US2049706A - System for transmitting intelligence - Google Patents

Description

Aug. 4, l36. w. s. I EMMON v SYSTEM FOR TRANSMITTING INTELLIGENCE 2 Sheets-Sheet 1 Filed March 2, 1955 INVENTOR. Wa/rer 62 Lemma/7.

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' A TToRNEYS.

Aug. 4, 1936.

SYSTEM FOR TRANSMITTING INTELLIGENCE w. s. LEMMON Filed March 2, 1955 2 sheets-sheet 2 IN V EN TOR. Wd/'f 5. Lem/7700.

A TTORNE YS.

practice to provide inthe sender a multiplicity oi of the sender.

Patented Aug'. V4, 1936,"

vUNrraD s'r-A-'rrlsl PATENT OFFICE v'waiter s. y., miglior, by

mesne assignments,

poration-of NewYork application March 2,

to International Business Machines Corporation, New York,

N. Y., a cor- 1935, serial No. asis 4 claims, '(01. 11s-s2) y 'I'his invention relates tothe transmission of intelligence either through wired circuits or by radio, and more particularly to that vtype of transmission wherein the signal impulsesvpro- 5 duced by the operation of a typewriter or like machine, are so timed in their transmission that -they may be picked up and differentiated on a time basis by the receiver for causing the appropriate characters to be reproduced.

In systems of the kind referred to it is the circuits, each individual to a Vparticular charac ter, and each including a contact ysegment of a commutator, together with a rotary collector '15 adapted to engage each commutator segment at a predetermined point in its cycle of operations. The arrangement is such that an actuation of a key of the transmitting machine causes the cir'- cuit individualto thatkey -to be charged and 20 stored with electrical energy. When the rotary collector engages the commutator segment included in that particular circuit a discharge takes place causing current to now, and this discharge f is'inductively transmitted into the output circuit' The receiversimilarly 'includes a eceiving distributor which comprises a rotary rm or contact member and a commutator over w ch the rotary distributor arm runs. When the signal comes through it is transmitted through the particular` commutator contact which is at that instant en-.v gaged by the rotary distributor and hence provduces an actuationof a signal. character key in the receiving typewriter associated with the circuit of that particular contact.

It is important in such a system thatthe sending collector and the receiving distributor bev operated 'synchronously and in 'phase with one another', and lto this end it is desirable that the motors for operating them be alike and that the operatingcurrent supplied to the motors be exe actly the same in character. It isaccordingly afeature ofthe present invention to utilize' the vordinary alternating line current such as the 60 cycle current-commonly supplied by electric light and power companies or ob-l Y tained from local generators for operating the motor of the transmitting collector, and at 'the same time to transmit a portion of said current with the signal impulse to the receiver and there -to detect andl amplify this alternating current component for driving the motor of the receiving Y distributor.

It is a further feature of the invention to pro- 55 vide suitable iiltering and amplifying means in a one terminal of one of the contact with branch circuit of the Ireceiver for amplifying th signal impulses and transmitting them to the writing instrumentalities while suppressing the arnating current component in the branch circ Other objects and advantages will hereinafter appear.

In the drawings cation,

Figure 1 isa diagrammatic View illustrating the transmitting and receiving apparatus of the system, and

Figure 2 is a certain features of thev tail than Figure 1.

An alternating current generator I supplies alternating current through line conductors 2 and forming part of thisl specidiagrammatic view illustrating transmitter in greater de- 3, andthence through a suitable switch 4, to a circuit comprising a conductor 5, a primary transformer coilI, and a conductor rl. Branch conductors 8 and 9 are connected to the conduc- -tors 5 and 1, respectively, and run to the terminals of amotor III which, through its output shaft II, drives a determined speed.

of 'a stationary commutator I6. The conductor I3 -is vconnected to a primary transformer coil I1 and the coil Il in turn is connected to a conductor I8. The conductor throughya multiplicity of 'parallel wires I9 to condensers 20 each of the wires I 9 running to condensers. The opposite terminal oi each condenser 20 is connected through a switch arm 2| ,which is normally in contact with a conductor 22 running to vone of the segments I4 ofthe commutator I6. The condensers are normally discharged and hence the circuits which are successively completed through the condensers by the running of the distributor arm I 2 upon the contacts I4 are dead circuits eircept when' one of them has been ener- EachA condenser is adapted to be charged by the actuation of a particular type key or other operating instrumentality of Vthe transmitting typewriter 23. When a key of the 'typewriter is depressed one of the switches 2I (associated exclusiveiy with that key) is moved-away. from the terminal of the associated conductor 22 and into the terminal of an associated conductor 24. This closesa circuit for charging the condenser 20 individual to thaty switch, such cirrotary collector'arm I2 at pre-t I8 is connected automatically by a spring, into engagement with the terminal of the;l associated conductor' 22. The momentary engagementof Athe switch with the conductor 24 iseective to charge the associated condenser but the condenser eannotxbe discharged until the distributor arm l2 wipes.

