US3079528A

US3079528A - Electronic counters

Info

Publication number: US3079528A
Application number: US122780A
Authority: US
Inventors: Somlyody Arpad
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1961-07-10
Filing date: 1961-07-10
Publication date: 1963-02-26
Anticipated expiration: 1980-02-26
Also published as: GB964380A

Description

Feb. 26, 1963 A. soMLYODY 3,079,528

ELECTRONIC COUNTERS Filed July 10, 1961 2 Sheets-Sheet 1 O PuLsEs 8 I8 3o V L20 r L20 2 V, o lan/Q l// 4 H O 1 2" 8 9 CLEAR 46 Vg PuLsEs 2z FLIP FLoP l s2 vg P g'. 1

\ 88 g4 FLIP FLoP f` 8O :F g. 4 INVENToR.

HRP/,7D 30ML YODY Feb. 26, 1963 A. SOMLYODY ELECTRONIC COUNTERS Filed July l0, 1961 :Fig 2 SPA DE CURRENT 2 Sheets-Sheet 2 VC C le J+1 ELEcmoN :1:25 BEAM '-5' E Lqf 5 DYNAMIC LOAD SPADE VOLTAGE STATIC LOAD LINE IN V EN TOR.

ARP/47D 50ML YDY ttes This invention relates to electronic counters and particularly to electronic counters using multi-position magnetron beam switching tubes.

A magnetron beam switching tube is an electron discharge device which has a central cathode and a plurality of groups of electrodes surrounding the cathode, each group of electrodes comprising a position to which an electron beam may flow from the cathode and from which an output signal may be derived. Each group of electrodes includes a target electrode which is adapted to receive an electron beam and produce an output signal therefrom, a spade electrode which serves to form and hold an electron beam on its associated target electrode, and a switching electrode which is used to switch an electron beam from one position to the next. The tube also includes permanent magnet means providing a longitudinal magnetic field which operates with electric fields within the tube to control the ow and switching of an electron beam. The orientation of these tields urges an electrc-n beam in a characteristic direction with respect to each group of electrodes, and this direction is known as the leading direction.

There are many circuits known for using a magnetron beam switching tube as a counting device, and these circuits are generally satisfactory. However, in each of these circuits, the counting speed of the beam switching tube has a characteristic upper limit which is determined generally by the time required to (1) move an electron beam from one position and lock it in at lthe next position, and (2) return the spade electrode at the one position to normal operating potential so that it can properly perform its function when the beam again returns to its position. The speeds at which these operations take place is affected to a great extent by spade interelectrode capacity.

Accordingly, the principles and objects of the present invention are directed toward the provision of an improved high speed electronic counter circuit using a multiposition magnetron beam switching tube as the basic counting unit thereof.

Briey, the circuit of the invention utilizes a magnetron beam switching tube of the general type described above in a circuit in which means are provided (1) for causing an electron beam to switch from one position7 known as the J position, and lock in at the next position, known as the J+1 position, and (2) for causing the spade electrode at the J position to recover to normal operating potential-these operations occurring at high speed. In one embodiment of the invention, all of the spade electrodes are clamped at their operating potential which may be higher than the normal spade operating potential, as taught in the prior art. With the spade electrodes thus clamped, higher-than-normal current may flow to a I position and higher-than-normal leakage current may flow to a J+1 spade without causing undesired switching of an electron beam to the J+1 position. This J+1 current, in effect, primes the J+1 `spade for the next desired switching operation. A high-speed driving source is used to trigger each switching step. Thus, operation (1) above is achieved. Operation (2) is achieved by means of a source of constant current which is coupled to each spade electrode and which causes a J spade to recover rapidly to normal operating potential after a beam has switched to the J +1 position.

3,079,528 Patented Feb. 26, 1953 In another embodiment of the invention, the spade electrodes are clamped at operating potential as described above and a relatively large J +1 leakage current flows and primes the J+1 spade. The spade electrodes are arrayed in two sets, with adjacent spades being in different sets. A high-speed driver is coupled to each set of spades and is adapted to apply alternately relatively high and relatively low potentials to the sets of spade electrodes. The operation of this driver in combination with the priming of the J+1 spade provides the desired high-speed operation.

