US2403873A - Impulse emitter - Google Patents

Description

R. E. Mmm/1Av 2,403,873

IMPULSE EMITTER Filed Aug. 6, 1942 9 Sheets-Sheet l July 9, 1946.

lim *im Robert E. Mamma Inventor By ff/Aly m His; uitney R. E. MUMMA 2,403,873

IMPULSE EMITTER Filed Aug. 6, 1942 9 Sheets-Sheet 2 July 9, 1946.

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His Attorney July 9, 1946. R. E. MUMMA IMPULSE EMITTER Robert E. Mumma Inventor By M M His Attorney R. E. MUMMA IMPULSE EMITTER July 9, 1946.

Filed Aug. 6, 1942 9 Sheets-Sheet 5 FIG. 4B

Robert E. Mumma Inventor By M His Attorney July 9, i946.

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Filed Aug. 6, 1942 9 ShetS-Shee 9 Robert E. Mumma I Inventor v By M M His Attorney Patented July 9, 1946 UNITED STATES PATENT OFFICE IMPULSE EMITTER Robert E. Mumma, Dayton, Ohio, assigner to The National. Cash Register Company, Dayton, Ohio, a corporation of Maryland Application August 6, 1942, Serial No. 453,834

Claims. (Cl. 177-380) This invention relates to means for producing discrete electric signals at high speed in any selected number.

The invention more particularly pertains to means for producing discrete electric impulses at the rate of 150,000 or more per second in a non-denominational burst of a selected denominational number. The number of impulses so produced in a burst may be counted denomina.- tionally by an electronic counter of the type disclosed in applicants co-pending application for United States Letters Patent, Serial No. 395,995, which was filed May 31, 1941, and which issued as United States Patent No. 2,401,657 ,on June 4, 1946.

The impulse producer consists of an impulse generator and a transmitter, constituting a unit, which unit is controlled by denominational banks of digit-representing electron tubes forming a selecting counter, said generator-transmitter as a whole being in turn controlled by denominational banks of selectively operable keys. Upon the completion of transmission of a selected number of electric impulsesproduced by said generator, as selected by the keys, the electron tube selecting counter will act to render the transmitter ineffective. Although the selector counter is denominationally arranged and controlled by the denominational banks of keys, the impulses are not produced by denominations, but in the exact number of discrete units expressed by the denominational numerical notation. The impulses, because they have no denominational characterization, may be transmitted over a single transmitting medium, such as a wire or other transmission channel, by identical signals having no significance but unity. The counter or accumulator of the produced and transmitted impulses, such as that described in the above identified application, consists of denominational banks of electron tubes, the tubes of each bank being connected in an endless operating counting ring. The tubes in a bank represent digits of that denomination. The impulses produced by the structure disclosed herein are impressed through the lowest denominational bank of such an accumulator, and the counting is completed by carrying overflow data from bank to bank by highspeed electronic transfer devices. It will become apparent that the denominational base of the selector counter and receiver need not be the same. I y

Therefore, it is the principal object of this invention to provide a selectively controlledv highspeed electric impulse generator and transmitter.

2 Another object of the invention is to provide a high-speed electric impulse generator-transmitter producing a selected number of discrete unit-representing electric impulses under con- 5 trol of denominationall'y arranged bank of keys.

Another object of the invention is to provide means to selectively control an electric impulse producer, which is producing impulses at very high speed, so as to accurately stop transmission of said impulses when the exact required selected number of impulses has been transmitted.

Another object of the invention is to provide means to control the starting and stopping of a transmitter of impulses produced by an electronic oscillator, whereby an exact selected number of impulses is transmitted.

Another object of the invention is to provide a producer of electric impulses,` an electronic gate for controlling the transmission of said impulses, and a closing and opening means for operating said gate to pass an exact selected number of electric impulses produced at intervals as short as one-hundred-and-fty-thousandth of a second.

Another object of the invention is to provide an electron tube oscillator for producing electric impulses, an electron tube gate, control devices associated with the oscillator and the gate to control the starting and stopping of transmission of said produced impulses through the gata and a selecting counter actuated by the impulses and in turn actuating the control devices so as to let a selected number of electric impulses through the gata With these and incidental objects in view, the invention includes certain novel features, circuits, and combinations of parts, the essential elements of which will be set forth in the claims and in the description which follows, and which is further disclosed in the circuit drawings to be described 4in connection with the specification, as the preferred form or embodiment of theY invention.

Of said drawings:

Fig. 1 is a diagrammatic showing of the relationship between the variousunits of the device.

Fig. 2 is a representation of lpart of the operation control relays and the switching circuits operated thereby.

Fig. 3 shows the electric impulse producing means, the transmission gate and controls, the key release control means, and the tube controlling the entry ofl an extra unit impulse in u the tens decimal denominational order of the asoaevs views which together show the selector counter denominational `banks and associated key banks.

General description In the on of rapidly produced electric signals from one point to another for the purpose of conveying intelligence, it is desirable. in order to simplify transmission, that each of the impulses represent the same unit of data and that the impulses be rapidly propagated. Consequently, when it is desired to convey data expressed indenominational form by means of discrete signals each representing the same unit, it becomes necessary to translate the denominational data to such units, to transmit the data, and thereafter, for `economy oi' space, to arrange it in denominational form for storage, accumulation, or indication.

' In the sending oi' numerical intelligence by mais having no denominational characterization, a great many more impulses must be sent than are represented by the addition of the digits representing the number denominationally. For example, if the decimal number "851" is to be vtransmitted by denominationally characterized impulses, it would require possibly three channels or three periods of communication and in addition would require Vthe sending of one signal for the "units" order, ve signals for they tens order, and eight signals for the hundreds" order,

`making in all a total of fourteen signals. On the other hand, if the same data is to be transmitted by discrete unit-representing signals over a single on channel, then there would have to be eight hundred and fifty-one discrete signals sent. 'I'his Vinvention is directed to that last-named mode of transmission of data. In the sending of such signals by units only, it is obvious that very rapid propagation of the signals is to render it commercially usable, and consequently there must be a means for rapidly producing the signals so as to be accurate to the unit. The general method ot accomplishing this will be described nrst in connection with the schematic diagram oi Fig. 1.

'Ihe output oi an electronic oscillator produclng electric impulses at a high frequencysay, at 150,000 a second-is fed through an electron tube relay. acting as a gate," under control oi a key-controlled selecter counter, which counts the produced signals, and a start-stop gate control means. The produced and "gated" impulses are to be transmitted to an accumulator or receiver such as that indicated by the dotted lines. The transmitted impulses are fed into the lowest denominational bank of the accumulator, and the data is accumulated by denominations. Such an electronic accumulator is shown in the reference patent application and forms no part of the present invention, but is mentioned to demonstrate the utility of the disclosed electric signal propagating device.

