US2192121A - Television system and the method of operation thereof - Google Patents

Television system and the method of operation thereof Download PDF

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Publication number
US2192121A
US2192121A US728147A US72814734A US2192121A US 2192121 A US2192121 A US 2192121A US 728147 A US728147 A US 728147A US 72814734 A US72814734 A US 72814734A US 2192121 A US2192121 A US 2192121A
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United States
Prior art keywords
signals
synchronizing
framing
impulses
tube
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Expired - Lifetime
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US728147A
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English (en)
Inventor
Alda V Bedford
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RCA Corp
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RCA Corp
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Publication date
Priority to BE434568D priority Critical patent/BE434568A/xx
Priority to BE409634D priority patent/BE409634A/xx
Priority to NL44375D priority patent/NL44375C/xx
Priority to BE414635D priority patent/BE414635A/xx
Priority to BE424847D priority patent/BE424847A/xx
Priority to BE414088D priority patent/BE414088A/xx
Priority to US728147A priority patent/US2192121A/en
Application filed by RCA Corp filed Critical RCA Corp
Priority to FR790492D priority patent/FR790492A/fr
Priority to GB15685/35A priority patent/GB448065A/en
Priority to DER93472D priority patent/DE716028C/de
Priority to DER97973D priority patent/DE685918C/de
Priority to DER95917D priority patent/DE714155C/de
Application granted granted Critical
Publication of US2192121A publication Critical patent/US2192121A/en
Anticipated expiration legal-status Critical
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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
    • H04N3/36—Scanning of motion picture films, e.g. for telecine
    • H04N3/40—Scanning of motion picture films, e.g. for telecine with intermittently moving film
    • H04N3/405—Scanning of motion picture films, e.g. for telecine with intermittently moving film with film moving only during the field blanking interval
    • 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
    • H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
    • H04N3/24—Blanking circuits
    • 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
    • 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
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/52—Automatic gain control
    • H04N5/53—Keyed automatic gain control

