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US2479880A - Discontinuous interlaced scanning system - Google Patents

Discontinuous interlaced scanning system Download PDF

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Publication number
US2479880A
US2479880A US151806A US15180637A US2479880A US 2479880 A US2479880 A US 2479880A US 151806 A US151806 A US 151806A US 15180637 A US15180637 A US 15180637A US 2479880 A US2479880 A US 2479880A
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Prior art keywords
exploration
sweeping
points
line
image
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Expired - Lifetime
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US151806A
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English (en)
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Toulon Pierre Marie Gabriel
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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

  • This invention refers to television apparatus in which the exploration either in transmission or reception is efiected by means of a movable cathode beam. It especially refers to transmission apparatus in which the exploration is efiected by the displacement or shutting off of the electronic image.
  • the invention furthermore makes it possible to considerably improve the definition of the points of the image in the direction of the sweep.
  • the cathodic beam or its electric circuit or electric circuits connected therewith are acted upon in such a manner that the exploration no longer is made in a continuous manner, but by separate points.
  • the points explored/during the sweeping may be at a certaln distance from each other. either on the same line or on diiferent lines, at equal or different distances.
  • a further object oi the invention is to provide means which make it possible to assure this exploration in such a manner that all the points of the image are explored once during a certain time interval.
  • the action in accordance with the invention consists of a complete modulation of the intensity, namely the cathodic beam is caused to appear and to disappear periodically on the swept line.
  • an electronic transmitter for instance an iconoscope
  • the action exercised in accordance with the invention is periodical, that is, the different points of each line are explored by skipping an always equal number of points which are to be explored subsequentlyduring the subsequent sweepings.
  • the appearance and disappearance of the electronic beam are obtained preferably by acting on the potential of an electrode of the cathodic beam tube by means of an auxiliary I such a manner that the cathodic beam is periodically interrupted at the corresponding frequencies and as the sweeping occurs at constant speed, the points explored are located at successive equal distances from oneanother.
  • the frequency of this auxiliary current is synchronized with the image frequency of the transmitter, in such a manner thatall the points of the surface are explored always in the same order. This frequency may furthermore show a certain fixed ratio with the frequency of the lines; in other words, in a line there is always found the same number of points explored at each sweeping. The ratio between these two frequencies need not necessarily be an integer.
  • the order of the sweeping may be such that the points explored on each line are placed one below the other.
  • the analysis thus realized corresponds to an interlaced line exploration or interlaced scanning in a direction perpendicular to the sweeping, that y is, perpendicular to the motion of the beam.
  • Each one of the lines 'of the image may be swept several times'in succession by exploring different elements of this line each time, which elements complement each other. In'this way all the points of the line are explored before passing to the following line; it is also possible to explore one part of the elements of the line swept, then pass to the next line, exploring again certain points and in this way sweep the entire surface; after this sweeping is over, a return may be made to the first line in order to explore a certain number of points which have been missing, and so on,
  • Fig. 6 shows diagrammatically the. generalv arrangement of a complete transmitting assembly using the principle of the invention
  • Fig. 6a shows the receiving assembly corresponding to the transmitting assembly of Fig. 6;
  • Fig. 7 indicates as a function of time the currents which circulate in the different parts of the 'assembly of Fig. 6 and thus makes clear the operation of the embodiment of Fig. 6.
  • Fig. 1 shows the tracing of a special manner of exploration in which, as the electronic beam moves horizontally, the explored points of each line are located with respect to'the points of the neighboring horizontal line in such amanner as to form continuous vertical strips.
  • 1! designates the number -of contiguous points which constitute the horizontal line and p the number of contiguous lines arranged one above the other in the vertical direction and which constitute the image. It is assumed that the sweeping of each line is effected from left to right and that the sweeping of the successive lines of the image is done in a downward direction. It is also assumed that the electronic beam starts to strike exploring in this way all the points of the image during several successive sweepings of the entire surface.
  • FIGs. 1, 2 and 3 show diagrammatically the tracings of the special manners of exploration in accordance with the invention
  • Fig. 4 shows the partial tracing of another improved variant of exploration
  • Fig. 5 shows an assembly making possible, among other things, the realization of the exploration in accordance with Fig. 1;
  • point 1 which belongs to the electronic image in the case of a transmitter of the iconoscope type or belongs to a fluorescent screen in the case of a Braun tube receiving apparatus.
