US2808535A

US2808535A - Resettable variable radix counter

Info

Publication number: US2808535A
Application number: US462877A
Authority: US
Inventors: Donald H Lee
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1954-10-18
Filing date: 1954-10-18
Publication date: 1957-10-01
Anticipated expiration: 1974-10-01

Description

D. H. LEE

RESETTABLE VARIABLE RADIX COUNTER Oct. 1, 1957 2 Sheets-Sheet 1 Filed Oct. 18, 1954 INVENTOR DONALD H. LEE BY ORNEY .Gmmm 3: 242

. humum Ebium mm mow FIIIIIIIIIIIIIIIIII Oct. 1, 1957 f D. H. LEE 2,808 5 RESETTABLE VARIABLE RADIX COUNTER Filed Oct. 18, 1954 2 shee s-sheet 2 INVEN TOR.

DONALD H. LEE

ATTORN EY States Unite REJSETTABLEVARIA E ADDQ COUNTER Donald Lee, "Philadelphia, "Pa,, assignor to Burroughs fiorporation,'Detroit;-Mich., a-corporationof Michigan -Appligation October 18, 1955}, Serial filo-462,877

Claims. (Cl.15-.j-8 5) This-invention-relates to pulse counting circuits, and

-more particularly to resettablepulse counting'circuits includingmeans for selectively altering the radix.

To enable high speed counting, a multi-position electron beam-magnetron switching tube is usedof the general typedescribed in the United States Patent No. 2,721,-

"955;issued to'sin pih Fan and SaulKuchin'skyon 0c.-

prises a spade electrode for locking the beam. in position,

-a target electrode for receiving the beam, and a switchingielectmde arte p n he e m f om o p on to another. The spade electrodes are positioned concentrically about the cathode and spaced apart'from each other'to permit twoadjacent spades to define the edges ofiabean'r receiving compartment. Thetarget electrodes are arranged concentrically about the spade electrodes and are positioned. to individually extend across the spacings between adjacent ones of said spade electrodes to thereby receive substantially the entire beam passing into the compartment. The switching electrodes are arranged concentrically about the cathodeand each switching electrode is individually positioned in a separate compartment in the vicinity of one spade electrode and the target electrode. A magnetic fieldis caused to permeate the tube with flux'lines substantially'parallel to the electrodes. As well known in the art, this magnetic field in conjunction with the electric field set up between the cathode and target electrodes will cause the electron beam to follow apath extending between two spades'when one is at a i potential and the other is'at about the catholdepotential. As. the beam enters the compartment, part of it will bereceived by the'lowpotential spade tohold its potential at a'low value and keep'the'beam-lockedin.

To provide switching oftheb'eam to Jthenext .compartment, the switching electrode is placedto alter-the beam path so that the otherwise high potential spade receives'beam current. This'lowers the. potential of the spade enough to cause the beam to step into the adjacent compartment. The beam normally progressesfrombne compartment" to the next in that direction defined by the polarity of the magnetic field. 'By coupling {the switching electrodes into'two sets, each includingalternate electrodes,fthe electron beam can be caused to advance from one compartment to the next by changing the potential of the two sets of switching electrodes alternately.

This hereinbeforedescribed tube is utilized in aresettable counter system providing a selectively variable radix in accordance with the present invention. 'In this system the counting may begin from some pre-selected number such as one and terminateuat any other presse lected number such. as two orten. Inthismanner the counter may be set for any desired-radix. :The electron beam of the above described tube therefore can be caused -to advance consecutivelytrom -afirstslectab1e target atent v masses Patented Oct. 1, 1957 electrode through.-the intervening target electrodes to a .second selectable targetelectrodeand then is'caused' to Iautomatically.proceeddirectly from the second 'targetelectr-ode. back to the first target electrode.

A general object of theinvention is to provide'improved counter systems.

A further object of the invention is to provide variable radix counters utilizing magnetron beam switching tubes.

'Anotherobjectof the presentinvention is to'provide means whereby the electron'beam of a multi-position electron beam switching .tube'may be' reset automatically to a particular electron beam starting position each time {the electron beam advances to a dilierent predetermined beamposition.