Definitions

  • My invention relates to improvements in television systns and the method of operation thereof.
  • Vit has been found to be advantageous to cause the cathode rays to scan the respective screens in such manner that the horizontal lines of alternate frames fall in 'the spaces between the horizontal lines ⁇ of the intervening frames.
  • the 'horizontal lines of the odd frames are spaced a distance about equal to the width of a line
  • the Vhorizontal lines of the even frames which are similarly spaced, fall between the lines of the odd frames.
  • the optical effect is the same as though each frame comprised twiceA the number of lines.
  • interlaced scanning This distinctive action of scanning is sometimes referred to as interlaced scanning.
  • the cathoderay.v is deflected horizontally an odd number of times every two frames, the relation of the line frequency to the frame frequency being such that the scanning of each odd framey starts at the same point at the upper left hand corner of the screen, while the scanning action for each, even frame starts at the same point which is a distance of one-half a line to the right from the common starting point for the rodd frames.
  • the lines of the even frames are disposed in the spaces between the lines of the odd frames.
  • a synchronizing signal is transmitted at the end of each scanning line and utilized at the receiver to drive the circuit for defiecting the cathode ray horizontally.
  • a framing signal is transmitted and utilized at the receiver to drive the circuit for deiiecting the ray vertically.
  • the odd and even framing signals occur at different times with a respect to the synchronizing signals.
  • occurrence ofthe framing signals prevents any synchronizing signals from being eective during the periods of occurrence of the framing signals. During these periods, therefore, a relatively slight electrical disturbance or misadjustment is effective to cause the scanning action at the receiver to fall out of time with that at the transmitter.
  • undesirable electrical effects are developed due to return deflection of the cathode ray at the transmitter, the action of cutting oi the ray during the return line periods, and, in the transmission of moving picture film, the action of iiashing images of the pictures onto the photos'ensitive surface of the usual screen.
  • the direct current component of the signals is lost during the operating action at the transmitter.
  • the effect of this is manifested at the receiver by production of an image whose overall brilliancy or background does not necessarily correspond with that of the object being transmitted.
  • Another object of my invention is to provide an improved television system and method of operation in which the undesirable electrical signals or other disturbing electrical effects referred to are either eliminated or compensated for at the y transmitter without interfering with the development and transmission of the desired picture, synchronizing and framing signals.
  • Another object of my invention is to provide an improved television system yand method of operation whereby there is developed a signal wave which forms part of and is transmitted with the entire signal wave.
  • 'Ihis signal Wave is representative of the required. direct current component which can be utilized at the receiver to vary the background of the reproduced picture automatically and in accordance with occurring variations of the overall brilliancy or background of the ⁇ object at the transmitter.
  • framing signals are interrupted, and synchronizing signals are caused to occur during the interruption periods whereby the circuit for horizontal deection of the ray is supplied with synchronizing signals during the framing periods.
  • the picture signals developed at the transmitter are supplied to an ampliier comprising a plurality of tubes, some of which are driven to saturation during the periods of return deection of the ray so that the undesirable electrical signals developed during these periods do not appear in the output wave from the amplier.
  • the synchronizing and framing signals aresupplied and transmitted with the picture signals.
  • My invention resides in the improved system and method of operation of the character hereinafter described and claimed.
  • Figure 1 is a diagrammatic view of a television transmitting system constructed and operating in accordance with my invention
  • Fig. 2 is an enlarged, detail, sectional view
  • Fig. 3 is an enlarged elevational view of the disc in Fig. 1 for developing the synchronizing and framing signals;
  • Fig. 4 is an enlarged fragmentary view, taken from Fig. 3;
  • Fig. 21 is a diagrammatic view of one form of television receiving apparatus for intercepting and utilizing the signals transmitted by the systernl in Fig. 1 to produce an image of the object;
  • the picture signals are developed by a cathode ray tube I 0 provided-
  • This screen is of the usual construction and comprises a sheet of insulation j.
  • the insulating sheet is provided over the opposite 'surface thereof with a sheet or coating of electrically conductive material to which an output connection I6 is made.
  • the tube I0 is provided with an electron gun I8 for developing a ray 20 of electrons and diresting the same at the mosaic photosensitive surface I4 of the screen.
  • the gun comprises a cathode 22, a grid 24 for controlling the intensity of the ray, and an anode 2S-for accelerating the Fig. 22 is a detail diagrammatic view'of one of l electrons.
  • a second anode 28, which may be in the form of a lsilver coating on the inside surface of the tube, is maintained at a relatively high potential positive with respect to the potential on the nrst anode 26, and operates in cooperation with the latter to focus the ray of electrons to a relatively small spot on the screen I2.
  • the various electrodes of the tube are supplied as usual with suitable operating potentials, as represented in the drawings.