  • the regular sweeping makes possible the exploration of point 2, located in the third compartment of the line, then points 3, 4 and so on, arranged respectively in the 5th and 7th compartments up to the point n/2 which is located in next to the last compartment of the line.
  • the second line is then swept.
  • the exploration then starts at the point located in the first compartment of the second the second line.
  • the sweeping is continued up to the exploration of the point located in the next to the last compartment of the last line, which is pn/Z.
  • the beam starts again sweeping a second time the first line and exploring the missing points of this line in the following order:
  • Fig. 3' shows an exploration arranged like a checker board.
  • the first line is explored in the following order: 1, 2, 3, 4 n/2.
  • the second line is explored in the following order:
  • the first sweeping of the image is terminated at point zm/2 and the sweeping starts 'again with the exploration of the point pit/2+1 located in the second compartment of the first line. and so on.
  • Fig. 4 shows a fraction of the image on which there can be seen surrounded by heavy black lines a group containing 16 compartments.
  • all the points 1 of each group are explored.
  • all the points 2 of each group are explored, and so on.
  • the complete exploration, of an image is terminated after the 16th sweeping. As all the successive points appear irregularly on the screen and at points which are very far from each other. this process stron ly increases either the definition or the persistence of the luminosity of the screen.
  • Fig. 5 shows an assembly making it possible to realize an exploration like the one described in Fig. 1.
  • the principle of this assembly consists in operating the Wehnelt cylinder of the receiving Braun tube by an alternating voltage supplied by a heterodyne and in reversing the phase I of the coupling between the heterodyne and the Wehnelt cylinder at the end of each sweeping.
  • the television receiving apparatus comprises a radio receiving set I and a Braun tube 2, the Wehnelt cylinder 3 of which receives the modulation coming from set I.
  • the system 4 selects the line and image synchronization signals; the latter release two relaxation devices respectively; the relaxation device 5 (lines) ove ates the horizon al deflecting electrodes 1 of the Braun tube while the relaxation device 6 (images) operates the vertical deflecting electrodes 8 of the Braun tube 2.
  • the modulation voltage which operates the Wehnelt cylinder an alternating voltage supplied by the.
  • transformer 9 which itself receives it from a group of amplifier tubes In and H.
  • the latter 5 receive it from a heterodyne I: with constant frequency through a transformer l2.
  • the atrangement of the tubes l0 and H assures a connection between the transformer l2 and the transformer 8 the phase of which connection is periodically inverted atthe end of each "image" sweeping.
  • the grid ll of the tube It is connected to the first anode grid I! of the tube ll through the condenser 22 and the grid I5 is connected with the grid It by means of the condenser 23.
  • the tubes In and II operate alternately and transmit the modulation from the heterodyne l3 to the transformer 9, periodically inverting the phase; for this the second control grids 25 and 26 are connected with two opposite ends of the secondary of the transformer l 2 and thus receive modulations in phase opposition.
  • the plates of the tubes i0 and H feed in parallel the primary of the transformer 9.
  • the heterodyne continues to extinguish the beam pe riodically but in view of the fact that the connection occurs each time through the circuit which comprises the tube H, the phase of this extinction is staggered or displaced to the extent v of half a cycle of the alternating voltage of the heterodyne i3 and the points explored during the second sweeping are staggered to the extent of one compartment.
  • the frequency of the heterodyne l3 may be any frequency whatsoever provided it is sufficiently high and remains quite constant with respect to time. I It is, however, advantageous in order to obtain a good relative position of the points-explored during successive sweeping-s. to control this frequency in connection with the frequency of the sweepings of the lines in such the tubes operates, the other is out 'of operation 7 a'manner that the centering 'of each exploration is again well defined at the beginning of the sweeping of each line. This result may be obtained, for instance, by inducting on the control grid circuit of the heterodyne l3 a voltage taken from the circuit-of the line relaxation device 5.
  • the discharge current of the thyratron constituting this relaxation device may be utilized in order to obtain the current impulse which is necessary to assure the stabilization of the heterodyne l3plf the assembly of Fig. 5 is used with present methods of transmission with interlaced lines, a checker board exploration is realized in accordance with that of Fig. 2 and in this way a greater precision of the points is assured and the flickering is reduced to a further extent.
  • this circuit may be interrupted periodically and the interruptions staggered during the successive sweepings.
  • the staggering between the points explored during consecutive sweepings is realized by a suitable choice between the frequency of the heterodyne of the receiving station and the frequency of the line synchronization signals. If necessary, special end of lines synchronization signals or signals which are suitably staggered in .time may be used for this purpose.
  • the heterodyne execute an odd number of alternations in the interval between two end of lines synchronization signals.
  • the periodical extinction of the beam, realized by the heterodyne then produces automatically a checker board exploration in accordance with that shown in Fig. 3, this being done without having recourse at the place of reception to any phase inversion artifice at the end of each line, as was necessary in the example described in connection with Fig. 5.
