Патент USA US2405070код для вставки
July so, 1946.‘ L, TONKS Em - 2,405,070 SQUARE WAVE PULSE GENERATING SYSTEM Filed Feb. 23, 1942 Fig. I. ' ’ /0 TRANSMITTER \(l? 3a ' ‘ 3 7080/7195”, sauna: 1w] I) 6Q ' -' 7 1/ l2 /.9 30‘ 32 ' . 1 um} _|_1 I has“; - a7 6345 F/LZED DISCHARGE DEV/CE ~ + 40.. Fig.2. ' € 75\I § TIME Inventors: Lewi Tonks, Milton Davis, JV b 3 6.5 Th ir' Attorney. Patented July 30, 1946 2,405,070 UNITED STATES PATENT "OFFICE. ' 2,405,070 , SQUARE WAVE PULSE GENERATING SYSTEM Lewi Tonks, Schenectady, and Milton Davis, Al plaus, N. Y., assignors toGeneral Electric Com pany, a corporation of New York 7 Application February 23, 1942, Serial No. 432,010 5 Claims. v (01. 250-37) 2 1 Our invention relates to pulse generating sys tems, particularly to such systems employing 0 than the pulse provided by the latter system. In accordance with our present invention this ob ject is attained by the provision, in a system spark gaps as switching mechanism, and the gen eral object of the invention is to provide improved systems of this character which produce pulses such as disclosed in the above-mentioned appli cation, of an auxiliary spark gap switching means so'arranged as to terminate the transmission at a relatively high rate, and operate at a high charging voltage, and which supply a large value of instantaneous power with a high order of pre cision of sparking of the switch means proper. In pulse generating systems for supplying in line-formed pulse abruptly apredetermined rela tively short interval of time after the initiation of the pulse by the main spark gap switching f means. The novel features which are considered to be characteristic of our invention are set forth with stantaneous high power at a rapid rate which have been proposed and used heretofore in an extended range of applications, di?iculties have been encountered in obtaining pulses of the re quired power and repetition rate and at the same‘ time with the desired timing accuracy. In‘v a copending application S. N. 432,009, ?led February 23, 1942, and assigned to the same as, particularity in the appended claims. Our in vention itself, however, both as to its organiza tion and method of operation together with fur ther objects and advantages thereof may best be understood ‘by reference to the following descrip tion taken in connection with the accompanying signee as the present application, a pulse gener drawing wherein Fig. 1 is a diagrammatic repre ating system" is described wherein these disad-I 29 sentation of a pulse generating system in which our invention has been embodied, and Fig. 2 illustrates a voltage pulse produced in accordance vantages are overcome by the provision of a pulse generating apparatus in which a charged capac itive storage element is connected to a load by with our invention. , ' ' In Fig. 1 the numeral 1 designates a capacitive a spark gap assembly providing two spark gaps in series, and in which a- predetermined initial 25 element adapted to be charged periodically from an alternating current source through a trans apportionment of the voltages across the two former 2, a recti?er 3 and an inductance 4 shunt gaps is changed or disturbed at the desired trig edlbya resistor 5, and to be discharged during gering instant thereby to cause breakdown of the the reverse period of the current source through spark gaps and to initiate the discharge, through 30 a load element such as a resistor 6, across which the load, of a pulse from the storage element. may be connected a desired output or utilization ’ An alternating current source is arranged to circuit 1. For example, the pulses from the re charge the storage element at each cycle through sistor 6 may be supplied to radio apparatus or a recti?er, and during the interva1 at each cycle the like employed to transmit high-power signals, when the voltage of the alternating current source is reversed the spark gap switch means is 35 rapidly repeated, and accurately timed, and of short duration. For illustrative purposes the uti triggered thereby initiating the discharge of lization circuit is shown herein as including a the storage element through the load. The ca magnetron upon the anode-cathode circuit of pacitive storage element is of such character as which the pulses from resistor 6 are impressed to v‘produce a discharge pulse approaching a rec tangular wave form and for this purpose is con 40 and which is connected to an antenna to trans mit therefrom rapidly-repeated and short-dura stituted by a section of a suitable transmission tion pulses of intense microwave radiation utilized, for example, in the detection of distant objects. The capacitive storage element l is constituted line. The initial apportionment of the voltages is disturbed or changed to initiate the discharge by reducing, close to zero, the potential initially impressed on one ‘of the conductive electrode ' by a section of transmission line of such char acter that the discharge therefrom approximates members which provide the two spark gaps. The reducing of the potential close to zero is accom a rectangular wave form. plished ‘by pulsing positive the control electrode section comprises a‘ plurality of condensers 8, preferably at least live in number, connected in of a space discharge device normally in cut-off parallel, with one-side of each connected to a common lead 9 and with the other sides of ad condition connected to the electrode member, the conduction periods of the space discharge device being synchronized, through timing means which may comprise a multivibrator, with the frequency jacent condensers connected by inductances 10. To discharge the storage element I through the load 6 a main switching means is provided comprising three spark gap members or conduc~ of the alternating current source which charges the storage element. ‘ p . .