  • a circuit 36 For the purpose of causing the ray 26 to scan the screen I2, a circuit 36, connected as shown to the coils 3.2, develops a voltage wave of the required shape and frequency to cause a sawtooth current Wave to pass through .these coils at a frequency of 7290 cycles, and a circuit 34,'connected as shown to the coils 36, develops a voltage wave o1' the required shape and frequency to cause a saw-tooth current wave tov pass through the coils 36 at a frequency of'60 cycles.
  • the object is represented as being a moving picture nlm 38, and the apparatus for projecting the individual pictures onto the screen surface I4 is shown as being the same as that descn'bed in detail in my copending application, Serial No. 653,947, filed January 28, 1933.
  • This apparatus comprises a disc 40 provided with diametrically opposite openings 42 and 44 and driven at a constant rate of revolutions a second by a synchronous motor 46.
  • the lm 38 is fed intermittently through a gate 48 atthe rate of 24 pictures a second by means of suitable intermittent during the periods that theopenings 42 andA 44 expose the screen I2 to the light, and these periods are equal to and occur simultaneously with the periods during which return deflection of the ray 20 takes place in the vertical direction.
  • the ray 20 scans the screen once.
  • each of the odd pictures for example, is left stationary in the iilm gate 48 for projection three times onto the screen I2, while each of the even pictures is held stationary in the film' gate for projection twice onto the screen. Since 12 odd pictures and 12 even pictures are fed through the gate 48 every second, there will be periods every second during which an image of a iilm picture isflashed onto the screen I2. Due to this action, it is possible to feed the lm at the rate of 24 frames a second and to scan the screen I2 at the rate of 60 times a second.
  • the means for developing the synchronizing and framing signals comprises a disc 54 which is rotated at the rate of 30 revolutions per sec.- ond by a synchronous motor 56 supplied from the same source 58 as the motor 46.
  • a connection 88 from the filter supplies the framing signals to the vertical deflection circuit 3,4.
  • the lens 18 is used to focus the light from a source 68 on a slit 12 in a mask 14, and a second lens 16 is used to focus the light from the slit 12 on the openings in the disc 54, as more clearly shown in Fig. 2.
  • the openings in the disc 54 through which light from the source 68 shines are in the form of slits 18, 243 in number, evenly spaced, and disposed at the outer edge of the disc.
  • the slit 12 is about the same size and shape as the slits 18.
  • the 'Ihe disc 54 is also provided with two openings 88 and 82 diametrically opposite to each other, and through which the light shines to develop the framing signals.
  • the framing opening 88 is interrupted tovmake room for a synchronizing slit 18, and the framing opening 82 is likewise interrupted to make room for a synchronizing slit 18.
  • the areas of the sectional openings comprising the openings 88 and 82 are such that the total open area in each case is equal, so that the same amount of light will pass through each of these openings.
  • Additional slits 84 similar to and spaced the same as the slits 18, are disposed as shown about the framing opening 88 and between the slits 18.
  • One of the slits 84 is disposed in the remaining gap in the framing opening, as shown.
  • additional slits 86 also similar to and spaced the same as the slits 18, are disposed about the framing opening 82.
  • One of the slits 86 is disposed, as shown, in the remaining gap in the openings 82.
  • connection 88 and through a resistance 98 to the output connection 82 from an amplifier comprising the tubes 94, 96, 88,
  • the disc 54 is also provided with a second set oi' slits
  • 88 are disposed diametrically opposite and on the same circumference as the slits
  • 88 extends over a distance equal to about seven times the distance between two adjacent slits
  • the amplied signals from the amplifier 4 are applied by way of a condenser
  • 4, at positive polarity, are also applied by Way of a resistance
  • 'I'he disc 54 is also provided with openings
  • 28 is focused on the openings
  • These signals are amplified by an amplifier
  • the framing signal for every odd frame represented at 88:1: in Fig. 5
  • the framing signal for every even frame represented at 82:1:v in Fig. 6, would occur at different times with respect to the synchronizing signals represented at 18x.
  • the effect of this, in the systems proposed heretofore, is illustrated in Fig. 7.
  • 35 represents what the output wave in the line 68 from the filter 65 would' be for the even frames
  • 31 represents what the output wave in the line 68 would be for the even frames.
  • 31 will differ in size and shape, as represented.
  • the framing signal for each odd frame, represented at 88g, and the framing signal for each even frame, represented at 82g, will therefore be different in size and shape. For this reason, the timing for vertical deflection of the cathode ray tends to be inaccurate, in which case the odd and even lines will not ⁇ have the required spacingand positions with respect to each other to obtain a properly interlaced pattern.
  • auxiliary signals occurs during a period of interruption of the framing signal for the even frames, as shown.
  • auxiliary signals will occur at the same times as the synchronizing signals would occur if the frequency of the latter were doubled during a period of. time slightly greater than and embracing the period of occurrence of theframing signal for the even frames, represented at 80h. h
  • Figs. 8 and 9 may be described from a somewhat different viewpoint.
  • the several portions of the framing signal 80a which are separated by the interruptions are indicated as 80m, 80a2 and 84aa While the several portions of the framing signal 80h are indicated as 88171, 80172 and 80173.
  • the space between the signal portions 80a1 and 84a may be referred to as a slot.
  • the space between portions 80a2 and 18a is another slot.