  • the new exploration in accordance with t e invention makes it possible to realize transmissions of images destined for television, the sharpness and definition of which are considerably increased when the pass band utilized for the transmission is the same width. This result is very important if the difliculties which occur in connection with increasing the transmission passband width are considered.
  • Figs. 6 and 6a show complete basic diagrams of a transmission system based on the new process which is the subject matter of the invention.
  • Fig. 6 shows the transmitter and Fig. 6a the receiving station.
  • Fig. 7 makes it possible to understand why an improvement of the definition of the image is obtained although the band width for the transmission is not extended.
  • Figs. 6 and 6a 25 represents an iconoscope tube on which there is formed the image 46 to be transmitted and 26 is the Braun tube on which this image is received.
  • the sweeping of the cathode beam of the iconoscope is accomplished by means of deflecting electrodes 21 and 28 connected respectively with the two relaxation devices 29 and 30 for the lines and images, these two relaxation devices being fed by a common multivibrator 3
  • the modulation supplied by the sweeping. of the elements of the photoelectric surface of the iconoscope is transmitted to the amplifier '32 which modulates the radio transmitting set 33.
  • This station receives at the same time the "line" and image" synchronization signals suitably arranged after extraction starting from the relaxation devices 29 and 30 through the intermediary of the amphfier 34.
  • the image current of the iconoscope is periodicall interrupted by means of a member 35 operated by a heterodyne'36.
  • the latter is controlled by an oscillatory member with fixed frequency, for instance. the multivibrator 3
  • the amplifier 32 reduces the amplitude of the cuts made on the modulation transmitted, as will be explained below.
  • the radio receiving set 31 in Fig. 6a receives at the same time the modulation and image signals.
  • the sorting device 40 separates the line" and "image synchronization signals. These signals are transmitted to the relaxation devices ll and 42, respectively, acting on the deflecting plates of the Braun tube 26.
  • the modulation received by the set 31 controls the Wehnelt cylinder due to the amplifier 43.
  • a member 44 periodically interrupts the cathode beam.
  • This member 44 is operated by the heterodyne 45, the frequency of which is stabilized due to the modulation supplied by the heterodyne 36 of the iconoscope a slight residue of which is superimposed upon the useful vision modulation during the course of the transmission.
  • This stabilization is obtained, for instance, by placing at he output of the receiving set 31 an oscillatory circuit tuned to the frequency of the heterodyne 36.
  • Fig. 7a there is shown the brightness of the successive points of a line of the image to be transmitted.
  • Fig. 71 there is shown the corresponding vision current generated by a standard iconoscope and not possessing the improvement of the invention.
  • the heterodyne 36 supplies a voltage represented as a function of time by the curve in Fig. 70. This heterodyne acts on the vision current through a suitable interrupting member 35. The thus interrupted vision current is represented by the ,curve of Fig. 7d.
  • the curve corresponds to the exploration of odd points.
  • the amplifier 32 is especially arranged to prolong the duration of signals and comprises one or more coupling elements between its stages having a certain time constant.
  • the latter may be obtained with the aid of several parallel capaoitors in the plate circuit of one of the tubes and of series resistors joining the capacitors, which arrangement also functions as a low-pass filter.
  • the curve of Fig. 7e represents the retarding eflect produced systematically on these signals due to the amplifier 32. In the place of a complete interruption of the current between each point explored, only a very slight reduction of the current is obtained. However, this slight variation sufiices to assure the synchronism of the heterodyne 45 at the receiving station with the heterodyne 36.
  • th necessary pass-band width is clearly less than that for the curve of Fig. 7d.
  • the present invention covers also any other manner of transmission in which the exploration is realized in accordance with the invention place 45 Number Name Date 2,034,704 Nakashima Mar. 24, 1936 2,082,093 Bedford June 1, 1937 2,093,157 Nakashima Sept. 14, 1937 FOREIGN PATENTS Number Country Date 420,391 Great Britain Nov. 30, 1934 431,339 Great Britain July 3, 1935 443,896 Great Britain Mar. 10, 1936 451,745 Great Britain Aug. 11, 1936 456,564 Great Britain Nov. 11, 1936 797,332-
  • one elemental area in each of said groups is scanned during each field and that dif Schlierentelemental areas in each of said groups are scanned during successive ones of said fields.
  • An electron beam scanning system comprising an explored surface defined by a plurality of groups of at least four substantially equal elemental areas extending substantially equidistantly along two coordinates, means for generating an electron scanning beam, means for defiecting said beam along said coordinates in synchronism with a line and a field sequence, means for periodically interrupting said beam, and means for so synchronizing said means for deflecting and said means for'interrupting that a corresponding elemental area in each of said groups is scanned during each field, and that different elemental areas in each group are scanned during succ ssive ones of said fields.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)
  • Television Systems (AREA)
US151806A 1936-07-04 1937-07-03 Discontinuous interlaced scanning system Expired - Lifetime US2479880A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR708061X 1936-07-04