.In accordance'with' one embodiment of the invention,

the target electrode of a particular compartment is chosen by sele'ctor'rneans to provide a signal in response to beam impingement in'that compartment. This signal operates agating circuit which, inturn, transmits a pulse to'both the catl odean'dv that particular spade electrode which is chosen by further .selector means. The pulse on the cathode functions to turn off the electron beam thus .preventing it'from steppingfrom one target to the next until eventually arriving .atthe chosen spade as it normally would "due to'the influence ofthe magnetic field Lin the sole presence of the signal to the spade. However, as the potential of the particular spade electrode is reduced by the signal pulse in the absence of the beam and retained at reduced potential after the electron beam is turned on again, a' beam path between the cathode and the chosen spade electrode is'formed causing the beam to impinge upon the chosen spade electrode, thereby holding it at reduced potential. 1 This affords .a selective reset operation which permits variable radix operation with assurance that the beam will step directly from one compartment to another compartment not adjacent thereto.

"To cause the beam to step from one position to the next, a counter system is used such as described in the copending application of Donald H. Lee for United States .Letters Patent, Serial No. 459,-697,filed October 1,1954. '11] this counter system the switching electrodes are divided into two sets of alternating electrodes hereinafter'designated as the odd numbered and even numbered electrodes. A 'feedback circuit is provided from the target electrodes of one set'tothe switching electrodes of one set thereby to cause the switching electrodes of only one set to become primed with. internal signals dcrived from the switching tube beam, to thereby enable an external pulse applied commonly to all the switching electrodes to advance the beam from "one target electrode to the next. In this manner t-he'beam.may bestepped a single posiinvention.

Referring nowv to the figures simultaneously, like referencecharacters identifysimilar component parts in orderto facilitate comparison.

The magnetron-beam switching tube is supplied with an --external:magnet 8'which supplies flux lines parallel to the elongated electrodes. :The cathode 225 is centrally located withinrthe tube envelope and "has positioned-'ab out it three concentric {rows :of electrodes.

" -Fhe's'e elec'trodes' are respectively beam forming and holdrequired switching time.

ing electrodes 20 through 29 commonly termed spades,

which direct the beam to corresponding target electrodes tube 209'is normally conducting. The beam is therefore formed and directed between the low potential spade and the adjacent high potential spade so that the low potential spade receives enough beam current. flowing through a spade resistor40 through 49 .tomaintainits low potential and assure that the beam is locked in a stable position as long as statictube potentialsiaremaintainedI The beam is moved from one stable position to the next by means of switching electrodes 70 through 79, which are associatedwiththe respective beam receiving compartments containing target electrodes 10 through 19. By decreasing the potential to the switching electrode of any particular compartment receiving the beam, the beam isdefocussed or spread so that the normally high potential spade receives enough offlthe beam to lower'its potential and thus cause it to transfer the beam into the adjacent compartment. By connecting the switch- 7 ing electrodes into two sets, respectively.containing/the alternate odd and even switching'electrodes, the beam .may be made to advance only'one compartment, even though the switchingpulse duration is longer than the The respective sets of switching electrodes for this reason are diagrammaticallyshown in Fig. l as odd electrodes 223 and even electrodes 222. I

' Output signals may be taken from the respective target electrodes by means of separate connectors which are coupled to the output terminals To, Ti' etc. inFig. 1.

Thus, the tube may be used as a counter or commutator.

With the operation of the tubeiin the foregoing manner in mind, the details of the circuit connections may be considered' The ten switching electrodes of Fig. 2 are represented in Fig. 1 as two-combined groups of commonly connected even numbered and odd numbered electrodes each schematically represented at the terminals identified by

reference characters

222 and 223. The cathode 225 is connected to a negative source of potential at lead 289 as supplied at the anode of 212 of normally conducting tube 229. The cathode 225 is connected by an alternate circuit to ground potential'through A the parallel combination of resistance 233 and capacitor 232 connected in series with the resistance 224. The odd numbered switching electrodes 223 are connec'ted'to the cathode 225 through

series resistances

220 and 224 and the even numbered switching electrodes 222 are .con-

nected to the cathode 225 through

series resistances

221 and 224. The odd numbered switching electrodes .223

further are connected by capacitor 283 to conductor 236 and the output lead of a pulse standardizer circuit. contained withinthe dotted box 234. The even. numbered switching electrodes are connected through capacitor 282 and lead 237 tothe output lead of a similanpulse standardizer' circuit contained within the dotted box 235.