  • the space between 80171 and 18h and the space between 801m and 86a may be referred to as slots in the framing signal.
  • framing signals are made substantially the same in size and shape, might be improved further by making some of the slits 84 andA 86 slightly wider or narrower than the others, or by making one or more of. these slits wider and one or more of these slits narrower than the others.
  • the eiect of this is to cause the duration of one or more of the auxiliary signals to be less than that of the others, as represented by dash lines in Fig. 8, or the duration of one or more of the auxiliary signals to be greater than that of the others, as represented by ⁇ clash lines in Fig. 9.
  • Another modification of wave shape which would produce substantially the same result is one inv which the additional impulses 84a and 86a are omitted and the vertical synchronizing impulses 80a ⁇ and 80h are made slightly different from one another in shape or duration in order to compensate the dissymmetry of timing of the horizontal synchronizing impulses 18x with respect to the vertical synchronizing impulses.
  • the synchronizing signals which occur during the periodsof. interruption of the framing signals are eiective to drive the horizontal deilection circuit 30. This circuit is therefore positively driven at all times, so that it does not drift out of synchronism during the interval of the framing signal.
  • the filter 65 permits substantially only the synchronizing signals to pass to the horizontal deiiection circuit 30 by way of the connection 66, and only substantially the framing signals, which have a substantially diierent steepness of wave front than the synchronizing signals, to pass to the vertical deflection circuit 34 by way of they been exposed. ⁇ As the ray 20 is deiiected horizontally across the screen from left to right, as
  • 31 will be as represented in Fig. 11, with the picture signals representative of conditions of light at the object, of positive polarity.
  • This wave is applied to the grid circuit of the tube 94, as shown.
  • this wave will be the same shape as that in the grid circuit, but will be reversed in polarity, as represented in Fig. 12.
  • 20 will be as reprtfented in Fig. 13, with the signals of positive p larity.
  • 36, will be as represented in Fig. 14, with each signal of positive polarity.
  • the waves yas represented in Figs. 13 and 14 are applied by the connection A
  • 02 will therefore be as represented in Fig. 19.
  • This wave is comprised of the picture signals represented at
  • 52 make the undesirable signals represented at
  • 48 also, are effective to cut ofi the ray during the periods of return deflection thereof in both the horizontal and vertical directions.
  • 48 serve as pedestals upon which the synchronizing and framing signals appear, andthe latter are of the same polarity as and substantially greater in amplitude than the peak black picture signals.
  • the receiving apparatus can therefore readily distinguish the picture signals from the synchronizing and framing signals by amplitude selection.
  • the synchronizing signals are of very short duration as compared with the duration of the signals as represented at
  • the framing signals are of very short duration as compared with the duration of the signals represented at
  • the receiving apparatus shown diagrammatically in Fig. 21 comprises a radio receiver and A resistance
  • 18 is disposed at one end of the tube
  • 85 similar to thecircuit 30, operate to deflect the ray
  • 86 and an associated The wave in the connection 88 from. the output of the amplifier 64 is as represented circuit'V
  • 82 is therefore made to scan the screen
  • a filter connected in the output circuit of the tube
  • This filter comprises a falling ⁇ in the spaces between the spaced hori-V zontal lines of the' thirty odd frames.
  • 82 is varied bythe picture signals to produce the image on the screen
  • The'construction of the filter 65 lin the trans mitting apparatus is the same as the filter shown in the receiving apparatus.
  • a photoelectric cell 200 In operation, as the pictures of the film pass through the gate 48, the light is reflected from the surface of the disc 40 to the cell 200, whereupon a current is developed whose amplitude varies proportionally with occurring variations in the average brilliancy or background of the amplifier 202, shown in detail in Fig. 22.
  • the current from the cell 200 flows through the battery 203 and the potentiometer 204 in Fig. 22,
  • the grid of the tube 206 is made more or less negative, depending upon the value of the current. This causes the plate current of this tube to decrease correspondingly through the rheostat 298 to cause the potential at the point 2
  • This positive voltage is filtered by a condenser 2
  • 02 is variedvl in accordance with" variations inthe average brilliancy or so-called backgroundbrilliancy of the] ⁇ pictures being transmitted, and vvthis action controls the heighth lor eiiectivevamplltude cfjthei synchronizing signals by varying theff voltage input to this tube at whichl cut oiIoccurs.
  • the amplitudev of the synchro ⁇ r nizingsignals measured from'jtfhe A. C. axis' of l the entire wave as represented in Fig.
  • the intensityfof the ray is varied so that the background Vo'raverage brilliancy of the reproduced picture varies with ocf curring variation of the background at the'object.
  • thefcell 200 may be supported to the left of the lensv 220. in Fig. 1 to receive the light reflected the light reflected from the disc 40. Also", the cell 200 may be supported therefrom instead of adjacent the tube
  • control wave which provides for the so-called direct current component at the receiver, circuit of the tube
  • the various sets of openings or slits in the single disc 54 may be made in as many differentdiscs, all fixed yon the shaft of the motor 56 and angularly related to produce the signals in the same way as the single disc. It will be understood that in such case the photoelectric cells and-the light sources will be associated with their respective discs.