' A starting switch is provided, said starting switch having several functions, among which are to operate relays which energize the selector counter, to enter selected data therein, and to operate certain sequence ot operation control relays. one of said relays starting the oscillator. another of said relays causing operation of the transmitting "gate starting device, which permits the "gate" to transmit the electric signals to the accumulator, and another of said relays conditioning the selector counter, whereby, upon a certain number of impulses being issued from the gate, which not only are transmitted to the accumulator but are additionally transmitted simultaneously to the selector counter, the selector counter energizes a stopping device to close the gate so that an exact selected number of impulses is transmitted. Signals from the oscillator produced before the "gate" is opened and after the "gate is closed are not utilized or transmitted.

'I'he selector counter consists essentially of an l electronic accumulating counter having banks of electron tubes, each bank representing a denomination and there being in a bank a tube representing the digits or in certain instances pairs of digits in the denomination. Said tubes in a bank are arranged in an endless operating chain by reason of the cathode of one tube being connected to the grid of the next tube, so that they are rendered conducting in sequence, one at a time, in response to each of received impulses l impressed on the lowest denominational bank by the produced and gate-passed" signals. Transfer devices are caused'to operate upon each complete sequential operation of a ring of tubes to transmit carry-over data from a lower denomination to a higher denomination of the selector counter. In the selection of the number of impulses to be sent, the selector counter is provided with a key-operated multiple switch for each digit of the denomination. Those keys representing the selected digits in the various denominations which make up the data to be transmitted are operated, causing corresponding digit tubes to become conducting. The issued signals are thereafter transmitted from the gate tube into the selector-counter until the selector counter reaches its full capacity, upon which event happening the stop device cuts oil' the transmission of signals through the gate The tubes associated with the keys are selected so that the selected number of impulses will thereafter ll the counter to capacity.

Provision is made for addition of a fugitive unit in the presetting of data in the selector, as will be further described.

The operation control relays are operated in a certain sequence, the operation of a given relay in some instances depending upon the operation of a previously operated relay, so that the electron tubes in the various units will be made ready to become conducting in a definite order.

It will be apparent that any accumulator that is used may be placed at a distance from the novel device disclosed and coupled thereto by wire or radio. It will also be obvious that the selector counter need not be based on the decimal system of numerical notation illustrated, but may be based on any other numerical notation having denominations, and further that the selector counter and accumulator need not be based on the same numerical notation system. For instance, the selector counter may be based on the decimal system and the accumulator may be based on the binary system of numerical notation. 'Ihe latter useof the invention, wherein different denominational bases are used, makes it particularly adapted to translation of data from one numerical notation to a notation oi' a diilerent denominational base. Alphabetical data may be handled by enlarging the counting rings to twenty-six tubes each to accommodate the 'Il twenty-six letters oi.' the alphabet. In a similar manner, other coded data may be handled on a numerical count.

In the first denominational ring of the selector counter. advantage has been'taken of the faster K response to electric signals of a trigger-connected pair of high-vacuum tubes, which trigger pair is used in cooperation with tive Thyratrons connected in a counting ring, to take the place of what normally would be a ring of ten Thyratrons. By counting one Thyratron tube of the live-tube ring once with each tube of the trigger-connected pair, ten conditions are obtained to represent the ten decimal digits. Such a counting circuit system, having but seven tubes to represent a decimal denominational order, is described in applicants co-pending application for United States Letters Patent, Serial No. 402,791, filed July 17, 1941,

4 wherein the five-tube counting ring is of vacuum tubes, to which reference is made for a more complete description, although sufiicient disclosure will be given herein to give a complete understanding of such a ring system.

The oscillator produces sine wave impulses, whereas the input signals into the tubes composing the trigger pair of the selector counter require impulses of steep wave front, so a certain modification of the sine waves generated by the oscillator is made by using a pulse Sharpener electron tube circuit whose output is fed into the trigger pair, which pair changes its mode of operation once in response to each positive portion of the produced sine waves.

The disclosed device has a capacity of 999 in the decimal system, but it is evident that the system as outlined is indefinitely expansible as such.

The selector counter Broadly, the selector counter based on the decimal notation includes a units denominational order, shown in Figs. 4A and 4B; a tens denominational order, shown in Figs. 4C and 4D; and a hundreds denominational order, shown in Figs. 4E and 4F. The units order (Figs. 4A and 4B) includes five gaseous triode electron tubes 50, 5i, 52, 53, and 54, connected in an endless operative chain, and a transfer tube 55, to provide for a denominational transfer of a unit at the conclusion of the entry of data into the said units order to its full capacity, which tubes work in conjunction with two triggereconnected high-vacuum pentodes T-I and T-2 to provide ten conditions to represent the units order digits of the decimal system.

Thus, if tube 50 (Fig. 4A) is conducting at the Sametime that tube T-2 is conducting (tube T-I perforce being at that time non-conducting), then the said units order bank will represent the entry and accumulation of one certain unit of data, whereas, if tube 50 and tube T-I are both conducting (tube T-Z perforce at that time being non-conducting), then the condition of conduction represents the entry and accumulation of another unit of data. In a similar manner, the concurrent conduction of tube 5I and tube T-2 represents an accumulation of another unit of data, whereas concurrent conduction in tube 5| and tube T--l represents the accumulation of still another unit of data. In this manner, the two tubes T-I and T-2, used in conjunction with tubes 50, 5I, 52, 53, and 54 (Figs. 4A and 4B), will accommodate the representation of ten units of data, constituting the units denominational bank of the selector counter. The tubes T--I and T-2 alternate in operation in response to each of the steep wave front potential impulses impressed commonly upon their control grids.

The gaseous triodes 50 to 54 inclusive, as has been said, are connected in an endless operative series, cathode to control grid, and are so arranged in a potential supply circuit that they are caused to become conducting one at a time in sequence, in response to potential impulses impressed commonly on their control grids, said impressed impulses being of positive polarity produced under control of negative impulses issuinsr from the anode of tube T-Z as said tube T-2 becomes conducting, said negative impulses being due to a resistor in the anode potential supply conductor of said T-2 tube. The negative impulses from tube T-2 are relayed as porsitive impulses by an amplifier tube 56 (Fig. 4A), which issues a positive pulse from its anode as it becomes non-conducting due to the negative impulse from tube T-Z impressed on its grid.