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US2479880A true US2479880A (en) 1949-08-23

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US (1) US2479880A (fr)
DE (1) DE708061C (fr)
FR (1) FR819883A (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2623196A (en) * 1950-02-28 1952-12-23 Products And Licensing Corp Television apparatus and method for phase-shift scanning
US2678349A (en) * 1949-09-14 1954-05-11 Forbes Gordon Donald Periodic line interruption with vertical alignment of segmented portions of kinescope raster
US2695330A (en) * 1950-05-08 1954-11-23 Rca Corp Color television
US2777971A (en) * 1948-05-22 1957-01-15 Ibm Information storage means
US2798114A (en) * 1950-10-12 1957-07-02 Motorola Inc Dot-arresting, television scanning system
US2804495A (en) * 1950-02-28 1957-08-27 Marconi Wireless Telegraph Co Color television transmitting system
US2823258A (en) * 1951-03-07 1958-02-11 Motorola Inc Television dot scanning system
US2824904A (en) * 1949-02-17 1958-02-25 Moore And Hall Band compression television system
US2906812A (en) * 1954-05-18 1959-09-29 Pierre M G Toulon Television scanning system
US2909600A (en) * 1956-07-26 1959-10-20 Bell Telephone Labor Inc Two-way television over telephone lines
US2926338A (en) * 1955-04-20 1960-02-23 Rca Corp Method of and system for storing data magnetically
US2940005A (en) * 1950-07-19 1960-06-07 Moore And Hall Variable discontinuous interlaced scanning system
US2939909A (en) * 1955-07-06 1960-06-07 Westinghouse Electric Corp Television system
US2955159A (en) * 1958-10-01 1960-10-04 Itt Narrow-band video communication system
US3065294A (en) * 1949-03-22 1962-11-20 Moore And Hall Television system for high definition and secrecy of image
US3119949A (en) * 1961-02-06 1964-01-28 Jr William H Greatbatch Television type selected raster lines display
US3200195A (en) * 1960-10-26 1965-08-10 Marconi Co Ltd Television systems
US3268763A (en) * 1962-06-20 1966-08-23 United Aircraft Corp Space-time sequence generator for electron beam machining
US3499980A (en) * 1967-05-04 1970-03-10 Itt Sequential dot interlace system and method for television
WO1994003013A1 (fr) * 1992-07-21 1994-02-03 Dr. Sala And Associates Pty. Ltd. Systeme de traitement d'image
US5940051A (en) * 1994-08-11 1999-08-17 Dr. Sala & Associates Pty Ltd. Display system

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR959300A (fr) * 1940-12-19 1950-03-28
US2472774A (en) * 1945-10-17 1949-06-07 Farnsworth Res Corp Irregular interlace scanning system
BE506424A (fr) * 1950-10-14
DE942933C (de) * 1951-06-10 1956-05-09 Nordwestdeutscher Rundfunk Anordnunger zum farbigen Fernsehen
US2911465A (en) * 1952-05-22 1959-11-03 Moore And Hall Television systems
DE1042672B (de) * 1953-09-11 1958-11-06 Siemens Ag Verfahren zur Verringerung des Frequenzbandes bei der UEbertragung von Radarschirmbildern
DE1169501B (de) * 1961-07-26 1964-05-06 Siemens Reiniger Werke Ag Fernseheinrichtung fuer die Aufnahme und Wiedergabe von Roentgenbildern
GB2048609B (en) * 1979-03-30 1983-05-25 Hitachi Electronics Solid-state colour imaging camera