  • the method of operation which comprises developing synchronizing signals at a, relatively high line-scanning frequency and framing signals at arrelatively low framing frequency, amplifying said signals, and causing the synchronizing signals to occur at a frequency substantially greater than the linescanning frequency only during substantially the periods of occurrence of the framing signals.
  • a scanning device for developing picture signals, means for causing scanning action of said device at a given uniform rate, a multi-tube electrical circuit supplied with picture signals from said device, means supplying a tube of said amplifier with signals occurring at said rate and each of the same polarity as and greater in amplitude than any of the picture signals representative of conditions of shade at the object, and means supplying to a tube between said first-named tube and the output tube of said circuit control signals occurring at said rate and being of the same polarity as and in phase with said second-named signals.
  • a scanning device for developing picture signals, means for causing scanning action of said device at a given uniform rate, a multi-tube electrical circuit supplied with picture signals from said device, means for supplying to said circuit a first set of control signals occurring at said rate, at least one of the tubes of said circuit being cut off by each of the control signals, and means for supplying to said circuit a second set of control signals of the same polarity as and in phase with the rst set of control signals, each of the signals of the second set being of shorter duration than those of the rst set.
  • a scanning device means for causing scanning action of said device, means for developing and supplying to said firstnamed means control signals at a relatively high line frequency and other control signals at a relatively low framing frequency and with the individual framing signals interrupted and with signals at the relatively high frequency occurring during the periods of interruption of the framing signals
  • said second-named means comprising a light-sensitive device, a light source, a rotatable member for controlling the manner of illumination of said light-sensitive device by the light source and for interrupting the light at least once during the periods of occurrence of the individual framing signals, and means for rotating said member in time with the frequency of occurrence of the framing signals.
  • a cathode ray scanning device provided with a screen, means for developing a ray of electrons and directing the ray at said screen, means for deflecting the ray in one direction at a,relatively high frequency and means for simultaneously deecting the ray in a different direction at a relatively low frequency to cause the ray to scan said screen, means for generating and supplying synchronizing signals at the relatively high frequency to said secondnamed means and framing signals at the relatively low frequency to said third-named means, with the individual framing signals interrupted and with some of the synchronizing signals occurring during the periods of interruption of the framing signals, and ,an amplifier for amplifying the synchronizing and framing and picture signals.
  • a scanning device for developing picture signals
  • a multitube amplifier for amplifying the picture signals
  • a scanning device for developing picture signals
  • a multi-tube amplifier for amplifying the picture signals
  • the method of operation which comprises generating a picture-signal wave, generating and adding to said wave electrical signals occurring at a given frequency and which are of the same polarity as the picture signals representative of conditions of shade at the object and at least of the same amplitude as the peak picture signals of said polarity, and generating and adding to said wavel control signals at said polarity and which occur in phase with said electrical slgnalsjand which are of shorter duration than the latter.
  • a scanning device for developing picture signals, means for causing scanning action of said device at a given frequency, means for generating control signals at said frequency, a multi-tube amplifier for the picture signals, means for generating blanking signals and for applyingthem to one of 'the tubes of said amplifier, means for developing a. direct current which varies in accordance with occurring variations in overall brilliancy of the object being transmitted, a connection for applying the direct current to the grid circuit of a tube of said amplifier which is subsequent to said one tube, and a connection for applying the control signals to the amplier on the output side of said last-mentioned tube.
  • means for generating horizontal scanning synchronizing impulses means for generating vertical scanning synchronizing impulses each of longer time-duration than a horizontal synchronizing impulse, means for interrupting the continuity of each vertical synchronizing impulse, amplifying means for said impulses, and means for introducing into the system a horizontal synchronizing impulse during each interruption period whereby, at a receiver, the periodicity of the horizontal synchronizing impulses is not impaired.
  • means for generating horizontal scanning impulses means for generating vertical scanning synchronizing impulses at a frequency incommensurable with the frequency of the horizontal impulses and means for periodically increasing the inte ⁇ grated energy-content of the horizontal impulses at time periods immediately before the occurrence of the vvertical whereby.
  • the ,energyl contentof each ⁇ vertical impulse is substantially., the same as that of every other verticalinipulse.
  • Control apparatus comprising,means fordeveloping vcontrol 4signalsv at .a relativelyA high frequency, means for developing control signals@l at a relatively low frequency and .with the lindividual signalsat the relatively low frequency ⁇ interrupted, and meansforr supplying Van elec-- tricalfcircuit with said highfrequency signals ⁇ and said lowfrequencygsignals at-,the same 1 polarity with respect to each other and with some.,