Keys are provided, numbered "1 to 9 (Figs. 4A and 4B) inclusive, each of which keys operates a multiple switch to control the preliminary introduction of data into the date-representing tubes T-l, T-2, 50, 5I, 52, 53, and 54. This units order key-selected data is entered into the units bank of the selector counter previous to the reception of generated impulses, so that, when the generated impulse signals are first impressed upon the input circuit to the units order of the selector counter, the number of signals necessary to fill the said units denomination of the selector counter to its capacity and cause a transfer will be that number represented by the operated key. For instance, if key "5 were operated, the tubes T-I and 5I will, because of the application of a potential on their grids, become conducting when the operation is commenced, as will be shown, and it therefore requires the entry of five units of data into the counter to bring it to the full capacity, wherein the tube T2 and the tube 54 are conducting, said occurrence causing the overflow of one unit of data to the next higher denominational onder due to the temporary conduction in transfer tube 55 on receipt of the next impulse from the generator, which simultaneously causes tube T-2 and tube 54 to become conducting.

The tens denominational order, shown in Figs. 4C and 4D, includes ten tubes of the gaseous triode type arranged in an endless chain operating circuit connecting the cathode of a tube to the grid of the next tube of the chain, so that they become conducting one at a time in sequence, there being a step of operation in response to each of the electric potential impulses from the transfer tube of the units bank which are impressed commonly on the tubes. In the tens denominational order, each tube represents a digit of the denomination, as the speed of response necessary in the tens order is only one-tenth that of the units bank, all received data coming through the units bank. There is no need for using the high speed of the trigger-connected vacuum tubes, as was done in the units bank, and the simpler ten-tube counting ring may be used, but it is evident that a seven-tube ring like the one described for the units bank could be substituted. The tens denominational keys n10, U20, :13u11: 40, 50, 60, n70, 80) and control the preliminary entry of data into this order as in the units bank, so that the number of tens transfer impulses from the units bank as is represented by the key used will illl the tens bank to capacity. For instance, pressing the key 50 would condition the 40 tube to become conducting by impressing a positive potential upon its control grid, which, when an operation is commenced, causs said tube to becomo conducting. In the event no key in the tens bank is operated, the "90 tube is thereby conditioned to become conducting. The hundreds order bank shown in Figs. 4E and 4F is similar to the tens bank, having ten gaseous triodes representing the ten digits oi the denomination and 11100,!) lfzoo '(300'!) (64001)! 115ml!) "300." "700. "800." and "900" for controlling the introduction of data therein.

Input electric signals in sine wave form, as produced by the impulse-generating device to be described and transmitted through the gate, are received by the selector counter at terminal 58 (Fig. 4A) and cause a high-vacuum pentode electron pulse sharpener tube 51 to become highly conducting on the positive portion of each signal. The cathode of tube 51, heated by means shown conventionally, is connected to ground by means of conductor 59, point 80, point 6|, and ground conductor 69. The anode of tube 51 is supplied with a positive potential of 120 volts through terminal |55 (see also Fig. 2) conductor 10, point 1|, resistor 12 of 2,500 ohms, and point 13. The suppressor grid is connected to the cathode, and the screen grid is connected to the positive 120- volt conductor 10 through point 1 I. The control grid is connected through point 14 to the input terminal 58 by means of conductor 15. The control grid is given a normal potential bias of 12 volts negative by being connected, through current-limiting resistor 16 of 50,000 ohms and grounded potentiometer 11 oi 25,000 ohms, to terminal 18, supplied with 160 volts negative potential, which holds the tube in non-conducting condition. A sharp drop in potential will occur at point 19, due to resistance 12, as the tube becomes fully conducting on the positive half of each of the sine wave impulses. Such drop in potential is impressed through capacitors 19 and 80|, each of 10 micro-microfarads, respectively,

onto the control grids oi the trigger tubes T-I and T-2.. Capacitor 19 is coupled to the control grid of the tube T-2 through point 90 and conductor 8|. Capacitor 80| is coupled to the control grid of the tube T-I through point 82, conductor 88, and point 90. The anodes of tubes T-I and T-2 receive their potential through point |02, connected to the positive 120volt terminal |55, energized on operation of solenoid III (Fig. 2), tube T--I having its anode connected thereto through resistor 99 of 2,500 ohms and tube T-2 having its anode connected thereto through resistor |0| of 2,500 ohms. The anode of tube T| is connected through point 8|, resistor 85 of 50,000 ohms in parallel with capacitor 590 of 50 micro-microfarads to the control grid of tube T2, and the anode of tube T-2 is connected to the control grid of tube T-I through resistor 98 of 50,000 ohms in parallel with capacitor 9| o! 50 micro-microfarads. The control grids of tubes T-I and T-2 are given a negative bias by being connected each through a resistor to a potentiometer 88 of 25,000 ohms, which potentiometer is connected on one side to ground by conductor 90 and on the other side to negative i60- volt terminal 18.

Point |02 is connected to the screen grid and, through point 98 and -the resistor 98 of 2,500 ohms, to the anode of said tube T|, and point |02 is connected through point |00 and the resistor |0| of 2,500ohmstothe anode oftubeT-2, wtbbmlidoftubOT-I. mmm

grids ot each of the tubes are connected to their respective cathodes.

Prior to the institution of the impulse-generating and transmitting operation, either the tube T-I or the tube T--2 must be conducting, depending upon what data is preset in the units order. To cause the proper one o1 the trigger tubes to be in conducting condition, the cathode supply is switched to the trigger tubes, so that, i! an even-numbered units digit key is depressed or no key at all is depressed, then the tube T-2 is conditioned to be conducting at the commencement ot the operation, whereas, if an odd-numbered digit key is depressed, it is arranged that the tube T---Il be conducting at the beginning or the operation. To accomplish this result, as a key is depressed, the cathode supply circuits are so switched that a resistance is placed in the cathode circuit of the T tube which it is desired to be non-conducting, which resistor limits the initial current o1 said tube and allows the other tube to come to full conductivity, which, through :the trigger coupling, causes the extinction ot conduction in the tube that has the resistor in its cathode circuit. After certain relays have functioned in the inception of the operation, and after the trigger pair has assumed the proper mode of operation, the resistance is cut out of the cathode circuit oi the non-conducting T tube by a relay to be described. The grounded point |05 (Fig. 4B) is the source of cathode potential oi the T tubes. Resistor |09 of 5,000 ohms is connected in series in the cathode supply circuit of the T tube that is meant to lbe nonconducting at the inception of the operation, and terminal |01, which is later grounded, serves to shunt out the resistance |09 so that the supply conductor to both of the cathodes will be grounded without resistance after Athe inception oi the operation to balance the trigger pair for normal operation. The cathode of the tube T--l l(Fig. 4A) is normally connected to ground through the following circuit, containing resistor |06: point |08, conductor |09, upper contacts oi switch ||0, upper contacts of switch l, upper contacts o! switch ||2 (Fig. 4B), upper contacts of switch I3, upper contacts of switch I4, upper contacts of switch H5, upper contacts oi.' switch Ill, upper contacts oi.' switch |'|1, upper contacts o! switch |I8, upper contacts of switch ||9 (Fig. 4A) upper contacts of switch |20, upper contacts ot switch I2I, and upper contacts of switch |22, through conductor |23 (see Fig. 4B) to point |24, which is grounded through said resistor |08. The cathode o! the tube T--2 normally is given its potential supply through point |32, conductor |25, the upper contacts oi switch |21, the upper contacts of switch |20, the upper contacts of switch |29 (see Fig. 4B), the upper contacts of switch |80, the upper contacts of switch |3I, to point |05 and ground. Therefore, if no key is depressed. the cathode supply circuits, just described, place the resistance in the cathode circuit o! tube TI, and tube T-2 will become conducting when operatlon is initiated upon application of anode potential.

