US2207716A - Multiplex television system - Google Patents

Description

July 16, 1940. R. w. BuMs'rfI-:AD

' l LTIPLEX TELEVISION SYSTEM Filed April 2o, 1935 4 Sheets-Sheet 1 .www

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July 15,1940 Rfw. BuMsTr-:AD 2,207,716

- IULTIPLEX TELEVISION SYSTEM Filed April 2 0, 1935 4 sheets-sheet 2 [NvsN-ron @www July 16, 194'0 R. w. BUMSTEAD 2,207,715

MULTIPLEX TELEVISION SYSTEM VOLUME{ 35 a9 oTHER STOCK GROUPS ASABovE NUME 4\ -36 p I 'I I -o-A-BR'EQIA IMAGE PRO WMM P @www - July 16, 1940'. R. w. Bums-nm 22.07316 I MULTIPLEX TELEVISION SYSTEM Filed April 20, 1935 4 Sheets-Sheet 4 Patented July 16, 194i) I UNITED STATESl PATENT OFFICE 18 Claims.

'I'his invention relates to television systems and more particularly to a device for' the dissemination of news items and other pieces of intelligence.

It is a prime object of my invention (l) to provide a system of multiplex transmission and reception of picture images over a single channel of communication.` Other objects are, (2) to provide a. device for the dissemination of news items and other pieces of intelligence; (3) to enable the recipient of a train of signals representing multiplexed picture images to select a portion thereof for control oi an image producing device while suppressing the eii'ects of picture signals unrelated to `the image which it is desired to view; (4) to provide at a transmitting station suitable means for forming on a screen an image constituting interwoven character images, and for so scanning the images that Y picture signals representing multiplexed pieces .of intelligence may. be transmitted over .one channel of communication; (5) to embrace in the useful apparatus of a transmitting station a keyboard, a storing mechanism operable from the keyboard, and a time controlled news reviewing device by which different divisions of the storing mechanism may be successively and periodically brought into operative association with an image projecting device.

My invention has particular utility in a system for the dissemination oi intelligence such as stock and commodity quotations, game scores, and for producing Word pictures having any desired newssigniiicance. The scope of the invention, is,y however, by no means limited to the elds of usefulness above indicated. Other useiul applications will readily suggestthemselves to those skilled in the art.

When the system of my invention is to be used Vfor quoting stock market prices and the like, it is preferable to employ a storing mechanism in which the transactions may be tabularly set up as on a quotation board. For my purposes, however, it is unnecessary that the prices should be made visible in the storing mechanism itself. It would be possible, of course, to post prices on an automatic quotation board of well known type and then to set up in front of such a board a television viewing and scanning device of any well known type such as would compose a train of picture signals representing an image of the quotation indicators or any portion thereof. Such an arrangement would, however, be encumbered with various disadvantages and would not utilize the signalling channel at maximum eiilciency;

primarily due to the fact that a very considerable portion of the picture area (the spaces between the characters and between the lines) would have no signiiicance. Hence I find it preferable to provide a screen on which may be projected 5 diil'erent patterns representing interwoven images of the characters used to display the quotations or other news items. The elemental areas constituting character images may, ii' desired, be fitted together closely,llike blocks in a mosaic. Subl0 stantially the entire screen area is then covered with significant elemental light and dark areas,

so that, when the image thereof is sensed by photo-electric scanning means, the resulting picture signals will be substantially continuously significant. lThat is to say, there will be a minimum of time wasted by scanning background areas. i

In order to produce a suitable background on the receiving screen so that the character images may be re-formed legibly and distinctly, I preferably provide a novel system of deecting circuits for a cathode ray tube which is comprised in the receiving apparatus, all as will be fully explained hereinafter.

A feature of my invention which greatly adds to its utility is that it embodies means enabling anyone at a receiving station to review periodically and at frequent intervals the progress of the transactions in any particular security or 80 group of securities without asking for special service as is now'required in the case of inactive stocks. By multiplexing methods the signalling channel may be so utilized as to convey signals for quotations in far greater number than the number it would be possible to read before new quotations were made available. Hence I preferably provide selectve means at each receiving station whereby any desired train of related signais may be utilized to the exclusion of those not 40 desired. The various stocks are then grouped according to some predetermined classiiication, so that, at a moments notice, a group-selecting key may be depressed at the receiver, thereby to properly condition the receiving apparatus for accepting the desired signals and for displaying the desired items on a picture reproducing screen.

Another feature of my invention is that 'by v suitably coordinating the operation of a pricestoring mechanism (a master quotation board) with a time controlled program device, it is possible to review the price iluctuations of the very active stocks at very frequent intervals, say twice every minute; the less active stocks at less lrequent intervals, say once a minute; and the inactive stocks less often than that, say at intervals of three minutes, ilve minutes or ten minutes, depending upon the number of stocks in the en-I tire list to be quoted. Upon connecting a given section of the price-storing mechanism with the transmitter, a comprehensive picture of the market for any stock up to the minute may be obtained. Such a picture preferably includes, according to present practice, the Previous days closing price, and prices for the Opening, High, Low and Last transactions. In laddition thereto I may,`if desired, display a quantityrepresenting the total number of shares in units of shares sold up to the minute of display ofthe particularstock quoted.

My invention in its broader aspects may include any of the features hereinabove setforth and many others as well. The^scope of the invention is by no means limited except as defined by the appended claims. In the detailed description to follow I have illustrated the principles and practice of the invention in respect to a preferred embodiment. It will, therefore, be understood at the outset that other embodiments readily suggesting themselves to those skilled in the art may -properly be comprehended within the scope vof the invention as claimed.

In the drawings:

Figure 1 shows somewhat dlagrammatically and somewhat in perspective a group of apparatus units suitable for transmitting picture sig- 'nals representative of multiplexed character Fig. 5 shows certain details of the electricalr system at the transmitter,

Fig. 6 shows certain wave shapes useful in the sweep circuits of a cathode ray tube, and in otherwise controlling an electron beam therein,

Fig. 7 ls a circuit diagram of a picture selecting and reproducing device; and

Fig. 8 is a sectional view of one of the. character image projectors which may be used at the transmitting station.

THE TRANSMITTER Referring first to Fig. l, a television transmitter I0 is shown with its optical system including a lens l2 which may be caused to focus an image of the screen I4 upon a photo sensitive surface (concealed within the housing of the unit Ill) to be scanned by a cathode ray according to the well known teachings of the art. It is immaterial.