The invention is described in greater detail by reference to the drawing wherein:

FIG. 1 is a schematic representation of a circuit embodying the invention;

FIG. 2 is a schematic representation of a portion of the circuit of FIG. l;

FIG. 3 shows typical current-voltage characteristics curves of J and J+1 spade electrodes and a typical spade load line for the circuit of FIG. 1;

FK?. 4 is a schematic representation of a modiiied circuit embodying the invention;

FIG. 5 is a schematic representation of a portion of the circuit of FIG. 2; and

FIG. 6 shows typical current-voltage characteristic curves of l and J+1 spade electrodes and typical spade load lines for the circuit of FIG. 2.

The circuits described below are particularly suitable for use with the various commercially available magnetron beam switching tu-bes such as the type 6700 tube or the Burroughs type 13K-1000 switch. in actual construction, a magnetron beam switching tube is cylindrical in form, `but it is shown schematically in linear form as tube 10 in FIG. 1. The tube 10 includes an envelope 12 which contains a central lonoitudinally elongated cathode 14 and ten groups of electrodes spaced radially equidistantly from the cathode and surrounding the cathode. For simplicity, only tive groups of electrodes are shown numbered 0, 1, 2, 8, and 9. Each group of electrodes includes a generally U-shaped elongated spade electrode 1'6 and a generally L-shaped target electrode 18 positioned so that each target occupies the space between adjacent spade electrodes. Each spade electrode serves to form and hold an electron beam on its corresponding target electrode. A generally rod-like switching electrode 20 is also included in each group of electrodes and is positioned between each target electrode and the adjacent spade electrode. The switching electrodes are known as switching grids. The shield electrodes which are employed in the BX-1000 switch are not shown. Suitable means is also included in tube 10 for providing -an axial magnetic eld which is utilized in conjunction with electric fields within the tube to form an electron beam and to switch a beam from one group of electrodes to the next. The direction in which the beam is urged, that is, clockavise or counterclockwise, is always the same and is determined by the orientation of the electric and magnetic fields. The direction in which a beam is urged is called the leading direction.

Briefly, in operation of tube 10, electrons emitted by the cathode are retained at the cathode if each of the spades, targets and switching grids carries its norm-al operating electrical potential. When a spade experiences a suitable lowering of its potential, -an electron beam is formed and directed to the corresponding target electrode. The electron beam may be switched from one target electrode to the next by suitably altering the electrical potentials of a spade or switching grid. Under normal operating conditions, whenever electrode voltages are such that a beam might be supported at several positions, the beam switches to the most leading position and locks in at this position.

In the circuit of FIG. l, the cathode 14 is connected to a source of reference potential such as ground. A source 25 of positive pulses for clearing the tube 10 is coupled to cathode 14, and a similar source Si? of negative reset pulses is coupled Ito the spade, that is, the spade electrode 16 at the 0" position. Beam clearing and reset circuits for magnetron beam switching tubes are well known and need not be described in detail. The target electrodes 18 are each connected through a suitable load resistor 32 to a comomn target bus 3S which is coupled to a positive D.C. power supply Vt. In addition, an auxiliary output tap 44 is .provided at each target for connection to a utilization device such as an indicator tube, a printing mechanism, or the like.

The switching grid electrodes 24J are connected in two sets, with the grids iat the even-numbered positions in one s et and the grids at the odd-numbered positions in another set. of positive bias potential and to one of the outputs of a high-speed ip-op cricuit 46. Y

According to the invention, each spade electrode in is connected to the anode of a clamping diode G, the cathode of which is connected to a bus 54 which is coupled to a positive D.C. power supply Vs. Each spade is also connected through a suitable relatively large load resistor 53 to a bus 62 Vwhich is connected to another position, and the adjacent leading position is designated larger than Vs. Source Vss and resistor d are selected to provide a constant current source ttor the spade electrodes. In one suitable operative arrangement, Vs is about 60 Volts, Vss is about 100G volts, resistors 53 are about 1 megohm, Vt is about 80 volts, and Vg is about 20 volts.

In the circuit of FIG. l, the tube 1G operates as a counter by switching an electron beam from position to position under the control of the flip-nop circuit 46. An output current ows from each position to which the electron beam tlows. A position or group of electrodes to which an electron' beam is flowing is designated the J position, and the adjacent leading position is designated the J+1 position. In the operation of a beam switching tube, it is known that an electron beam flowing to a group of electrodes has a certain cross-sectional area and density, and, if a certain maximum density and area is exceeded, leakage electrons flow to the adjacent leading J+1 position. The spade electrode at the J+1 position receives the leakage current, and in typical prior art operation, its potential is gradually reduced to a potential at which involuntary switching of .the entire beam to the J+1 position occurs. Thus, in the past, the current in the beam had to be limited to a relatively small value.

