sep1.l24, 1946. N. H. YOUNG, JR 2,408,117! METHOD AND MEANS FOR THE REPRODUCTION OF INTELLIGENCE . Filed Feb. 20,' 1943 ` 18 AT' my Patented- Sept. 24, 1946 'y 2,408,117 L i UNITED- STATES. , OFFICE; ¿ f Q ` v,2,408,117 METHOD AND’- MEANS FÓRï'TI-JIÉÍ REPRODUC TION'’OFfINTELLIGENCEv « Norman H. Young. .Ir.,-Jackscn«Heights, N. Y.,v as- I signor to kFederal YTelephone’ and’ Radio Corpo ration, Newark, N. J., a corporation of Dela Y Application February 20, 1943,.- SerialNo.Y 476,604 10y claims. (c1. 17e-»7.3) . This invention relates. to~ method and means for the` reproducti'on of intelligence; and more- par. ticularly'to a communicating system which is vdif ñcuit of interference by jamming; 1 - into signa‘isby the> pick-up coil 2U. This is con nectedjth’rough a suitable rectifier 2.2 to produce, foreach signal component, an unblocking poten gencefrom transmitted and received signals. , . 2l ' minedtime interval be picked up` and reconverted a novel; system for the reproduction of intelli Another object' is to provideV such a system , the art. The magnetization of the Wheel I6' will, upon rotation of. the latter and-,after a> predeter An object of this invention is'the provision'o'f which is difficult to‘jam.4 , and'in a ,mannerV which is. per se Well-known in - tialiappli'edto the normally blocked amplifier lli. A suitable reproducer 24,` which may be a cath ' A further, morespecific object of this` invention 10 ode ray tube is fed from the block amplifier Iâ. is tovprovide- a' communicating 'system wherein' ~ After the signals have loteeifipickedV up by the coil the successful reproduction of‘intelligence de pends upon vthev repetition cfaV signal at’a con > 26, the magnetization vof the wheel producing such isignals is erased-bysuitable magnet 26. , i It vvillïbe clear from'the foregoing description stant, variable, or'continuallyîvarying predeter=' ` minedv interval. y ‘ i of ‘the’ illustratedv apparatus that when va signal Other objects and advantages of the present inventionvvill:become- apparent fromn the follow ing'description of a preferredfembodiment, to gether with afm'odiñcation thereoñillustrate‘d in is'derived from thereceiver lll it will be impressed upon the magnetizable Wheel 'through the coil !2,. but cannot pass through the reproducer 2f?. since vthe amplifier Ill` isnormally'blocked. However, » 20 ifV this-signal is‘ repeated at an interval such that Fig. lis a block circuit diagram of a communi cating system in accordance with the present in the amplifier `Avvill be unblocked by the first signal the accompanying drawing, in which: ' vention, schematically showing certain novel fea-tures thereof; - . ` . Y ' Fig. 2 diagrammatically shows examples of re ceived intelligence; ` » j ' Fig.»3 diagrammaticalfly shows examplesof sig nalscorresponding tothe examples of'reproduced` intelligence shoWninFig. 2; ~. Fig. .4 illustrates a modification of; theN appa at the same time. that the second signal is re ceived, this. second signal willpass through the amplifier to the reproducer. It is accordingly 25 contemplated-by the present system that each signallt'o be reproduced as intelligence must vbe repeateoi‘at a time interval which will be the equivalentïoi‘ the: time which it takes' for the Wheel I6 to move from beneath the coil i2 to 30 beneath' the -coil- 2B. Accordingly, unless the jam ming- signals are' timed synchronously with theV interval* between duplicated signals the jamming effect thereof will be> lost. Thus, essentially, in ratus illustrated in Fig. 1. The system of the present invention- isf particu larly- directed to the> reproduction'oi intelligence in the form of letters or correspondingk indicia the form of invention illustrated in Fig. l, I have upon the screen of a cathode ray tube. The me . provided a system vvhichY can only be jammed if chanics of such reproduction are in themselves well-known and the inventionv contemplates using present methods in the step of reproduction per se. However, the method of transferring the re ceived signals to the intelligence reproducer ‘pro vides, in accordance with the present invention, thejammingsignals are in synchronism with the a new system which, as will becomey apparent as duplication of Ysignals to be jammed. ` They manner in which the foregoing system works may be made clearer in connection withy the; examples illustrated in Figs. 2 and 3'. Using for. example,]norrna1 and’ knownv scanning meth ods _to produce visual intelligence from received the description proceeds, provides an arrange-signals,„it willv be clear to those skilled in this art ment which is extremely diflicult to jam. thatif it‘isdesired to reproduce the letter ‘"lî',”k AS illustrated in Fig. 1, my system utilizes a 45 Fig. 2'Y (A), the signal producing' this letter will receiver l0 for demodulating the received sig have. somewhat the form as» illustrated in Fig. 3 nals. The receiver Ill thus acts as a signal source, the output of which is applied simultaneously to (A)- ' When the first series of pulses such as Y shown in Fig. 3' (A) c'omethrough the receiver a Inagnetizingv coil I2 and a normally blocked I0 theyV will not ‘passthe blocked amplifier id but amplifier I d. The magnetizing coil I2 is placed 50 will be impressed. upon themagnetizable wheel in juxtaposition to a