US2037577A - Television method and apparatus - Google Patents

Television method and apparatus Download PDF

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Publication number
US2037577A
US2037577A US499322A US49932230A US2037577A US 2037577 A US2037577 A US 2037577A US 499322 A US499322 A US 499322A US 49932230 A US49932230 A US 49932230A US 2037577 A US2037577 A US 2037577A
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Prior art keywords
scanning
force
picture
circuit
producing
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US499322A
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English (en)
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Harries John Henry Owen
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Individual
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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
    • H04N3/34—Elemental scanning area oscillated rapidly in direction transverse to main scanning direction

Definitions

  • the invention relates in general to the transmission and reproduction of pictures, scenes, views, images and the like by television and is concerned more particularly with forms of television apparatus in which a scanning point or beam is moved over the picture proportionally to electrical or electrically controlled scannin forces.
  • the object of the present invention is to pro vide a method and means whereby such an unevenly defined picture may be employed in television. thus economizing the total amount of detail which need be transmitted and enabling a larger picture to be used than would otherwise be possible.
  • the electrical or electrically controlled scanning forces are arranged to have a suitable amplitude/time wave form so that the picture is scanned more slowly, and therefore is greater in detail over the center I of interest than elsewhere.
  • scanning forces the electrical or electrically controlled scanning forces
  • the speed of the scanning beam may be reduced as herein described in passing over that part of the 40 picture which it is desired to emphasize or conversely in case it is desired to transmit pictures from a moving film the speed of the film relative to the scanning beam may be reduced when the beam is passing over that partof the picture 45 which it is desired to emphasize, (the operative part of the wave being arranged to be the most useful portion).
  • Fig. 1 illustrates an example of wave shape useful in employing the invention.
  • Fig. 2 illustrates an additional wave form for the "purpose.
  • Fig. 3 illustrates one form of apparatus for pro- 55 .ducing the desired wave forms.
  • Fig. 6 illustrates another form of apparatus for the purpose in which the desired wave form may be produced by variations in the scanning ,5 force itself.
  • Fig. 7 illustrates diagrammatically one form of circuit in which the invention, may be employed for television.
  • Figs. 8 and 9' illustrate details of the apparatus 10 shown in Fig. 7.
  • y (a sin w) sin 3 w)
  • the wave is plotted in Fig. 1 of the accompanying drawings, the operating part being between A and B.
  • the desired wave form may be generated by a plurality of coupled generators, each delivering a component of the desired-complex wave, which 86 would appear in a circuit to which the components are fed.
  • the relative characteristics of the individual components may be varied by suit- I able adjustments to the generators or to the couplingbetween the generators.
  • the generators may themselves be driven by a motor to act as a motor generator convertor. In Fig. 3 this is illustrated as applied to two alternators 3, 4, and
  • the desired wave may bade
  • stants e. g., resistance or capacity.
  • a cam 10 is'rotated at a constant speed by any suitable means; one end of a fol lower or rod ll, slidably mounted in brackets I2,
  • the terminals of the external circuit are con:
  • the cam profile is of such a shape as to cause the resistance and therefore the current in the external circuit to vary pe-' riodically as shown by the curve Fig. 1.
  • a disc 15 is steadily rotated by any convenient means, and a resistance wire or strip I6, is arranged around its edge; one end I! of said wire being connected to the external circuit, the other end is free.
  • An electrode I 8 rubs on the wire, and is connected to the other terminal of the external circuit.
  • the resistance I9 is connected between the external circuit, where the end I I of the wire l6 joins it, and the middle point of the wire l6.
  • a further series of arrangements will consist 01' devices wherein the circuit constants change with difierent magnitudes of the scanning forces; in this -manner a sine wave, or transient force, may be made to produce the desired wave form.
  • One example consists of a pair of triode valves in push-pull amplifier arrangement.
  • the valve grids are biased so that the'lower values of a sine wave impressed on the grids are partially suppressed, the peaks being reproduced normal- 1y, resulting in an output wave form similarto Fig. 1.
  • a second example is where a series of devices (e. g. diode or triode valves orother relaying devices) are biased so as to come intooperation in shunt or series in a circuit at difl'erent values of the input volts, hence varying the current output wave form, either by their varying load on the circuit or by switching in or out additional apparatus, e. g., capacities, etc.
  • a series of devices e. g. diode or triode valves orother relaying devices
  • Fig. 6 the present invention is applied to a known form of apparatus wherein the potential across the plates of a condenser, which is charged through a constant current device, is utilized to give the deflecting force to a cathode'ray tube.
  • the condenser 20 has in parallel therewith the deflecting plates 2
  • triode 26 (which are in parallel with each other) is a battery 21.
  • Resistance 28 is merely to provide a path for the D, C. plate current to diode25 and triode 26 when the relay switch 22 is open.
  • 'I'hegrid of triode 26 is connected to a biasing battery 29 and the other terminal of said battery is connected to the top of the condenser 20 at 30.
