US2451812A - Electron tube variable impulse transmitter - Google Patents

Description

Oct. 19, 1948. J. R. DEscH 'Er AL sLEc'rnoN TUBE VARIABLE InULsE TRANSMITTER original Filed sept, 1e, 1942 6 SheefS-Sheet 1 Alll AAAI

Oct. 19, J. R. DEscH Erm. 2,451,312

ELECTRO TUBE VARIABLE IIPULSE TRANSIITTBR Original Filed Sept.. 16.; 1942 6 Sheets-Shee-t 2 INVENTORS JOSPH R. DESGH ROBERT E. MUN/HA ERNEST M GULDEN ,gw Mm M THElR ATTORNEY Oct. 19, 1948'.

Original Filed Sept. 16, 1942 FIG. 3

.L R. DEscH Erm. .2,451,812

ELECTRON TUBE VARIABLE IMPULSE TRANSMITTER G'Sheets-Sheet 3 INVNToRs JOSEPH R. aEscH RosERr E. Humm a ERNEST u 4z/LamvV THEIR" ATTORNEY Oct. 19, 1948. J. R. Dl-:scH ETAL 2,451,312

ELECTRO TUBE VARIABLE IIIPULSE TRANSMITTER Original Filed Sept. 16, 1942 6 Sheets-Sheet 4 L WVY AVAVAVAY f t x21 INVENTORS JOSEPH R. DESGH ROBERT E. NUNMA 8 ID U ERNEST l. GULDEN N l` l 2 -v 2 ,BY M

Y) o `o \c la/b THEIR ATTORNEY Oct. 19, 1948. J. R. DEscH ETAL ELECTRON TUBE VARIABL IMPULSE TRANSMITTER original Filed sept.l 1e, 1942 6 Sheets-Sheet 5 INVENTORS JOSEPH R. DESGH ROBERT E NUNMA 8 ERNEST I( GULDEN THEIR ATTORNEY Oct. 19, 1948. .1. R. DEscH yET AL ELECTRO TUBE VARIABLE IMPULSE TRANSMITTER 6 sheets-sheet 6 Original Filed Sept. 16, 1942 I3 INVENTORS JOSEPH R.

ERNEST Y `GULDEN Y @n e THEIR ATTORNEY Patented Oct. 19,1948

ELECTRON TUBE VARIABLE IMPULSE TRANSMITTER Joseph R. Desch, Ernest V. Gulden, and Robert umina, Dayton, Ohio, assignors to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Original application September 16, 1942, Serial No. 458,546, now Patent No. 2,425,307, dated August 12, 1947. Divided and this application February 19, 1944, Serial No. 523,024

(ci. 11i-sab) 24 Claims.

This invention relates to communication systems and is directed particularly to a sending apparatus or signal generating means for usein a system in which various symbols making up the data to be transmitted are transformed into spaced bursts or trains of discrete rapidly recurring signals, the number of signals in each, burst being dependent upon the symbol which is represents. The bursts -representing the different symbols are sent one after another over 4a single communication channel with suitable spacing between bursts, and a marking signal Iis provided for each burst to indicate the completion of the burst. The marking signal is used .to control a receiving apparatus to govern the allocation and storage of the symbols therein. The signals by which the symbols may be representedl may take various forms, as, for instance, interruption or modulation of a continuous carrier wave and/or discrete rapidly recurring impulses, or representations thereof. i

This application is a division of the application 'for United States Letters Patent, Serial No. 458,- 546, which was filed by Joseph R. Desch. Ernest V. Gulden, and Robert E. Mumma on September 16, 1942, now U. S. Letters Patent 2,425,307, granted Aug. 12, 1947.

The sending apparatus is provided with means for generating the spaced bursts of signals yand controls the number of signals in ,each burst according' to the symbol being sent. Y The 'signals can be transmitted by any convenient means; for instan-ce, over a wire or by radio to a receiving and storing apparatus, where they are transformed back into single representations of the symbols and are stored.

High-speed communication of data is obtained with applicants novel arrangement because the sending apparatus can generate the signals at a 'high -frequency and because the signal bursts which Iare used to represent the various -symbols require only the time necessary to produce the number of sign-als Kneeded to represent the symbols and can follow one after the other in transmission without unnecessary loss of time between bursts. f

Furthermore, there is no particular sequential relation between the various symbols and the number of signals which may be used to represent them, so that the number of. signals which represent any symbol m-ay be chosen arbitrarily.

It is an object oi the invention, therefore, to

provide novel high-speed means Ifor sending data in the iorm'of bursts of different numbers of signals.

A .further object of the invention is to provide a means for producing bursts of signals, each burst comprising a 4predetermined number of symbolrepresenting signals followed by a control signal.`

A-further object of the invention is to provide a novel means for transforming a data-representing symbol into a number of discrete rapidlyrecurring signals.

A further object of the invention is to provide a means to transform any data-representing symbol into a signal train comprising a number of discrete signals of one type for indicating the symbol and a control signal of another type for indicating the end of the signal train.

A further object of the invention is to provide a means upon which may -lbe set a plurality of symbols comprising data to be transmitted, which symbols are transformed Vone after another Iinto bursts of different numbers of like discrete signais representing `the symbols and are sent out over a single communication channel.

A Ifurther object of the invention is to provide a means to transform a plurality of data-representing symbols into bursts or individual trains of different numbers of discrete signals corresponding to the symbols, with a marking signal included in each burst to distinguish the bursts.

With these and incidental objects in view. the Y invention includes certan novel features of construction and combinations of parts, the essential elements of which are set forth in appended claims and a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form .a part of this speciilcation.

In the drawings:

Fig. 1 shows a portion of a set, of keys for setv ting up a symbol in the sending apparatus and a portion of the symbol-transforming means controlled thereby for controlling the number of impulses which will be sent to represent the symbol set up on the keys.

Figs. 2 to 5 inclusive are similar to Fig. 1 and, together with Fig. l, provide means for setting up and controllng thesending of five symbols in succession.

Fig. 8' shows the start and stop controls for the sending apparatus and also shows the means for forming the symbol-representing impulses and the marking signals. j

Fig. 7 is a representation of live bursts which may be generated in succession and illustrates the general character of the trains of signals by which the symbols are transmitted.

GENERAL DESCRIPTION T-he symbols which may be sent and received by the novel apparatus may represent any selected data such as the digits of numerical notation, the letters of the alphabet, or any other arbitrary data which may be chosen.

The disclosed embodiment of the invention is shown with a capacity for automatically transmitting lve symbols in succession and is arranged to transmit the letters of the alphabet.

For the purposes of thisdisciosure, the signals by which the symbols are represented will consist of discrete rapidly recurring impulses, and these impulses will be transmitted from the sending apparatus to the receiving apparatus over a wire. However, it is not intended to limit the invention to this particular form of signal and transmission medium, as the invention is capable of being carried out by using other equivalent arrangements.

The sending apparatus or impulse generating means contains ilve groups or banks of keys. The keys of each group represent a space symbol and the letters A to Z and are used for setting up l symbols to be transmitted. Associated with each key in any bank selects the starting point in the l firing sequence by preparing its related symbolrepresenting control tube to be red in response to an impulse commonly impressed on all of the symbol-representing control tubes. Once a tube in a bank is fired, it will start the automatic firing of the other tubes in the sequence one after another until the shift tube is fired and becomes conducting. By means of these tubes, the symbol is transformed into a series of rapidly recurring impulses. The symbol-representing control tubes are connected to an impulse line and send an impulse over the line each time one of the tubes is fired, and these impulses are utilized to control the output of a small-amplitude impulse generating tube which sends out a small-amplitude impulse to the receiving apparatus each time one of the symbol-representing control tubes is fired.