magnetizable Wheel I 6 driven I’B‘. When the magnetized impression’upon fthe at constant speed by any suitable means such as motor I8. The received signals operating through the coil I2 will, accordingly,> magnetize the rim of this Wheel IB in accordance with such" signals, vvhe'elllìv pass beneath the pick-up 2€),Y the dupli cation >`ofthe‘original signal, Fig. 3 (A) will come `through the receiver III, but at this time the sig, , nal„willi_.pass throughi the amplifier .i4 since- the 2,408,117 LE 4 amplifier will be synchronously unblocked by the link 34. It is specifically pointed out however, pick-up 20 and the rectiñer 22 by an unblocking potential which will be of a duration correspond ing to the individual signal components simul taneously applied from the pick-up device 20. Thus, the second signal coming from the receiver IB will be used to produce a letter while the ñrst signal at a later time is used to unblock the amplifier. If, now, it is desired to send a second letter such as the letter “E,” Fig. 2 (C) there may be one period of overlap during which the second signal for the letter “T” will be app-lied to unblock the ampliñer I4, at the same time the'ñrst signal that the means for particularly oscillating the magnet 20 such as illustrated in Fig. 4 have only been given by way of >example and that any one of the many well-known linkages for transferring rotary 'motion in'to oscillatory motionl could be used. Attention is also directed to the fact that while the reproduction of intelligence is, in the pre ferred embodiment illustrated, controlled by the blocking and unblocking o-f an ampliñer, this control is, in eiîect, an electronic on oil“ switch between the receiver and reproducer and it is contemplated that other equivalent switching for the letter “E” is coming from the receiver. 15 devices either electronic or electromagnetic could be used. This overlap will produce a signal on the screen The invention has been particularly described of the cathode ray tube such for example as shown in connection with the reproduction of the ñrst in Fig. 2 (B), but it will be immediately recog of two signals upon a'magnetizable wheel to give nized by the operator as having no meaning and will not seriously interfere with the interpreta 20 the required time -delay between duplicated sig nais in accordance with the principles of my in tion of the intelligence to be conveyed. This vention. It is contemplated, however, that other false indication is caused by the unblocking of equivalent and well-known means might be used the amplifier i4 in accordance with the pulses in place of a magnetizable wheel. For example, shown in Fig. 3 (A) representing the letter “T,” and the simultaneous application of the directly 25 a continuous magnetizable tape could be used in the same manner as a magnetizable wheel. The applied signal shown in Fig. 3 (B) representing principles of the invention would, moreover still the letter “EL” The amount of overlap is rep apply if the first signal were applied to- a paper resented by the short pulses shown in Fig. 3 (C). or similar tape either 'by inking the signal therein It will be recognized _that the amount of over lap and consequent false signal will be greatest 30 or forming the signal by suitably perforating the tape, in which' case thepickup 20 would be spaced when the signals representing the least sequen longitudinally along r`the tape in its direction of tial letters or indicia follows the prior letter at a time interval which is exactly the same as movement, the typeof pick-up 20 depending upon that between the duplicate signals of each letter». ' the type of recording> device used. If however, the spacing between duplicated sig tape system were used, the paper would prob nals' for each letter is sufficiently great no inter ably be discarded after use and no erasing device If a paper would be required. These possible applications ference whatsoever will be produced, since by this of my vinvention make use of well-known ar time the second impression of the prior signal rangements and since their use is believed to be upon the magnetizable wheel will have already passed the pick-up 2l), and probably the demag 40 obvious to those skilled in this art, no illustra tion of these equivalents is deemed necessary. netizing device 26 before the iirst signal for the second letter has been received. _While the aforedescribed system is, as pre viously pointed out, difficult to jam, there is still While the invention appears to be particularly applicable to systems in which the signals are reproduced as visual intelligence upon the screen the possibility that a jamming station might dis 45 of a cathode ray tube, it is deemed obvious thatI cover the periodicity between duplicated signals other types of reproducers known in the art may for each letter and if the jamming were in _Syn be used. In all cases, however, the principle of chronism with the interval such jamming would requiring a duplication of signal before the same be effective. It is therefore contemplated that can be reproduced is to be considered as the basic the position of either the coil I2 or the coil 20 novel feature. be varied, either manually in accordance with .Accordingly while I have described above the some prearranged signal from the transmitting principles of my invention in connection with cer station, so that the time interval would be tain specific apparatus, and have described one changed from time to time, or the position of one of these coils could be made to vary con 55 particular modiñcation thereof, it is to be clearly understood that such description is made only by tinuously in some predetermined manner which way of example and not as a limitation on the is synchronized in a corresponding change in scope of my invention as set forth in the objects sending interval at the transmitter. In Fig. 4, andthe accompanying claims. I have illustrated diagrammatically one arrange I claim: ment which permits a continuous controlled 1.