  • the apparatus described may be employed in a. television system when periodic impulses are used as the scanning force for framing purposes, said periodic impulses being caused to momentarily close the switch 22 between the transmission of successive pictures. The operation of this circuit is as follows:-
  • the said condenser 20 On the condenser 20 being periodically short circuited it is discharged.
  • the switch 22 When the switch 22 is opened the said condenser 20 commences to charge up from battery 21 through the diode 25, which is arranged to pass a constant current.
  • the diode 23 and triode 26 are respectively biased so that they do not operate at the initial values of the rising voltage across the condenser 20 as it commences charging up.
  • a triode with the grid suitably biased and connected to-point 30 may be substituted for the diode 23.
  • the increasing current through this triode after the point 3 on the curve, (Fig. 2) will partially counteract the effect of the triode 26 in raising the curve, and must be allowed for in design.
  • the position of the highly defined part of the image may be moved over the remainder of the image.
  • the relative (mechanical) phase and excitation of the two alternators may be varied, or in the apparatus shown in Fig. 4 the cam may be altered or adjusted.
  • is fed past a cathode ray scanner 32 and photo-electric cell 33.
  • Scanner 32 includes a cathode 4
  • Light rays from the consequent light spot on the fluorescent screen 33 are focussed by lens 35 onto the film 3
  • the film is moved past the cell 33 and scanner 32 by means of the sprockets 36 which are both mechanically coupled to shaft 31.
  • Shaft 31 is driven through a gear mechanism 36 by a prime mover 39.
  • the prime mover 39 also drives the generators 3, 3 which supply scanning currents to the circuit l, as previously illustrated in Fig. 3.
  • Circuit 1 is connected to the deflecting plates 44 of the transmitting scanner 32, and also to the corresponding plates 45 of a receiving cathode ray scanner 46.
  • the receiving scanner 40 consists of a cathode 41 and anode 36 in series with a battery 49 in the usual manner to produce a jet of cathode rays 56, which impinge on the fluorescent viewing screen 5
  • the jet 50 is defiectable by potentials applied to the plates 2
  • by the impact of the jet 50 is controlled, also in known manner, by the potentials applied to the electrode 52.
  • the picture currents from the photo-electric cell 33 are transmitted through lines 53 and amplifier 54 to the cathode 41 of the receiving scanner 46 and to the control electrode 52 therein.
  • of the receiving scanner 40 are connected across the condenser 26.
  • Condenser 20 is discharged and charged up once for every picture transmitted from the film 3
  • the lines 56 and battery 5] are connected to switch arm 58 and contact 59.
  • Switch arm 58 is fastened to sprocket 36 so that contact is made to 59 between the transmission of each picture on the dim 3
  • a high resistance 61 and battery 69 maintain the grid of the triode 55 ata sumciently negative potential to make the plate circuit virtually non-conducting when contact 56, 59 is open.
  • the gear mechanism 36 is shown in greater detail in Figs. 8 and 9'.
  • pinion 66 is in mesh with a gear wheel 6 I rotated at a constant speed by the prime mover 39 (in Fig. 7) said pinion also engaging teeth in an eccentrically mounted gear wheel 62, mounted on the shaft 31.
  • the pinion 60 is supported by a member 63 secured to a collar loosely mounted on shaft 31, said member 63 being angularly adjustable by means of a pinion 65 engaging teeth 66 on the member 63, said pinion being rotatable for this purpose by any convenient'means, or by known remote control means (not shown); so that the position of pinion 60 may be angularly adjusted in relation to gear wheels 6
  • at the receiver are scanned synchronously.
  • the scanning movement is provided by the combination of the movement of the jet of cathode rays 46 over the fluorescent screen 34 by the potentials on the plates 44, and the movement of the fllm 3
  • the scanning is performed by the combination of the movement of the jet 56 over the fluorescentscreen 5
  • the light from the point of impact of the jet 46 on the fluorescent screen 34 is focussed by means of the lens 35 onto the film 3
  • the instantaneous value of the current given by the cell 33 is proportional to the density of the film 3
  • the special scanning wave forms may be modified over a part, or only be used over part, of each picture scanned. This may be accomplished, for instance, in the case of the application shown in Fig. '7, by arranging a further series of contact arms and contacts on the prime mover or sprocket shafts, to alter the point on the potentiometer 5 to which the generator 3 is connected, or by cutting out the generator 3 altogether.
  • a sinusoidal wave may be employed and converted at the receiver by suitable means to the desired wave form.
  • a sinusoidal cur .rent driving the prime mover may be transmitted to. the receiver and caused to drive a prime mover similar to 39 which drives generators such as 3, l in Fig. 3 to produce a special scanning wave identical with that in circuit 1 for application to the plates 45 of the receiving scanner 40.
  • I mean to refer to methods or apparatus either for the sending or receiving thereof in accordance with the invention or two systems which employ the invention both in sending and in receiving.
  • Television apparatus comprising means for producing a scanning beam, means for producing a force in wave form, the waves of said force having a retarded rate of change adjacent zero amplitude, means for applying said force to the scan ning beam to effect movement thereof across an object to be scanned to scan a portion thereof at a slower rate than that at which the remainder is scanned.