  • vIn a television system comprising a scan- 'f ning device for obtaining scanning action at a relatively high rate kof m lines per second and z a relatively low rate of n frames per secondff an electrical channel for amplifying synchronizi-v ing signals effective at the rate of m times per 1 second and for amplifying framing signals effective at the rate of n times per second, means for developing and supplying the synchronizing signals to said amplifier channel, and means for developing and supplying the framing signals to Y said amplifier channel and in an interrupted fashion during each framing period with at least some of the interruption periods in phase ⁇ with the periods of occurrence of they synchronizing signals.
  • the method of* operation whichy comprises developing av synchronizing signal which recurs at high frequency, developing an interrupted frama relatively Y ing ⁇ signal which recurs atarelatively low fref quency ⁇ with the interruption .periods in phase with and of greater durationthan the periods of occurrence of the synchronizing signals, 'and amplifying said signals.
  • the method ofy being equal to :v-I-y, a: being a whole number and y being less than one, and developing additional signals which are similar to the synchronizing signals and which occur only during substantially the periods of occurrence of the framing signals at the frequency of at least m per second 'region of saidlpicture signals, means for clipping and in such time relation to the synchronizing signals that the effect is produced of having synchronizing signals occur at the rate of at least 2m per second.
  • a scanning device means for causing scanning action of said device, means for developing synchronizing signals at a relatively high line frequency and framing signals at a relatively low framing frequency with the individual framing signals interrupted and with the synchronizingy signals occurring during the periods of interruption of the framing signals,'and means for supplying said signals to said first named means.
  • a television system including means for generating picture signals periodically, there being undesired signals generated 'at the end of each period of picture signal generation, the method of operation which comprises so changing the amplitude location of said undesired signals that they are removed from the region of said picture signals, clipping off said undesired signals whereby4 a pedestal is produced at the end of each of said periods, and adding a synchronizing impulse to the top of each of said pedestals.
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of each period of picture signal generation, means for so changing the amplitude location of said undesired signals that they are removed from the region of said picture signals, means for clipping oil said undesired signals whereby a. pecl, estalis produced at the end of each of said periods, and meansfor varyingthe heighth of said pedestals in accordance with the average illumination of the image being transmitted.
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of each period of picture signal generation, means for so changing that amplitude location of said undesired signals that they are removed from the region of said picture signals, means for clipping off said undesired signals whereby a pedestal is produced at the end of each of s aid periods, means for varying the heighth of said pedestals in accordance'with the average illumination of the image being transmitted, and means for generating synchronizing impulses and for adding one of said synchronizing impulses to the top of each of said pedestals.
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of'each period of picture signal generation, means for so changing the amplitude location of said undesired signals that they are removed from the region of said picture signals, means for clipping off said undesired signals whereby a pedestal is produced at the end of each of said periods, means for varying the heighth of said pedestals in accordance with the average illumination'of the image being transmitted, and means for generating synchronizing impulses which are narrow as compared with the width of said pedestals and for adding one of said synchronizing impulses to the top of each of said pedestals.
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of each period of picture signal generation, means for'so changing the amplitude location of said undesired signals that they are removed from the oif said undesired signals whereby a pedestal is produced at the end of each of said periods, and means for increasing the heighth of said pedestals in response to an increase in the average illumination of the image being transmitted.
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of each period of lpicturejsignal generation, means for producing blanking impulses which occur at the same time as said undesired signals, means for adding said blanking impulses and said picture and undesired signals whereby said undesired signals are removed from the region of said picture signals, means for clipping o2 said undesired signals whereby a pedestal is produced at the end of each of said periods, means for producing synchronizing impulses which occur at the same time as said pedestals, and means for adding said synchronizing impulses to said pedestals.
  • the method of operation which comprises developing a synchronizing signal which recurs at a relatively high frequency of m per second, developing an interrupted framing signal which recurs at a. relatively low frequency of n per second with theinterruption periods of the framing signals occurring in phase with and being of greater duration than the periods of occurrence of the synchronizing signals,