Whether the screen i4 be made opaque and viewed from a position on the same side thereof as that from which the light beams are projected thereon, or whether the screen ifi is made-translucent so that it can be viewed from the rear as shown in the gure. The only difference between these two alternative arrangements is that the images as projected by different projectors I5 would in the one case be positive images and in the other case be mirror images. The transmitter l0 is provided with sweep-circuits which Vintroduce both horizontal and vertical deiiecting components into the electron beam scanning operation. The-number of scanning linesnecessary to made up of elemental light and dark areas each of which'has definite significance when coordinated with the others. rows of such4 elemental areaspreferably represents a scanning line. 'I'he cathode ray tube scanning device is arranged so that the electron beam successively impinges upon these different elemental areas along each scanning line and scans different lines successively in order to sweep over the entire scanning area. Upon scanning a single line the transmitter translates successively scanned elemental areas into a train of television signals.` In this way each'integral portion of thesignal train lscaused to represent a single elemental area, of the transmitting screen where Each of the horizontaleach such elemental 'area is v controlled by a sharply focused light beam emanating from the various light sources presently to be described. 'Ihe image pattern may, if desired, bemade up of interwoven character images. Any letter of the alphabet and .any of the numerical gures may be legibly formed by suitably disposing black and white squares in a mosaic constituted by seven horizontal rows of such squares and ve squares in a row. In some instances the necessary number of squares in a mosaic for a single character may be fewer than thirty-five. If preferred, the number may bel made greater, either by increasing the number of elemental areas along a scanning line or by increasing the number of scanning lines. For the sake of simplicity in the description of my invention I will illustrate character images covering a block of thirty-five squares, arranged in seven horizontal rows of ve squares each.

Now in orderto provide a multiplex system of transmission of signals representing character images, it is desirable that the elemental light and dark areas of each character image be interspersed with those of other character images. To do this, each elemental area on the screen. I4 is definitely assigned to some portion of a character image. Fig. 2 shows how this may preferably be accomplished. YIt will be noted that a fragmentary portion of the screen is indicatedl as having a multiplicity of elemental areas blocked out in horizontal rows representing scanning lines., Actually there are no lines on the screen but they can only be observed as boundaries between light and dark areas when light is projected thereupon.-

A multiplicity of light sources l5 is provided,

' each having a mask for composing the elements of a single character. Such a mask is shown in section at 23 in Fig. 8. The character formation i thereon may be obtained by perforations in an opaque sheet or by the-use of a film which is for'. the most part opaque but which has small translucent spots thereon arranged so as to form the elements of a character image. On the screen the character elements arespaced apart so that intervening areas may be occupied by light spots from other projectors. Thus, images become interwoven although they are not in any sense superposed because the screen areas appropriate to one character image are mutually exclusive of the screen areas appropriate to other character images.

For illustrative purposes, I have shown groups of ve elemental areas in each of three horizonthe character y tal rows bounded by heavy lines o! reference. These fifteen elemental areas are each assigned to corresponding elemental areas offifteen different character images. Their light and dark values are each under control of different 'groups of image projectors I5, and thecontrol of each is, therefore, independent of that for the others. However, it is not necessary to provide as -many projectors as there are elemental picture areas to be illuminated. Each projector is equipped with a film or mask by which a multiplicity of light beams may be-'projected on the screen so a`s to c ompose a complete character image. It is optional whether the nlm or mask in each projector be disposed so as to project a positive or a mirrorv image on to the screen, except that intheone case and screen I 4 would be made opaque and would be viewed from the side on which the light is projected, while in the other case the screen would be made translucent and would be viewed from the opposite side. Such beams may be of circular, elliptical or rectangularl cross section, but generally speaking, they are discrete in order that there may be no overlapping of elemental portions of different interwoven character images. It will be seen from the foregoing description that various character images may be outlined upon the screen by focussing sharp pencils of light upon different elemental areas thereof. Each of the projectors I5 controls as many as thirty-five such .elemental areas. Different projectors I5 may, however, be illuminated simultaneously and caused to project interwoven images upon the screen without overlapping. The method of obtaining this result is to carefully aim each projector I5 so that corresponding portions of different character images will have a slight horizontal lead one beyond another and also a corresponding vertical angular variation in order to satisfy the condition that different scanninglines of the entire screen area should be appropriate to different groups of image projectors.

From the foregoing description the method of interweaving the elemental areas of fifteen different character images has been illustrated. The arrangement of the projectors is such that they may be selectively illuminated for'the purpose of variably displaying different character images. If, therefore, a space is to be reservedion the screen for displaying letters of the alphabet, then, preferably, twenty-six projectors will be focussed on identical spots of the screen and any one of the twenty-six projectorswhen illuminated will display its respective letter. If figures only are to be displayed on certain areas then the number of projectors to be alternatively actuated will be ten.

Only seven or eight projectors are necessary in v half. The group of quotations for asingle stock: is displayed on seven character-lines, including a line for the stock abbreviation. Each character line has the height of twenty-one scanning lines,

although only seven scanning lines are used in forming a character image. The interspersed scanning lines-are used lfor the multiplexingof different character images.' The quotations usu- .ally comprise tensand units-'- digits, and a digit Arepresenting a fraction. A hyphen may be displayed when the quotation is nat The'other fractions are usually indicatedas 1, 2, 3, 4, 5, 6, and 7], the denominator /8 being understood in each case. If a stock is quoted between 100 and 200,` the tens-iigure can be represented (on the receiving. screen) in a space the width of which comprehends only three elemental areas. This leaves room to show a lhundreds-figure l as a vertical line at the extreme left of the space ordinarily occupied by the tens-ligure. Ii other hundreds-digits are to be indicated, they can usually be provided for by showing two or more dots, vertical dashes, or combinations thereof in place of the l which indicates 100. g

The seven horizontal rows of characters for a stock group may, if desired, comprise quotations larranged thus:

Previous close Stock abbreviation Opening High Low

Last (or Market) Volume omitted) v If, asshown in Fig. 3, the prices of two stocks are to be displayed simultaneously on a receiving screen, then, preferably, the width of the screen will be divided into six character spaces. On the Y area division thus far described may be tabularly summarized thus:

Horizontal aspect Each scanning line is occupied by 150 elemental areas, of which are appropriate to each of 30 characters; there being 5 characters interwoven laterally, 3 characters per stock quotation and two stock groups separated by the vertical center line of the screen. A synchronizing signal pref cedes and follows the transmission of a train of signals representative of the elemental light and dark areas along each scanning line.

Vertical aspect There are 168 horizontal scanning lines occu pied by seven character bands plus one band the `time of scanning which is utilized for trans- .mitting a frame synchronizing signal.

