US2057773A - Electronic distributor - Google Patents

Description

Oct. 20, 1936.

we. H. FINCH ELECTRONIC DISTRIBUTOR Filed Dec. 4, 5 Sheets-Sheet 1 msc'awan FILTER RF. AMPLIFIEK I INVENTOR. William BY 5 rich ATTORNEY Oct. 20, 1936. w. G. H. FINCH 2,057,773

' ELECTRONIC DISTRIBUTOR Filed Dec. 4, 1955 s shee s-sheet 2 14 ITL 1 7" MODULATOR 2 51 Q l J oaolLLn LE I l I 1 13 3 R.|=. R. 1-

osclu-ATOR AMPLlFlER 58 II I IIM M RECEIVER ROTATOR PULSE- AMPLIFIER INVENTOR. zm'zzia qmJim/z ATTORNEY.

Oct. 20, 1936. w. G. FINCH 2,057,773

I ELECTRONIC DISTRIBUTOR Filed Dec. 4, 1935 s Sheets-Shet s 21 'IIIIIIIIIIFIII'M Z2 Z5 RECEIVER P t-5E. 7 AMPLIFIER "ZZZ 7 Fig: 6' I I ATTORNEY.

atentesi @ct. 20, 1936 umrsos'rrs's' PATENT. OFFICE ELECTRONIC DISTRIBUTOR ,Willlarn G. H. Finch, New York, N. Y. Application December 4, 1935, Serial No. 52,871

'42 Claims. My invention relates to electronic distributors useful in signalling systems, and more particularly, relates to the application of an electron beam distributor for high speed printingtelegraph operation.

Modern high speed printing telegraph systems operate with a Baudot or five unit code. 'A continuous tape is successively punched with a predetermined combination of holes for each character. It is the practice to pass the tape through apparatus having five mechanical feelers which in turn operate contactors connected to contact plates on a mechanical distributor. The mechanlcal distributor, as is well known in the and substitute therefor an electronic distributor- The electron beam of a cathode ray tube is made to scan a plurality of metallic plates or targets corresponding to the individual contacts of a mechanical distributor. The substitution of an inertialess selector for the mechanical selector in a distributor makes possible accurate transmission of telegraphy signals at much higher speeds than heretofore possible. A receiver is arranged having an electronic distributor similar to that of the transmitter and selects the transmitted code signals to operate standard telegraph printing apparatus. It is accordingly an obiect'bf my invention to provide a novel high speed signalling system.

Another object-of my invention is to provide a novel electronic distributor'to-replace the mechanical distributor in printing telegraphy systems.

still another object 01m invenuonistt proemploying an electronic distributor according to my invention. I i

. Figure 21s a schematic illustration of a receiver for' translating the printing telegraphy signals I transmitted according to Figure 1. 5

Figure 3, is another modification of an electronic distributor used in the transmission of printing telegraphy signals.

Figure 4 is a schematic illustration .of a receiver correspondingto the transmitter of Fig- 1 we 3. t

Figure 5 is a further modification of a printing telegraph transmitter according to my ln-' ventlon.

Figure 6 is a schematic illustration of a receiver 1 I for use with the transmitter 01 Figure 5.

In carrying out my invention, I employ an electron beam it produced in a highly evacuated vessel ii. The generation of the electron beam is familiar to those skilled in the electronic art 20 and is schematically shown in Figure l. The

cathode I2 is heated by the heater H which is connected to suitable battery supply. The first anode M concentrates the emitted electrons into an electron beam. The high voltage anode I5 5 accelerates the electrons of the beam M which passes between the electrostatic deflecting plates l6, ll, l8 and i9 and on to the opposite end 20 of. the vessel ll. I Y t A high voltage direct current potential source 30 2i supplies the operating potentials for the elec trodes of the cathode ray tube I l. A potentlometer 22 is connected across the battery 2|. The second or high voltage anode I5 is connected to the positive side 23 of the potentiometer 22 which 5 point is connected to ground in my preferred embodiment. The first anode I4, is connected to a suitable intermediate potential by tap 24. The

control grid is negatively biased with respect -to the cathode l2 by a suitable tape 26 of the 40 potentiometer 22 Deflecting plates l6 and I8 are "connected to the grounded high potential point 28 to assume the same potential as the anode it. The plates l1 and is are connected to ground through high resistances 21 and 28 45 so that the electrostatic deflecting plates and the anode I! have a common static potential which is at ground potential, on operating expedient commonly employed.