Generally speaking, the pulse standardizer circuits 234 and 235 operate to apply pulses of standard waveshape to the switching electrodes for assuring that the beam may 'be switched from onetube compartmentto the next.

Because of input circuits connected to the pulse standardizing circuits 234 and 235, only one of the pulse standardizing circuits will be operable at any time. Each pulse standardizing circuit requires a threshold pulse of sulficient magnitude to its associated control grid electrodes toproduce an'output signal, as will be'discussed in more detail hereinafter."

Each of the spade electrodes20' through 29 .is ,connected to a commonregulated '-75'- volt busHliucQ238 through an individual seriescircuit comprising. one ,each' of resistances in the group 40 through 49 and 60 through 69 and an inductance of the group through 59. For example, the spade electrode 20 is connected to the common bus 238 through the series combination of resistance 40, inductance 50, and resistance 60. Similar circuits connect the remaining nine spade electrodes to the common bus bar 238, which in turn is connected to the ISO volt power supply or battery source 239 through resistance 188 to maintain the spades at a positive potential with respect to the cathode 225. The inductance 50 and the resistance 6%) serve the function of developing a spade switching potential from a pulse applied to the junction point 261 from a pulse amplifier and shaping-circuit contained within the dotted line 241 by way of capacitor 273, switch arm 271 and contact 250. The switch 272 permits a negative pulse from source 241 to be impressed upon any one of the spade electrodes 20 through 29 with sufiicient magnitude to cause the electron beam to be selectively directed to a corresponding compartment.- This serves as a reset signal developed in response to a pulse at terminal 189 from an external source 295. In order to assure that'the beam is reset without passing through intermediate compartments, the beam is cut-off by application of the reset pulse directly to the cathode 225 along lead 289. Cut-off is effectedby reducing the conduction of tube 209 thereby causing the cathode 225 to be nearer ground potential. I

The electron beam'can be caused to impinge upon a selected target electrode by two different methods in the circuit of Fig, 1. One of these two methods is to apply the proper'potentials to one of the spade electrodes 20 to 29 through the corresponding position of reset switch 272 to form the beam in the compartment containing that spade electrode; The other method is to apply switching ,pulses alternately to the

respective switching electrodes

222 and 223 by way of standardizing circuit 234 or 235 to cause the electron beam to advance consecutively. from one target electrode to another. Each of the switch contacts 250 through 259. are connected to an individual spade electrode through an isolating resistance of the. group 40 through 49.' As a specific example the contact 250 is connected through the junction point 261 and the resistance 40 to the spade electrode 20. Similarly, contacts 251 through 259 are connected to the spade electrodes 21 through 29, through resistances. 41 through 49 respectively. v

The pulse shaping circuit 241 can receive an input excitation pulse from one of three sources. The first of these three sources is obtained'internally and is used in order to provide a ring counter. In this case a pulse is taken'fromoutput terminal 275 of'the counter system as supplied by'the pulse forming circuit within the dotted line 274. Thus, a pulse is received from any target electrode which is selected by means of the switch within the dotted line 276. The second source is the external input source 295 at remote reset terminal 189'. The third'source comprises an internal pulse forming circuit associated with the manual reset switch 196. V V i The pulse standardizing circuit 241 is comprised of two triode sections 208 and 209 ofa 5687 type vacuum tube. The triode 208 has an anode 215, a control grid 214, and a cathode 213. The control grid 214 is connected by capacitor 205 to the output terminal 275 of the pulse.

standardizing circuit 274 through conductor 277, which 'The grid 214 is connected to the cathode 213 through V series resistances206 and 218. A clamping diode 207 p is connected across resistance 206. Accordingly, the

" tube 20 8 conducts throughthe grounded anode resistance 202 because of the negative-cathodepotential.of. about 250 volts supplied through resistor 219, from the potential source 229.