When the last symbol-representing control tube 'in a chain is ilred, it causes the marking impulse tube to re. The marking impulse tube sends an impulse to control a second impulse generating tube. which sends to the receiving apparatus an impulse having a larger amplitude than the impulses sent out under control of the symbolrepresenting control tubes. The impulses from the small and large-amplitude impulse-generating tubes are impressed on a single output conductor and may be sent to the receivingapparatus. The marking impulse tube, when it is ilred, causes the shift tube of this bank to be ilred symbol-representing control tubes of the next bank of the tubes to re the prepared symbolrepresenting control tube therein and start sequential firing of the tubes of that bank. By means of the shift tubes, various banks of tubes are rendered operative one after another in succession, and this successive operation of the banks of tubes enables the symbol-representing control tubes of all the banks to control the same small-amplitude impulse-generating tube, and the marking impulse tubes of all the banks to control the same large-amplitude impulse-generating tube so that the impulses representing the dierent symbols can be sent in succession over a single communication channel. The output from these generating tubes will therefore consist oi bursts of rapidly recurring impulses for each bank of tubes, each burst being made up of a series of small-amplitude impulses followed by a largeamplitude impulse.

It is clear that the invention is not limited to the use of small-amplitude impulses as the plurality of signals, and large-amplitude impulses as terminal signals, because the large-amplitude impulses could obviously be used to make up the plurality of signals, and the small-amplitude impulses could be used as terminal signals.

A delay is provided in the ring of the shift tube of each bank by its related marking impulse tube. This delays the initiation of the ilring of the tubes of the next bank and provides the space or time interval between the successive bursts.

After the symbols have been set up on the keys, transmission of the symbols is initiated by operating a start key, which causes a firing impulse to be sent to the symbol-representing control tubes ofthe first bank of tubes to start the sequential ring of the tubes therein. The remaining banks of tubes will be rendered operative automatically in succession, and the shift tube of the last bank will cause the termination of the transmitting operation.

The invention is not limited to the use of a multiple-bank sending apparatus, because a single bank could be used repeatedly to send out successive bursts of signals or impulses which could control a receiving apparatus in the same manner as though the signals were generated by the five banks automatically in the five-symbol sequence explained above.

Thus it is seen that applicants have provided a novel sending apparatus or signal generating means which can operate at a high rate of speed to generate different numbers `of signals which represent symbols of data to be transmitted.

` DETAILED DESCRIPTION The disclosedI embodiment of the invention is adapted to send ve symbols automatically in succession in the form of bursts of impulses. Fig. '7 shows, in a general way, a representation of a train of impulses made up of the bursts oi impulses Which would be generated to represent the 4for A'n uspalce'n uc," nA'nand NB."

A consideration of these bursts shows that the "space symbol is represented by a burst containing one small-amplitude symbol-representing impulse followed by a large-amplitude marking impulse; the letter A" is represented by a burst containing two small-(amplitude impulses and a large-amplitude impulse; and the letter B is represented by three small-amplitude impulses after a suitable time, and send 'an impulse to the (5 and a large-amplitude impulse. In the instant embodiment, this relation between the various letters and the number of small-amplitude impulses extends to the letter "Z," which would be represented by twenty-seven small-amplitude impulses and a large-amplitude impulse.

The form of the impulses as shown in -this iigure is .one form which maybe used, but the invention may be carried out' with other `forms of impulses just as long as a distinction is maintained between the variable number of impulses and the marking or controlling impulses. The

cate the order in which the symbols are transmitted and similar numerals have been applied to the parts of the sending apparatus which deal with these symbols.

Symbol-transforming means t Five. banks of keys are provided for setting up the symbols, and associated with each bank is a symbol-transforming control means which controls the transformation of the symbols into different numbers of impulses. The banks are shown in Figs. 1 to 5 inclusive, and, as the banks are substantially alike, it is believed that the operation of all -theibanks will be clear from a description of the elements of one bank and their operation.

' Itis not intended that the invention 5e limited v proper relation between the various parts of the circuit. Throughout the drawings the cathode heater elements are shown conventionally.

Referring to Fig. l, which shows a symbol-V transforming means for the first symbol ,to fbe transmitted, it will be seen that the symbol-transforming means is made up of a plurality of gaseous electron Itubes. The tubes are of the, type having an internal potential drop of about volts when conducting and having an anode, a

cathode, and a control grid which is given a nega-A tive bias with respect to the cathode and will prevent the tube from firing until this bias is reduced to less than 15 volts negative with respect-to the cathode. The tubes making up the bank fall into three classiilcations--namely, symbol-representL ing control tubes; a marking impulse tube; and a shift tube.

As many symbol-representing control tubes will be included in each bank as there are symbols which may be selected for transmission. and these tubes will control the creation of different numbers of impulses by which the symbols are represented., In the present embodiment, each-group will include a tube for a space symbol and one for each of the letters Aof thealphabet, though in Fig. 1 only the uspacen uA," UB." Y'n ,and uz" tubes are shown. the symbol-representing control tubes for the letters C to iX inclusive having been omitted to simplify the showing of the bank because the circuits for these tubes `are identical with those of other symbol-representing controll annoia l One marking impulse tube "mark" lsprovided -ior the bank and is operated to control -the crea- J tion of a marking impulse for indicating the end of a burst after the symbol-representing control tubes of the bank have caused the creation of control impuises. One shift tube shift is provided for the bank and is operated to shift the control of the sending of impulses, from one. bank to another, by impressing a starting impulse on another'bank to start the sending of another burst of control impulses after the marking impulse Ytube of one bank has operated to cause a marking impulse to be created to indicate the completion of the symbol-representing burst of impulses.

The circuits for supplying'potential to the ele- `ments of the symbol-representing control tubes and for inter-connecting these tubes for sequential operation are similar for all these tubes and will be clear from the explanation of the circuits shown. f

Negative potential is suppliedto the cathodes of l the symbol-representing control tubes by means ofparallel circuits, one for each tube, extending to ground from a negative potential supply conductor 8i, to winch a negative potential of 150 volts is applied at terminal 62. The circuit for the A tube is representative and extends from the supply conductor 6| at point 63 over resistor 84 of 150.000 ohms, point 65, a resistor 66 of r[5,000 ohms, points 61 and 68, and over resistor 69 of 15,000 ohms and capacitor 'I0 of .002 microfarad in parallel, to ground. l

The cathode Il of the fA tube is' connected to this circuit at point 01 and has a negative potential of approximately 9 volts when the tube is not conducting. When the tube is conducting, the cathode is also conductively coupled to its related Aanode by the discharge path through the tube, so that the positive potential which is applied to the anode will also be impressed on the cathode potential supply circuit and will cause .the potential of the cathode to rise from a negative potential of 9 volts to a positive potential of about '70 volts.

Each cathode potential supply circuit is utilized to supply' negative biasing potential for the control grid of the next tube in the sequence, which is, in this case, the space" tube. From the point 85 in the cathode circuit for the A" tube, the circuit extends through point 12, over resistor I3 of 500,000 ohms,'point 14, a resistor 15 of 50,000 ohms, to the control grid 16 of the space" tube and provides this grid with a negative biasing potential of approximately 56 volts. YThis connecquence, the control grid "I1 oi' this'tube is given a,

biasingpotential of the' same value as the Vgrids of the other tubes by means of acircuit which is equivalent to the other cathode potential supply circuits and extends from the negative potential supply line il, over point 18, resistor 19 of 150,000 ohms, point 80, and resistor 8i of 90.000 ohms to ground,I to which circuit the grid 11 ,is connected from point l0 over resistor 82 of 500,000 ohms, point 83, and resistor Il of 50,000 ohms.

Each control grid of the symbol-representing control tubes is. electrostatically connectedV to a starting limpulse conductor 00, the connection for the gridgl o! the "space tube extending from point 14 in the grid circuit, over a capacitor 0| oi' grid bias reduced to near the critical point so that the starting impulse can reduce the bias below its critical point and cause the tube to nre and become conducting. The manner in which the tubes can be "primed will be explained hereinafter.

Positive potential is supplied to the anodes of the symbol-representing control tubes by a circuit which extends from terminal 02 (Fig. 6), upon which is impressed a positivevpotential oi' 105 volts, and continues over conductor 00, point 84, conductor 05, points and l, a resistor 00 of 500 ohms, point 99, a resistor |00 of 3,000 ohms, point |0|, and conductor |02 to the common anode potential supply terminal |00 for the symsol-representing control tubes.

Point 90 in this circuit is connected to ground over a capacitor of 0.1 microfarad, which absorbs the shock of any abrupt potential application or change in 'the circuit.