The picture frame As constituted at the transmitter, eighteen numerical image patterns are simultaneously arrayed on the screen for each stock group. 'IVhese eighteen image patterns are divided into six lines of three figures each representing the tens, units Each and fraction digits of 'different quotations lon each line. The quotations usually provided on an indicator of this type include the following:

Previous closing price, open, high, low, mar.

ket (or last),` and volume. The last mentioned quotation may, if desired, express hundreds of shares of stock sold up to the moment of display of the prices. From one to three letter-images are also arrayed along one character band to represent each stock abbreviation. Thirty stock groups within the picture frame X21 character images per stock group X35 elemental areas per character 22,050 elemental areas on the screen.

A group of twenty-eight projectors is adequate for displaying any possible quotation`from 1/8 to 99%. In order, therefore, to provide complete interchangeability of price images for thirty stock groups, each group comprising five prices, 5x30x28=4200 projectors are needed. If volume of transactions is also to be indicated,

` 30X30=900 additional projectors would then be arranged to cover the bottom character line of the picture.

The image pattern for all the interwoven letters of thirty stock abbreviations may, if desired, be flxedly obtained by'using a stencil or mask in a single projector for this'purpose. Such projectors, however, will be multiplied in number by the number of different stock groups to be successively displayed during a cyclic survey of all the stocks whose prices are stored in the intelligence storing device I6. In the illustrative embodiment herein shown, twenty such changes of scene are provided for. Hence there are twenty projectors for the interwoven letter images representing stock abbreviations. The 22,050 elemental screen areas may therefore be controlled by 4200+900+20=5120 projectors, if the news disseminating system is made as herein illustrated.

Referring to Fig. 8, a typical Iprojector I5 is shown swivelled on a support I'I which has a yoke I8 with bearings I9 in which two lugs 20 may rest for vertically adjusting the aim of the projector. The axis of the projector may therefore be oriented both horizontally and vertically in order that its projection of light beams may be properly aimed at the appropriate elementalv areas on the screen I4.

The projector comprises a lamp 2|, lenses 22 for diffusing the light uniformly over the area of the image lm or mask 23 and a lens 24 for focussing the image on the screen I4. Suitable adjustability of these elements with respect to one another is obtained by mounting the lamp 2| on a holder 25 and the lens 24 in a holder 26. Both of these holders slide telescopically within the cylindrical housing 21. Binding screws 28 serve to maintain all adjustments, once they are made. l

Fig. 2 illustrates further how the interwoven Y image patterns may be produced bythe cooperation of different projectors. In each rectangle comprehending fifteen elemental areas the spot in the upper left hand corner is assigned' to one message which will be termed the A1 program. On the same scanning line four other picture programs A2, A3, A4 and A5 arel arranged in succession. On the second scanning line are the five programs B1 to Bs, inclusive, and on the third scanning line programs C1 to C5, inclusive. It will now be seen that the thirty-ve elemental areas reserved for the representation of each numerical character image in program A1 are controlled by not more than -ten selectively actuated projectors I5, while similar projectors are arranged to control corrponding elemental areas o f the other fourteen programs. Thus, on the fragmentary screen area of Fig. 2 certain numerals are represented by distinguishing marks I merely to denote, by way of example, the. spots thatV would preferably be illuminated for showing- Numeral Program vMark AI X A: 0 Ci I The angle oi? incidence of the light beams as projected upon the screen I4 should be held as closely as possible to Nevertheless, departures from that angle are necessitated by the fact that a pluralityo! projectors I 5 is aimed to cover a mosaic inclusive of many interwoven character images. To compensate for possible distortion of the screen image, the image on the nlm or mask 23 within the projector maybe purposely distorted. One method of doingvthis is to take photographs of perfectly formed character image subjects with a camera set in the same position relative to the subject as a given projector will occupy relative to the screen. The resulting film, or a stenciled mask patterned therefrom, may then be used in the correspondingly situated projector. 'I'he elemental areas of each of the interwoven character images should therefore occupy their proper positions on th mosaic in perfect registration.

THE INmLIcENcn Sroanva DEVICE segments 3|, one segment being dead, and the remaining segments being connected respectively to different feeder wires 32 each leading to an appropriate lamp 2| in the projector system.

The switches may be arranged in groups, in the same manner that rotary drum dials are grouped to indicate the desired digits and'fractions of stock quotations. The wiper element 33 of each switch may be set and reset as often as necessary to store the intelligence which is to be communicated by a cyclic review of the price fluctuations. 'Ihe Wipers or selector-rotors 33 may be actuated!Y from a keyboard 34 (Fig. 1) according to a System for remote control of stock quotation boards as shown in my co-pending application Serial No. 584,431, flied January 2, 1932, or other well known means may be employed. y U. S. Patent 2,052,539 granted August 25, 1936 to Frischknecht et al. also shows a quotation board system having akeyboard and selective means for controlling rotary switches, indicators, and the like. No specific actuating mechanism is herein shown because, for the purposes of this invention, itv

tinuously cyclic survey of all the prices posted,v

corresponding segments Il lof a plurality of switches. In order to prevent "feed-back and uncontrolled dissipation of energy through the wipers of switches other than those selected from time to time to assume control,l rectiilers l! may be placed inseries with each wiper ll. Such rectiiiers may be of the dry copper-oxide plate type, and because of their low cost, their use is preferable to an alternative arrangement in which an individual make-and-break device would be necessary in the circuit for each wiper.

All of the wipers u to be simultaneously fed with current at any one moment may be permanently connected throughv a conductor I8 to one segment 31 of the timing control switch 40. Some of the conductors 3l may, however, be connected to a plurality of segments 38 or 39 in order that the frequency of feeding current to the storage switches may be greater than in the case of the conductors leading to segments 31. The object of this arrangement is to provide a review of quotations for the very active stocks at intervals, say, of thirty seconds; for the less active stocks once every minute; and for the generally least activ'e stocks once every five minutes. In the circuit diagram of Fig. 5 such a program is indicated, where the control switch has a total of fifty segments (arranged in ytwo semi-circular banks as is usual)` of which, the segments 3l lead to the storage switches for stocks that are to be quoted onceevery five minutes; while segments 3,8 lead to the storage switches for the once-aminutef quotations and segments 39 to switches for .the twice-a-minute quotations. Only one Atiming control 'switch 40 is required for the entire system.-

In order that the drawings might not be con'- fusingly elaborated by the number of lines for showing the multiplicity of conductors and rotary switches 30, the ygeneral scheme has been illustrated .by simply showing the connection to a few such' switches. "I'lie two groupseach comprising three vertical columns of switches 30 are typical of as many "switchgroups as there are stocks to be quoted." Howeventhe system as herein contemplated isof suchcapacity as to cover 600`stocks, ,and the control switch vmakes fifty changesoi sceneA within a ve minute period,y allowing sixseconds for'ea'ch display period. During the five minuteperiod, quotations for certain stocks are to be communicated by ten showingsonl the tscreen, others by lfive showings, and still others only once;` I'his is all provided for by the'arrangement"of` the twenty conductors 36, to the fifty segmentskf and 39.