However, the cathodes 213and1210 of :the triodes. 208

and 209 are connected together .to source229 through the' series combination of resistancel219 and resistance'218.

,Since the grid" 211 of tubeii209 is connected to. ground potential through the resistance"204, the tube normally conducts to ground through resistors 201 and 203. This supplies a bias potential through resistor 218 which keeps current through tube 208 norrnally ata low value. Tube 209\ is maintained at a safe-conduction value by grid leak bias through resistor 204. The tap200 of variable resistance'201 is also connected, to ground potential and constitutes a-uoltage adjustment means for the plate 212 of tube'209. The plate 215 of tube 208 is connected to the grid211 ot-tube209'through coupling capacitor 216.

through the capacitance 273 and also upon the cathode 225 of the beam position switching tube. The coupling capacitor 216 will shortly discharge, however, in a predetermined interval of time, thus causing the potential of the grid 21-1 and the anode 212 of triode 109 to returnto their initial values and accordingly end the cutoff pulse to the cathode 225 of the beam position switching tube. However, because of the inductors 50 through 59, resistorsfidthrough 69, and capacitor 273, the potential at the -armature 271 ofthe selector means 272 will become low for a long enough time atthe end of the pulse to assure that a newly formed beam is directed to that spadedesignated by the selected one of switch contacts 250 through 259.

The pulse standardizing circuits within the dotted lines 234 and 235'are similar and thus will be discussed to gether. It will be noted that the grid 104 of triode tube section 101 is connectedby way-of the diode 115 through one of the

resistors

30, 32, 34, 36, and 38 to each of the even numbered target electrodes. Conversely, .the grid 125 of the tube 123 of the pulse standardizing circuit withingthe dotted line 235 is connected by diode 121 to the odd numbered target electrodes through

resistors

31, 33, 35, 37, and 39. Since the even numbered target electrodes and the odd numbered target electrodes are all connected together through separate load impedance devices comprising either inductor 310 and resistor 311 r inductor 312 and resistor 313, and further since the electron beam at ,any one time will ,be impinging upon only one target electrode, only one of the grid electrodes 104 or 125 will be at a low potential due to the electron beam impinging upon one of the targets, and other grid will be a relatively high potential, Assume that the electron-beam is impinging upon an even numbered target electrode such as 10. Under these circumstances the grid 104 of tube 101 of the pulse standardizing circuit within the dotted line 234 will be held at a relatively low potential. Both grids 104 and 125 are normally below plate current cut-ofi value because of the -15 volt bias potential coupled thereto by resistors 113 and 122 respectively. The potential of the grid 125 of the tube 123 of the pulse standardizing circuit within the dotted line 235 however, will be relatively high and will be closer to the plate current conductive value so that there will be a plate current flow therein in response to a further positive pulse at capacitor 120 as derived from source 278 at input terminal 199.

When a-pulse is transmitted-from the input source 278 it will simultaneously be impressed uponboth the grid 1104of tube- 101 and the grid of tube 123. However, only the plate current. of the tube 123 will flow thereby, since the grid 104 of the tube 101 is biased sufficiently below cut-off so that the applied pulse will not raise it above cut ofi. Consequently, of the tubes 101 and -123'on1y the potential of the plate 127 of the tube 123 will'be changed due to the applied pulses from source 278. This decrease in potential of the plate 127 will cause a current flow through the winding 280 of the transformer 131. This current will induce a voltage in the winding 281 of such a polarity that a positive pulse will be applied to the grid129 of the other tube section 124. 'The tube 124 is ordinarily in a non-conductive condition because of the -15 volt grid bias potential at resistor 137. The positive pulse causes the tube 124 to conduct in the manner: of other vwell known'blocking oscillators and produce a single output pulse at lead 237, which, is applied to the even z-switching electrodes .222 through capacitor. 282. zThiS pulse output will causethe electron beanrto advance from the even numbered target ;elect r,ode10 to the: next odd numbered target electrod 11 which conversely will cause .the'grid 125 of the triode ;tube 123 tobecome-biased-below cut-off and the grid 1.04 of triode..tub e*1011 to become biased so that: asucwill, be caused to, generate a pulseat-itsanode 106 which will-be'applied -totthe-odd control grid electrodes 223 t;.throughtthe lead 236 and capacitor-2 83.