Terminal |00 is connected to terminal |04 (Fig. i), to `which is connected an anode potential supply conductor |00 ior the symbol-representing control tubes of this bank. Each of the anodes si the symbol-representing control tubes of this bank is connected over a resistor of 1,000 ohms to the anode potential supply conductor |05, as, for instance, resistor |00, over which the anode |01 cf the A" tube is connected to the anode potential supply conductor |05.

When none of the symbol-representing control tubes is conducting, a positive potential oi |05 volts is applied to the anodes; however, when one of these tubes is conducting, the potential will be reduced to about 85 volts due to the drop across the resistors 00, |00, and |08. f

At the moment one of these tubes is tired, its cathode will remain at a negative potential of 9 volts while the capacitor, as 10, is charging, and. due to the resistance in the common anode potential supply circuit for the symbol-representing control tubes and the internal potential drop of the tube, the potential of the anode will drop to within about l5 volts of the cathode potential. This will cause a drop in potential of the anode potential supply conductor |05, which drop provides a negative potential impulse on the conductor. As the anodes of all the symbol-representing control tubeso a bank are connected to the anode potential supply conductor |05, a series of negative impulses will be impressed on the conductor as these tubes are tired one after another. These impulses are used to control a `signal-generating tube |45 (Fig. 6), which, in a manner to be described later herein, creates symbol-representing impulses corresponding in number to those required to represent the symbol being transmitted.

The drop in the potential oi the anode potential supply conductor |05 is also used to extinguish any previously conducting tube which has its anode connected to the common source of anode potential for the symbol-representing control tubes, which includes the resistors 00 and |00.

The extinguishing action occurs because the potential of all the anodes of these tubes will drop as the potential of the anode supply conductor drops, and this4 will cause the potential of the anode of a previously conducting tube to drop below the potential of its cathode, which cathode potential has risen due to conduction in the tube, and will cause conduction to cease in that tube and enable the control grid to regain control.

Negative potential is applied to the cathode |00 of the marking impulse tube mark by means of a circuit similar to the ones for the symbolrepresenting control tubes, the circuit for the marking impulse tube extending from the negative potential supply conductor 8| at point |00, over resistor ||0 of 150,000 ohms, point i||, resistor -||2 of 75,000 ohms, point lili, and over a resistor H4 of 15,000 ohms and a capacitor ||5 of .002 microfarad in parallel, to ground. to which circuit the cathode |08 of the marking impulse tube is connected at point ||3. As in the case lof the symbol-representing control tubes, the

cathode of the marking impulse tube will acquire a positive potential when the tube is conducting.

Negative bias for. the control grid ||8 of the marking impulse tube is obtained by .connecting the control grid to point ||1 in the cathode potential supply circuit for the space" tube. This connection enables the potential rise of the cathode of the space tube to be reflected on the control grid of the marking impulse tube and cause the negative bias to be reduced below the critical point and the tube mark to re and become conducting automatically after the space" tube has become conducting.

The control grid of the marking impulse tube has no connection to the starting impulse conductor 00 and accordingly can be fired only when conduction occurs in the last symbol-representing control tube of the sequence, whichl in the instant embodiment is the space tube.

The potential supply circuit for the anode of the marking impulse tube is similar to that for the symbol-representing control tubes. The circuit extends from the terminal 92 (Fig. 6) upon which is impressed a positive potential of volts, conductor 03, point 94, conductor 95, point 96, resistor ||8 of 500 ohms, point ||9, resistor |20 of 4,000 ohms, point |2|, and conductor |22 to common anode potential supply terminal |23 for the marking impulse tubes. Point ||9 in this circuit is connected to ground over a 0.1 microfarad capacitor, which absorbs the shock of any abrupt application or change of potential in this circuit. Terminal |23 is connected to terminal |24 (Fig. l), to which is connected the anode |25v of the marking impulse tube mark'i of this bank. The anode |25 will have a normal positive potential of 105 volts, but, due to the resistance in the common anode potential supply circuit, this potential lwill drop asv the tube isred and will uctuate ipotential drop which occurs while the capacitor ||5 ischarging provides a negative potential impulse which is used to control a signal-generating tube |40 (Fig. 6) for creating a marking signal in a manner to be described later herein. This impulse, which occursat the moment the marking impulse tube mark is fired, can also cause 'autels any othertiibe which is connected to the common anode potential supply circuit forl the .marking impulse tubes, over resistors IIB and |20, to be Y extinguished. Itshouid be .noted that, since the symbol-representing control tubes have a difier- Vent anode potential supply circuit from the marking impulse tube, the firing of the marking impulse tube will not be effective to extinguish the last symbol-representing control tube o! the sequence which has been fired and is conduotpoint |21 to the terminal |3| to enable the potential rise of the cathode |26 to be used as a starting impulse for starting the ilring of symbolrepresenting control tubes` in bank II.

The control grid |32 of the shift tube obtains its negative bias from the cathode potential supply circuit for the marking impulse tube. The connection is from point in the cathode potential supply circuit of the marking impulse tube and over point |33 and resistor |34 of 500,000 ohms to the control grid |32. The potential rise oi the cathode of the marking impulse tube, when that tube is conducting; is effective to reduce the negative bias on the control grid |32 and cause the shift tube to fire and become conducting. A capacitor |35 of .001 microfarad is connected between point |33 in this circuit and ground to delay potential rise of the control grid |32 and the consequent firing i the shift tube after the firing of the marking impulse tube. This provides a time interval batween bursts, which interval may be made longer or shorter as desiredk by varying the capacity of capacitor |35.

Potential is supplied to the anode |38 of the shift tube by a circuit which starts at the terminal |31 (Fig. 6), which has a positive potential ,'10 tively biased so that a starting impulse impressed on the conductor --will not be effective to reduce f thebias below its critical point to cause the tubes `the control grid almost to its critical point, and, when the starting impulse is impressed on the tubes, the bias of the control gridv of the A tube of 150 volts impressed thereon, and continues over conductor |38, point |33, resistor |40,of 500 ohms, point |4|, and resistor |42 of 4,000 ohms to the common anode'potential supply terminal |43 for the shift tubes. Point |4| in this circuit is connected to ground over a capacitor of 0.1 microfarad. Terminal |43 is connected to terminal |44 (Fig. 1), to which the anode |36 of the shift tube is connected. Asv inA the case of the anodes of the other tubes of the bank, the potential of the anode will drop to about 15 volts -above ground, the potential of the cathode, while the capacitor |29 is charging, and this potential drop will be effective to extinguish any previously conducting tube which derives its anode potential over the resistors |40 and |42 (Fig. 6) in the common anode potential supply for 'the shift tubes. Since the anodes of the marking impulse tube a'nd the symbol-representing control tubes have diierent anode potential supply circuits from that of the shift tube, the iiring of the shift tube will be ineffective to extinguish the marking impulse tube or the space" tube'.

The sequential and 'automatic ilring of the tubes of a bank always begins with a symbolrepresenting control tube and is initiated by la starting impulse. The control grids of the symbol-representing control tubes ar'e electrostaticaliy connected to the starting impulse' conto be iled and rendered conducting. In order that a starting `impulse will be eiectivc to'ilrea tube, the tube must be primed by having the normal biasot its grid reduced to such a degree that thestarting impulse will be suilicient` to carry the bias below the critical value and cause the tubeto re and become conducting; accord` ingly, the se ection of the tube with which the sequential op ration of the tubes in the bank 'is to begin can be eiected by the selective priming of thetubes. This is accomplished under control oi' keys upon which the symbols may be set.

Fig. 1 shows schematically a portion of the row-of keys upon which the first symbol to be transmitted'is set up. Only the keys ,for the space symbol and for the letters A and Z" are shown, the keys for the letters B to .Y

inclusive having been omitted to simplify the showing' of vthe bank, inasmuch as the circuits controlledby the omitted keys are similar to the circuits shown and the operation of the keys to selectively. prime the tubes can be understood from the circuits shown.

The A key |50 (Fig. l) is shown depressed, completing a priming circuit which starts at the terminal |53, upon which is impressed a positive potential of 105 volts, and continues over a conductor |54 to point |55, closed key switch |56, conductor |51, and resistor |58 of l700,000 ohms to point |59 in the circuit by which negative biasing potential is supplied to the control grid of the A tube.