across the segment or contact I4 which is in circuit with that particular condenser. vWhen this occurs the condenserl is discharged and a.v signal impulse lscaused to iiow through the primary winding I1. i

'A The alternating line current flowing through` the primary winding is inductively transmitted' finto a secondary` circuit 28 through a. secondary winding 29, and the signal impulses which flow through the primary winding I1 are inductively transmitted vinto thel secondary circuit through a secondary winding 30. The current thus in- .duced in the secondary circuit is fed-into a modulator 3l yand is there impressed upon a'carrier current generated by an oscillator 82 and broadcast from an antenna 33.

vIn order to guard against inductive transmission of the alternatingline current ,into the cirv cuits of the condensers 26 through the coils 30 and I1 as primary and secondary, respectively, provision is, desirably made ofi-'a resonant shunt circuit 34 between the conductorsV I 3 and I8, said circuit comprising an inductance 85 and a condenser 36, whose characteristics'are such that vthe shunt circuit will short circuit any alternating current voi' line frequency present; l i

y In addition to the alternating line current andA the signal impulses which are transmitted, itis desirableftha't a phase control impulse be trans-k mitted at a. predetermined pointV in each cycle' which may be and tothis end the commutator contact I5 is,V i

provided. 'A conductor 31 connects the conductor 21 andhence the battery to contact I5. It

will seem that each time the arm I2 engages the contact I5` a circuitisclosed through the battery --and the primary coil I1 causing a. phase control impulse to. be transmitted. This occurso'nce in e each revolution', and at a predetermined point.

The receiver comprises an aerial 98 and a" groundv 39 forming parts of a-,radio receiving set i 40 of conventionaldesign. In this receiving. 'set the received energy'may beampliiied. and the currentof Yline frequency aswell 'as the signal and phase control impulse maybe detected. The

output circuit 4I of the receiving setv 40 includes a.4 primary winding 42 which is'inductivelyl `coupled to secondary windings 43 and 44 of separate circuits45 and 46. The circuit 45 is a motor operating circuitandds supplied Y with 1 received and amplled alternating \current impulses identical in character with the alternating current impulses whichl drive themotor I 9 oi the transmitter. This currentin the circuit 45 is used to drive a-motor 41 which, throughits-output shaft 46, drives thereceivin'g distributor 49 and phase control contact arm 50. The motor 41 is exactly likethe motor I0, and since the current supplied 'plien shaft 48 through diii'erential mechanism `(not Ishown) and each time that the 'electromagnet toboth motors is identical in character the tendency of .the two motors is to operate identically as to speed. l

I Thecircuit 46 -is designed to segregate the signal and control impulses from the alternating current and to amplify them and transmit them f to the receiving typewriter.` To this end the circuit includes a filter 5I to suppress. current of the known frequency of thealternating current received, and an amplier 52.y A conductor 53 `connects the amplifier .with the inner ends f-the armsjS-and 50. The arm 49 runs in engagement with contact segments 54 of a stationary com- I mutator 55 and each contact segment 54 is connected through a conductor 56 to operate a particulartypeharor other operating instrumentality of the receiving typewriter. After passing through vthe receiving typewriter the current fromallA of these conductors56 passes back .to

the' amplier through a conductor 51. The operating `and phase control impulsesv are all iden- `tical `in character, and are distinguished from ,one another solely by the period in the cycle of lthe sender during which theya're respectively transmitted. It is necessary, therefore, to makeprovision for securing and maintaining phase,

correspondence between the sender and distribumentality of v`the receiving typewriter which it is intended tor operate; To this end provision is made of phase'control means of the same kind as illusrated'in my pending application `Serial No. 684,362, iiled Augustl 9th, 1933, for Synchro-A nizing system.

This mechanism may be 'described briefly as follows: The conductor 53, as has been mentioned, is always connected to the inner end of A armv 50 and to the inner cnd' of arm 49. The phase control impulse, transmitted whenever the .arm I2 of the transmitter engages contact I5,

occursoncein each cycle and at the same. point in Yeach cycle. When the sender'and receiver A- tor in order to cause a received impulse to opcrate the particular type bar or other instruare'ilrst coupled they will presumably be out of phase correspondence. N'o signalling impulses are ktransmitted until a suiiicient interval has elapsed to permit phase correspondence to be secured. The arm 50 runs upon a ringvsegment 58 and contacts 59, 60, and 6|. If the first signal impulse is transmitted through the ring 58 it is caused to pass vthrough a conductor 62, a yswitcharm 63, a conductor 64,-a conductor 65, an

advancing-electromagnet 66, and a conductor 61, tothe conductor 51 which runs back to the am- The arms' 49 and 50 are driven-from' the ,66 is energized it operates a pawl and ratchet device for advancing the varms 49 .and 50 one contact space of the commutator`55` relative to the shaft 48. As the operation contin es one of these adjusting steps will be applied in each revolution untilv the arm 56 hasadvanced to a point where it will no longerengage the contact ring 58 at the moment ot reception of the control impulse but will engage the contact 6I. Th current now flows throughthe contact 6I and conductor 65 to the advancing electromagnet,

so that the next impulse will be received through the contact 60, thel condition desired.