  • Television apparatus comprising means for producinga scanning beam, means for producing a force in wave form, the waves of said force havinga retarded rate of change adjacent zero amplitude, means for producing another force of increasing magnitude, means for applying said forces to the scanning beam to effect movement thereof across an object to be scanned to scan a portion thereof at a slower rate than that at which the remainder is scanned.
  • Television apparatus comprising means for producing a scanning beam, means for producing a force in wave form, the waves of said force having a retarded rate of change adjacent zero amplitude, means for applying said force to the scanning beam to effect movement thereof in a path across the object to be scanned to scan a portion thereof at a slower rate than that at which the remainder of the object is scanned, andmeans to effect relative movement of said beam and object transversely to said path.
  • Television apparatus comprising means for producing a scanning beam, means for producing a force in wave form, the waves of said force having a retarded rate of change adjacent zero amplitude, means for applying said force to the scanning beam to effect movement thereof in a path across the object to be scanned to scan a portion thereof at a slower rate than that at which the remainder of the object is scanned, and means to effect relative movement of said beam and object transversely to said path at a periodically varying rate of speed.
  • Television apparatus which comprises means for producing a scanning beam, means for producing a wave form scanning force and applying the same to said scanning beam to effect vibration thereof along a straight path, and means for modifying said scanning forces to retard the time rate of change of position of said scanning beam over the central portion of its path.
  • Television apparatus which comprises means for producing a scanning beam, means for producing a wave form scanning force and applying terest of the object is scarmed'than during the scanning of the remainder of the picture.
  • Television apparatus comprising means for producing a scanning beam, a plurality of generators having difierent outputs and coupled to produce awave form force having a retarded rate .of change adjacent zero amplitude, and means for applying said force to said beam to effect movement thereof corresponding to changes in amplitude of said force.
  • Television apparatus comprising means for producing a scanning beam, a plurality of generators having different outputs and coupled to produce a wave form force having a retarded rate of change adjacent zero amplitude, means for applying said force to said beam to efifect movement thereof corresponding to changes in amplitude of said force, and means to effect relative movement of the object to be scanned and said versely to the path of one beam, translating the beam transversely of the said first movement at a periodically varying rate of speed.
  • Television apparatus comprising means for producing a scanning beam, a circuit for produc-; ing ai'force proportional to a voltage of progressively increasing magnitude, means in said circult responsive to variations in the magnitude of said voltage for varying the constants of the circuit to vary the rate of change of magnitude of said voltage, and means for applying said force to said scanning beam to effect movement of the same corresponding to the change in magnitude of the force.
  • Television apparatus comprising means for producing a scanning beam, a circuit for producing a force proportional to a voltage of progressively increasing magnitude, means for applying said force to said beam to effect movement thereof corresponding to changes in magnitude of the force, and thermionic devices in said circuit biased to operate at different values of said voltage for varying the rate of change of magnitude of said force.
  • Television apparatus comprising means for producing a scanning beam, a. circuit for producing a force of progressively increasing magnitude,
  • Television apparatus comprising means'to produce a pair of scanning beams, means for producing a wave form force having a slower rate of change adjacent zer o amplitude than elsewhere, means for applying said force tosaid scanning beams to eifect vibration thereof along straight paths, means to advance the object to be scanned transversely to one beam at a periodically varying rate of speed, means for producing a force of progressively increasing magnitude proportional to the extent of movement of said object, and means for applying said force to the second beam to effect movement thereof normal to its vibrating movement at the same rate of movement as'said object.
  • Television apparatus comprising means to produce a pair of scanning beams, means for producing a force in wave form, the waves of said force having a retarded rate'of change adjacent zero amplitude, means for applying said force to second beam to effect movement thereof normal to the movement effected by the first force.
  • the method of transmitting an image of an object by television which comprises vibrating a pair of scanning beams along straight paths, moving the object to be scanned transresulting light various into image currents, causing these image currents to modulate the second beam, moving the path of the second beam transversely in proportion to the movement of the object, and retarding the rate of movement of the scanning beams and object during the interval of time during which the center of interest of the object is being scanned.
  • a method of television scanning which includes causing a spot of light to traverse a subject in such a manner that the instantaneous angular velocity of the spot is a minimum at the center of the traverse, and a maximum at the extremities of the traverse.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Electric Information Into Light Information (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
US499322A 1930-06-16 1930-12-01 Television method and apparatus Expired - Lifetime US2037577A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB18358/30A GB357143A (en) 1930-06-16 1930-06-16 Improvements in and relating to television and the like