The application of positive potential -by this circuit reduces the negative biasing potential of will be reduced to within 15 volts negative with respect to the poten-tial of the cathode, and the tube will 'fire and become conducting. In av similar manner, .the closure of a priming circuit to any of the other symbol-representing control tubes will select that tube to begin the sequential and automatic ring of the tubes of the bank..

Thev operation of the symbol-transforming means shown in Fig. 1,'by which the control of the formation of a burst of impulses corresponding to the first symbol to bel transmitted is obtained, will now be explained.

The key |50 corresponding to the letter A has been depressed and completes the priming circuit for the A tube. A starting impulse is impressed on the starting impulse conductor 90 and causes the firing of the A" tube. At the moment the "A tube is red, its anode potential will drop because of the resistor |06 and the re-I sistors 98 and |00 in the symbol-representing control tube anode potential supply circuit, causing a drop to occur on the conductor |05, terminal |04, andterminal |03 (Fig. 6) of the anode potential supply circuit, which drop is used as an impulse to control the small-amplitude impulse generating tube |45. 'I'he potential of the cathode of the-conducting A tube will rise and,

through the connection between point |55 (Fig.

- tential of the control grid 16 to rise and reduce the bias below its critical value and cause the space" tube to fire and become conducting. The

ductor 80, but are normally suiliciently negapotential of the anode of the space tube will assaut drop and cause another impulse ,on conductor l potential supply conductors |33, |13, 11|, and |12 |33, terminal |34, and terminal |33 (Fig. 3) in pulse generating tube |43 and in addition willalso extinguish the conducting A" tube. The

' potential of the cathode of the "space" tube' will rise and cause the potential of the grid ||3 (Fig. l) of the marking impulse tube "mar to rise. reducing its bias below its critical value and causing the marking impulse tube to ilre and become conducting.

When the marking impulse tube is fired, the

. potential of its anode will drop.' which drop occurs at the terminal |24 and terminal |23 (Fig. 3) and is used as an impulse to control the large-amplitude generating tube |43 (Fig. 6). The potential drop of the anode of the marking impulse tube will not be effective to extinguish the "space" tube, because the anodes of these tubes are included in different anode potential supply circuits. The

potential of the cathode of the marking impulse tube will rise when the tube becomes conductive point (Fig. 1) in its cathode potential supply circuit, will cause the potential of the control grid |32 of the shift tube to rise and reduce the grid bias below its critical value. There is a slight delay in the potential change on the control grid |32, due to the capacitor |33, which connects the point |33 in this circuit to ground.

When the shift tube fires, there will be a potential drop in its common anode supply circuit, due to the resistors |43 and |42 (Fig. 6). However. this drop will not be effective to extinguish the marking impulse tube or the space" tube, because their anodes are included in different anode potential supply circuits. The potential rise of the cathode |23 (Fig. 1) of the shift tube is used as a starting impulse for the next bank of tubes to be fired.

It is seen that, during the sequential firing of the tubes of the bank, two impulses will occur on the terminal |33 (Fig. 6) for controlling the small-amplitude impulse generating tube 45. and these impulses will be followed by an impulse at the terminal |23 to control the large-amplitude impulse generating tube |43. After the signal generating control impulses have been provided, an impulse will be impressed on the terminal |3| (Fig. l), which is used to start the firing of the next bank of tubes. Also it will be noted that.

at the end of the operation of the tubes of a bank,

the shift tube. the marking impulse tube, and the space tube will remain conducting. These tubes will be extinguished in a manner to be described later.

Each of the other symbol-transformed banks operates in the same manner as the bank described above. The banks shown in Figs. 2, 3, 4 and 5 control the sending ofthe second, third, fourth, and fifth symbols, respectively, and are accordingly numbered "l1," IIL IV," and V to indicate the sequence of their operation.

The coordination and interconnections between the various symbol transforming banks which form the controls for the sending of five symbols are as follows:

Each of the negative potential supply conductors |3|. |33. |33. and` |34 for the banks "II," "m," "IV," and V, (Figs. 2, 3, 4 and 5) is connected. respectively. to a terminal, as |33, |33, |31, and |33, upon which is impressed a negative potential of 150 volts.

The symbol-representing control tube anode and, through the connection extending from Y nected over the common resistors 33 and |33 toA the source of potential. In this network, the firing of any symbol-representing control tube in any bank will cause a potential drop in the supply conductors of all the banks. thus enabling the firing of a tube in any bank to extinguish a previously conducting tube in any other bank: for instance. the space" tube. which remains conducting when the operation in the iirst bank is completed. is extinguished by the firing of the first symbol-representing control tube in the second bank. This arrangement also enables the ilring of a tube in any bank to cause a potential drop at the terminal |33, which drop can be used to control the signal generating tube |43 to create a small-amplitude impulse.

In asimilar manner, the anodes of the marking impulse tubes for the various banks have their terminals |11, |13, |13, and |33 (Figs. 2, 3, 4 and 5) connected to the common anode potential supply terminal |23 (Fig. 6) for the marking impulse tubes. As a marking impulse tube in the various banks is fired, the potential drop of its 'anode will cause the potential of the anodes of the other marking impulse tubes to drop and extinguish any previously conducting marking impulse tube, so that the marking impulse tube of the first bank will be extinguished when the marking impulse tube of the second bank is fired. The potential drop of the anode of any marking impulse tube will also control the signal-generating tube |43 to create a large-amplitude impulse.

The anodes of the shift tubes of the various banks arev all connected to the common anode potential supply circuit by having the terminals |3|, |32, |33, and |34 (Figs. 2, 3, 4, and 5), to which they areconnected, connected with the terminal |43 (Fig. 6). The potential drop of the anode of any shift tube as the tube is fired will cause any previously conducting shift tube to be extinguished, thus enabling the firing of the shift tube for the second bank to extinguish the shift tube of the first bank.

The various banks of tubes are connected for sequential operation by having the starting lmpulse conductor of a bank connected to the cathode of the shift tube of the bank previously operated. The terminal |3| (Fig. l), which is connected to the cathode |23 of the shift tube of the first bank, is also connected to the terminal |33 (Fig. 2), to which the starting impulse conductor |33 oi' the second bank is connected, so that the potential rise of the cathode |23, (Fig. l) as the shift tube is fired, can be impressed on the starting impulse conductor |33 (Fig. 2) of the second bank to fire any primed symbol-representing control tube therein and initiate the sequential firing of the tubes of the second bank. The terminal |31 (Fig. 2), which is connected 'to the cathode of the shift tube of the second bank.

is similarly connected to the terminal |33 (Fig.-

yand terminal |32 (Fig. 4) is connected to terminal |33 (Fig. 5) to start the vsequential operation in the fth bank after the fourth bank has comthe one shown in Fig. 1 for selectively closing priming circuits to the symbol-representing control tubes. Y l

- Signal generating means The signal generating means consists of two normally conducting vacuum tubes |40 and |40 (Fig. 6), which can be controlled to create the small and large-amplitude impulses by which til symbols are sent from the sending apparatus to the receiving apparatus.

The small-amplitude impulse generating tube |45 is controlled from the symbol-representing control tubes and is effective to impress a smallamplitude positive impulse on a signal output terminal of the sending apparatus each time one of the symbol-representing control tubes in any bank lires and becomes conducting. Similarly, the large-amplitude impulse generating tube |40 is controlled from the marking impulse tubes and is effective to impress a large-amplitude positive impulse on the signal output terminal of the sending apparatus each time a marking impulse tube in any ofthe banks ilres and becomes conducting.

Obviously the control of the small and the large-amplitude impulse generating tubes |40 and |46 could be reversed to enable the symbolrepresenting control tubes to control the largeamplitude impulse generating tube |40v and the marking impulse tubes to control the smallamplitude impulse generating tube |45, thereby to produce bursts of impulses containing diierent numbers oflarge-amplitude impulses followed by a small-amplitude impulse.