Considering that there are vvthree numerical designations per quotation, six lines of quotations (including vthe volume) and 'fifteen interwoven patterns of thecharacter images and two stock groups to be displayed side by side on each "program,"'it 'will be seen thatA the number oi' rotary switches to be-simultaneously connected with ,a

power source through the timing control Vswitch 40 is 3' 6 `15 2=540, and for thetwenty conductors I6 which are successively selected by the operation of theswitch 4I.' the number of switches 30 tobefedfwith poweris 10,800. f f

Ehgch ot the twenty conductors 1 `I6 y is also branched to an abbreviation projector, twentyof which are to bef understood .as comprehended wiuunthe .rectangle m. -It wm be be recaned that'on'e interwovenimage pattern for thirty stock abbreviations.- may be displayed on fthe screen I4 by a single projector Il, provided the selection of stock groups to be simultaneously quoted remains fixed. v

Thus with each change a multiplexed image pattern according to the latest settings of the rotary switches in the price storage mechanism, an identincation of the vquotations is obtained by appropriate simultaneously projected images of the stock abbreviations. The means for actuating the timing control, or program switch 40 includes preferably a clock 4| having a contact device for periodically closing or less, and the wipers may be permitted to rest on each contact forabout six seconds to permit of the persistence oi' a given image on the receiving screen for sufllcient time to comprehend the same.

Due to the'considerable wattage of the power 5 for ligthingas many as 540 projector lamps simultaneously. `it may be desirable to employ relays, .either electromagnetic, 'mercury-pool, or electronic for feeding current to the conductors 36. If this is done, only a feeble current would be required to pass through the Wipers 44. It is also desirable thatv the connection between. the

power supply 42 and the wipers 44 be broken during the brief interval of stepping from one segment to another. Such arrangements have not been shown in the drawings because they` constitute obvious expedients well known in the art, and would only introduce unnecessary complications into the diagram. l

The photo-electric camera l ywhich senses the images formed on the screen I4 hasvits own photo-electric screen 48 on which corresponding images are formed. The electron beam scans these images'in a line-for-line manner under control of horizontal and vertical deiiecting circuits 49 which are fed with suitablesaw-tooth waves from the generator 50. The scanning lines followed by the electron beam vmust" ,trac":l with the lines' of elementaol light and dark areas of the character l.images in order yto avoidconfusion of signals; This can `be accomplished bysuit-A ably focussing and locating the optical image on the photo' sensitive surface 48.

mitter may be of any well known type.. It isl of scene that produces' The'generator 50 supplies the necessary synchronizingiimpulses adapted to send out the synchronizing and picence of each image forA a period of preferably six seconds is provided for; it may not be neces sary to repeat the scanningoperation as' rapidly as would be the practice in transmitting moving pictures.. )bjecvztionabley dicker effects canbe avoided in the display of the received image if the decay period for such an image formed on a fluorescent screen is prolonged, according toy known methods.

Tim R At any one or more points of reception'apparatus may be employed which reproduces any one of the multiplexed picture programs independently of the others. Also, a choice of the programs may be had at any receiving station which is changeable thereat under control of an observer during the periods of tron.

Fig. 7 shows apparatus to be used at each receivinsr station. First .there is a conventional radio receiver 68 for amplifying and detecting the signals. The output energy is distributed three ways- (1) as "framefrequency synchronizing impulses, (2) as scanning line frequency synchronizing impulses, and (3) as picture signals. Tuned lters 6| are provided for passing the synchronizing impulses under control of which saw-tooth waves are generated for vertically and horizontally deecting the electron beam in a cathode ray tube.

A program selector switch 62 follows the filters 6 I. In the illustrative embodiment herein shown this switch is manually controlled and has fteen positions to cover a choice of programs A1 to As, B1 to Bs and C1 to Cs as heretofore described. The choice is made by introducing more or less delay into the generation .of impulses by which all of the picture signals are suppressed except those which are to form the selected picture image. The generation of saw-tooth Waves for the sweepcircuits is also conveniently delayed, though it may not be essential to do so.

The selector switch 62 comprises a brush carrier 63 which has two brushes 64 insulated one from the other. Contact segments 65 are fed with frame-frequency impulses at, say, 16 cycles per second. Segments 66 are likewise fed with impulses at a line scanning frequency of say 2,688 cycles per second.

No delay is introduced into either of the circuits established by setting the selector switch into the rst position. The next four segments 66 (reading from left to right) lead respectively to different delay networks La to Ls for differentially delaying the generation of line-scanning waves. 'I'he rst five positions are for horizontal shifts of the picture frame independently of the picture signals. 'Ihe delay network utilized in each case is such as to render effective every fth elemental area signal, starting either with the first, second, third, fourth, or fifth signal from the beginning of each scanning line.

'I'he other delay networks Fa and Fa may be used for delaying the frame frequency scanning operation by as much as one or two line-scanning time-intervals respectively. It is to be understood that these delay networks function not only to shift the scanning lines and the vertical framing of the picture with respect to the picture signals, but also (as will hereinafter be shown) to vary therelation between the impulses transmitted through the illters 6I and the picture-signal impulses, so as to suppress all of the generator 6 8. The next'flve positions of the selector switch are such as to feed the framefrequency synchronizing impulses through the delay network F: and thence to the generator 68, thus obtaining a delay4 in the vertical scanning operation of In the remaining ve positions of the selector switch 62, the delay network F3 is brought into play, thus doubling the delay period and making it 1 403200 sec' If, therefore, the delay action of the networks La to Ls, inclusive, corresponds respectively with the time values for from one to four elemental area signals, these values will be as follows:

la-1 sec 1- sec l 1 11g-m S80.

A cathode ray tube 15 is provided having the usual electrodes for controlling the emission of electrons in a beam against a fluorescent screen 16. This tube is preferably provided with vertical dei'lecting coils 11 and electrostatic plates 18 for horizontal deflection. In place of the coils 11, electrostatic plates may be used if desired. The deflecting coils. 11 are variably energized through a circuit 19 which is fed-with power from a source 86 through the choke 81, across which variations in potential are developed when the electron tube 8| becomes more or less conductive. 'I'he return circuit from the coils 11 leads to ground (the negative side of the source being grounded) through a portion of the potentiometer 13 and, for surges, through the capacitor 1I.

The input circuit of the tube 8l includes a control grid 82,- a grid bias resistor 83, biasing battery 84, and the cathode 85. The tube 8l is controlled by thesaw-tooth wave generator 68, which may be of any well known type. Fig. 6 shows an outline of a wave 86 which may be so generated and impressed across the capacitor 81 for controlling the tube 8|.

