resulting on the screen I is reproduced on the film ll through the medium of a lens system Ill.
  • the light passing through falls on to a photo-cell II, which is situated in the input of an amplifier l3, which posseses a transmission range of approximately 24 to 300,000 periods.
  • the amplified photocell potential is conducted to a filter chain H (impervious for frequencies which are smaller than the number of pictures per second), and after the frequencies below the image frequency have been filtered out controls the control grids of the valves l5 and I5, whereby the line or image potential for producing straight line wave form are modulated.
  • a filter chain H (impervious for frequencies which are smaller than the number of pictures per second), and after the frequencies below the image frequency have been filtered out controls the control grids of the valves l5 and I5, whereby the line or image potential for producing straight line wave form are modulated.
  • the effect of excluding the low frequencies from the modulation of the straight line wave form developed by the valve l6 and the condenser 21, 5 may be seen by analyzing the modulating current into its component sine waves, and considering the effect of one of these components modulating the straight line wave form.
  • Each half period of the sine wave produces a time variation, which 10 is annulled by the following half period and following this process up to the end of the image period it is evident that the total variation in time will be due to a fraction of an old half period of the sine wave.
  • This variation will be small for the modulating sine waves of high frequency but will be large on those of low frequency.
  • the variations of the image periods may be made small.
  • the alternating potential from the output side of the amplifier I4 is passed to the grid of the additional valve i1, provided for the purpose of 35- rectification.
  • the alternating potentials at the grid of this valve contain both the high highfrequency components as well as the critical low components. Owing to the fact that in the anode circuit of this valve there is connected a resistance system, which is small as regards all frequencies above the image frequency, but large for all frequencies below the image frequency, it is accomplished that variation in the cathode potential and therefore the grid bias of the image- 45 tilting valve takes place only at the critical frequencies below the image frequency and compensates for the low frequency components applied to the g d.
  • the additional valve H which is controlled by the filtered photo-cell potential, has in its anode circuit the resistance system l8, which provides the grid potential for the image potential modu- 65 lator i6.
  • a resistance system which consists of the parallel cone section of a condenser and a resistance, whereby in the case of an image frequency amounting to 25 pe- 70 riods suitable values result for the condenser amounting to approximately 4 microfarads and for the resistance a preferably variable resistance from a few thousand ohms up to approximately 5,000 ohms. 75
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the-lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, said means consisting of a filter chain being preferably situated in the output circuit of the photocell amplifier.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, means for performing an additional slow modulation corresponding with the mean intensity of the image, said modulation resulting in a constancy of the scanning period of one or more images.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, means for performing an additional slow modulation corresponding with the mean intensity values of the image, said modulation resulting in a constancy of the scanning period of one or more images, said additional modulation being'selected in such fashion corresponding with the ability of the amplifier to amplify low frequencies that the frequencies situated below the image frequency exert no effect on the intensity of the image.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of lines, means for withholding the frequencies below the image frequency from the modulation 5 of said deflecting voltages for the purpose of maintaining the scanning periods constant, and means for producing the bias of the image potential modulator by the drop in potential occurring at a resistancesystem and controlled by the filtered and'ainplified photo-cell potential.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of. the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, and means for producing the bias of the image potential modulator by the drop in potential occurring at a resistance system and controlled by.
  • the filtered and amplified photocell potential said resistance system being so dimensioned that the same possesses a low resistance as compared with the frequencies situated above the image frequency, and on the other hand a high resistance as compared with those situated below the image frequencies.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, and means for producing the bias of the image potential modulator by the drop in potential occurring at a resistance system and controlled by the filtered and amplified photo-cell potential, said resistance system for producing the bias of the image potential modulator consisting of the parallel connection of a condenser and a resistance.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, and means for producing the bias of the image poten.
  • said resistance system for producing the bias of the image potential modulator consisting of the parallel connection of a condenser and a resist- 7 ance, said condenser possesses a capacity of 4 microfarads, and said resistance a preferably variable value of up to approximately 5000 ohms.
  • means for producing a line deflecting voltage and an image deflecting voltage for scanning said line frequency being modulated by the instant intensity of said image and said image frequency being modulated by the mean intensity values of the lines for producing constant spacing of the lines, means for withholding the frequencies below the image frequency from the modulation of said deflecting voltages for the purpose of maintaining the scanning periods constant, and

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US635406A 1931-10-06 1932-09-29 Television method Expired - Lifetime US2047533A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE397688X 1931-10-06

Publications (1)

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US2047533A true US2047533A (en) 1936-07-14

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US635406A Expired - Lifetime US2047533A (en) 1931-10-06 1932-09-29 Television method

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US (1) US2047533A (enrdf_load_stackoverflow)
FR (1) FR743576A (enrdf_load_stackoverflow)
GB (1) GB397688A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428926A (en) * 1943-06-04 1947-10-14 Rca Corp Modified sweep circuit for cathoderay tubes
US2429226A (en) * 1942-09-14 1947-10-21 Hammond Instr Co Electrical musical instrument
US2487641A (en) * 1946-09-07 1949-11-08 Philco Corp Electronic pointer for television images
US2582014A (en) * 1948-05-08 1952-01-08 Radio Ind S A Soc Scanning device for television transmitters
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television
US2627051A (en) * 1950-08-29 1953-01-27 Rca Corp Electron tube voltage protection circuit
US2629067A (en) * 1950-07-18 1953-02-17 Teletone Radio Corp Deflection circuits for television receivers
US2681382A (en) * 1950-08-11 1954-06-15 Earl D Hilburn Video recording and reproducing
US2701850A (en) * 1951-02-02 1955-02-08 Philco Corp Automatic focus control for cathoderay tubes
US2851519A (en) * 1952-01-31 1958-09-09 Jr John C Schira Mechanical to video transducer for superimposing additional information on a television scene

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429226A (en) * 1942-09-14 1947-10-21 Hammond Instr Co Electrical musical instrument
US2428926A (en) * 1943-06-04 1947-10-14 Rca Corp Modified sweep circuit for cathoderay tubes
US2487641A (en) * 1946-09-07 1949-11-08 Philco Corp Electronic pointer for television images
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television
US2582014A (en) * 1948-05-08 1952-01-08 Radio Ind S A Soc Scanning device for television transmitters
US2629067A (en) * 1950-07-18 1953-02-17 Teletone Radio Corp Deflection circuits for television receivers
US2681382A (en) * 1950-08-11 1954-06-15 Earl D Hilburn Video recording and reproducing
US2627051A (en) * 1950-08-29 1953-01-27 Rca Corp Electron tube voltage protection circuit
US2701850A (en) * 1951-02-02 1955-02-08 Philco Corp Automatic focus control for cathoderay tubes
US2851519A (en) * 1952-01-31 1958-09-09 Jr John C Schira Mechanical to video transducer for superimposing additional information on a television scene

Also Published As

Publication number Publication date
GB397688A (en) 1933-08-31
FR743576A (enrdf_load_stackoverflow) 1933-04-01

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