The various elements of these tubes, except the control grids, have similar connections. The cathodes 200 and 20| (Fig. 6) for the tubes, |40 and |46, respectively, are connected to ground, as are the suppressor grids 202 and 203. The anodes 204 and 205 are supplied with positive potential by a circuit starting from terminal |31, which has a positive potential of 150 volts applied thereto. and continuing over conductor |30, point |39, resistor 206 of 250 ohms, point 201, resistor 208 of 2,500 ohms, point 203, and 'conductor 2|0 to the anodes 204 and 205, to which conductor 2|0 is also connected the signal output terminal 2| I for the sending apparatus. anode circuit is connected to ground over a capacitor of .1 microfarad to absorb any shock resulting from an abrupt application or change of potential in this circuit. As both tubes are normally conducting, their anodes will have a positive potential of approximately 40 volts, due to the resistors in their anode circuit. However, when the current' in either tube is reduced, the potential of the anodes will rise toward 150 volts, depending upon the extent of the reduction in the current in the tube. The screen grids 2|0 and 2|1 for these tubes are connected together and over point 2|8. resistor 2|9 of 250'ohms.

points 01 and 96, conductor 05, pointitjand conductor 93 to terminal 02, which has applied thereto a positive potential of 105 vol-ts.

The difference in the amplitude of the impulses which are obtained from these tubes is due tothe control exerted by their control grids. Control grid 220 lfor the small-amplitude impulse generating tube |45 vis given a zero bias by means of aumen r4 of 10,000 ohms, and point 224 to the grid 220.

Point 222 is connected to ground over a capacitor of 8 microfarads to absorb the shock of any abrupt change of potential in this circuit. Control grid 220 for the large-amplitude impulse generating tube |40 isgiven azero bias over a similar circuit extending from the potential divider 220; however. the bias on this grid is adjusted to have s.

lower positive threshold than the grid 220 of the;

` 'I'he terminal |03 (Fig. 6), upon which negative potential impulses are impressed as the symbolrepresenting control tubes are iired, is connected over conductor |02, point and a capacitor 221 of 10 micro-microfarads to point 224, to which the control grid 220 is connected. By this con- Point 201 in the acircuit which extends from the adjustable potential Vdivider 22| over point 222, resistor 223 nection, these negative impulses are able to reduce the current through the tube |40 to a degree which will. due to the resistors 200 and 203 in the vanode potential supply circuit, cause the potential of the'anode 204 Yto rise and provide a smallamplitude positive potential impulse on the output terminal 2|.|.v v

The terminal |23, upon which the negative impulses are Vimpressed as the -marking impulse tubes are fired, is connected over conductor |22, point |2|, and a capacitor 220 of 20 micro-microfarads to point 220, to which the grid 220 of the tube |40 is connected. Due to the fact that the grid of this tube is adjusted to have a positive threshold of less value than the grid 220 of the tube |40, these negative impulses have a greater -eillect on the grid and will cause the grid 2 20 t9 reduce the current in\the` tube |40 to a smaller amount than was the case with tube |40, and, due to the resistors 200 and 200, the potential of the anode 205 will rise a greater extent and provide a large-amplitude positive potential impulse on the-output terminal 2| In the above manner, the negative potential Y impulses which result from the firing of the symbol-representing control tubes and marking impulse ytubes are used to control the creation of the positive potential impulses. of ditlerent amplitudes which makeup the bursts sent from the sending apparatus to the receiving apparatus.

Symbol transmission initiating and terminating means lay 23| is energized by the start key 230,'it closes a holding circuit for itself from terminal 232, point 233, normally closed contacts 230, contacts 231 closed by the starting relay, point 230, and over the winding of the starting relay 231 to ground. This circuit will maintain the starting relay in energized condition after the starting key has been released and until the normally closed to cause the iiring of ay start tube 240, which aunar:

` forming bank.

starting tube un (Fig. s) has its catnaeul connected to ground over a resistor 242 of 152000 ohms. Before the starting relay is energized, the control grid 243 of the starting tube is given a negative potential bias of 150 volts by means of a circuit which starts at the terminal 244, upon sistor 28|of 300,000 ohms, conductor 262, point 283, and resistor 254 oi 2,500 ohms.

When the starting relay 29| closesgits contact '239, positive potential is applied to the anode 250 over a circuit which starts at the terminal 92, upon which is impressed a positive potential of 105 volts, and continues over conductor 93, point ,94, conductor 95, point 88, conductor 280, contacts 239, point 28|, resistor 282 of 250 ohms,

point 253, and resistor 264. When the positive potential is applied to the anode 280 by the closlng of the contacts 239, the circuit from point 253 to point 248 in the grid circuit causes the positive potential to. be applied to the grid 243 and causes its potential to change from 150 volts negative to 9 volts positive. The application of positive potential by the closing of the contacts 239 has caused the anode 288 of the start tube to acquire a positive potential and the grid 243 to become more positive than the cathode 241, which will cause the start tube 248 to fire and become conducting.

AResistor 242 in the cathode circuit will cause the potential of the cathode 24| to rise when the tube 240 is conducting, and this rise is utilized as the starting impulse for the first bank of symbol-transforming tubes. V'The starting impulse is derived from a potential-tapping member 283 cooperating withthe resistor 242 and enabling the amplitude of the starting impulse to be adjusted. Conductor 264 connects the potentialtapping member 283 to the terminal 285, which terminal is connected to the terminal 285 (Fig. l), to which the starting impulse conductor 90 of the first bank of symbol-transforming tubes is connected.

After the transmission of the symbols has been initiated, the symbol-transforming banks will be operable one after another in sequence until the shift tube of the fifth bank has red and become conducting. The potential rise of the cathode of this tube is utilized to lre a stop tube 281 (Fig. 6), which causes the termination oi'. the transmission by energizing the stop relay 238 and thereby opening the holding cir'cuit for the start relay.

The cathode 288 of the stop tube is at ground potential, being connected to ground over conductor 288. 'I'he grid 210 is given a negative biasing potential of 17 volts by being connected A circuit extends from the point 215 over a capacitor 211 of 100 micro-microfarads to the ter- `minal 219, wwhich is connected to the terminal 219 (Fig. 5), to which the cathode of the shift tube is connected. lThis circuit enables the potential rise of the cathode of the shift tube of the fifth bank to reduce the bias of the grid 210, causing the stop tube to nre and terminate the transmission.

The anode 288 of thestop tube 281 has positive potential applied thereto when contact 238 is closed by the starting relay. The circuit extends from the terminal 92 and over the contacts 239 to the point 28|, as explained above, and then continues over conductor 28|, resistor 282 of 500 ohms, the winding of the stop relay 238, and conductor 283 to the anode 289. Until the stop tube res and becomes conducting, there will be no current in the circuit which includes the winding of the stop relay" 239; however, as soon as the tube is fired and becomes conducting, current will flow through the winding of the stop relay 238, which will be energized and will open the contacts 238. The contacts 236 will break the holding circuit for thestart relay 23|, which will be deenerglzed and will open contacts ,231 and 238. Contact 231/ will also interrupt the Aholding circuit for the start relay 23| to prevent its reenergization when the contacts 238 close as the stop relay is deenergized. Contacts 239 open the anode circuit for the start and stop tubes, extinguishing these tubes and deenergizing the stop relay.

The operation of the stop tube 281, therefore, causes the termination of the transmitting operation and restores the starting controls to the condition which existed prior to the operation 1 of the start key 238.

OPERATION In the operation of applicants novel sending apparatus or signal generating means, the symbols making up the data to be transmitted are set up on the plurality of banks of symbol-representing keys in the sending apparatus. These keys control banks of gaseous electron tubes to control the number of impulses that will be ineluded in the various bursts which will be used to represent the symbols. A start key is depressed to start the automatic and sequential firing of g and capacitors in the various circuits. the impulses are generated at a frequency rate of about 50 kilocycles. and the time interval between bursts is about micro-seconds.