In order that suitable separation between certain of the scanning lines may be obtained for producing a background effect between the character lines, I preferably cause the vertical scanning operation to be producedin successive steps as shown in the curve 88V of Fig. 6. This is accomplished by superposition upon the frame-frequency wave 86 of another wave 89 of saw-tooth shape but inverted. There is considerable-choice of well known means for obtaining such superposition, or mixing of two waves. I have shown, by

-to feedv current positively across the capacitor way of example, how the saw-tooth wave 88 may be impressed upon the screen grid 88 of the tube 8|. The'circuit for this purpose may be traced starting from a frequency multiplier 8| which produces the eighth harmonic of the framescanning frequency, in order that there may be eight groups, or bands of scanning lines, the lines of each band being crowded together so as to create background bands constituting horizontal character-line spaces on the screen area.

- The frequency multiplier 8| feeds energy to a saw-tooth wave generator 82 which provides impulses at the rate of 128 cycles per second.

Although I have shown only seven character lines onthe screen 16 of the cathode ray tube 15, it will be understood that a. certain time allowance must be made for the return stroke of the vertical deflection. I have conveniently ilgured thisreturn stroke as taking place during the transmission of 2| blank scanning lines, equivalent to a band of scanning lines for one character-line, or character height. It is for this reson that I preferably use the eighth harmonic of the frame scanning frequency to control the generation of saw-tooth waves as shown by the wave pattern 88 in Fig. 6. I have not shown eight such waves as occupying the time interval of one frame-scanning cycle, although, for this purpose, the showing might have been more accurate; but these curves 88, 88v, 88h, and 88 are referred to in connection with the description to follow relative to the horizontal scanning operation# However, the superposition of two such waves 86 and 88 to form a composite wave 88v may readily be understood from the appearance of the wave patterns given in Fig. 6, where t1 represents the time constant of the vertical scanning cycle, or (from another aspect) of the line-scanning cycle, while t2 represents the time constant of the saw-tooth wave to be superposed upon one of these frequencies in either case.

The wave produced by the generator 82 may be impressed across a capacitor 88 and thence to the control grid of an electron tube 84. The anode circuit of the tube 84 may be fed with energy from an intermediate point 85,on the source 88 and through an inductive impedance 86. The anode 88 has a connection to the screen grid 80 of the tube 8|.

The operation of the vertical deflecting circuit may now be described as follows:

Assuming that the gradual slope of the curve 86 is represented by a positive impulse impressed across the capacitor 81, it will be seen that the tube 8| becomes more and more conductive until suddenly this wave is interrupted completely and the tube is biased to cut-olf. At that moment the anode potential will be suddenly built up to full positive value, due to the saturation of the inductance 8,1 and to the fact that the tube 8| affords a substantially infinite impedance to the further flow of current. The eiect is to produce a strong and sudden reversal of current flow in the deecting coils 11 for producing the return stroke in the vertical 'deflection of the clectron beam in the cathode ray tube 15.

While the current is gradually being increased in value in the tube 8|, that increase may be made at twoxdiiferent rates, one while certain of the line scanning operations are being effectively performed and another for causing separation between the bands of scanning lines. This is accomplished through the use of the sawtooth wave generator 82 which maybe assumed inclusive.

88 and with gradually increasing intensity so that the tube 84 becomes gradually more conductive and the potential on the anode 88 gradually falls. This likewise gradually lowers the potential on the screen grid 88 and slows up without nullifying the increase of conductivity of the tube 8|. 4When, however, the tube 84 is suddenly biased to cut-011 by the steep return stroke of the wave 88, then the .anode 88 and the screen grid 88 become suddenly more positive and the shape of the wave 88v is caused to be formed into steps. 'Ihis provides the'desired band separation between successive groups of 21 scanning lines.

Referring now to the horizontal, or line-scanning operation, the frequency for synchronizing the waves generated by the saw-tooth generator 68 is obtained directly from the line scanning frequency signals over the conductor or through any one of the delay networks Lz to L5 'I'his frequency is assumed to be of the order of 2,688 cycles per second. Here again, the output energy from the generator 68 may be assumed to be increasingly positive as the saw-tooth wave 86 slopes gradually upward. This impulse increases the conductivity of the discharge tube |08 in the same manner as was described above in respect to the operation of the tube 8|. The tube |88 also has a screen grid |8I, which is connected to the anode of an electron tube |82. The tube |88 may be caused to operate above and below the cut-off of its characteristic in the same manner as hereinabove described in respect to' the tube 8|. The anode of the tube |8 is, however, preferably fed with current from the source 88 through an inductive impedance |83. I'he step formation of the Wave generated by superposing the two waves which are the respective outputs of the saw-tooth wave generator 68 and of the saw-tooth wave generator 88 may be as shown in the wave pattern 88a of Fig. 6. This Wave may then be impressed across two capacitors |04 and thence to one of the horizontal defiecting plates 18 of the cathode ray tube 15. The other of the deflecting plates 18 is connected to the lower end of a resistor |85 and to a capacitor |86 which may be energized contraphasally to the capacitors |04 by virtue of the delay action introduced through the inductive impedance |81. The circuit arrangement of the elements |84, |85, |86 and |81 is not new and no claim is herein made to. this circuit arrangement as such. One of the features of the circuit however resides in the provision of a central tap on the resistor |05 from which a, connection may be made to the most highly positive anode .|88 in the cathode ray 4tube 15. 'This last mentioned connection serves to maintain suitable balance in the horizontal deflection forces so that pictures may be properly framed on the fluorescent screen 16.

The frequency of the saw-tooth wave generator 98 is preferably six times that of the generator 68 in order that six characters and six character separations may be obtained and suitable background areas formed between the characters along a character-line. Hence I provide a frequency multiplier ||8 to produce the sixth harmonic of the line-scanning frequency. This multiplier receives its energy from the line scanning frequency impulses at the rate of 2,688 cycles per second. The output energy. from the frequency multiplier is vin the form of sharply peaked impulses at the rate of 16,128 per second. In this case, therefore, the output waves-from the saw-tooth wave generator 99 have a time con- The cooperation of the tubes |00 and |02 for producing a wave of the pattern shown at 88h in Fig. 6 is the same as was previously described in respect to such a wave 88V for the vertical scanning operation. The two waves 88v and 88h differ only in their frequencies and in the matter of how many steps occur within one cycle of each fundamental frequency, whethersof the frame scanning or the line scanning circuits.