It any one o! the even-numbered keys is da pressed, the following occurs in the cathode supply circuit Ior the T--l tube. It key 8, i'or instance, is depressed, switch III will be moved to the lower contacts, causing the supply conductor |29 to be connected to the cathode of the T-I tube, and, as supply conductor |23 is connected through resistor |09 to point |05, the cathode o! the tube T-I will stili have resistance |08 in itl cathode supply, and consequently tube T-2 will become conducting when anode potential is supplied, which event is desired. The lower switch |2|, operated by the "8 key, is moved to the lower contacts, which grounds the portion oi.' the T-I cathode supply conductor which was cut out by the movement of switch to the lower contacts, said cut-out portion including switches HI, H2, ll3, |I4, II5, H6, H1, H8, IIS, and |20. The same condition is brought about by depression of the 6 key or the 4 key or the 2 key, which moves, respectively, the switches ||2, or i 3 to the lower contact.

Ii an odd-numbered key is depressed--for instance, the 9 key-it is desired that tube T-I become conducting on the application of anode potential, and, when key "9 is depressed, switches |21 and |22 move to their lower contacts. Switch |21 connects T-l-2 cathode supply conductor |26 to conductor |23, which thereby connects the said cathode of tube T-2 to ground. through resistor |06. At the same time, switch |22 connects the cathode of the tube T-I directly to ground through switches |2 |20, I9, IIB (Fig. 4B), ||1, ||'6, ||5, |I4, H3, ||2, (Fig. 4A), and ||0 and conductor |09. Keys 7, 5, 3 and l similarly switch the resistor |06 normally in the cathode supply circuit of tube T-l to the cathode supply circuit of tubes T-2. However, terminal |01 (see also Fig. 2), when grounded through normally closed contacts |40, shunts out resistor |06 (Fig, 4B). Contacts |40 (Fig. 2) are opened as solenoid I is energized at the inception of the control relay operation, thereby causing thatone of the tubes T--I and T-2 to become conducting according to its association with the depressed key. After such operation has been initiated in the T tubes, the solenoid I is deenergized, as will be described, the contacts |40 are closed, and terminal |01 is again grounded, which grounds lboth cathodes of the 'I' tubes for normal trigger operation.

At each commencement of conduction of tube T-2 (Fig. 4A), the anode point 82 will fall in potential due to the anode resistor 93, which fall in potential will be impressed through a capacitor 4| of 10 micro-microfarads onto the normally zero biased control grid of vacuum ampliiier tube 56, normally conducting, causing it to cease conducting and thus causing a positive potential impulse at point |43, due to anode resistor |44 of 5.000 ohms, which is impressed on conductor |58.

The amplifier tube 56 receives its anode supply through point |43, resistor |44, conductor |45, and point |46, which is connected through point |02 and conductor 10 to terminal |55 (Fig. 2) supplied with 120 volts positive potential, as has been described. The cathode of tube 56 is connected to the negative 16o-volt conductor 90| and through capacitor |48 of 4 microfarads is electrostatically coupled to ground conductor 66. The screen grid of ampliiier tube 56 is connected to point |49 and, through resistor |50, of 3,750 ohms, to terminal (see also Fig. 2), which is connected through resistor |52 of 500 ohms, contacts |53, and point |54 energized with 120 volts on operation of solenoid III, as has been described. As solenoid II is energized, positive potential of the screen grid of the amplier tube 56 is removed and then reinstated only when solenoid II is deenergized, to prevent an anomolous impulse in the impulse conductor |58, due to the preliminary firing of T-2 if an even-numbered key is used to preset 10 data therein. This will be further described in connection with the operation of the relays which control the program of the complete operation of the device, when it will be observed that tube T--2 cannot ilre for its preset condition until solenoid II operates, at which time the amplifier tube 56 is incapacitated. The suppressor grid of tube 56 is tied to the cathode. The control grid connects to the cathode through resistor |56 of 50,000 ohms. The screen grid is by-passed to cathode through capacitor |51, of 4 microfarads. After the presetting has taken place, every time the tube T-2' changes from a non-conducting condition to a conducting condition, the sharp potential i'all of point 92 is impressed through capacitor |4| onto the control grid of the amplifier tube 56, which tube thereupon temporarily becomes non-conducting, resulting in a positive potential impulse at point |43, which is impressed upon the input conductor |58 coupled to the control grids of each of the tubes 50, 5|, 52 (see Fig. 4B), 53, and 54 through an individual small capacitor such as capacitor |59 of 10 micro-microfarads. For each two impulses issuing at point 13 from the .pulse sharpening tube 51 (Fig. 4A) and commonly impressed through capacitors 19 and 80|, of l0 micro-microfarads each, onto the control grids of tubes T--I and T-2, there will be one impulse issued from the point |43 of the amplifier tube 56, which impulse is impressed upon the conductor |58 and through the capacitors like capacitor |59 onto the grids of the digit-representing tubes 50 to 54 (Figs. 4A and 4B) inelusive. In the event lthat tube T-2 is caused to be preset in a conducting condition, the rst impulse received from point 13 will cause it to extinguish and the second received impulse will cause it to conduct and thereby cause the amplier tube to become temporarily non-conducting, which sends an impulse onto conductor |58.