The

cathodes

103 and 108 of

tubes

101 and 102 are connected to;=ground,--potential directly and through resistance -116'respectively. Likewise the

cathodes

126 and 128 of

tubes

123 and 124 are connected to; ground potential directly and through'resistance: 13,6 respectively.

"In the outputpulse forming circuit within the dotted 'line 1274, thegrid154of tube .152 is connected for receiving aninput-@pulsefromthe armature 141 of-the :selectorswitch276. -When the armature is-making contact with one of thecontact buttons 142 through 151, the grid electrode 154 :will be -at the potential of a corresp n ing r e e ec r de '1 hro O ly e resentative leads are shown connected forpurpose of, circuitsirnplicity, butyeach switch contact-iscoupledto a corresponding target. If the electron beam is not impinging upon a, particular selected target electrode, the potential of the grid-'154 will behigh at about groundpotential and the tube 152 will be in a conductive condition. Thus, theplate T'Will be at a potential considerably lower than that when the potential of the grid 154 is lowered to the value of a target electrode having vthe electron beam impinging thereon. At its high value plate current is reduced, and by-means of a circuit extending through diode158 a. positive signal is conducted to tube 166. The normal condition of tube 166,.when

an electron beam isnot impinging on a target electrode connected to a contact means of selector means 276 with which the armature 141 is making contact, is cut-off because of'the 15 volts bias applied to grid 167 through resistors .161, and 162. ,Whenthe plate 155 of'tube152 isin its high condition: the potential of thegrid 7167' of tube .166 which is connected thereto through'the diode 158 is brought near ground potential. This-will cause thetube 166-to become conducting in response toafur ther synchronizing pulse of positive polarity; applied by 'of the target electrodes.

lead 291 and capacitor 160 from input source 278. The synchronizing pulse itself is not of sufiicient amplitude to cause tube 166 to conduct, but does serve to'assure that the output pulse is timed with the input source for synchronous operation therewith. The tube 166 is bas- 5 ically a pulse amplifier. The output pulse is not referenced to any direct current level because of transformer 180, but will appear as positive at the upper terminal of the double pole double throw switch 185. Thus, an output pulse of either polarity may be taken from terminal 275. It is to be recognized that the hereinbefore described ring-count action necessitates a positive pulse at lead 277, but for other output conditions a negative pulse might be convenient. Diodes 181 and 184 serve to shape the pulse and isolate the circuit from an external load, re'-' circuit of Fig. 1 is made hereinafter with the assumption that it is desired to have the electron beam cycle from the 3 position target electrode, through the intervening target electrodes to the 8 position target and then directly back to the 3 position target electrode to begin the cycle again. selector means 272 is set to'make contact with contact 253 which is connected to the 3 position spade electrode 23 through resistance 43. The armature 141 of the scale selector means 276 is set to make contact with the contact 150 which is connected to the 8 position 5 target electrode 18. a

The electron beam may initially be impinging upon any In order to start the electron beam upon the 3 position target electrode the manual reset button 196 is depressed thus closing the lower con- 40 tacts and permitting the capacitor 198 to produce a reset pulse. This pulse is impressed upon the grid 214 of the tube 208. This results in a positive pulse at the plate 212 of triode 209 which is connected directly to the cathode 225 of the beam position tube and also to the arma,

ture 271 through the capacitor 273. This pulse applied a to the cathode 225 of the beam switching tube will extinguish the electron beam. The pulse applied to the armature 271 can be traced further through the contact 253 and the resistance 43 to the spade electrode 23. The potential of the spade electrode23 will, when the pulse is first applied thereto from the pulse standardizing circuit 241, increase in a positive direction without effect on the beam formation. However, at the expiration of this pulse when the cathode is returned to operating potential, the potential of the'spade electrode 23 will decrease because inductor 53, resistor 63 and capacitor 273 and the spade electrode 23 will tend to assume a negative potential. The reformed electron beam will therefore be caused to flow to the spade electrode 23 due to the decreased potential thereon, and will be locked into position because of beam current through resistor 43."