The picture signals from the receiver 60 may be directed through a conductor ||5 to-a compensating delay network ||6 and thence to a control grid ||1 of an electron tube ||8. The control grid ||1 is preferably one of a pair of co-planar grids, the other grid being employedalso as a control grid. The purpose of the compensating delay network H6 is to adjust the phase of the picture signal impulses with respect to the phase of the signal-selective impulses as derived from the synchronizing signals passed through the filters 6|. It may well be seen that, due to the complexity of the filter circuits and the delay networks, it may not be possible to obtain this phase agreement but for a, compensating delai1 network. The constants of such a network, however, may be maintained fixed, once they are suitably established. The output circuit of the electron tube ||8 includes an anode source I9 and a resistor |20 on which it is preferable to provide a tap |2| leading to a capacitor |22. The control grid I |1 may be suitably biased by means of a grid resistor |23 and a biasing battery |24. A second control grid |25 is similarly biased by means of a grid resistor |2 and the biasing battery |24. The two grids ||1 and |25 may be normally biased so far below the cut-off point on the tube characteristic that the tube will become conductive only when positive impulses are simultaneously impressed upon both grids. If then, a signal representing an elemental light area is impressed as a positive impulse upon grid ||1 and simultaneously a sulciently positive impulse is impressed upon the grid |25, then the tube ||8 will operate to pass the selected picture signal along to the cathode of the tube 15. In this .case the light area signals produce an anode current flow in the tube H8. The potential on the anode will be lowered, thereby causing a negative surge across the capacitor |22 which lowers the potential of the cathode |30 in the cathode ray tube 15. The control electrode |3| of this tube may be grounded and through the use of a tap |32 on the potentiometer |33 leading'to one end of a biasing resistor |34 a suitable negative bias may normally be maintained on the control electrode |3I. When, however, a negative picture signalling impulse lowers the potential on the cathode |30, then the control electrode bias is reduced and a volley of electrons is emitted from the cathode and toward the uorescent screen 15 at some point determined `by the time components of thelhorizontal and verticaldeilecting circuits. The use of the so-ca-lled electron gun in the cathode ray tube 15 is well known and needs no detailed explanation here except by Way of mentioning that its control is rendered suitably effective by the aid of focussing and accelerating, electrodes |35 and |36 respectively and by the anode |08. All of these electrodes receive their polarization charges from a high voltage supply |31. The potentiometer |33 may be placed across the terminals of they voltage supply |31 and taps of! the potentiometer may be adjusted to supply suitable potentials to 4the tube ||8 for transmitting picture signals to the cathode |30 of the cathode ray tube may be made contingent upon the impress of a positive charge upon a second grid |25. It will 'now be shown how this positive charge may be obtained for the purpose of rendering effective only those picture signals which are desired to'form a given selected picture.

A frequency multiplier |40 is fed with impulses from the output side of the frequency multiplier 9|. A seventh harmonic of the eighth harmonic of the frame frequency is thus obtained, this, as illustrated, being 896 cycles per second. These impulses may be fed to the control grid |42 of an electron tube |4I. to permit current flow therein but when a sharply peaked negative impulse is delivered to its ,control grid |42, the tube is biased to cut-off and its anode potential is raised to a point where a strong positive pulse will be delivered across the capacitor |43 and thence to the control grid |25 of the electron tube H8, provided such impulse is not dissipated through a shunt circuit which includes the capacitor |44 and the space current path through a companion tube |50. y

This electron tube |50 may be controlled in a similar manner through frequency multipliers ||0 and |5|. The frequency multiplier |5| delivers sharply peaked impulses which are the fifth harmonic of the impulses delivered by the frequency multiplier ||0. These impulses, in turn, have been shown to be the sixth harmonic of the line scanning frequency. Hence the frequency delivered by the frequency multiplier |5| is of .the

order of 80,640 cycles per second, or one impulse l for every ve elemental area picture signal impulses.-

If, now, it be considered that the electron tube |50 becomes biased to cut-off once for every fifth picture signal it, too, will deliver a strong positive impulse to the control grid |25. The potential derived from a battery |55 and impressed across the resistors |45 and |40 respectively may be such as to permit of the dissipation of energy in the resistor-capacitor loop including the capacitors |43 and |44 without carrying an effectively positive impulse to the grid |25, if some of this energy leaks o through either one of the tubes |4| and while it is conductive. If, however, both of thesev tubes become biased to cut-off simultaneously then both capacitors |43 and |44 would simultaneously receive charges such as to raise 'I'his tube is normally biased the potential of the grid |25 high enough to reny to let pass one signal out of everyr ve, for the duration of one scanning line while its anode is lowered in potential to avoid the charging of the condenser |40 during the period oi' two scanning lines. It is, therefore, only the one signal out of ve along a scanning lin/e, and only such signals as occur along one scanning line out of three that become effective. Thus all signals along two subsequent scanninglines are blocked out, since they do not represent any portion of the selected picture.

The frequency multipliers |40 and |5| may be of any suitable well known type. Coupled thereto, but not shown, are suitable wave 'shaping devices for determining the time intervals to be taken up by the positive peaks in relation tothe time components of the negative peaks, for properly controlling the tubes |4| and |50 respectively. Where inequality between the positive andl negative peaks is required, this can be accomplished in a well known manner through the use of an asymmetric multivibrator. Furthermore, if desired, the wave'peaks may be shaped in accordance with the requirements for limiting the effective time components thereof as shown by the curves and |0| in Fig. 6.

'I'he curve |00 represents a wave form suitable for controlling the tube |4|. In this case the positive impulse has a time value of whereas the negative peak of this wave has a time value of o The wave form as shown by the curve |0 Fig.

6, is preferably such that its' positive and negative peaks have a time ratio 1 :4.l Since the full wave time value is of the order of 1 l4=ml S60. I Y

'it will be seen that the positive peaks endure for a period of 1 403,200 ec and the negative peaks persist for a period of l m Sec.

In the foregoing description all of the circuits shown'in Fig. 'I have been traced. It remains now to show by-means of further wave diagrams what is accomplished by the jointoperation of these circuits. Fig. 6 is again referred to. Wave form |02 represents the combined output from the two discharge tubes |4| and |50, as impressed across the capacitors |40 and |44. Thebroken line g represents the cut-oil' point of the negative bias applied tothe grid |25 from the battery |24 through the resistor ||2. The peaks p which lie above the level of the line g are obtained only when the waves |00 and |0| are positively peaked at the same time. The wave portions Ic, m and n all lie below the level of the line g and are, therefore, effective in suppressing the effects of the picture signals which have not been selected rendered effective.

according to a given setting of the selector switch 02.

'I'he picture signals are `typically represented by the curve |03. Ii the duration of a positive peak is for some multiple of an elemental area signal, the correct inference is that there are contiguous elemental light areas belonging to two interwoven but unrelated picture patterns. The positive picture signals are of sufficient intensity to overcome the steady negative bias on the grid I as indicated by the level of the cut-oil line Iz, but the cut-off point of the tube characteristic is such that it becomes conductive only when the grids and |25 are simultaneously raised to a potential above their respective cut-off points. The wave form |04, therefore, represents the composite effect of varying the potentials on the two grids. The cut-off point of the tube characteristic is represented by the broken line i. Fluctuations of the composite grid bias, such as the peaks u, which are below the cut-off point, are ineective, but when peaks of grid bias occur as shown `at s, then anode current flows in the tube.