While the form of apparatus herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the' one form or embodiment shown herein, for it is susceptible of embodiment in various forms all gaming within the scope of the claims which fol- What is claimed is: f i y l. In an electric impulse generator. the combination of electron discharge tube means selectively operable to produce smallamplitude and large-amplitude rapidly recurring discrete positive impulses: and selectively operable means to control the selective operation of the electron discharge tube means to produce an impulse train containing a plurality of groups of selected numbers of small-amplitude impulses separated by large-amplitude impulses. 2. In a communication system in which difi ferent numbers of signals'are assigned to represent different symbols which may betransmitted, the combination of a first electronic means vari iously operable to generate different numbers oi similar signals 4and further electronic means to generate a distinctive control signal; manipulative means selectively operable according to the particular symbol to be transmitted: means connectlng the manipulative means to said nrst electronic means to enable the manipulative means to selectively control said ilrst electronic means according to` the symbol being transmitted to govern the number of similar lsignals which will vicetowardsaidoneendoithechainoielectrcn devices. s

t. I nan apparatus of the class described, the combination oi a bank oi gaseous electrondischarge tubes. each tube containing anelectrode pairand a means to control conduction therein: means connecting the electron tubesin a chain sequence, the'connection between adjacent tubes 'of the chain sequence including one of the pair ofelectrodesinthepriortubeintheeequenceand thecontrolmeansofthenexttubeintheaequence so that, when anytube of the sequence isnredandbecomesconducting,itwi llcansethe next tube in the sequeuce automatically to become conducting, thus enabling the tubes to be nred and become conducting automatically one after another in sequence toward one end of the be generated; and means controlled by said connecting meansand operableto'cause said fur-V ther electronic to generate before the distinctive control signal following the desired num@ bers ot similar signals. f

s 3,- In a communication system in which difierent numbers of signals are assigned to represent the diilerent symbols which may be transmitted. the combination of electronic means for generating spaced groups of supersonic signals, each group containinga desired number of similar rapidly recurring signals followed'by a fdistinctive control signal, said electronic means including a first electron tube means for generating the similar signals and a further electron tube means for generating the distinctive control signal: manipulative meansselectively operable according to the particular symbols to'be transmitted: means connecting the manipulative means to said iirst electron tube means to enable the manipulative means to selectively control said nrst electron tube means to control the various numbers oi' similar signals which will be generated before the distinctive control signal in the various groups of signals; and means controlled by said connecting means and operable to cause said further electron tube means to generate the distinctive control signal after the last similar signal of the group. l

4. In a'n apparatus of the class described, the.

chainaiteranyelectrontubeinthebankhas been tired and rendered conducting; means to vary the control by the control means in the tubes v to select any one of the electron tubes with which the sequential operation is to begin, so that the tiring of the tubes may begin at any point in the chain. thus enabling different numbers of tubes in the bank to be selected for sequential opera# tion: and means to modify the control by the control-means in the tubes further to cause the .which follow 'the selected tube in the chain see combination of a bank of electron devices; means connecting theelectron devices in a chain sequence. the connections between adjacent electo thereby select the'number of 'electron devices which will operate; and means to cause the seinitiate the automatic sequential operation of the electron devices from the selected electron tie- -means connecting the electron tubes in a cinanapparatusoftheclassdescribedthe combination of abank o! gaseous electron chain sequence, the connection between adjacent tubes of the chain sequence including one of the pair of electrodes in the prior tube in the sequence and the control means of the next tube in the 1 sequence so that, when any tube of the sequence if nred and becomes conducting, it will cause the next tube in the sequence automatically to become conducting. thus enabling the tubes tobe fired and become conducting automatically oneafter another in-sequence at-.supersonic quency toward one end of the any electron tube in the bank hasbeennredand rendered conducting; manipulative means to modify the control by the control-means in the tubes to select any one of with which the sequential operation isj-tobefginr-so that the anne of the tubes peint ina the chainrthus enablingdinerent `numbers of tubes. in the bank; to bev selected for sequential operation: means to modify Lthe control by the control meansl in the tubes further to cause the selected-electron tube to be nredand becomecon- 'ducting-to initlate the automatic sequential nring oi' the selected Inumber of electron tubes which follow the' selected tube in the chain ysequence: and nsignal generating means controlledby the tubesinthebankastheyarenredinsiiacessicn .tocreateaburstofsignalshavingsfjnperaonic frequency and .containing a number vas determined b/ytne selected 'pointinthe bank at which the sequential firingv 0i' the tubes began. 7. In a'device ofthe class described, theeonnbinatlon ora plurality of gaseous electmn'tubes, -each tube containing -an anode. a cathode, and.-

a control grid; means tof supply positive potential to the anodes of the tubes: separate negative iw-v tential supply means for the cathode lected electron device to become conducting and tube, said separate supply means including renstorswennsetne uname-catanese: a tube-tos-lsewhenfthat tube automatic sequential firing o'f the tubes after any tube has been fired and rendered conducting; means to impress a starting impulse on the control grids oi the tubes, said starting impulse being ineffective to overcome the normal negative bias on the control grids; and means to select with which tube in the sequence the sequential firing will begin, said means being effective to reduce the negative bias on the control grid of the selected tube so that the starting impulse can iire that tube and initiate the automatic sequential ring of the tubes succeeding the selected tube in the sequence.

8. In an apparatus of the class described. the combination of a plurality of banks of electron devices; means connecting the electron devices of each bank in an operating chain sequence, the connections enabling a device, when operated, to cause the next device oi the sequence to operate so that the devices of a bank will operate and become conducting automatically one after the other in sequence after any electron device of the bank has been operated; a plurality of banks of manipulative devices, one bank related to each bank of electron devices; .means ccntrolled by the manipulative'devices for selecting the electron device in each bank with which the sequential operation is to begin; means to cause the selected electron device in the rst bank to be operated. to operate and initiate theautomatic operation of the electron devices succeeding the selected electron device in the sequence in that bank; and means to connect the banks of electron devices for sequential operation, including a connection from the last electron device in the sequence in one bank to the electron devices of the next'bank to be operated, whereby the operation ,of the last electron device in the sequence in one bank will cause the selected electron device in the next bank to be operated and initiate the automatic operation of the electron devices in the next bank.

9. In an apparatus of the class described. the combination of a plurality of banks of electron devices; means connecting the electron devices of each bank in a chain sequence, the connections enabling a device, when operated, to cause the next device of the sequence to operate, so that the devices of a bank will operate and become conducting automatically one after the other in sequence toward one end of the chain after any electron device of the bank has been operated to initiate the sequential operation of the electron devices of the bank; a plurality of banks of manipulative devices, one bank related to each bank of electron devices; means controlled by the manipulative devices for selecting the electron device in each bank with which the sequential operation is to begin; means tol connect the banks of electron devices for sequential opera.- tion, including a connection from the last electron device of the chain sequence in one bank to the electron devices oi the next bank to be operated, wherebytthe operation of the last electron device in the chain sequence in one bank will cause the selected electron device in the next bank to operate and initiate the automatic operation of the electron devices in the next bank; operation-initiating means to cause the selected electron device in the ilrst bank to be operated, to operate and initiate the automatic operation of the electron devices vsucceeding the selected electron device in the chain sequence in that bank and. through the connection between successive banks, to enable the sequential operation of the electron devices in the various banks in succession; and means operated by the last device in in the chain sequence in the last bank tc restore the operation-initiating means for f urther operation.

10. In an apparatus of the class described. the combination of a plurality of banks of gaseous electron tubes; means connecting the electron tubes of'each bank in a chain sequence sothat they will be iired and become conducting automatically one after the other in sequence toward one end of the chain after any electron tube of the bank has been fired; a plurality of banks oi' manipulative devices, one bank related to each bank of electron tubes; circuits selectively closable by the manipulative devices for selecting the electron tube in each bank with which the sequential firing is to begin; means to cause the selected electron tube in the rst bank to be operated, to be fired and initiate the automatic firing of the electron tubes succeeding the selected electron tube in the chain sequence in that v bank; means to connect the banks of electron tubes for sequential operation, including a connection from the last electron tube in one bank to the electron tubes of the next bank to be operated, whereby the tiring of the last electron tube in the sequence in one bank will cause the selected electron tube in the next bank to be red and initiate the automatic firing of the electron tubes in the next bank; and means to delay the operation of the last tube in the chain sequence in each bank to delay the initiation of the firing of the tubes in the next bank, thereby to provide a time interval between the operation of the diiferent banks of tubes.