In entering data initially into the units order of the selector counter by means of the digit keys, not only is the proper tube of the tubes T--I and T-2 made ready to be conducting, but the proper one of the tubes 50 to 54 inclusive is made ready to be conducting. This is done by applying a positive potential at a point in the grid-priming circuit of the concerned one of said tubes 50 to 54 inclusive. Thus, for instance, if the 6 key (Fig. 4A) were depressed, the switch |60 would be moved to the lower contacts, which would connect conductor |6| to the grid of digit tube 5| by means o1' conductor |62, point |63, conductor |64, point I 65,'resistor |61 of 62,000 ohms, point |68, resistor |69 of 500,000 ohms, and point |10. Tube 5| is that one necessary to preset together with tube T2, so that six impulses from point 13 will cause an operation of the transfer tube, as will be described. C'onductor |6| is connected through resistor |1| (see Fig. 4B) of 250 ohms and terminal |12I (see Fig. 2) to open contacts |13 closed by operation of solenoid II, as will be described. The said terminal |12 is given a positive potential of volts from source terminal |14 as contacts |13 close. The positive potential applied to the grid of tube 5| (Fig. 4A) will, when the anode potential is applied to said tube, cause the tube to become conducting. In the same manner, the operation of any other key oi. the bank causes the proper one of the tubes 50 to 54 inclusive to become conducting (together with the associatedv T tube) when anode potential is applied. For instance, the operation of either 11 ofthe keys l or "2" will place a positive presetting potential on the grid of tube 59. The operation of either of the keys "3 or "4" causes positive presetting potential to be applied to the grid of tube 52. 'I'he operation of either of the keys "5" or 8 causes the application of positive presetting potential to the grid of tube 5|. and the operation of either of the keys "1 or "8" causes application of the presetting potsntial to the grid of tube 50. The operation of key "9" will cause presetting potential to be applied to the grid of tube 54. When no key is operated. tube 54 also receives the presetting potential on its grid through conductor 19| and associated closed switches like switch 192. Anode potential is supplied to the tubes 50 to 54 inclusive by means of conductor |89, resistor |9| of 5,000 ohms. point |92, resistor |93 of 2,500 ohms. conductor |94, terminal |95 (see also Fig. 2), conductor |95, point |91, conductor |99, contacts |99, which, when switch blade |99 is in the upper position due to operation of solenoid V. connects said contact |99 with conductor |9|, which. through point |92 and point |99, is connected to the 1Z0-volt positive supply terminal |14. The time of the application of the potential to the anode of the units bank tubes will be made apparent when the operation of the relays of Fig. 2 is described. The cathode of each of the digit tubes 59 to 54 inclusive (Figs. 4A and 4B) is grounded; as, for instance, the cathode of the tube 50 is grounded by means of conductor |99, point |94, resistor |95 of 20,000 ohms, conductor |99, point |91, and conductor |99, which is connected to ground conductor 99. Each point like point |94 is coupled through a resistor of 2.500 ohms, like resistor 200, and a capacitor like capacitor 20| of .001 microfarad, to ground. Points like point 202 are connected through a resistor like resistor 209 of 62,000 ohms, a point like point 204, a resistor like resistor 205 of 62,000 ohms to conductor 90|. which is connected to terminal 19 supplied with a negative potential of 160 volts. Points like point 209 are connected by a capacitor like capacitor 201 of 250 micro-microfarads to points like point 204. Points like point 20| are connected to the grid of the next higher digit tube in the denominational order through a point like point |99 and through a resistor like resistor |59 of 500,000 ohms. By this network of resistors and potential supplies, the grids and cathodes of the units tubes 50 to 54 inclusive are given a normal grid bias potential far more negative than the critical point. When a tube becomes conducting by being fired by the presetting operation, it causes a rise in potential of the grid of the next higher tube, which tube, being thus primed, ilres on receipt of a positive potential upon its grid by reason of a positive impulse from point |59 (Fig. 4A) impressed on conductor |59, which in turn raises the potential of the grid of the next higher tube sufiiciently near to the ring point so that the next positive impulse from point |49 impressed on conductor |59 will fire only said next tube. Such a counting ring is described in the above identified applications. The cathode of the last tube of the series is connected to the grid of the first tube of the series to form an endless operating chain.

A gaseous triode transfer tube 55 (Fig. 4B) is provided, to be fired by an impulse occurring on conductor |59 while tube 53 is conducting. 'Ihe rise in potential of the cathode of tube 53 negative potential of 160 volts.

259 to point 25|. through resistor 252 of 120,000 ohms, points 259 and 254, and resistor 255 of 500,000 ohms to the grid of transfer tube 55. It is apparent that both the tube 54 and the transfer tube 55 become conducting on the same mpulse in conductor |59, both of said tubes thus being conditioned to be responsive to the next impulse by the fact of conduction existing in tube 53. The anode of the transfer tube obtains its potential through a resistance 2|0 of 2,000 ohms, a resistor 2|| of 250 ohms, and terminal 2|2 (see also Fig. 2). The terminal 2|2 (Fig. 2) is connected through resistor 2|3 of 500 ohms through normally closed contacts 2|4, conductor 2|5, open contacts 2 I5, which are closed on operation of the solenoid V, to connect with conductor |9|, which is connected through points |92I and |99 with the 120 volts positive potential of terminal |14. The cathode of the transfer tube 55 (Fig. 4B) is connected to ground conductor 95 through a 100,000-ohm resistor 2|1 in parallel with a capacitor 2|9 of .00025 microfarad. The cathode is also connected through Ipoint 2|9 and a resistor 220 of 600,000 ohms to conductor which carries a The coupling of the transfer tube cathode to ground through the parallel resistor-capacitor network, together with the distributed inductance of the wiring, leads to an oscillatory phenomenon in the cathode circuit of the ltransfer tube 55 as the tube comes to full conductivity, which, as capacitor 2|9 becomes charged, causes a rise in the cathode potential to such a degree that it overshoots the potential of the anode, which has in the meantime dropped to within 16 volts of ground, allowing the control grid of the transfer tube to resume control. Thus the transfer tube is selfextinguished and has, by reason of the rise in its cathode potential. passed on through point 2|9 and conductor 22| (see also Fig. 4C) a positive impulse to cause one step in the operation of the tens bank counter tubes shown in Figs. 4C and 4D.

The units bank of the selector counter, as has been explained, has had rendered conducting therein originally, by means of the key operation, the proper selected tubes, so that it will take the number of impulses over the input circuit, as indicated on the key, to fill the units bank of the counter to capacity. As the units bank is filled to capacity and the transfer tube is operated, the same impulse causes tube 54 (Fig. 4B) to become conducting. The rise in cathode potential of tube 54 as it fires is conveyed by conductor 222, resistor 223 of 62,000 ohms. point 224, point 225, resistor 225 of 500,000 ohms, and conductor 221 to the grid of tube 50 (Fig. 4A), which tube fires and becomes conducting the next time tube T--2 becomes conducting. In the meantime, the transfer tube 55 (Fig. 4B) has become extinguished and is ready to re, so that, when it receives another nring impulse and tube 52 is conducting, it will become conducting and consequently will carry over another impulse to the tens denominational order. The extinguishment of a preceding conducting tube of the units bank of tubes 50 to 54, by the conducting starting in the succeeding tube of the series, is caused by the common resistance |9| of 5,000 ohms (Fig. 4A) in the anode supply conductor and the individual capacity coupling to ground of the cathode of each tube. 'I'he anode supply resistor |9| causes a fall in poten- (Fig. 4B) is conveyed by means of conductor 15 tial of the anode supply conductor |99 as any of tubes 60 to 54 ilres, such fall in potential being due to the charging of the cathode-ground capacitance. As any conducting tube before has had its cathode-ground capacitor charged and its cathode has risen to within about 16 volts of the anode, the drop in the anode supply conductor causes the anode oi such conducting tube to drop below its cathode in potential. For further description of this extinguishing action, see applicant Mummas co-pending application for United States Letters Patent. Serial No. 395,995, to which reference has been made.