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB420391A (en) * 1932-07-19 1934-11-30 Marconi Wireless Telegraph Co Improvements in or relating to television systems
GB431339A (en) * 1934-01-03 1935-07-03 John Logie Baird Improvements in or relating to television or like systems
GB443896A (en) * 1934-10-06 1936-03-10 Gen Electric Co Ltd Improvements in or relating to television
US2034704A (en) * 1932-03-30 1936-03-24 Nakashima Tomomasa Television receiving system
FR797332A (fr) * 1934-11-05 1936-04-24 Farnsworth Television Inc Procédé d'exploration par lignes décalées, en particulier pour la télévision
GB451745A (en) * 1934-11-17 1936-08-11 Loewe Opta Gmbh Television
GB456564A (en) * 1935-03-26 1936-11-11 Marconi Wireless Telegraph Co Improvements in and relating to television systems
US2082093A (en) * 1933-01-28 1937-06-01 Rca Corp Television system
US2093157A (en) * 1932-12-12 1937-09-14 Nakashima Tomomasa Television receiving system

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2034704A (en) * 1932-03-30 1936-03-24 Nakashima Tomomasa Television receiving system
GB420391A (en) * 1932-07-19 1934-11-30 Marconi Wireless Telegraph Co Improvements in or relating to television systems
US2093157A (en) * 1932-12-12 1937-09-14 Nakashima Tomomasa Television receiving system
US2082093A (en) * 1933-01-28 1937-06-01 Rca Corp Television system
GB431339A (en) * 1934-01-03 1935-07-03 John Logie Baird Improvements in or relating to television or like systems
GB443896A (en) * 1934-10-06 1936-03-10 Gen Electric Co Ltd Improvements in or relating to television
FR797332A (fr) * 1934-11-05 1936-04-24 Farnsworth Television Inc Procédé d'exploration par lignes décalées, en particulier pour la télévision
GB451745A (en) * 1934-11-17 1936-08-11 Loewe Opta Gmbh Television
GB456564A (en) * 1935-03-26 1936-11-11 Marconi Wireless Telegraph Co Improvements in and relating to television systems

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2777971A (en) * 1948-05-22 1957-01-15 Ibm Information storage means
US2824904A (en) * 1949-02-17 1958-02-25 Moore And Hall Band compression television system
US3065294A (en) * 1949-03-22 1962-11-20 Moore And Hall Television system for high definition and secrecy of image
US2678349A (en) * 1949-09-14 1954-05-11 Forbes Gordon Donald Periodic line interruption with vertical alignment of segmented portions of kinescope raster
US2804495A (en) * 1950-02-28 1957-08-27 Marconi Wireless Telegraph Co Color television transmitting system
US2623196A (en) * 1950-02-28 1952-12-23 Products And Licensing Corp Television apparatus and method for phase-shift scanning
US2695330A (en) * 1950-05-08 1954-11-23 Rca Corp Color television
US2940005A (en) * 1950-07-19 1960-06-07 Moore And Hall Variable discontinuous interlaced scanning system
US2798114A (en) * 1950-10-12 1957-07-02 Motorola Inc Dot-arresting, television scanning system
US2823258A (en) * 1951-03-07 1958-02-11 Motorola Inc Television dot scanning system
US2906812A (en) * 1954-05-18 1959-09-29 Pierre M G Toulon Television scanning system
US2926338A (en) * 1955-04-20 1960-02-23 Rca Corp Method of and system for storing data magnetically
US2939909A (en) * 1955-07-06 1960-06-07 Westinghouse Electric Corp Television system
US2909600A (en) * 1956-07-26 1959-10-20 Bell Telephone Labor Inc Two-way television over telephone lines
US2955159A (en) * 1958-10-01 1960-10-04 Itt Narrow-band video communication system
US3200195A (en) * 1960-10-26 1965-08-10 Marconi Co Ltd Television systems
US3119949A (en) * 1961-02-06 1964-01-28 Jr William H Greatbatch Television type selected raster lines display
US3268763A (en) * 1962-06-20 1966-08-23 United Aircraft Corp Space-time sequence generator for electron beam machining
US3499980A (en) * 1967-05-04 1970-03-10 Itt Sequential dot interlace system and method for television
WO1994003013A1 (fr) * 1992-07-21 1994-02-03 Dr. Sala And Associates Pty. Ltd. Systeme de traitement d'image
US5940051A (en) * 1994-08-11 1999-08-17 Dr. Sala & Associates Pty Ltd. Display system

Also Published As

Publication number Publication date
DE708061C (de) 1941-07-11
FR819883A (fr) 1937-10-28

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