The present invention permits the use of electron beams many times greater than in the prior art without involuntary switching occurring.

In operation' of the circuit of FIG. l and referring to the portion thereof shown in FIG. 2, it is assumed that an electron beam is `tlowing to one position, the J position, and the'bea'm is to be switched to the adjacent J+1 position. With a beam owin-g to the J position, @at all of the other positions, current flows from the Vss supply through the spade resistors 58 and the diodes 50 to the Vc supply. This current serves to clamp all of the spade electrodes except J spade at positive operating potential Vc. At the J+1 position, current I splits into two portions, Id which ows through diode 5() and Is which flows through the spade electrode. Current IsV is leakage current which is derived from the electron beam at the J position. Since the J+1 spade is clamped at positive potential Vc, it can accept considerably greater leakage current than in prior art operation without its potential being lowered and without its causing undesired switching of an electron beam. ri-hus, the current to the J position and :the resultant output current from the J target can be considerably increased over that possible in the prior an. As an example, 400 microamperes or more Each set of grids is connected to a source Vgl A can be tolerated in the J+1 circuit of the invention, whereas, in the prior ant, this current was generally limited to about 10 mi-croamperes. In addition, the J current may be about 8 milliamperes compared to 3 lrnilliamperes in prior art operation.

In FIG. 3, are shown typical static and dynamic current-voltage characteristic curves -ior the J spade and for the J+1 spade, respectively, and the load line for the spade resistors 5S. Since the spade resistors are comparatively large, vthe load line is relatively flat. The load line intersects the X-aXis at point-A and the static characteristie J curve at two points B and C. The dynamic J+1 and static J characteristic curves very nearly coincide in the vicinity of point C. The various currents which ow at the J+1 position are indicated. In eitect, the large leakage current Is which flows in the J+1 spade prebiases this spade and primes it for performing its function when the beam is switched from the J position to the J+1 position.

When it is desired to switch the electron beam from the J to the J+1 position, a negative switching pulse is applied by tne liip-op 46 to the switching electrode l at the J position. The actual switching of the electron beam to the J+1 position occurs more or less conventionally. However, the speed with which the J+1 spade charges and locks the beam in position is increased by the high J+1 spade leakage current and the primedcondition of the J+1 spade. In addition, since the J spade is connected to the constant current source, comprising power supply Vss and resistor 58, the J spade discharges rapidlyy and linearly, `and .returns to normal spade potential Vc rapidly. Thus, the J spade is quickly prepared for the return `ot the electron beam as it completes its counting cycle. This sequence is repeated each time the beam moves from one position to the next in tube 10.

A modication of the invention shown in FIG. 4 operates by means of spade switching rather than grid switching, as in FIG. 1. In spade switching, the switching pulses which drive the beam switching tube 10 are applied .to the spade electrodes 16, rather than the switching electrodes 2t). In the circuit of FIG. 4 including tube 10, the target electrodes 18 and their connections are not `shown since they may be the same as in F-IG. 1. The switching electrodes 20 are arranged to set a rel-atively high level of J +1 leakage current, and, in one suitable arrangement, they me connected together and to cathode potential which, in this case, is ground. v

According to the invention, the spade electrodes 16 are arranged in two sets, with the even-numbered electrodes in one set and the odd-numbered electrodes in the other set. The even-numbered electrodes are connected through normal spade load resistors '74 of about 150,000 ohms to a bus 7S which is connected to one output terminal Sil of a ip-i'lop $2, and the odd-numbered spade electrodes are similarly connected through normal load resistors 74 to a bus 84 which is connected to the other output terminal S6 of the flip-flop. The flip-hop 82 has a sui-table, high speed of operation. Each spade electrode 16 is also connected to the anode of a clamping diode 91%, the cathode of which is connected to a bus 94. The bus 94 is coupled to a positive D.C. power supply, Vc, the clamp voltage for lthe spades 16. Voltage Vc is always below the potentials applied to buses 7-8 and S4 by the flip-flop to provide the desired clamping action. Typically, in the circuit of FIG. 4, Vc may be ground potential, ,and the Iflip-flop outputs may alternate between about 2O volts and about 8O volts.