The units bank of the selector counter, including tubes 50 to 54 (Figs. 4A and 4B) inclusive, will operate in endless chain sequence as long as operating potentials are applied and impulses are received from amplifier tube 56 (Fig. 4A).

'Ihe tens denominational order of the selector counter (Figs. 4C and 4D) includes ten digitrepresenting gaseous triodes 260, 26|, 262, 263, 264, 265, 266. 261, 268, and 269, representing the digits 10| 2051, 3019, 4011, n50, H60, n70, 1:80, 90, and 00, respectively, and is controlled by keys designated by the same digits. Each key controls the tube of complementary digit value on the base of nine.

The tubes of the tens denominational order are arranged in an endless chain operating circuit, constituting a counter, by cathode-to-grid connections as illustrated, for example, by the connection from the cathode of tube 262 (Fig. 4C) through point 210, resistor 21| of 50,000 ohms in parallel with capacitor 212 of 200 micro-microfarads, point 213, and resistor 214 of 500,000 ohms to the point 215 leading to the grid of the tube 263. Each cathode is given a negative potential by being connected, as is the cathode of tube 262, through a point like point 210 and a resistor like resistor 216 of 25,000 ohms to ground, and through a point like point 210, a resistor like resistor 21| of 50,000 ohms, a point like point 213, and a resistor like resistor 211 of 50,000 ohms to conductor 90| (see also Figs. 4A and 4B) supplied with i60 volts negative potential. Each point corresponding to point 210 is coupled to ground through a capacitor like capacitor 218 of .005 microfarad and a resistor in series with it like resistor 219 of 2,500 ohms. Each grid is coupled from a point like point 215, point 28|, and a capacitor like capacitor 280 of micro-microfarads to the common input conductor 22| connected to the cathode of the transfer tube of the units bank. With the connections shown, a conducting tube primes the next tube of the chain to become conducting as the next impulse is commonly received over the input conductor 22|. For each operation of the transfer tube 55 (Fig. 4B) the tens denominational bank operates a step. As a tube becomes conducting, any previously conducting tube is extinguished by reason of the drop in the potential of the anode supply conductor in the same manner as was explained in connection with the units bank tubes 50 to 54 (Figs. 4A and Anode potential for the tens bank is supplied through supply conductor 282, common to the ten tubes 260 to 269, through resistor 283 (Fig. 4D) of 5,000 ohms, point 284, resistor 285 of 2,500 ohms, terminal 286 (see Fig. 2), conductor- 281, normally open contacts 289, which are closed by operation of solenoid IV, to be described, conductor 290,` point 29|, and conductor |9|, which, as before said, leads to the 120-volt positive supply terminal |14. A voltage-dividing resistance 292 (Fig.

4D), connected to ground, is used to regulate the anode potential.

The selecting switches operated by they tens denominational keys (Figs. 4C and 4D) cause the 90 tube 268 to become conducting at the inception of the operation if no key of the denomination has been operated; or, if a key has been operated, that tube is caused to become conducting at the inception of the operation which is the number of steps in the ring below tube 268, which corresponds to the value of the key used.

The positive potential source terminal |14 (Fig. 2) leads through point |99, contacts 29,3, normally open but closed by energization of solenoid I, conductor l295, resistor 296 of 5,000 ohms, terminal 291 (see Fig. 4C), conductor 298 (see also Fig. 4D), closed switches 299, 300, 30|, 302, 303 (see Fig. 4C), 304, 305, 306, and 301, conductor 308 (see Fig. 4D), resistor 309 of 62,000 ohms, points 3|0 and 3||, and resistor 3|2 of 500,000 ohms to the grid of the 90 tube 268, so that the grid of the 90 tube 268 will receive a 120-volt positive potential during the time solenoid I (Fig. 2) is energized, if no key is depressed. If any tens key (Figs. 4C and 4D) is operated, the associated one of the switches 299 to 301 inclusive is opened, and the associated upper key switch is made to connect the positive potential conductor 298 to the grid of the proper tube. For instance, if the 70 key were depressed, switch 344 would connect contacts 313 and 3|4, energizing coriductor 315 connected through resistor 3|6 ci 62,- 000 ohms to points 3|1, 3|8, and through resistor 3|9 of 500,000 ohms to the grid of tube 26|, representing the number 20. Thus, with the tube 20 rendered conducting, seven impulses will cause the 90 tube to become conducting and ll the denomination. On the next impulse, the

00 tube is red, and, by direct connection of its cathode to the hundreds bank input conductor 326 (see also Figs. 4E and 4F), a positive potential transfer impulse is sent to the hundreds bank to operate it one step.

By means of conductor 3210 (Figs. 4D and 4C) the "10 tube is primed by the potential rise of the cathode of the 00 tube and is iired on the next impulse received from the units bank.

A fugitive digit" correction input impulse conductor 320 (Figs. 4C and 4D) is coupled to the grid of each of the tubes of the tens bank through a capacitor such as capacitor 32| (Fig. 4C) of 10 micro-microfarads, said conductor being energized through terminal 322 (see also Fig. 3) which is connected through a resistor 323 of 5,000 ohms to point 324 and to the cathode of the fugitive digit gaseous triode electron tube 325, whichl is caused to conduct once each operation to send a positive potential pulse through terminal 322 unless its grid 320 is held negative through application of an excess negative potential on terminal 321 (see also Fig. 4B), thus preventing firing. Terminal 321 is connected through a switch 328 to the negative 1GO-volt conductor 90| whenever a key is operated in the units bank, said key operation causing detent plate 329 to move and close the normally open switch 328. The fugitive digit. tube 325 (Fig. 3) receives anode potential of volts over conductor 330, through terminal |55 (see Fig. 2), when relay III is energized, closing contacts 4 I 2 and 4| connecting the circuit to the 120-volt supply terminal |14.

The capacitors 69 and 369 (Fig. 3), coupling the anode and the grid of tube 325 to ground, are illustrative of others placed in the circuits for eliminating shock phenomena in the involved circuits, because, during the sudden application of potential, the capacitors insure a gradual rise in the potentials of the circuits as voltage is applied.

When no preset key selected data is to be entered in the units order, it is seen that the fugitive one" correction is taken care of by the fugitive one tube.

When no preset key selected data is entered in the tens order, the nine tube 200 is caused to conduct, and, if the fugitive digit is entered into the tens order, it is passed on by the resulting tiring of the tube 200, which transfers the unit oi data to the hundreds order, as will become apparent.