When the electron beam impinges on the spade electrode 23, it also impinges on the associated 3 position target electrode 13. The target electrode 13 is an odd 65 numbered target electrode and all 0tv the odd numbered target electrodes are connected to a common bus bar 288 which in turn is connected to the grid 125 of tube 123 through the asymmetrical device 121. Thus, the grid 7 125 of tube 123 is biased well below plate current'cutoff' value. On the other hand, the grid 104 of the tube 101 which is connected to the even numbered targetelectrodes through the asymmetrical device 115 is biased only about ten volts below cutoff. Thus, when a thirtyvolt positive pulse is impressed uponthe grids 104 and 12 5;

Each of the neon tubes has one of its -20 The armature 271 of the reset 30 of tubes .102 and 123 from the input pulse source 278,

the grid potential of tube 123 will not be raised above the plate current cutoif value but the. potential of the grid 104 of the tube 101 will cause the tube to form a pulse. Consequently, there will be a negative pulse generated at' the .plate'106 of tube 102 and transmitted to the odd numbered switching grid electrodes 223 through the conductor 236 and the capacitor 283. No corresponding pulse will be transmitted to the even numbered control grid electrodes. When the pulse is applied to the odd numbered switching grid electrodes 223, the electron beam will be caused to advance from the odd numbered 3 position target electrode 13 to the even numbered 4 position target electrode 14. Thus, when the electron beam impinges upon the target electrode 14 conversely the potential of the grid 104 of the tube 101 is decreased to a value far below cut-oil since the grid 104 is connected to all of the even numbered target electrodes by diode at bus 287. The potential of the grid of the tube ,123 is similarly increased to a value just below plate current cut-oflf potential. When a positive pulse is now applied simultaneously to the grids 104 and 125 of

tubes

101 and 123 from source 278 there will be a negativ'e'output pulse generated at the plate of the tube 124 which will be impressed upon the even numbered switching grid electrodes 222 through the conductor 237 and the capacitance 282. This will cause the electron beam to advance from the even numbered target electrode 14 to the odd numbered target electrode 15 which will produce the same conditions with respect to the pulse standardizing circuits 234 and 235 as when the electron beam was impinging upon the odd numbered target electrode 13. Subsequent pulses from the input pulse source 278 will cause the electron beam to continue to advance along consecutive target electrodes until it reaches the "8 position target electrode 18.

a As has beendiscussed hereinbefore, the electron beam will be'impinging simultaneously upon the 8 position target electrode 18 and also upon the 8 position spade electrode 28. *Thus, the potential of target electrode 18 is low and is impressed upon the grid'154 of the triode tube 152 through a circuit extending from the target electrode 18, the conductor 269, the contact button of the scale selector means 276, armature 141, the parallel combination of resistance 139 and capacitor 140 to the grid 154 of the triode 152. The plate current of the triode 152 is cut-off thereby and the potential of the plate 155 thereof is caused to increase to ground potential by action of the diode 159. Under these conditions the controlgrid 167 of the pentode 166 can rise to conduction potential in the presence of a subsequent trigger pulse at input terminal 199. Howeven-until target 18 becomes 'low, the tube 152 is conductiveand the 214 of the triode 208. This'pulse is of the proper magnitude-to generate a pulse at the plate 212 of tube 209 in a manner described hereinbefore which will cause the electron beam to impinge upon the 3 positiontarget electrode 13 in the same manner as described at the beginning of the description of operation. Thus, a variable scale count is eltected with a reset to any desired tube compartment from any other desired tube compartment. V V

It. is to be observed that the pulse from the input source 278 that caused the electron beam to go from the 8 position target electrode 18 to the 3 position target electrode 13 is the same pulse that would cause the elec-C tron beam to advance to the 9 position target electrode 19 from the 8 position target electrode 18 with the scale selector 276 set for decimal counting, However, due to the fact that the pulse transmitted from the circuitry within the dotted line 274 in turn causes a pulse to be transmitted from the circuitry within the dotted line 241 of the cathode 225 to cause the electron beam to be cut-off, the time required for a pulse to be impressed upon the cathode 225 and cause the beam to advance is longer than the time required for the electron beam to advance from one target electrode to another target electrode in the intermediate steps. Consequently, the counter speed is lower when the reset feature is used than when the tube is used for freely counting in a repetitive closed loop established by tube electrodes alone.