In the circuit of FIG. 4 (FIG. 5), with a beam in the J position, current I flows through the J+1 spade load resistor 74 and splits into clamp current Id which ows through diode 9i) and spade leakage current Is which iiows through the J+1 spade. As set forth above, the switching grids 20 are arranged so .that the J+1 leakage current Is is relatively large. Again, since'Is may be large, the current to the J position-may be large. Witha beam in the J position, the llip-op 82 is in such a state, and it is so designed, that a =rst low potential is present on the J spade and bus 73 and a second higher potential is present on' -the J+1 bus S4. The J +-l spade, and all of the spades except the J spade, -are clamped at potential Vc.

FIG, 6 shows the typical static and dynamic currentvoltage characteristic curves for the J and J+1 spades, respectively. FIG. 6 also shows that the circuit of FIG. 4 operates with static J and dynamic J+1 load lines which are parallel to each other and intersect the X-axis at different places, A and A', determined by the two flip-flop output potentials. As in FIG. l, the relatively large J+1 leakage current Is primes or prebiases the J+1 spade and prepares it for the switching operation and for its function of locking the beam in position.

The switching operation is initiated by a change in state of the flip-op, and, when this change occurs, the potentials on the

buses

78 and 84 are quickly reversed. At this time, the bus 84 assumes the low potential, and the bus 7S assumes the higher potential. Thus, the load lines are switched, and the J+1 spade, which is in an unstable state due to the leakage current Is, quickly moves to stable point C, and the beam is locked in the J+1 position. At the same time, the J spade quickly returns to its normal operating potential Vc under the influence of the relatively high potential on bus 78. This cycle of operation is repeated each time the flip-Hop changes state, and, for all practical purposes, the counting speed of tube 10 may be as high as about 10 megacycles.

The present invention provides a counter which is relatively simple and inexpensive and which operates at speeds of at least l() megacycles. This speed is at least ve to ten times higher than speeds which were readily attainable in the past. In addition, output currents about three times greater than in the past are obtainable.

What is claimed is:

l. An electronic counter circuit including a magnetron beam switching tube having an electron-emitting cathode and a plurality of groups of electrodes,

each comprising a position to which an electron beam may ow and from which an output signal may ow;

a position to which an electron beam is ilowing being designated the J position and the adjacent leading position being designated the J+1 position;

each group of electrodes including a target electrode which receives an electron beam and produces an output signal therefrom,

a spade electrode which holds an electron beam on its associated target electrode,

and a switching electrode which serves to switch an electron beam from one group of electrodes to the next;

clamp means coupled to each of said spade electrodes for clamping each spade at a rst normal operating potential at all times except when an electron beam is flowing to it, said clamp means thus allowing considerable leakage current to flow to a J+1 spade electrode without switching an electron beam thereto from the J spade;

and relatively high voltage supply means coupled to each of said spade electrodes for quickly returning a J spade to normal operating potential after an electron beam has left it.

2. An electronic counter circuit including a magnetron beam switching tube having an electron-emitting cathode and a plurality of groups of electrodes,

each comprising a position to which an electron beam may ow and from which an output signal may flow;

each group including a target electrode which receives an electron beam and produces an output signal therefrom,

clamp means coupled to each of said spade electrodes for clamping each spade at a first normal operating potential at all times except when an electron beam is owing to it,

said clamp means thus allowing considerable leakage current to :How to a J+1 spade electrode without switching an electron beam thereto from the J spade;

and a relatively constant current source coupled to each of said spade electrodes for causing rapid charging of the J spade capacitance immediately after an electron beam has switched to the J+1 spade electrode, the J spade thus being quickly returned to normal operating potential.

3. An electronic counter circuit including a magnetron beam switching tube having an electron-emitting cathode and a plurality of groups of electrodes,

each comprising a position to which an electron beam may ow and from which an output signal may ilow;

diode clamp means coupling each of said spade electrodes to a source of normal operating potential therefor;

a constant current power source coupled to each spade electrode for quickly returning a J spade to normal operating potential lafter a beam has left it;

means coupled to said switching electrodes for causing a relatively large leakage current to flow to a J+1 spade when an electron beam is owing to a J spade,

said diode clamp means preventing undesired switching of the electron beam due to said leakage current.

4. The circuit dened in claim 3 and including a flipflop circuit coupled to said switching electrodes for causing said switching electrodes to switch a beam from position to position in said tube.