The sequential operation of the relays of Fig. 2 arranges the application of potentials so that the "fugitive digit" will be entered at the proper moment in the inception of the operation.

The hundreds bank of the selector counter includes ten gaseous triode tubes representing the hundreds digits as shown in Figs. 4E and 4F, which tubes are arranged in a counting ring by connecting the cathode of one tube to the grid of the next tube. as has been described for the tens bank. 'I'he common anode supply conductor 03| (Fig. 4F) is connected through resistor 232 oi' 6,200 ohms, resistor I of 2,500 ohms to terminal |00 (see also Fig. 2), which is energized with 120 volts positive potential, by the closing of contacts |00 as solenoid V is operated. Point 334 (Fig. 4F) is grounded through voltage-dividing resistor 335 of 50,000 ohms.

The cathodes of the tubes of the hundreds bank are given potential by being grounded on one side, as. for instance, the cathode oi' the "l00 tube (Fig. 4E) is grounded through resistor 330 of 25,000 ohms and on the other side is connected to the negative i60-volt conductor 90| through resistor 331 of 50,000 ohms and resistor lll of 50,000 ohms. The connection of each cathode to the ground through a capacitor, such as capacitor 330 of .005 microfarad in series with an oscillation-suppressing resistor. together with the resistance in the common anode supply conductor, causes any conducting tube to become extinguished as another tube of the counting ring lires as has been explained in connection with the lower denominational banks. The cathode of the l00" tube is connected to the grid of the 200" tube through resistor 321 in parallel with capacitor 040 of 200 micro-microfarads to prime the "200" tube grid, when the l00" tube is conducting. by elevating its normal controlling negative bias to near the critical point. Each grid is biased with a normally controlling potential by being connected, through a resistor like the resistor 24| of 500,000 ohms and a resistor like resistor Il! of 50,000 ohms, to the negative 160- volt conductor 00| and to ground through resistors like resistors 331 and 330, giving such grid a normal potential of 96 volts negative as against 32 volts negative for the cathode. The rise in potential of the preceding cathode will raise the potential oi' the succeeding tube of the ring to a point where a positive impulse on the input conductor 020. which is impressed on the grids of all the tubes of the bank each through a capacitor, will nre the primed tube. The digit keys are connected as in the tens bank to cause the tube to be iired at the inception of the operation which is that number of steps in the ring below the "000" tube which corresponds to the value of the key used, the nring potential being impressed on terminal 842 (ses Figs. 4E and 2), which is energized as contacts 043 are closed when solenoid I is operated, connecting thereto the positive -volt terminal |14.

As the "000" tube lires (Fig. 4F), its cathode potential rises, giving terminal 345 (see also Fig. 3) a positive rise in potential, which causes conduction in stop tube 240 to block the transmission of "enerated impulses, as will be described.

The impulse generator A vacuum tube 400 (Fig. 3) of the tetrode type, having its screen grid connected to the anode, is placed in a circuit as an oscillator of the Hartley type. 'Ihe cathode is grounded through connection to a mid-point of induction coil 40|, which is grounded by connection to point 402. The control grid is connected to the other end oi' the coil through resistor 403 of 10,000 ohms in parallel with capacitor 4000 of SOO-micro-microiarads. The tube 400 will oscillate as soon as anode potential is applied to terminal |55 and the capacitor 404 is charged.

The high-frequency output of the oscillator is fed through capacitor 400 and impressed on the anode of the gate tube 401, which is a. highvacuum tetrode with the screen grid connected to the anode. Its anode is supplied with potential through point 400, resistor 400 of 50,000 ohms, and terminal 4|0 (see Fig. 2), which is energized with 120 volts positive potential by being connected to terminal |14. The cathode of the "gate" tube is grounded through resistor 4|! (Fig. 3) of 8,200 ohms.

'I'he variable inductance 4|4 of about 25 ohms resistance is supplied to neutralize the effect of the anode-grid capacity on the gate tube during the time when the oscillator is operating and no signals are to be sent. and is adjusted so that no signal appears at the cathode of the "gate" tube when the stop tube is conducting. The control grid of the gate tube is connected through "stop tube 340 and to the cathode of start tube 4|5. Tubes 4|! and 340 are gaseous triodes. The resistor 420 of 25,000 ohms in the cathode potential supply line of tube 4|! and the resistor 42| of 37,500 ohms common to the cathode potential supply of start" tube 4|9 and the anode potential supply ofstop tube 046, which potential is obtained from conductor 4200 energized through terminal 2|2 (see also Fig. 2), before described. causes a change in potential at point 4|! when either of said tubes is conducting, as compared with the non-conducting condition. When the "start" tube is iired, the rise in potential in its cathode due to resistor 420 is transmitted through point 4| to the control grid of the "gate tube, causing the "gate" tube to become conducting and to respond to the highfrequency application of potential to its anode as impressed thereon by the oscillator tube 400. 'I'he cathode of the "gate tube 401 follows the oscillator-induced anode excursions of potential, which creates high-frequency impulses in output conductors 42| and 424, connected, respectively, to the selector counter through terminal 5l and to an accumulator through terminal 444, to actuate them.

Due to the fact that the control grid of the gate" tube 401 accompanies the anode excursions of potential to some degree, and to the fact that said grid is connected to the cathode of the "start" tube 4|0, the transmission of impulses from the gate tube always begins at the nega- 17 tive part of an oscillatory excursion of the anode potential of tube 401 because tube 4|9 fires on the negative excursion of the cathode of tube 4|8 which follows the oscillation of the grid of the "gate tube.

As the selector counter (Figs. 4A to 4F) receives the impulses over terminal 58, the said counter advances step by step from its preset condition until the "000 tube (Fig. 4F) fires, causing a rise in its cathode potential, which rise in potential is transmitted over terminal 345 (see also Fig, 3), through capacitor 440 of 250 microfarads to the grid of stop tube 346, firing said tube, which normally was kept non-conducting due to connection through point 44| and resistor 442 of 36,000 ohms to the negative 180-volt conductor and connected to ground through resistor 443 of 150,000 ohms. Upon the firing of the stop tube, its anode drops in potential, which potential drop is transmitted through point 4|8, resistor 4|1, point 4|6, and resistor 4|5, stopping conduction in the gate tube, which stops the transmission of impulses.

By this means, an exact number of impulses, corresponding in number to the selected denominational keys, is sent as a non-denominational burst.

A key release tube 445 (Fig. 3) of the gaseous triode typel having its cathode grounded, is normally biased against conduction by having its grid connected at point 446 to a source of negative potential, and receives anode potential through terminal 441 (see Fig. 2) through the winding of solenoid VI, point |81, conductor |88, and contacts |89 and |90 joining to the positive supply terminal |14. As the positive potential stopping impulse is received over terminal 345 (Fig. 3), the key release tube 445 is red, causing solenoid VI to operate, closing contacts 450, en-

ergizing the key release solenoids 45|, 452, and` 453 (see also Figs. 4B, 4D, and 4F) to release any depressed keys.