0n the back face 20. f the tube II, I arrange to a plurality of metallicplates or targets 29 within the tube. As illustrated in Figure 1; these plates 29 are spaced around a circle within the tube l'l "and have connections projecting through the tube at points 80. Five of the metallic electrodes 29 to r are connected to corresponding contactors 3| of a selector mechanism 32. In modern printing telegraphy, a message tape, if employed, has a succession of holes-punched according to a predetermined code. The commonly used Baudot code, for example, employs combinations of five units to correspond to individual letters or symbols'. The punched tape is passed through a selector mechanism which has flve feelers which coact with the tape and operate contactors 3| as is well known in the art. I 1'. ve schematically illustrated such a selector mechanism at- 32.

I The contacts of the contactors 3| are connected in parallel across the input circuit 33 of a thermionic amplifier stage 34. The output 33 of the amplifier 34 is connected to a modulator 33 for modulating a radio frequency carrier produced by the radio frequency oscillator 31 connected to the radio frequency amplifier 33 to be transmitted for radio transmission by the antenna 33.

A local oscillator 43 is connected to the electrostatic deflecting plates l1 and I3 through a rotator circuit 4| comprising a condenser 42 and resistance 43 connected as shown. The impedance of the condenser 42 is adjusted to be substantially equal to the resistance 43 at the frequency of the local oscillator 43. The electron beam |3 will be moved in a circular path as is well known in the art. The diameter of this circular path 44 at the end 23 of the tube depends upon the voltage output of the oscillator 43 which is adjusted so that the diameter of the path 44 coincides with the mean diameter of the circularly arranged plates 23. I thus provide means for successively scanning the electrodes 23 at a predetermined rate.

When the electron beam |3 impinges on a target 23, the electrons will be conducted to ground through its corresponding contactor 3| if it is not actuated by its selector feeler, but connects to the lower contact. However, if a feeler of theselector mechanism 32 at that time projects through a hole in the perforated tape, an arm of the corresponding contactor, for example, 3|a, will be moved to connect to its upper contact point 43 and the electrons of beam l3 impinging on the corresponding target 23a will be conductively connected to the grid 43 of the thermionic amplifier 34. The electrons of the beam l3 are attached to ground since the high potential side of its accelerating battery source 2| is connected to ground. The electrons of the beam l3 accordingly pass to ground through the input circuit or grid resistor 33*. The electrons flowing through the grid resistor 33 produce a potential change upon the grid 43. A corresponding impulse is transmitted through the amplifier 34 to its output 33. Accordingly, while the electron beam I3 is passing over an electrode 23 having its corresponding contactor 3| actuated by a selector feeler projecting into a hole in the perforated tape, electrons will be conducted to the input circuit 33 of the amplifier 34 and produce a pulse or signal therethrough. This pulse or signal is introduced to the modulator 33 for radio tion as described.

v the modulator 33 by leads 41.

its corresponding electrode 23 corresponds to a predetermined component of the five unit code of the perforated tape. With each symbol group punched in the .tape, a corresponding arrangement of contactors 3| will be actuated'to their upper contacts during the transmission of the code group. The frequency of the oscillator 43 is adjusted so that it successively scans all the electrodes 23 once for each code group advanced through the selector-mechanism 32. Each contactor 3| actuated by a hole in the perforated tape conductively connects its corresponding elec; trode 23 to the grid 43 of the amplifier 34, and a signal pulse will be produced by the amplifier 34 when the electron beam |3 passes over this target 23. Accordingly, a succession of signal pulses is transmitted corresponding to the code group on the perforated tape being presented to the mechanical feelers in the selector mechanism.

The selecting mechanism feeds the perforated tape at a predetermined rate in accordance with the frequency of scanning of the electrodes 23 and each code group is retained by the selector pins during the execution of each cycle of scanning. The electron beam will therefore be conductively connected to the grid 43 of the amplifier 34 as it successively scans the electrodes 23 in accordance with the code group being transmitted. The oscillator 43 is connected to The radio frequency carrier wave which is radiated by antenna 33 is modulated by the signal impulses and by the scanning frequency. The purpose oi transmitting the scanning frequency from os- .pawl and ratchet arrangement schematically shown as 320. I provide a sixth target electrode 23b, which is connected directly to the stepping mechanism 32a. A signal amplifier is included in the electro-magnetic unit 32a to suiliciently amplify the impulse to operate the mechanical stepping means. The electrode 23b sets off the five signal targets 23 into one group. At the end of a code group transmission, therefore. the electrode'23b is impinged by beam i3 and the electromagnetically operated stepping mechanism automatically advances the message tape to the next code group to be transmitted. The cycle is then repeated. The rate of transmission of the code groups is accordingly predetermined by adjusting the frequency of the oscillator 43. the number of groups transmitted per second being equal to the generated cycles per second of the' oscillator 43.