The eiectiveness of the delay networks Le to Ls inclusive is apparent for selecting any one of five elemental area signals successively transmitted. Also, when one such signal is chosen, every fth successive signal on the same scanning line is All picture signals occurring during the scanning of the two succeeding lines are blocked out by the condition of conductivity of the tube |4|. When, however, it is desired to select a program occurring on either of these heretofore rejected scanning lines, the selector switch 62 may be shifted into any one of its' last ten positions, five of which bring into play the delay network F2 and the other five of which render the delay network Fs effective. 'I'his provides a choice of picture signals starting with the second or third scanning line from the beginning of a frame scanning cycle.

In the embodiment shown', it is possible to 0btain any desired selection of programs from among the fifteen multiplexed signal trains, where each train of signals is understood to be related to an independent picture program. 'Ihe word program it will be recalled, is considered apt in view f the intention to change the scene after every lapse of a six-second time interval, or other time interval sufilcient to read the message conveyed by one scene.

Fig. 3 shows, by way of example, how the characte'rs of a selected scene may be formed on the fluorescent screen 16. Apparently the elemental light areas are, in many instances contiguous, although it will be appreciated that the selected signals for controlling the actuation of the electron gun are discrete. 'I'his very desirable effect is obtained by de-focussing the electron beam in the cathode ray tube so that its coverage will be equal to the coverage of fifteen elemental areas if there were to be no suppression of sigsov loss of detail in the image pattern. The persistence of the image without noticeable ilicker is the prime desideratum. Flicker eiects can be overcome to a large extent by careful choice ot the nuorescent material with which the screen 16 is coated.- Some of these materials when electronically excited have a much longer "decay periodv It is known that different uorescent sub-A stances may be used on the screen 'I6 for lvarying the color eiects produced by electronic impact. Accordingly, it may be desired, in the case of quoting fractional price variation, that the character representing a fraction be shown in a color diilerent from the color of the other characters. If this is done, it then becomes unnecessary to under-line the fractional numerators as shown at |82. Instead, it may be preferable to display numerator digits for the eighths fully as high as the unitsand tens-figures, but distinguished only by their color.

The screen 16 may, if it is to be used solely for quoting prices, be permanently marked as shown at l80, as a guide tothe interpretation of each line of quotations. A space between two ruled horizontal lines l8| on the screen surface may be permanently reserved for stock abbreviations. If two or more stocks are to be quoted simultaneously, as herein shown, lin different columnar groups, then vertical lines may be ruled on the screen for stock group separation. All such aids to an intelligent presentation of the bare picture impressions will,of course, contribute to the effectiveness of the display without imposing further demands upon the signaling equipment.

Fig. 4 illustrates an arrangement for feeding picture signals from one receiver simultaneously to a plurality of cathode ray tubes, each of which may present a program diierent from the others. In this case it may be desirable to provide independent selector switches and delay networks in connection with each cathode ray tube. Thus, I have shown (in front view) ve such tubes and have designated them B1, A2, B3, A4 and C5, correspending to the programs thereto allotted. The line synchronizing signals are to be understood as fed through different delay networks d, 2d, 3d and 4d for the cathode ray tubes other than B1, whereas, the latter has no such delay network because the choice of programs assignable thereto may not needvto be varied horizontally of the multiplexed picture pattern, but only vertically. Each of the circuits for controlling the vertical synchronizing is, however, fed through a device |10 which includes a three-point switch and two delay networks, such as F2 and F3. In`the rst position of each switch the networks are shunted out. The middle position connects network Fa and the third position connects network Fa. It will thus be seen that any one of three programs is available to each cathode raytube, whilethe selection made for each tube isalways diierent from that of the others.

It will be apparent from the foregoing that news can be disseminated from one transmitting station to as many receivers as are situated within range of the signals, but that means are associated with each receiver for making a desired choice oi program from 'among those multiplexed at the transmitter. q

' Rncmrmnoz In the foregoing description I have set forth the details ofstructure preferably employed for achieving certain new and useful results in the art of news dissemination. The methods adopted are replete with novelty, as will be set forth with particularity in the appended claims. Modiiications of structure and of method, if adopted byV those skilled in the art, may, possibly, lead to more general applications of the invention than were at rst contemplated. For example, it may be found useful to provide a communication system in which code signals are caused to represent successively scanned light and dark areas on a screen. These code signals may also be interwoven lfor the sake of rendering the intelligence quasi-secret. The method herein shown of ses lecting desired elements from multiplexed trains of signals for reproducing a given communication at the point of reception lends itself to photographic recording of code messages and to a subsequent deciphering in any well known manner. If the number of elemental areas to be skipped in the sorting process is unknown to a person attempting to intercept a message, then the risk of unauthorized de-ciphering of the message becomes negligible.

The method I have disclosed in which the entire mosaic of the transmitting screen is occupied by significant light and dark areas of an image pattern, and in which character images are disposed on said mosaic without any background areas intervening, leads to a more economic use of signaling channel time than was possible when character image signals were interspersed with insignificant lapses of time representing background areas. By my method the character separation is obtained on the receiving screen in accordance with a non-linear control of the horizontal and vertical deecting circuits.

'Ihe eldvof utility of my news dissemination system can, of course, be extended to cover the transmission of bid and asked prices on stocks, bonds and commodities. 'I'he system may also be found useful in communicating details of sporting events, game scores, racing results, betting odds, and word pictures covering any conceivableitem of news or other intelligence.

My method of storing in tabularly arranged individual market transaction. Tolcertain parties the details of4 each transaction may be of interest, but to the'majority of people who watch the ticker the matter of chief concern is-how does the last quotation on a given item compare... with the opening price, the high and the low for the day. Next tov that in importance is the.y question of volume, up to the minute in respect to the transactions in any particular security. If the market is dull, then a tape watcher may have to wait many minutes for a transaction on some particular stock to be quoted, and even then, in the absence of a quotation board, there is no basis of comparison between the. last price and previous price range. This dimculty is, therefore, eifectively solved by the periodic surveyof all market quotations covered by a more 1| or less complete tabulation as obtained through the use of a price storing mechanism. Furthermore, in a very active market, ticker systems of the types now in use are inadequate; so much so that they cannot keep pace with the transactions as made on the exchange. In other words, the limit of speed for code-signaling of the quotations is soon reached and beyond that point inevitable delays of reporting occur. My periodic survey of the active stocks every thirty seconds and of the least actlvestocks every ilve minutes is entirely independent of the volume of transactions on the exchange. Hence it never need fall behind the market.