11. In an apparatus of the class described, the combination of a plurality of banks of gaseous electron tubes; means connecting the electron tubes of each bank in a chain sequence.' said connections enabling conduction in'one tube to c'ause the next tube .to be red so that thev tubes will be iired and become conducting automatically one after the other in sequence toward one end of the chain after any electron tube ci the bank has been fired to initiate the sequential firing of the electron tubes of the bank; a plurality of banks of manipulative devices, one bank related to each bank ci electron tubes; means controlled 4by the manipulative devices for selecting the electron tube in each bank with which the sequential ring is to begin to thereby select the number of tubes in each bank which will be nred; means to cause the selected electron tube in the ilrst bank to be operated, to be fired and initiate Pthe automatic firing of the electron tubes succeeding the selected electron tube in the sequence in that bank; means to connect the banks of electron tubes for sequential operation, including a connection from the last electron tube in a bank to the electron tubes of the next bank to be operated, whereby the firing of the last electron tube in the sequence in one bank will cause the se'- aannam 21 lected electrongtube in the next bank to nre and initiate the automatic nring of the electron tubes in the 'next bank. thus enabling the sequential ,firing of the electron tubes in the various banks to take place in automaticsuccession after the selected tube in the rst bank has been operated; and signal-generating means controlled by the tubes inthe several banks to create a lburst of signals foreach bank. each burst containing a number of signals as determined by thenumber of tubes selected in the various banks by the manipulative devices.

12. In a device of the class described, the com- A bination of a pluralityI of groups of gaseous electron tubes; means connecting the tubes of each group so that they will be ilred and rendered conducting one-after another in sequence: means connecting the groups so that the sequential ilring'of the tubes in the groups will take place in one group after another in sequence; means connected to all the tubes to produce an impulse each time any of -the tubes in any group is ilred and lbecomes conducting; and signal -generatlng means-controlled by the means connected to all `the tubesand operable to generate a signal each time an impulse is produced bythe firing of; a

tube in any group. Y

13. In a device of the class described, the com- J bination of a plurality of groups of gaseous electron tubes; means connecting the tubes of each group so that they will be red and rendered conducting one after another in sequence, said connections enabling a tube, when rendered conducting, to automatically cause the next tube in the sequence to be ilred: time delay means connecting the groups so that the sequential firing of the tubes in the groups will take place in one group after another in sequence with a time delay between the firing ofthe tubes in the different groups; means connected to all the tubes to produce groups of control impulses as the` tubes in the various groups are fired and become conducting: and signal-generatingv means controlled by said tubes, throughthe means connected to all the tubes, to produce bursts of similar signal impulses as the groups of control impulses are pro' duced by the il-ring ofthe gaseous electron tubes.

14. In a device of the class described, the combination of a plurality of groups of gaseous electron tubes. each tube having an anode. 'a cathode, and a control grid; means to supply negative poanodes of all the tubes; and signal-generating means controlled by the tubes to produce a burst -ofsignal impulses for eachv group, said signalgenerating means including a vacuum tube having a control grid connected to the means connesting the anodes, thus enabling the drop /in potential as any tube is tired to control vacuum tube to produce a signal impulse.

16. In a device o't the class described, the cornbination of a plurality of groups of gaseous electron tubes: means connecting-the tubes of each group so that they will be fired and rendered conducting one after another in sequence; manipulative means to differentially control the number oi' tubes that will be fired in sequence in ea'ch group:

means connecting the groups so that the sequential ilring of the tubes in the groups will takeplace in one group after another in sequence; means connected to all the tubes to produce an impulse each time any ofthe tubes in any group is ilred and becomes conducting; andslgnal-generating means controlled by the means connected to all the tubes and operable to generate a signal each time an impulse is produced by the tiring of a tube in any manipulative means.

1'7. In a device of the class described. the'combination of a plurality of groups of gaseous 'electron tubes; means connecting the tubes of each group so that they will be red and rendered conducting one after another in sequence. the connections enabling 'a -tube of a group. when rendered conducting. to cause the next tube in the sequence to be fired: manipulative means to select with which tube in each bank the sequential operi ation will begin, thereby to differentially. control tential to the cathode of each tube; cathode-control grid vcircuits for. connecting the tubes-in the groups so that the tubes in each group will be tired and renderedconducting one after another in sequence;` means connecting the groups of tubes to cause the sequential firing of thetubes t0 take placel in thel'liierent groups one group after another; means connecting the anodes of all the tubes in all the groups together and over a commonresistor to a source of positive potential to enable the ring of any tube in any group to cause a drop in the potential on the anodes of all the tubes; and signal-generating means connected to the means connecting the anodes together and controlled by the potential drop as each tube is fired. for generatingV a signal impulse` each time a tube in any group is iired.

15. In a device of the class described, the combination of a plurality of groups of gaseous electhe number of tubes that will be red in sequence in each group; means, including time delay means. for connecting the groups so that the seouential firing of the tubes in the groups will take place inone group after another in sequence with a time delay between the ring of the tubes in the various groups; means connected to all the tubes to produce an impulse each time any of the tubes y in any group vis tired and becomes conducting:

tron tubes, each tube having an. anode. a-cathode,

and a control grid; means to. supply negative potential to the cathodev of eachtube; cathode-control grid circuits for connecting the tubes in the groups so that the tubesain each group will be and signal-generating means controlled by the means connected to all' the tubes and operable to generate a signal each time an impulse is produced bythe firing of a tum'in any group. whereby -to produce spaced bursts containing diilerent numbers of signals as controlled bythe manipu lative means.

18. In a device of the-class described, the combination'bf a plurality of groups of gaseous electron tubes. each having at least an electrode pair and a control means; means connecting the tubes of each group so that they will be red and rendered conductinf.y rapidly one after another automatically in seouence. the connection between yadjacent tubes of the sequence extending from an electrode of the electrode pair of one tube to the lcontrol means of the next tube in the sequence and enabling conduction in said Vone tube to cause said next tubeto be fired automatically ;-a pluralthe# group under control of the ity of banks of manipulative devices, one bank for each group of tubes, for selectively modifying the control exerted bythe control means in the tubes to select with which tube of the group the automatic operation of the tubes of that group will begin, thereby differentially selecting the number of tubes of the groups that will -be red in sequence; means, including time delay means, for connecting the groups so that the sequential ring of the tubes in the groups will take place in one group after another in sequence with an interval between the ilring of the tubes in the various groups; meansconnected to similar electrodes in all the tubes to produce an impulse ea-ch time any f the tubes in any group is red and becomes conducting; and signal-generating means including a vacuum tube controlled by the means connected to `similar electrodes in all the -tubes and operable to generate a signal impulse each time an impulse is produced by the firing of a tube in any group. thereby to produce spaced bursts oi' diilerent numbers of rapidly recurring signal impulses containing different numbers of signal impulses as determined by `the selection made by the manipulative devices.

i9. In a. device of the class described, the combination of a plurality of groups oi' gaseous electron tubes; means connecting Ithe tubes of each group so that they will be ilred and rendered conducting one after another in sequence; means' connecting the groups so that the sequential ring of the tubes in the groups will take place in one group after another in sequence; and means connecting the tubes of all the groups together so that the ring of any tube in any group will cause any previously conducting tube in any group to be extinguished, whereby the ilrst tube to be fired in a succeeding group will extinguish the last tube which was ilred and remained conducting in the preceding group.

20. In a device oi the class described, the combination of a plurality of groups of gaseous electron tubes, each tube including at least an electrode pair and a control means; means connecting the tubes oi each group so that they will` be iired and rendered conducting one after another 'in sequence, the connection between adiacent. tubes oi' the sequence extending from one of the electrodes of the electrode pair in one tube, to the control means of the next tube in the sequence: means connecting the groups so that the sequential iirng of the tubes in the groups willtake place in one group after'another in sequence; and means including connections between similar ones of the electrodes of the electrode pairs in all of the tubes to produce an impulse each time any of the tube's in any group is ilred and becomes conducting, each oi said impulses being eil'ective to cause any previously conducting tube in any group to be extinguished. 21. In a device of the class described. the combination of a plurality of groups of gaseous elec- -trn tubes, each tube having an anode, a cathode.

and a control grid; 'means to supplynegative potential to the cathode of each tube; cathodecontrol grid circuits for connecting the tubes in the groups so that the tubes in each group will 24 oi' positive potential to enable the nring of any tube in any group to cause a drop in the potential 7on the anodes of all the tubes, which potential 'l drop is eilective to extinguish any previously conducting tube in any group, whereby the first tube to be fired in a succeeding group will extinguish the last'ltube which was fired and remained conducting in the preceding group.