  • a television system including means for generating picture signals periodically, there being undesired signals generated at the end of each period of signal generation, means for' so changing the amplitude location of said undesired signals that they are removed from the region of said picture signals, means for clipping off at least a portion of said undesired signals whereby the position of the alternating ciu'rent axis for the picture signals and the undesired signals is changed, and means for again clipping oi at least a portion of said undesired signals.
  • means for scanning a view to be transmitted and developing picture signals means for transmitting a horizontal synchronizing impulse at the end of each scanning line, said impulse having an edge which changes abruptly in amplitude in a certain direction with respect to time
  • means for transmitting framing impulses at the end of each picture frame which impulses have slots therein having an edge which changes abruptly in amplitude in said certain direction with respect to time and which occurs in the same time relation as the said edges of said horizontal synchronizing impulses whereby the time intervals between the successive abovementioned edges are the same.
  • means for generating horizontal synchronizing impulses which occur at a relatively high frequency means for generating slotted framing impulses which occurat a relatively low frequency, and means for generating a group of impulses immediately preceding each framingimpulse which impulses occur at arate which is a multiple of the frequency at which said horizontalv synchronizing impulses occur, said-slots occurring at said multiple frequency and the trailing edges of said slots occurring in the same time relation as the leading edges of said impulses in said group of impulses.
  • said last means includes means for making at least one of the impulses in said group of a diiferent width or duration than the other impulses in said group.
  • said last means includes means for generating a group of impulses immediately following each framing impulse which impulses occur at a rate which is a multiple of the fre- -quency at which said horizontal ⁇ synchronizing impulses occur, said last mentioned impulses having leading edges which occur in the same time relation as the trailing edges of said slots.
  • means for generating horizontal synchronizing impulses which occur at a relatively high frequency and means for generating groups of framing impulses which groups occur at the relatively low framing frequency, each of the impulses in one ofy said groups following one of said horizontal synchronizing impulses.
  • a method of providing synchronizingsignais for use at a television receiver employing interlaced scanning comprising generating line synchronizing pulses, generating 7g groups of pulses, each of which groups constitutes a. frame signal, causing said groups of pulses to provide, during at least the earlier part of each of said frame signals, leading edges which occur at n times the frequency of said line pulses where n is a small integer representing the number of traversals in which the object to be transmitted is completely scanned, causing certain of said leading edges to occur in phase with the leading edges of said line pulses, so that leading edges occur at line frequency throughout .said synchronizing signals, and transmitting said line pulses and frame signals.
  • a method of providing synchronizing signals for use at a television receiver employing interlaced scanning comprising generating line synchronising pulses in the intervals between trains of picture signals representative of lines of the object to be transmitted, generating auxiliary line pulses occurring-at n times the frequency of said line pulses where n is a small integer representing the number of traversals in which said object is completely scanned, causing every nth leading edge of said auxiliary line pulses to occur in phase with the leading edges of said line pulses, transmitting said line pulses during traversals of said object and transmitting said auxiliary line pulses between successive traversals of said object.
  • a method of providing synchronizing signals for use at a television receiver employing interlaced scanning comprising generating line synchronizing pulses in the intervals between trains of picture signals representative of lines of the object to be transmitted, generating frame synchronizing signals having a duration greater than the interval between successive line pulses, suppressing parts of said frame signals for forming in at least the early part of each frame signal leading edges which occur at n times the frequency of said line pulses where n is a small integer representing the number of traversals in which said object is completely scanned, causing certain of said leading edges to occur in phase with leading edges of said line pulses, and transmitting said line pulses and frame signals.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)
  • Transforming Electric Information Into Light Information (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Facsimiles In General (AREA)
  • Synchronizing For Television (AREA)
US728147A 1934-05-29 1934-05-29 Television system and the method of operation thereof Expired - Lifetime US2192121A (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
NL44375D NL44375C (fi) 1934-05-29
BE414635D BE414635A (fi) 1934-05-29
BE424847D BE424847A (fi) 1934-05-29
BE414088D BE414088A (fi) 1934-05-29
BE434568D BE434568A (fi) 1934-05-29
BE409634D BE409634A (fi) 1934-05-29
US728147A US2192121A (en) 1934-05-29 1934-05-29 Television system and the method of operation thereof
FR790492D FR790492A (fr) 1934-05-29 1935-05-24 Perfectionnements aux systèmes de télévision et au procédé d'utilisation de ceux-ci
GB15685/35A GB448065A (en) 1934-05-29 1935-05-29 Improvements in or relating to television systems
DER93472D DE716028C (de) 1934-05-29 1935-05-30 Synchronisierverfahren fuer nach dem Zeilensprungverfahren uebertragene Fernsehbilder
DER97973D DE685918C (de) 1934-05-29 1935-05-30 Einrichtung zur elektrischen Fernuebertragung der mittleren Bildhelligkeit bei Filmbildern
DER95917D DE714155C (de) 1934-05-29 1936-03-26 Fernsehuebertragungsverfahren mit Zeilensprung fuer Bilder mit gerader Zeilenzahl und zwei Zeilenzuegen je Bild