In my copending application Serial No. 329,427,

filed April 13, 1940, which is a continuation-inv part of the instant application, Il have again shown and described a multiplex television system embodying many of the features herein described. 'I'he claims of the two applications are, however, believed to be patentably distinct.

I claim:

1. The method of multiplex transmission and reception of television picture images which comprises, assigning adjacent elemental areas of a mosaic to diiierent ones of a plurality of different interwoven pictures, scanning said areas successively and forming an image at the locus of reception in conformity with the light and..

dark areas of a single one of said pictures.

2. 'Ihe method of multiplex transmission of picture images and reproduction thereof at different points of reception which comprises, as-

signing adjacent elemental areas oi a mosaic to different ones of a plurality of different interwoven pictures, scanning said areas successively, transmitting a train o! signals representative o! the light and dark areas oi.' the scanned mosaic and reproducing the different pictures simultaneously at the diierent points of reception by sorting 'out the signals respectively appropriate to each picture.

3. In a news disseminating system, a television transmitter including a photo-electric screen, means for projecting on said screen an image of interwoven characters, means for electronically scanning said screen, synchronized means for transmitting and receiving signals representative of the scanned elemental light and dark areas of said image, means for composing a visible image at the locus of reception of said signals, means for selecting a portion of the received signals representative of a desired group of vlegible characters while rejecting the remainder of said signals representing others oi' the interwoven characters, and means for causing only the selected signals to control the composition ci the received image. V

4. In a news disseminating system, a receiver 4having means for selecting discrete but related elemental portions of a train of signals while suppressing the effects of intervening and unrelated portions of said train, a cathode ray tubehaving a fluorescent screen and means responsive to the selected portions of said signals for electronically scanning said screen thereby to produce images on said screen, and means for so determining the size of the scanning spot which is projected y in response to the selected portions of said signals that areas scanned during the suppression of unrelated portions of the signal train are substantially covered by said spot and the related elemental areas of said images are rendered substantially contiguous.

5. In a system oi' the class described, television transmitting apparatus having a screen, means for projecting upon said screen a composite image pattern composed of elemental light and dark areas. of which certain non-adjacent elemental areas are pictorially related, while all adjacent elemental areas are pictorially unrelated, television receiving apparatus having a second screen, a device in said receiving apparatus for making a skip-selection oi signals emitted by said transmitting apparatus, each selected signal corresponding to an elemental screen area, and means controlled by the selected signals for producing on said second screen an intelligence-bearing image pattern composed of elemental light and dark4 areas of which adjacent areas are pictorially related to one another, said image pattern being in accordance with a selection of non-adjacent elemental light and dark areas on the iirst said screen.

6. vIn a system of the class described, in which a plurality of projectors is focused upona screen said image, employing a selected portion of said Y I signals constituting an intermittently transmitted array thereof to control the reproduction on the second said screen of a selected portion of the scanned image of the iirst said screen, and varying at will at the locus of the second said screen the image portion thus selected for reproduction.

'7. A multiplex television system having a transmitter, including an image screen, means for interspersing one with another on mutually exclusive portions of said screen different light and dark elemental areas respectively appropriate to different ones of a plurality of independent pictures, and a television receiver operable from signals propogated by said transmitter, said receiver having an image screen and means for reproducing on said screen a selected one of said pictures independently of the others.

8. A multiplex television system in accordance with claim '7 and having means for scanning the transmitting and receiving image screens synchronously and line after line, means for suppressing the effects of unrelated interspersed signals on each scanning line pertaining to the selected one of said pictures, and means for suppressing the effects of unrelated signals throughout the scanning of entire lines of unrelated pictures.

9. The method of transmitting and receiving pictures which comprises, interspersing the elemental picture areas of diierent picture images,

one with another, to form a composite image pattern, converting the varying light intensities of said pattern into trains of electric impulses, septween Veerwlin ef the elemental areas the light and dark intensities of which are controlled by successively utilized impulses. Y

11. In a communicatio system, means for projecting a composite ge representing a plurality of pictures, means for periodically scanning said image, means for transmitting a train of signals representative of said image, receiving means operable synchronously with said transmitting means, said receiving means comprising a device for accepting a skip-selection of said signals which when segregated apart from the entire body of signals is representative of characterimages constituting a single one of said pictures and bearing a given piece of intelligence, and means for rejecting interspersed signals representative of non-selected picture elements of said composite image.

12. In a device for the reception of a selected one of a plurality of interwoven picture image patterns, represented by multiplexed image signais, a cathode ray tube having horizontal and vertical scanning means connected thereto, selec- 'elemental light and dark areas along a scanning line.

14. A device in accordance with claim 12 and further characterized in that said selective means comprises means operable to control the acceptance of signals to be rendered eiective only along -certain selected scanning lines of the image 'area,`

and means to suppress the effects of signals applicable to the intervening scanning lines.

15. In a system of the class described, means for transmitting picture signals and synchronizing signals, a receiver having a line scanner and a frame scanner, each undercontrol of appropriate ones of said synchronizing signals, said receiver also having an electron gun and a fluorescent screen for composing a picture image whose elemental areas are in accordance with said picture signals, means localized'at said receiver for so controlling the line scanner that the effects o! the elemental area signals as projected on said screen by said electron gun are compressed into detached groups along each scanning line, thereby to form vertical image-free bands in the frame area, and means also localized at said receiver for so controllingthe frame scanner that the effects oi' the image signal trains comprehended in successive scanning lines are compressed into detached groups, thereby to form horizontal imagefree bands in the frame area.

16. A systemin accordance with claim 15 in which thetransmitting means includes means for correlating a predetermined plurality of said picture signals as a representation of a single character image, and means at said receiver for sol chronously with said terminal apparatus and hav-v ing means for accepting at least a portion of said signals and for translatingv the same into facsimile images, and selective means for rendering effective only the received signals which relate to the character images the grouping together of which serves to convey av desired piece of intelligence.

18. In a facsimile communicationsv system, a screen, means for forming character images within the frame area of said screen, each character image being formed in broken outline by a uniform number of discrete horizontal rows of elemental light and dark areas, each row having a uniformvnumber of mutually exclusiv/e and discrete elemental light and dark areas reserved to the use of said character, means for scanning the elemental areas successively, thereby to initiate a train of signals, transmitting and receiving apparatus for utilizing said signals, imagev reproducing means connected with said receiving apparatus, and means operative under control of saidI scanning means for compressing each reproduced character image into a, discrete portionl of'saidA frame area, diierent character images being thus separated by image-free horizontal and vertical spaces. RALPH W. BUMSTEAD.

Images