The target 23b is also connected to the input circuit 3 3 of the signal impulse amplifier 34 througha unidirectional impedance device 43. 43 may be a buffer stage of thermionic ampliilcation, or a rectifier. A unidirectional impedance 43 is used to transmit an electron beam '|3 impulse at ,target 23b to the signal amplifier 34, but to prevent any signal impulses from other targets from .reaching the stepp ng amplifier The stepping mechanism 32a will there- 76 thetap 62 of the potentiometer b3.

aosmre fore be actuated only by the impulses on target 2912 for proper actionv thereof. The impression of the impulse of target 2% upon the signal amplifier 34 is to transmit, at the end of each cycle, an impulse to be utilized at the receiver as a printing impulse. .The function of the printing impulse will be described hereinafter in connection with the receiver printing mechamsm.

In Figure 2, I have illustrated receiving apparatus for use in conjunction with the transmitter of Figure 1. The receiving antenna as is connected to the radio receiver 39' which detects and amplifies the telegraphy signals. A filter 5% is connected to the output of the receiver 59 and is tuned to the scanning frequency generated at the transmitter by the oscillator id. The output of the filter 50 is introduced to an amplifier 6| which is connected to the electro-static deflecting plates 53 and 55 through the rotator circuit 52. Their corresponding deflecting plates b5 and 56 are connected to ground potential. The second anode 51 is also connected to ground potential as is the positive terminal of the high voltage direct current source 58. The operating potential of the first anode 68 is adjusted with Resistors 83 and 64 having high resistance, connect the deflecting plates 53 and 54 to ground.

The receiver electronic distributor 65 is of similar construction to that of the transmitter of Figure 1. An'electronic beam 66 is produced and caused to scan a plurality of metallic electrodes or targets 61 arranged in a circular path on the back wall 68 of the evactuatecl envelope. The targets 67 are individually connected to ampliflers 88 at the outputs of which are connected relays iii. used to operate a local printing telegraph. The output of the receiver 49 is connected to a transformer H the output of which is impressed across the grid I2, and cathode 58. The grid l2 bias potential is adjusted to a suitable negative value by the potentiometer l3 connected across the grid biasing battery 14.

The synchronizing frequency impressed across the electrodes 63 and 55 through the rotator circuit 52 produces a rotatfori of the electron beam he. The voltage output of the amplifier 5i is preferably adjusted to produce a path diameter iii of the electron beam 8% about equal to the mean diameter of the circularly arranged targets Bl. The operating potentials of the electrodes are adjusted so that the beam 6% will be properly focused to impinge upon the targets 61 when a signal impulse is impressed upon the grid it. The bias of the grid 12 is adjusted so that when no signal impulse is transmitted through the transformer 1!, it will be sumciently negative to throttle the electron beam 66 and prevent it from reaching the electrodes ill. Accordingly, the electron beam 66 moves in the circular path H5 at a predetermined rate equal to the rate of beam Ill at the transmitter. In the embodiment of Figure 2, the signal impulses will bring the electron beam 66 into proper focus upon the electrodes 61, but during no signal" the negative potential of the grid will be such as to throttle the beam 66 to prevent its reaching the electrode 61. When the electron beam 86 impinges upon a target 61, a pulse is introduced to the input of the corresponding amplifier 69. The production of the pulse by the electron beam 66 at the amplifier 69 input is the same as the production of the signal impulse introduced at There are five relays it which are.

transmittedat thev end of each code group.

the grid 88 of the amplifier 34 of Figure 1 described hereinabove. The amplifiers 66 are made sumciently sensitive to suitably energize the corresponding relays Ill ior actuating the local printing mechanism.