If at any time during the operation of the device it is desired to reset the electron beam to the position selected by the selector means 272 such a function can be obtained in one of the three hereinbefore described methods. Assume that the selector means 272 and 276 are set for counting from 3 to 8 and that the electron beam is impinging upon the 6 position target electrode 16. If now a positive pulse is applied to the remote reset terminal 189 from the external pulse source 295, the grid 214 of the tube 208 will be caused to become positive which will generate a positive pulse at the plate 212 of tube 209 in a manner described hereinbefore which will cutoff the electron beam and further will cause the potential of the "3 position spade electrode 23 to be sufficiently negative at the termination of the pulse from the plate 212 of tube 209 to cause the electron beam, when reformed, to be in the 3 compartment.

Likewise, if the manual reset switch 196 is depressed to close the lower contacts, the capacitor 198 will discharge to transmit a pulse through diodes 193 and 190, and capacitor 205 to the grid 214 of the tube 208 to similarly cause the electron beam to be turned off and then be reformed on the 3 position target electrode.

Novel features and advantages contributed by the invention are to be recognized from the foregoing detailed description of its organization and operation. Those features believed descriptive of the nature and scope of the invention are therefore defined with particularity in the appended claims.

What is claimed is:

1. A resettable variable scale counter system comprising in combination, a multi-position magnetron beam switching tube having a plurality of output target electrodes each defining beam receiving compartments for one of the beam positions and beam holding electrodes connected for holding the beam in position in each compartment, inductance means coupled to the beam holding electrodes for selectively forming the beam in any particular one of said compartments in response to a positive electronic signal and means for selectively cycling the beam from any chosen one of said compartments directly to the compartment at which the beam is formed and successively from one compartment to another to the chosen one of said compartments in response to successive input pulses, the latter means including a feedback loop from the chosen compartment to the particular compartment at which the beam is formed.

2. A system as defined in claim 1 wherein the system includes an output circuit having a triggered pulse forming device in said loop, and separate output circuits from each of the target electrodes.

3. A system as defined in claim 1 including means for stepping the beam successively from one position to the next in response to successive input pulses comprising switching electrodes in said tube, a pulse forming device responsive only to a combination of internal signals derived from the beam positioning upon an electrode and an external trigger signal, and a circuit coupling said pulse forming device to selected switching electrodes.

4. A resettable counter system having a multi-position magnetron beam switching tube with a cathode and a beam forming electrode comprising in combination, means for passing a positive pulse simultaneously to the cathode and beam forming electrode, the circuit parameters being selected so that the pulse amplitude at the cathode is sufficient to extinguish the beam, and inductance means responsive to the expiration of the positive pulse to cause the beam forming electrode to pass into a negative excursion, whereby the beam is reformed at the beam forming electrode.

5. Means for providing a number of consecutive beam positions in a multi-position magnetron beam switching tube less than the number of consecutive electrode positions available in the tube comprising, in combination; an equal number of beam forming, beam switching and beam receiving electrodes respectively disposed in corresponding beam receiving positions in said tube; means coupled to the beam switching electrodes to step the beam from one consecutive position to another, means coupled to one beam receiving electrode to produce an output signal pulse, means coupled to one beam forming electrode in a non-adjacent beam position to said one beam receiving electrode to reduce the beam forming electrode potential in response to said output signal pulse, and means coupled to said tube to extinguish the beam in response to said output signal pulse during a time period expiring While the beam receiving electrode potential is still reduced by the etfect of said output signal pulse.

References Cited in the file of this patent UNITED STATES PATENTS 2,137,262 Bowman-Manifold Nov. 22, 1938 2,222,943 George Nov. 26, 1940 2,361,766 Hadekel Oct. 31, 1944 2,488,452 Van Overbeek Nov. 15, 1949 2,620,454 Skellett Dec. 2, 1952 2,706,248 Lindberg Apr. 12, 1955