The starting key may be made as a resilient key which is locked in position and released as are the digit keys; otherwise it must be held closed until the end of the operation.

Operation control switches The solenoids shown in Fig. 2 and numbered I, II, III, IV, V, and VI are energized and deenergized in a certain sequence shown in the chart adjacent the switches.

The operation of solenoid I removes ground potential from terminal |01 (Fig. 4B), which results in resistor |06 being inserted in the cathode supply circuit of tube T| (Fig. 4A) for the purpose of insuring that, on the application of anode potential to tubes T--l and T-2, the tube T-2 will become conducting. Tube T-2 is made to become conducting prior to the amplifier tube 56 becoming active, to prevent such an anomalous impulse from being transmitted to the selector counter. The solenoid I is denergized before transmission commences to remove the effect of resistor |06 and leave the trigger pair as nearly balanced as possible in their potential supply circuits, any selection of tube T-I thereupon resulting in its firing and the extinguishment of tube T-2. Contacts 343 and 293 apply firing potential to the grids of the selected digit tubes of the tens and hundreds banks. Contacts 50| energize solenoid II.

Solenoid II, when energized, closes contacts |13 connecting the 120-volt positive supply to terminal |12 supplying firing potential to the grids of the selected one oi tubes 50 to 54 inclusive (Figs. 4A and 4B) and opens contacts 2|4, removing the application of positivepotential to terminal 2|2 (see also Fig. 3) until solenoid V is later energized and solenoid II is deenergized. A circuit is completed through contacts |50| to operate the III solenoid. Contacts |53 open to disconnect the screen grid of amplifier tube 56 (Fig. 4A) from contact 4| later energized with 120 volts positive on energization of solenoid III. Contacts |53 are closed when solenoid II is deenergized just prior to the commencement of transmission of the impulses.

Solenoid III, when energized, closes contacts 4| and 4 2, which, in addition to energizing the upper contact |53 with 120 volts positive potential, as has been described, also energizes terminal |55 (see also Fig, 3), giving anode potential to the oscillator tube, the fugitive digit tube, the trigger pair (Fig. 4A), the pulse sharpening tube, and

the T-2 impulse amplier tube. A holding circuit is also closed for maintaining solenoid III in energized condition and energizing solenoid IV.

When contacts 288 close, the 120-volt supply conductor is connected to terminal 286 (see also Fig. 4D), supplying anode potential to the tubes of the tens bank of the selector counter. Contacts 504 energize solenoid V and hold solenoid IV energized.

When switch moves from its lower contact, a dummy load to ground is cut out, and contact |89 and terminal |85 are energized with 120 volts positive supplying anode potential to the tubes of the units and hundreds banks of the selector counter. Contacts 5| 0 are broken before contacts 5I| are made. Contacts 5|0 breaking deenergizes solenoid I, and contacts 5|| making locks in energized condition solenoids III, IV, and V. Contacts 2|6 make, and, when solenoid II is deenergized through deenergization of solenoid I, it energizes terminal 2|2, giving the impulse generator its start while capacitor 422 is being charged, permitting the fugitive digit tube to re rst. As the bias of the start tube 4|9 becomes critical, the tube fires at the low point of the swing of its cathode as influenced by said cathodes connection to the grid of tube 401. The grid of tube 401, as has been said, follows the excursion of the cathode of tube 401.

Solenoid VI is operated by means heretofore described.

rI'he remaining energized solenoids are deenergized when the starting switch is opened.

If more than three denominational orders are used in the selector counter, means similar to the fugitive digit tube must be provided for each such additional order to correct the complementary entry of data into the selector counter. Otherwise the described device may be expanded into as many denominational orders as are required.

What is claimed is: i

1. In combination, an accumulator of data including denominationally arranged electronic devices, the devices of a denomination being connected in a series for step-by-step operation by electric signals, each device representing a denominational number; means to enter data into said accumulator at a step by causing a selected device in each of the selected denominations to become operating; a signal producer for operating said accumulator, each signal causing an entry of a unit into the lowest denomination of said accumulator; connections between the signalproducing unit and the accumulator, said connections including a gate for blocking or admitting signals; and means under control of the accumulator, operative when the accumulator has been filled to capacity with data for causing said gate to block signals from passing.

2. In combination. a conductor; an electron tube having its cathode connected to saidconductor; a second electron tube having its anode connected to said conductor: means for causing a potential rise in the said cathode as said rst tube becomes conducting; means to cause a potential drop in theanodeof said second tube when said second tube becomes conducting; an electron output tube having a continuous output oi' electric energy as modified periodically by an oscillating means. said electron tube being controlled as to output by a control grid to which said conductor is connected. the conduction in the first-mentioned tube causing the potential upon said control grid to rise and allow output from the output tube, and said second electron tube when conducting overcoming auch potential rise on the control grid so as to prevent an output from said output tube; and selecting means actuated by the output from the output tube to control the said second electron tube to become conducting and terminate the output at the end of any seleced number of periodic modifications from the output.

3. In combination. a conductor; an electron tube havinga cathode connected to said conductor; a second electron tube having its anodev connected to said conductor; means for causing a potential rise in said cathode as said first tube becomes conducting; means for causing the potential drop in the anode oi' said second tube when the second tube becomes conducting; and an electron output tube having a. continuous output of electric energy as modiiled periodically by an oscillating means. said electron tube being ccntrolled as to output by a control grid to which said conductor is connected, the conduction in the first-mentioned tube causing a potential upon said control grid to rise and allow conduction in the output tube. and said second electron tube when conducting overcoming such potential rise on the control grid and preventing conduction in said output tube.

4. In combination, a high-vacuum electron tube having an anode. a cathode, and a control grid; means to supply operating potential to the anode and the cathode; means to supply bias potential to the grid to keep said tube normally non-conducting; means to impress an oscillating potential on the anode-cathode supply means; and means associated with the bias potential supply means and responsive to the electrostatic swing of the grid as the oscillating potential is applied on the anode-cathode supply means. for causing the tube to become conducting on a predetermined point in the excursion of an oscillation.

5. In combination. a potential oscillation producing device; a high-vacuum electron tube havlng an anode-cathode supply circuit and a control grid; means to supply normally controlling bias potential on said grid; means to impress the potential oscillations on said anode-cathode circuit; and a gaseous triode electron tube having its cathode connected to the control grid of the firstnamed tube and having a resistance in its potential supply circuit and a capacitor in its grid potential supply circuit so that as a positive potential is applied to the grid oi the gaseous tube it wil1 rise exponentially in potential and nre on the negative excursion of an oscillation, thereby causing conduction in said high-vacuum tube.

ROBERT E. MUMIEA.

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