> An intelligence reproducing system includ shifting of the position of the pick-up coil 20. In this case, the magnet 20 is mounted by any ing, in combination, a receiver, a normally suitable means upon a :block 30 whose motion is blocked ampliñer connected to said receiver, an intelligence reproducer connected to said `ampli constrained about the periphery of the wheel I6 by a suitable lever 32 which may be mounted ñer, movable signal-recording means, a recorder connected to said means for impressing received about the shaft of the wheel IB. The block 30 signals thereon, a pick-up device positioned ad is connected by a link 3e to a gear 36 by an oiïset jacent said means and spaced from said recorder pivot 38. The gear 36 may be driven by a smaller f in the direction of movement of said means for gear 3l) which is connected by a shaft 42 with the driving shaft of the wheel I6. Through this 70 reproducing the recorded signal, and mean@` ac tivated by said pick-up device for unblocking arrangement it will be clear to those Skilled in said amplifier. this art that upon rotation of the magnetizable 2. The combination according to claim l, in wheel I6 an oscillatory circular motion will be which said signal-recording means is a mag applied to the block 30 thus the magnet 20 by the gears 3B and 40 through the'pivot 38 and the 75 netizable wheel, said recorder is a magnetizing 2,408,117 , 6 5` device, and said pick-up is responsive to the mag netization of said wheel. Y 3. The combination according to claim l, in of a signal on said receiver, whereby said ampli ñer is only unblocked to pass intelligence to said ` reproducer whenever the signal is duplicated at Y , which said signal-recording means is a mag said amplifier at said predetermined time. netizable wheel, said recorder is amagnetizing 8. The combination according to claim 7, in combination with means for varying said time device, and said pick-up is responsive to the magnetization of said wheel„in combination with' means intermediate said pick-up and said re corder in the direction of rotation of said wheel for demagnetizing the latter. ’ - 4. The combination according to claim 1,'in combination with means *for longitudinally vary ing the position of said pick-up relatively to said signal-recording means. - ' delay means in accordance with the time interval . between lduplicated signals. 9. An intelligence reproducing system includ ing in combination, a signal source including a recorder adapted: to repeat each signal at least once at a predetermined time interval, means for converting a signal into visual intelligence, a normally blocked amplifier intermediate said sig 5. The combination according to claim 1, in combination with means for periodically longi nal source and said reproducer, and means re tudinally varying the position of said pick-up for unblocking said ampliñer after said prede relatively to said signal-recording means. 6. An intelligence reproducing system com prising a signal source including signal record ing means for repeating the signals, an intelli termined time interval, whereby the second of said identical signals will be applied to said gence reproducer, and control means intermedi ate said signal source and said reproducer, said control means including means solely responsive to a predetermined periodic duplication of a sig nal from said source for activating said repro ducer to reproduce said signal. 7. An intelligence reproducing system includ sponsive tothe ñrst of a pair of identical signals reproducen „ . 1 10. An intelligence reproducing system, in-cluding in combination, a signal source including a recorder adapted to provide at least one se quential duplication of each desired signalat a predetermined time interval, an intelligence- re producer, normally blocked connecting means in termediate said signal source and said repro ducer, means for unblocking said connecting ing, in combination a receiver, a normally blocked means, and means for activating said unblock amplifier >connected to said receiver, an intelli 30 ing means by the ñrst of each duplicated signal gence reproducer connected to said ampliñer, synchronously with the application of the sec means for unblocking said ampliñer for periods ond signal to said connecting means, whereby corresponding to the duration of individual sig the second of the two signals is converted into nal components, and time delay means including a signal recorder for energizing said unblocking means a predetermined time after the reception intelligence by said reproducer. NORMAN H. YOUNG, JR.