The phase of the scanning signal filtered at be and introduced to the amplifier 6| is adjusted by well known phase shifting means, schematically indicated at it, to cause the electron beam 6% to pass over predetermined targets 81 in synchronization with the corresponding targets at the transmitter in order to maintain the code combinations Therefore, when the electron beam IQ of the transmitter impinges on the electrode 280, the receiver electron beam 6ft will impinge upon the corresponding electrode 61a to actuate the printing relay Illa, in proper sequence. Once the beam at is adjusted in proper phase relation with the transmitted impulses, the electronic distributor according to my invention will continue to be in synchronism with the transmitter and operate to selectively print the letters or symbols which are selectedby the mechanism 32 of the transmitter according to the coded punchings in the perforated tape passing therethrough;

A sixth target 61b is included-in the target group of the receiver electronic distributor 65, and corresponds with the target 28b at the transmitter. A printing impulse" is transmitted at the end of each code group as hereinabove described, corresponding to the target S'lb. Accordingly, an impulse will beimpressed through target till) upon the amplifier 69b to actuate a printing impulse" relay 'llib. The printer relay 3% may be employed to directly print the charfor the printing mechanism.

acter selected by the other five relays 10, or may "it will thereafter be reset in readiness forthe next code group transmitted.

The scanning frequency in cycles per second is equal to the rate of transmission of code groups per second. There is no inertia, mechanical wear, sparking or dust troubles with the electronic distributor according to my invention. A greatly increased speed 01 operation is possible with my system as compared to existing printing telegraphy systems employing mechanical distributors.

other methods oi synchronization are feasible for the electron distributor. A local oscillator at the receiver may be used to scan the electron beam across the targets. The frequency of this local oscillator may be synchronized or interlocked with the transmitting oscillator by methure 1 in the omission of the connecting leads 41 fromthe scanning oscillator to the modulator 86. The scanning signal is accordingly not transmitted. The printing impulses" produced by electrode 2% are utilized at the receiver for its local oscillator synchronization. The system embodied in the schematic illustration oi- Figure 3, produces a succession oi impulses according to the five unit coded character beingtransmitted. plus an additional pulse which is always A series oi regularly timed synchronizing 1mm 6 the oscillator 40 of the transmitter. 85'

are accordingly transmitted. one pulse corresponding to each cycle executed by the local osclllator 40.

Figure 4 is a schematic illustration of a receiver for the transmitter described in connection with Figure 3. There are six electrodes '1. The synchronizing electrode i'lbcorresponds to the electrode 28b of Figure 3. A local oscillator 11 generates sinusoidal waves. The output of the oscillator I1 is introduced to the rotator circuit 52 connecting across the deflecting plates 53 and M to produce the rotation of beam 66 in the circular path 15. The local synchronizing impulse is obtained when the electron beam 68 impinges on the electrode 61b. The electron im'- pulse is introduced to the pulse amplifier I8, the

output of which is connected to the local oscillator 'Il. The frequency of the local oscillator 11 is adjusted close to that of transmitter oscillator 40. The synchronizing impulses introduced by amplifier 18 to they oscillator 11 interlock or synchronize it with the transmitting oscillator 40 to cause it to generate the same frequency as The interlocking arrangement for synchronization of two oscillators is familiar to those skilled in the communications art and is not described in the present disclosure.

The operating potentials of the electrodes are adjusted so that the beam 88 is properly focused upon the targets 61 and is rotated in the circular path 18. in synchronism with the transmitter beam i0. I have illustrated in Figure 4 a modifled method for causing the beam 86 to impinge on the proper targets 61 during the signal .pulses. The output of the'receiver 49' is connected to the transformer II, the output of which is connectcd in series with thehigh potential terminal 19 of the high voltage source 58 and ground.

The signal impulses accordingly, alter the de-- flectional sensitivity of the electron. beam. The signals are polarized so that during a signal impulse, the beam 66 is made more sensitive to the rotator voltage, and reaches the indicated path 15 to move across the targets l'l. During no signal impulse, the electron beam 88 rotates in a path smaller in diameter than I! and does not impinge on the electrodes 81: producing no actuation of corresponding relays l0.