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US728147A US2192121A (en) 1934-05-29 1934-05-29 Television system and the method of operation thereof

Publications (1)

Publication Number Publication Date
US2192121A true US2192121A (en) 1940-02-27

Family

ID=24925611

Family Applications (1)

Application Number Title Priority Date Filing Date
US728147A Expired - Lifetime US2192121A (en) 1934-05-29 1934-05-29 Television system and the method of operation thereof

Country Status (6)

Country Link
US (1) US2192121A (fi)
BE (5) BE414635A (fi)
DE (3) DE685918C (fi)
FR (1) FR790492A (fi)
GB (1) GB448065A (fi)
NL (1) NL44375C (fi)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415390A (en) * 1941-09-30 1947-02-04 Crosley Corp Intermittent motion device
US2513176A (en) * 1943-02-24 1950-06-27 John H Homrighous Stereoscopic television system
US2521009A (en) * 1943-02-24 1950-09-05 John H Homrighous Television system
US2548900A (en) * 1946-06-12 1951-04-17 Sperry Corp Data presentation apparatus
US2570249A (en) * 1947-03-29 1951-10-09 Sperry Corp Combining and separating circuits
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television
DE916178C (de) * 1934-08-31 1954-08-05 Emi Ltd Synchronisierverfahren fuer die UEbertragung eines im Zeilensprung mit Zeilenzuegen abgetasteten Bildes

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE756078C (de) * 1935-04-24 1953-03-16 Emi Ltd Schaltungsanordnung zur Erzeugung einer Impulsreihe mit mindestens zwei Gruppen von Impulsen verschiedener Frequenz
DE959375C (de) * 1937-07-22 1957-03-07 Telefunken Gmbh Schaltungsanordnung zur Synchronisierung eines Vorganges mittels Impulsen, insbesondere fuer Fernsehzwecke
DE1032314B (de) * 1938-06-03 1958-06-19 Loewe Opta Ag Trenneinrichtung zur Aussiebung der Zeilenwechsel- und Zeilenzugwechselsynchronisierimpulse bei Fernsehempfaengern
DE973317C (de) * 1948-04-17 1960-01-21 L Outil R B V Et De La Radio I Fernsehanordnung

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE916178C (de) * 1934-08-31 1954-08-05 Emi Ltd Synchronisierverfahren fuer die UEbertragung eines im Zeilensprung mit Zeilenzuegen abgetasteten Bildes
US2415390A (en) * 1941-09-30 1947-02-04 Crosley Corp Intermittent motion device
US2513176A (en) * 1943-02-24 1950-06-27 John H Homrighous Stereoscopic television system
US2521009A (en) * 1943-02-24 1950-09-05 John H Homrighous Television system
US2548900A (en) * 1946-06-12 1951-04-17 Sperry Corp Data presentation apparatus
US2570249A (en) * 1947-03-29 1951-10-09 Sperry Corp Combining and separating circuits
US2625602A (en) * 1947-06-26 1953-01-13 Rca Corp Film pulldown mechanism for television

Also Published As

Publication number Publication date
FR790492A (fr) 1935-11-21
DE685918C (de) 1939-12-29
GB448065A (en) 1936-06-02
BE434568A (fi)
BE409634A (fi)
BE424847A (fi)
NL44375C (fi)
BE414088A (fi)
DE716028C (de) 1942-01-12
BE414635A (fi)
DE714155C (de) 1941-11-22

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