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US2037577A true US2037577A (en) 1936-04-14

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US499322A Expired - Lifetime US2037577A (en) 1930-06-16 1930-12-01 Television method and apparatus

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FR (1) FR718663A (fr)
GB (1) GB357143A (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426201A (en) * 1943-01-04 1947-08-26 Standard Telephones Cables Ltd Radio detection system
US2428926A (en) * 1943-06-04 1947-10-14 Rca Corp Modified sweep circuit for cathoderay tubes
US2442583A (en) * 1942-10-10 1948-06-01 Rca Corp Scanning receiving system
US2473208A (en) * 1944-11-14 1949-06-14 Stromberg Carlson Co Apparatus for linearizing saw-tooth waves
US2523156A (en) * 1947-06-12 1950-09-19 Rca Corp Vertical sweep voltage correction for film movement in flying spot scansion
US2585865A (en) * 1948-02-06 1952-02-12 Rca Corp Film scansion apparatus
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television
US2628689A (en) * 1949-05-28 1953-02-17 Geovision Inc Dynamic scanning system
US2629829A (en) * 1945-08-03 1953-02-24 Int Standard Electric Corp Method of calibrating electric oscillation generators
US2700700A (en) * 1948-09-14 1955-01-25 France Henri Georges De Television system
US2703150A (en) * 1949-09-29 1955-03-01 Lu Garda Rieber Geophysical display system
US2798114A (en) * 1950-10-12 1957-07-02 Motorola Inc Dot-arresting, television scanning system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442583A (en) * 1942-10-10 1948-06-01 Rca Corp Scanning receiving system
US2426201A (en) * 1943-01-04 1947-08-26 Standard Telephones Cables Ltd Radio detection system
US2428926A (en) * 1943-06-04 1947-10-14 Rca Corp Modified sweep circuit for cathoderay tubes
US2473208A (en) * 1944-11-14 1949-06-14 Stromberg Carlson Co Apparatus for linearizing saw-tooth waves
US2629829A (en) * 1945-08-03 1953-02-24 Int Standard Electric Corp Method of calibrating electric oscillation generators
US2523156A (en) * 1947-06-12 1950-09-19 Rca Corp Vertical sweep voltage correction for film movement in flying spot scansion
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television
US2585865A (en) * 1948-02-06 1952-02-12 Rca Corp Film scansion apparatus
US2700700A (en) * 1948-09-14 1955-01-25 France Henri Georges De Television system
US2628689A (en) * 1949-05-28 1953-02-17 Geovision Inc Dynamic scanning system
US2703150A (en) * 1949-09-29 1955-03-01 Lu Garda Rieber Geophysical display system
US2798114A (en) * 1950-10-12 1957-07-02 Motorola Inc Dot-arresting, television scanning system

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Publication number Publication date
GB357143A (en) 1931-09-16
FR718663A (fr) 1932-01-27

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