Thesignal impulses transmitted by the system according to Figure 3 are detected and amplifled by the receiver 49' of Figure 4 and impressed upon the electrodes of the electronic distributor 66 to alter the defiectional sensitivity of the beam 06. A signal-impulse permits the beam II to travel in the normal path It, the diameter of which is determined by the frequency and voltage produced by the local oscillator There is one synchronizing impulse per code group or cycle of operation, which impulse is received by the electrode 81b, amplified by IO, and used to interlock'or synchronize the local oscillator II with the transmitter oscillator 40. Whenever a signal impulse is impressed on the apparatus, the

beam Cl is caused to impinge on the-proper target 01 and a signal impulse will be impressed upon the input of a corresponding amplifier N. A printer relay II is connected at the output of the amplifier ll. 'When no signal impulse is re-.

wind, the beam passes around the correspond- 7 ing target I! and no impulse is impressed upon its associated amplifier-l8, leaving the corresponding relay ll unactuated. A succession of combinations of live on and oil signals will set up the letter-or'character selected bythe transmitter selector mechanism 32 at the local printing apparatus.

The synchronizing electrode 61b is also con-' nected to the amplifier 69b at the output of which is connected a printing impulse" relay 10b. The

synchronizing impulses will accordingly also op-' erate printing of the set-up character and reset the relays 10 for the next code combination.

It is'not necessary for the targets to be arranged in a circular path. In the further modiflcation schematically illustrated in Figure 6, I have illustrated the targets- 61 at the receiver arranged in a linear path Ii. The scanning of the electron beam 86 produced by a linear or sweep circuit oscillator is normally in a straight line asis well known in the art. Atone end of the linearly .arranged electrodes 61 there is placed the synchronizing electrode 61b connected directly'to the pulse amplifier 18. The output of the amplifier I8 is connected to the sweep circuit oscillator 11' tointerlock or synchronize its frequency with that at the transmitter. .Ihe output of the sweep oscillator 11' is connected directly to the electrostatic deflecting plate it to cause the beam to normally traverse the linear path li'across the targets 61.

The signals received by receiver 48' are detected, amplified and directly impressed upon the deflecting plate 55. The output of the receiver 49' is polarized so that when no signal is impressed upon it, the action of the deflecting plates 53-55 is to deflect the beam'away from the path l5v through the targets 81. When a signal impulse is received, the beam is moved back to the path I! toimpinge upon a predetermined target 81. Itis not necessary in this embodiment of Figure 6 to impress the received signal impulses upon the deflecting plate 53.- This plate 53, may for example, be grounded and the signals be im- 'disposed targets 29 and have a sweep circuit oscillator .for linear scanning of the electron beam. Figure 5 is a schematic illustration of such a transmitter. However, I illustrate in Figure 5 a transmitter employing a novel optical method for scanning perforations in the message tape. If a selector mechanism similar to 32 of Figure 3 is to be used, the electrodes 28 are arranged exactly as shown in Figure 6 along a straight line instead of in a circular path.

In Figure 5 I illustrate an optical method tor producing the succession of impulses required to operate the receiver. described in connection with Figure 6. The electrodes of the tube II and their'opera ting potential connections and sources are identical with those in Figures 1- and 3 and are labelled with similar numerals; The oscillator .40 is a linear or sweep circuit oscillator and is connected to the deflecting electrode II. The electron beam ll passing betweenthe defleeting plates l6 and I1 isaccordingly swept across the linear path ll on the fluorescent screen 82 at the opposite face of the cathode ray oscillograph. A travelling spot oi light produces the visible line 8 (I.

The perforated message tape lit is arranged on rollers St and 85. One oi the rollers st is connected to an electrically operated mechanical advance mechanism lit. The mechanism so may be a simple electro magnetic pawl and ratchet arrangement actuated directly from the local linear oscillator it and connected thereto by leads 47'. The mechanical advancing means 86 is actuated once per cycle of the scanning frequenc and is accordingly arranged to advance the tape at one notch or code groups at the end of each scanning operation by electron beam it. The electron beam is impinges upon the fluorescent screen 82 along the linear pathlil directly in front of a code group being scanned.

The illustration of Figure shows six perforations being scanned corresponding to a predetermined symbol to be transmitted. Each perforation permits the moving light spot to impinge therethrough upon a photo-electric cell 81. A suitable lens t9 may be used to direct the light passing through the perforations to the photoelectric cell tl. There is, accordingly, in the illustrated code group being scanned, a series of six consecutive light impulses impressed upon the photo-electric cell 81. The photo-electric cell 81 is connected to a suitable amplifier 3t which in turn is connected to the modulator lit for modulating the radio transmitter system com?- posed of the radio frequency oscillator 3i, radio frequency amplifier 38 and antenna system 39. The perforations illustrated at the left edge of the tape E33 correspond to the synchronizing impulses of the previous modifications. According- 1y, at the end of eachflcode group transmitted, there is always a corresponding synchronizing impulse also transmitted for interlocking or synchronizing the oscillator at the receiving station in a manner already described. The transmitter of the type of Figure 5 is preferably in conjunction with the receiver of Figure 6 having linearly disposed electrodes S'l. v 1