22. In a sending apparatus for a communica- 10 tionfsystem in which different numbers of signals are assigned to represent different symbols which may be transmitted, the combination of a plurality of gaseous electron tubes, certain of said tubes being symbol-representing control tubes and another of said tubes being a marking signal control tube, each of saidtubes containing an anode, a cathode, and a control grid; means connecting the anodes of thsymbol-representing control tubes over a common resistor to a source oi positive'potential so that a negative impulse will be produced each time one of these tubes is fired and becomes conducting; means connecting the anode of the marking signal control tube over a resistor to a source of positive potential to -produce a negativeimpulse when the markingI signal control tube is ilred and becomes conducting; separate negative potential supply means for the cathode of each tube, said separate supply means including resistors to cause the potential -of the cathode of any tube to rise when'that tube becomes conducting; means for supplying negative potential bias to the control grids and for connecting the tubes for automatic operation one after another in a sequence beginning with the symbol-representing control tubes and ending with the marking signal control tube, said biasvsupplying means consisting of circuits extending between lsuccessively operated tubes of the sequence and connecting the cathode potential supply means for any tube in the sequence a tube inthe sequence to reduccthe bias oi-thc control grid oi' the next tube in the sequence-t9 cause the automatic sequential Bring of the tubes 1 Ain the sequence after any tube in the sequence has been ilred and rendered conducting: means to impress a starting impulse on the control grids of the symbol-representing control tubes, said starting impulse being ineffective to overcome the normal negative bias on these control grids; means to select with which symbol-representing cont'rol tube in the sequence the sequential ilring will begin according to the symbol to be ltransmitted, said means operating to reduce the bias on the control grid oi the selected tube s'o that the starting impulse can nre that tube andini- 0 nate the automatic sequential ming or the tubes succeeding the selected tube in the sequence; and means diilerentially controlled by the negative impulses in the several anode potential supply means to create a signal each timea symbol-representing control tube is red and to create a distinctive marking signal when the marking signal control tube is fired, whereby a group of signals is formed to represent a symbol, which group of signals contains a. number' of similar signals followed byv a distinctive marking signal. l

t 23. In a sending apparatus for a communication system in which diierent numbers of signals are assigned to represent different symbols 'which may be transmitted, the combination of a e a Pf2s plurality o! gaseous electron tubes, certain oi' said tubes being symbol-representing control tubes and another oi' said tubesbeing a' marking signal control tube.\ each of said tubes containing an anode. a cathode. and a `control grid; meansvs connecting theanodes ofthe symbol-representingcontrol tubes. over a common resistor to a source oi positive potential so that a negative impulsegwill be produced each time one on these tubesis nred and becomes' conducting; means connecting the anode oi the marking-signal control tube over-a resistor to a source oi positive potential to produce a negative impulse when the marking signal control tube is iired and becomes conducting; separate negative potential supply means for the cathode of each tube. said separate supply nieans including resistors' to cause the lpotential of the cathode of' anytube'to rise when that tube becomes conducting; means for supplying negative potential bias to the control y grids and for connecting the tubes i'or automatic operation one after another in a sequence beginning with the symbol-representing control l tubes and ending with the markingsignal control tube. said bias-supplying means consisting oi' circuits extendingbetween successively operated tubes of -thesequence and connecting the cathode potential supply means for any tube in the sequence to thecontrol grid of the next tube to be operated in the sequence, said circuits supplying normal negative" biasing potential to the control'grids and enabling the potential rise oi the cathode of a tube in the sequence to reduce the bias of the control grid of the next tube in4 the sequence to cause the automatic sequential nring oi the tubes in the sequence after any tube in the sequence has been red and rendered conducting; means to impress a starting impulse on the control grids of the symbol-representing control tubes, said starting impulse being ineffective to overcome the normal negative bias on these control grids; means to select with which symbol-representing control `tube in the sequence the sequential ring will begin according to the symbol to be transmitted, said means operating to reduce the bias, on the control grid of the selected tube. so that the starting impulse can nre that tube and initiate'the automatic sequential ilring of the tubes succeeding the selected tube in the sequence: a sma'll-amplitude` posi-tive impulse 4generating tube: means enabling the negative y enabling the negative impulse in the -marking signal control tube anode potential supply means to cause the large-amplitude impulse generating tube to operate and provide a large-amplitude positive impulse when the marking signal control y tube is liired. whereby a burst of impulses is` formed to'represent a symbol, said burst containing a 'group-oi' small-amplitude impulses iollowed by a large-amplitude impulse..l

24. In a sending apparatus for excommunica-l tion system in which diilerent lnumbers of signais are lassigned to represent difieren-t symbols which may be transmitted, the combination of a plurality of banks oi gaseous electron tubes, each bank containing a plurality ot symbol-representing control tubesra marking signal -control tube, and a shiittube, and each oi saiclwtubes ademen 26 containing an anode,

grid; means connecting the anodes'oi the symbol-representing control tubes in the several f banks over a common resistor to a source of positive potential so that a negative impulse will be produced each time one oi' thesymbol-representing control tubes is red and rendered conducting, said negative impulses being effective to extingulsh any previously conducting symbol-rep-- resenting control tube; means connecting the anodes of the marking signal control tubes 0f the various banks over a common resistor to a source of positive potential so that a negative impulse will be produced each time one oi these tubes'is fired and rendered conducting, said negative impulses being enective to extinguish any l vpreviously conducting mar g impulse tube: means connecting the odes of the'shiit tubes in the various banks o er a common resistor to asource of positive potential so that a negative impulse will be produced each time a shift tube in any bank is fired and rendered conducting.

said negative impulses being eilective to extinguish any previously conducting shift tube; separate negative potential supply means for the cathode of each tube; lcathode-control grid circuits between the tubes of eachbank for connecting the tubes in a bank for automatic sequential operation beginning with. any selected symbolrepresenting controll tube,v continuing through r the marking signal control tube, and 'ending with the shift tube; means associated with each bank to impress a starting impulse on the control grids of the symbol-representing control tubes of that bank, said starting impulses being ineffective to re these tubes unless the tubes have been prepared; means connecting the banks of tubes for sequential operation, comprising a circuit from the cathode ofthe shift tube of one bank to the starting means of-another bank so that theiiring of the shift tube in a bank can cause a starting impulse to be sent to the next bank in the sequence to initiate the sequential firing of the tubes therein; a plurality oi banks oimanipulative devices; means controlled by the'manipulative device to selectively prepare-the control grids l of symbol-representing control tubes in the vari-l ous banks to select with which tube in the several banks the sequential operation will begin; transmission-initiating means to supply a starting impulseto the rst'bank in the sequence, to startV the sequential tiring of the tubes in that bank; said connections between banks initiating the sequential firing of the tubes inthe various banks; one bank after another in succession; a signal-generating means controlled by the anode potential supply means for the symbol-representing control tubes to generate a signal each time l a negative impulse occurs in this supply means: 6.0i and a marking sign-al generating means controlled by the anodepotential supply means tor the marking signal control tubes to generate a distinctive marking signal each time a negative impulse occurs in this supply. means, said banks of tubes automatically in succession controlling the signal-generating means to 4create bursts of signals, each burst containing a number of similar signals followed by'a distinctive marking sig- Y nal. l JOSEPH R DESCH.

ROBERT E. MUMMA (References on following page) i w a cathode, and-a control ERNEST V. GULDEN.

REFERENCES CITED The following eferences are of record 1n the glle of this patent: f

UNXTED STATES PATENTS Number Name Date 257,969 Haight May 9, 1892 853,888 Leske May 1%, 1907 Number Name Date Molina. Oct. 1, 1912 McCoy Apr. 16, 1929 Riggs July 21, 1936 Blount Nov. 24, 1942 Prince, Jr Jan. 19, 1943 Logan et al. May 18, 1943 Massonneau Apr. 10, 1945

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