5. The circuit dened in claim 3 wherein said constant current source comprises a relatively high D.C. potential source and a relatively large spade load resistor coupled between said potential source and each spaced electrode. 6. An electronic counter circuit including a magnetron beam switching tube having an electron-emitting cathode and a plurality of groups of electrodes,

each comprising a position to which an electron beam may tlow and from which an output signal may ow; each group including a target electrode which receives an electron beam and produces an output signal therefrom, a spade electrode which holds an electron beam on its associated target electrode, and a switching electrode which serves to switch an electron beam from one group of electrodes to the next; means `coupled to all of said switching electrodes for causing relatively high leakage current to ilow to J+1 position when an electron beam is in the J position; means clamping all of said spade electrodes at a iirst potential which comprises a normal operating potential therefor and which allows said high leakage current to flow to a J+1 spade electrode without switching an electron beam thereto from the J spade; said spade electrodes being connected in two sets with every other spade being in the same set; a ip-op circuit; each set of spade electrodes being coupled to one of the outputs of said Hip-flop circuit whereby adjacent spade electrodes are successively at relatively low and relatively high potentials each time that the ip-op switching electrodes are connected together and to the changes state, each change of state of the flip-flop cathode of the tube, the desired flow of leakage current to causing a beam to switch quickly from the J position a J+1 yspade electrode thus being achieved.

to the J+1 position by the application of a relatively low potential to the J+1 position and a relatively 5 References Cited D the file 0f this Patent high potential to the J position, said relatively high UNITED STATES PATENTS potential causing the J spade to return quickly to its normal operating potential. 3008067 Somlyody NOV' 7 1961 7. The circuit dened in claim 6 wherein all of said UNITED STATES PATENT oEEICE CERTIFICATE 0E CORRECTION Patent No. 3,079,528 February 26v 1963 Arpad Somlypdy It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. y

Column.. 3, line. l,O..\Y for "eomomn" read .Common line 20, for "cricuitf'uread circuit g line 27, strike out "position, andy .the adjacent leading position is designated and insert instead positive D. Ce power supply Vss which is considerablycol-umn line 477 for "spaced" read -Y- spade Si.g.ne.d..,.and sealed this 24th day of September 1963.

SEAL) ttest:v

ERNEST W. SWIDER DAVID L' LADD Attesting Officer Y Commissioner of Patents

Claims

1. AN ELECTRONIC COUNTER CIRCUIT INCLUDING A MAGNETRON BEAM SWITCHING TUBE HAVING AN ELECTRON-EMITTING CATHODE AND A PLURALITY OF GROUPS OF ELECTRODES, EACH COMPRISING A POSITION TO WHICH AN ELECTRON BEAM MAY FLOW AND FROM WHICH AN OUTPUT SIGNAL MAY FLOW; A POSITION TO WHICH AN ELECTRON BEAM IS FLOWING BEING DESIGNATED THE J POSITION AND THE ADJACENT LEADING POSITION BEING DESIGNATED THE J+1 POSITION; EACH GROUP OF ELECTRODES INCLUDING A TARGET ELECTRODE WHICH RECEIVES AN ELECTRON BEAM AND PRODUCES AN OUTPUT SIGNAL THEREFROM, A SPADE ELECTRODE WHICH HOLDS AN ELECTRON BEAM ON ITS ASSOCIATED TARGET ELECTRODE, AND A SWITCHING ELECTRODE WHICH SERVES TO SWITCH AN ELECTRON BEAM FROM ONE GROUP OF ELECTRODES TO THE NEXT; CLAMP MEANS COUPLED TO EACH OF SAID SPADE ELECTRODES FOR CLAMPING EACH SPADE AT A FIRST NORMAL OPERATING POTENTIAL AT ALL TIMES EXCEPT WHEN AN ELECTRON BEAM IS FLOWING TO IT, SAID CLAMP MEANS THUS ALLOWING CONSIDERABLE LEAKAGE CURRENT TO FLOW TO A J+1 SPADE ELECTRODE WITHOUT SWITCHING AN ELECTRON BEAM THERETO FROM THE J SPADE; AND RELATIVELY HIGH VOLTAGE SUPPLY MEANS COUPLED TO EACH OF SAID SPADE ELECTRODES FOR QUICKLY RETURNING A J SPADE TO NORMAL OPERATING POTENTIAL AFTER AN ELECTRON BEAM HAS LEFT IT.