' prising a plurality of contactors; means for selec- Having described in detail several embodiment of electronic distributing systems, many inodifications thereof which fall within the broader spirit and scope of my invention will be evident to those skilled in the Thus, the various components in any particular practical application of my invention may have optional arrangements. Variations may be made in: the manner of producing the electron beam; the path of motion of the electron beampthe arrangement of the target electrodes; the type of scanning oscillator and synchronizing methods; the method of transmission such as over a wire line or by radio; the method of deflecting the scanning beam from the. receiver target electrodes according to signal impulses; or in the type 01 local printing mechanism and actuation employed. I have illustrated electrostatic means for deflecting and controlling the electron beam. Electro magnet deflecting means may, however, equally'well be employed.

I I have in the-foregoing described the application of theel'ectronic distributor in connection with five unit code for a printing telegraph. It will be understood that I do not intend to be limited to such applications oi the electronic distributor. A plurality of target groups may be ar-- ranged in one. tube for use with multiplex tele graph systems analogous to a similar application with mechanical distributors now employed. Al-

though I have de cribed unidire tional impu e for each signal, it will be understood that each signal impulse may be made intermittent or may comprise a plurality or successive impulses oper-- ating during the interval of the traverse oi the beam across a particular target. The intermittent nature of a signal impulse may have no particular significance as far as signal intelligence is concerned, or may comprise a signal group for further subdivision at the receiver so that one group letter will correspond to the intermittent traverse of the electron beam over a singletarget.

Still further modifications are possible and I do mechanism for setting up code combinations of signals to be transmitted; said selector mechanism comprising a plurality of contactors. each having a marking and a spacing signal position; an electronic disributor connected to said selector mechanism for transmitting the signals set up on said selector mechanism in accordance with a predetermined sequence; and means controlled'by said electronic distributor for periodically controlling said selector mechanism to set up a new code combination or signals for each cycle of operations of said electron stream.

2. In a. signalling system, atr'ansmitter comprising a plurality of contactors; means for selectively operatingsaid contractors; an electron distributor comprising a plurality of targets, an individual target being connected to each of said contactors, means for generating an electron beam, and means for cyclically scanning said targets with said beam; a transmitting channel; means for impressin code combinations of signal conditions on said channel in accordance with the operation'oi said i contactors as said beam impinges on said targets; and means including one of said targets i'or impressing a predetermined cyclic signal condition on said channel.

3. In a signalling system, 9, transmitter comtively operating said contactors comprising a perforated tape; an electron distributor comprisdng a plurality o1 targets, an individual target being connected to each of said contactors, means for generating an electron beam, and means for cyclically scanning said targets with said beam; a transmitting channel; means i for impressing code combinations oi signal conditions on said channel in accordance with the operation of said contactors as said beam impinges on said targets; and means including one of said targets for impressing a predetermined cyclic signal condition on said channel.

4. In a signalling system, a transmitter comprising a plurality of contactors; means for selectively operating said contactors comprising a. perforated tape; an electron distributor comprising a plurality of conductive targets, an individual target being connected to each of said contactors, means tor-generating an electron beam, and means for cyclically scanning said targets with said beam; 9. transmitting channel; means for impressing code combinations of signal conditions on said channel in accordance with the operation or said contactors as said beam impinges on saldtargets; and means including one of said targets for impressing a predetermined cyclic signal condition; on said channe I 5. In a printing telegraph system, t

ter comprising a plurality of contactors; means for selectively operating said contactors; an electron distributor comprising a, plurality of conductive targets arranged in a circle, an individual target being connected to each of said contactors, means for generating an electron beam and means for cyclically scanning said targets with said beam; a transmitting channel; means for impressing code combinations of signal conditions on said channel in accordance with the operation or said contactors as said beam impinges on said targets; and means including one .0! said targetsfor impressing a predetermined cyclic signal condition on said channel. i

6. In a printing telegraph system, a transmitter comprising a plurality'oi contactors; means for selectively operating said contactors; an electron distributor comprising a plurality of con-.- ductive targets arranged in a circle, an individual target being connected to each of said contactors, means for generating an electron beam, and means for cyclically scanning said target with said beam comprising an alternating current source; a transmitting channel; means 'for impressing code combinations of signal conditions on said channel in accordance withthe operation oi. said contactorsas said beam impinges on said targets; and means including one of said targets for impressing a predetermined cyclic signal condition on said channel; and means including said source for impressing a synchronizing signal condition on said channel.