'The current now flows from theeconta'ct 60 4through a conductor 68, an' electromagnet 69, and a conductor 10" to the conductor 61. The switch 63 constitutes the armature of. the electromagnet 69 and it is pulled away `from, engagecuited, and ineiective.

ready for the transmission of signal impulsesstore' pase correspondence.-

the ot er hand has advanced away from .phase ment with the terminal of conductor 82 when the electromagnet 69 is energized to open-circuit the ring segment 58. A retarding device 10, which may be a dashpot, is connected to the switch 63 to cause it to act slowly so that the switch 63 does no t return to engagement with the terminal of conductor 62 for a plurality of cycles of the arm 50. The control impulses should now continue to come in on the contact 60, which produces no adjusting step, and the ring segment 58 is held continuously open cir- The. apparatus is now since the transmission of signal impulses cannot now result in the production of adjusting' Should a condition occur tending to disturb the synchronous and in-phase relation of the arm with reference to the arm l2 of the transmitter, an adjusting step will immediately occur either in an advancing orretarding direction to restore phase correspondence. If the arm 50 has lagged the control impulse will be again transmitted through the contact 6i and an advancing step will immediately be applied to re- If the arm 50 on correspondence the control impulse will pass through the contact 59 thence through a conductor 1I, a retarding electromagnet 12, and con.

ductor 13 to conductor 61. This will immediately apply a backward adjusting step to restore phase correspondence. Switch 63 acts Aslowly enough to permit these momentary deviations without permitting the switch 63 to be closed.

I have described what I believe to be the best embodiments of my invention. I do not wish, however, to be confined to the embodiments shown, but what I desire to cover by Letters Patent is setforth in the appended claims.

I claimr- 1. In la system for transmitting intelligence, in combination, a sender comprising a sending machine having a keyboard, each key being adapted when operated to cause the transmission of a signal impulse, means comprising a rotary collector and a commutator for alloting to each key a definite period in the cycle of rotation, means in the sender for initiating a phase control impulse ata predetermined point in each cycle. a motor for driving the collector at uniform speed, a source of alternating current, means connecting said source to drive the motor, an output circuit means for transmitting the alternating current and the signal and control impulses into the output circuit, and a receiver comprising electrical receiving and amplifying equipment, a receiving machine comprising printing instrumentalities, a commutator and a rotary distributor for causing the received signal impulses to operate the printing instrumentalities selectively in accordance with the timing of the received signal impulse, a motor for operating the distributor, means for transmitting the received and amplified alternating current to operate the receiver motor, and means for transmitting the received signal impulse exclusive of the alternating current, through the distributorto the several printing instrumentalities, and means responsive to the reception of the control im- `pulse in all positions of the distributor other than that representing phase correspondence for automatically applying one or more adjusting steps to the receiving distributor for stepping the same into phase correspondence with the sending collector.

2. In a systemyfor vtransmitting intelligence, in combination, a sender comprising a sending machine having a keyboard, each key K being adapted when operated to cause the transmission of a signal impulse, means'comprising a rotary collector anda commutator for allotng to each means in the sender for initiating a phase control impulse at a predetermined point in each cycle, a motor for driving the collector at uniform speed, a sourceof alternating current. means connecting said source to drive the motor,

key a definite period in-'the cycle of rotation, 20

an output circuit, means for transmitting the 1 of the received signal impulse, 'a' motor for operl ating the distributor, means for transmitting the received and amplified alternating current to operate the receiver motor, and means for transmitting the received signal impulse exclusive of the alternating current, through the distributor to the several printing intrumentalities, and A means responsive to the reception of the control impulse in all positions ofthe distributor other than that representing phase correspondence for automatically applying lone or more adjusting steps to the receiving distributor for stepping the same into phase correspondence with the Vsending collector, and for automatically correcting the phase adjustment without interrupting the reception of signal impulses.

3. The invention set the means, for transmitting the alternating current and signal and control impulses comprises inductive means.

4. The invention set forth in claim 1 in which the means for transmitting the received signal impulse exclusive of the alternating current through the distributor comprises a transmitting circuit4 having a filter incorporated therein for iiltering out current of the known frequency .of the motor operating current.

WALTER. s. Lemmon.

forth in claim 1 in which

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