7. In a printing telegraph system, a transmitter comprising a plurality of contactors; means for selectively operating said contactors; an electron distributor comprising a plurality of conductive targets arranged in a circle and equispaced located at one end 0! said tube, an individual target being connected to each of said contactors, means for generating an electron beam, and means for cyclically scanning said target with said beam comprising an alternating current source; a transmitting channel; means for impressing code combinations of signal conditions on said channel in accordance withthe operation of said contactors as said beam impinges on said targets; and means including one tron distributor comprising a plurality of conductive targets arranged in a circle and equispaced located at one end of said tube, an individual target being connected to each of said contactors; means for generating an electron beam and means for cyclically deflecting said beam over each of said targets comprising'an alternating current source; a transmitting channel; means for impressing code combinations b1 signal conditions on said channel in accordance with the operation oi said. contactors as said beam impinges on said targets; means including one or said targets for impressing a predetermined cyclic signal condition on. said channel; and means including said. source for impressing a synchronizing signal condition on said channel.

9. In a printing telegraph system, a transmitter comprising a plurality of contactors; means for selectively operating said contactor's; an electron distributor comprising a plurality of 4 contactors;

conductive targets arranged in a circle and equispaced 1 ated at one end of said tube, an individual t rget being connected to each oi said means for generating an electron beam and means for rotating said beam over each t 01' said targets comprising an alternating current source; a transmitting channel; means for impressing code combinations of signal conditions on said channel in accordance with the operation of said contactors as said beam impinges 1 on said targets; means including one of said targets for impressing a predetermined cyclic signal condition on said channel; and means including said source for impressing a synchronizing signal condition on said channel. l

10. In a printing telegraph system, a transmitter comprising a plurality of contactors; means for selectively operating said contactors: an electron distributor comprising a plurality of conductive targets arranged in acircle and equi- 2 spaced, located at one end oi said tube, an individual target being connected to each of said contaotors, means for generating an electron beam, and means for cyclically scanning said target with said beam comprising an alternating 2 current source; a transmitting channel; means for impressing code combinations of signal conditions on said channel in accordance with the operation of said contactors as said beam impinges on said targets; means including one of a said targets for impressing an operating signal condition on said channel; means including said source for impressing a synchronizing signal condition on said channel; a receiver connected to said channel comprising an electron distributor 3 having a plurality of targets'corresponding to said transmitter targets and an'electron beam operable over the receiver targets in synchronism'with the received signal conditions.

11. In a printing telegraph system, a trans- 4 mitter comprising a plurality of contactors: means for selectively operating said contactors; an electron distributor comprising a plurality of conductive targets arranged in a circle and equispaced, located at one end of said tube, an individual target being connected to each of said contactors, means -forgenerating an electron I beam, and means for cyclically scanning said target with said beam comprising an alternating current source; a transmitting channel; means 5 i'o'r impressing code combinations of signal conditions on said channel in accordance with the operation 01 said contactors as said beam impinges on said targets; means including one of said targets for impressing an operating signal 5 condition on said channel means including said source for impressing a. synchronising signal condition on said channel; a receiver connected, to said channel comprising an electron distributor having a plurality oi targets corresponding to said a transmitter targets and an electron beam operable over the receiver targets; and means respc-nsive to said synchronizing 81811 1 condition for maintaining the receiver beam in synchronism with the transmitter beam. 6

dividual target being connected to each of said ,contactors. means for generating an electron beam, and means for cyclically scanning said target with said beam comprising an alternating n mos-137a I pinges on saldttargets; means including one or said targets for impressing an operating signal condition on said channel; means including said source for impressing a synchronizing signal condition on said channel; a receiver connected to said channel comprising an electron distributor having a plurality of targets corresponding to the selector mechanism.

, I I a 7 said transmitter targets and an electron beam operable over the receivertargets; meansresponsive to said synchronizing signal condition m maintaining the receiverbeam in synchronism with the transmitter beam; selector mechanism connected to receiver targets for translating the code signal conditions; and means connected to 1 one at the receiver targets and responsive .to said operating signal condition for controlling said WILLIAMQH. men.

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