- . l » tive electrode members ll, 12, and I3 providing In certain uses of the pulse generating system above described it has been found to be highly desirable'that the pulse discharge through. the load from the capacitive storage means be of a more nearly perfectly rectansular wave form. The transmission line two spark gaps i4 and I5 in series with the stor age element l and the load 6. The voltages ini tially impressed across the spark gaps I4 and I5 60 are preferably equally apportioned as by resistors 2,405,070 Q 4 It and IT connected respectively between member tial voltages of the gaps. To assist in determin= ing the instant of breakdown of the gaps 33 and II connected to the capacitor element I and the 34 a‘ resistance 31 is connected in shunt with one intermediate member I2, and between the inter of the gaps. The length of the gaps is such that mediate member l2 and member I3 connected to the load 3. A capacitor I8 for balancing the dis 5 with resistance 31 disconnected, breakdown of the gaps does not occur. To suppress undesired os tributed capacity of member I2 is connected be, ' ci'llations during the sparking period which tend tween members II and I2. to occur in the circuit comprising the transmis sion line I and the spark gaps I4, I5, 33 and 34, 23 of which is connected to the intermediate 10 a resistance v38 is" connected in series in the lat spark gap member I2, and the cathode 2! of ter circuit. > In operation of the system illustrated in Fig. which is connected to ground. To cause space l, the transformer 2 charges the transmission line discharge device I9 to become periodically con- } section I once per cycle through recti?er 3 and ducting, thereby to reduce periodically close to zero the potential of spark gap member I2, a 15 inductance 4. After charging is complete and during the interval when the voltage of trans means is provided to impress a positive pulse upon former 2 is reversed, the switching means con the control electrode 22 of the latter space dis stituted by the spark gap members or spark elec charge device. For this purpose aninductance ‘ trode members II to I3 is triggered, thus apply 23 included in the anode circuit of a space dis charge device 24 is provided which is connected 20 ing to the load 6 one-half of the voltage of the charged transmission line I. ' to the control electrode 22 of discharge device I3 In the absence of the auxiliary switch means to supply the positive pulse thereto. 29 the pulse voltage after persisting for a prede To initiate the supplying of the pulse from in termined period at substantially its maximum ductance 23 to the control electrode 22 of device I9 and to synchronize this pulse with the fre 25 ‘value and then decreasing, would not then drop from its maximum to its minimum value instant quency of the above-mentioned alternating cur The numeral I9 designates a space discharge device, normally in cuto? condition, the anode rent source, a space discharge device 25 of the gas ?lled type arranged to operate in a usual sweep circuit 26 is employed in connection with ly but during a de?nite, even though relatively short, time interval. The terminating or lagging edge of the pulse wave form would therefore be a multivibrator 21. Potentials are supplied to the 30 slightly sloped and the resulting wave would thus approach but not attain a square‘ wave form. control electrode of discharge device 35 from the However, with the auxiliary switch members 33 alternating current source through a transform to 32 connected into the system to provide the or 23 to initiate periodic operation of this dis spark gaps '33 and 34 in shunt with the load 6, charge device and thereby to cause negative po tentials in synchronism with the frequency of the 35’ the drop in pulse voltage occurs suddenly and the “slight slope'of the lagging or terminating edge of alternating current source to be impressed upon the pulse wave form is therefore avoided. an input electrode of the multivibrator. The auxiliary switching means 29 functions in The pulse rate of the multivibrator is thus syn~ the following manner. The gaps 33 and 34 are of chronized, by connection to circuit 26, with the predetermined frequency. The output circuit of 40 such length that they do not break down in the the multivibrator is in turn connected to the con trol electrode of space discharge device 24 to absence of means to change or disturb the initial apportionment of the voltage impressed there across by the charged line I. But when a suit able impedance, resistance 31, is connected in impress short pulses at this frequency upon the latter electrode. Danger of overloading of the anode circuit of device 23, which is liable to oc 45 shunt with one of the latter gaps a progressive unbalance of voltages thereacross occurs which cur unless the current-passing interval, or inter causes the gap to break down or ?re during the val during which current is traversing inductance pulse interval itself and at a predetermined short 23, is maintained at a small fraction of the total time interval after the initiation thereof. The time period of each pulse, is avoided since our rent-passing intervals of the required short dura 50 sudden breakdown of the gaps 33 and 34 causes the pulse voltage to drop abruptly from its maxi tion in device 24 are obtained corresponding'to mum to its minimum value. The pulse being thus the short pulses readily obtainable from the multi terminated abruptly, the lagging edge of the wave vibrator and impressed upon the control electrode form is effectively clipped, and the resulting volt of the device 24. In accordance with our present invention an 55 age pulse is of the substantially exactly rectangu auxiliary switching means, indicated generally by the numeral 29, is provided to cooperate with the lar wave form illustrated bythe curve of Fig. '2. The resistance 38 serves to damp out the oscil lation which tends to be set up, in the circuit above-described main switching means and its comprising storage element I and the spark gaps associated charging and timing elements in pro ducing a pulse of improved wave form. The 00 54, I5, 33 and 34, as a result of the short-circuit ing of load 6. The energy still stored in element I switching means 29 comprises three auxiliary when the gaps 33 and 34 ?re must be dissipated spark gap members or conductive electrode mem in some manner and if no element such as resist— bers 39, 3I and 32 similar respectively to the ance 38 is provided for this purpose a large part members II, I2 and I3 which are disclosed and described in the above mentioned application, 65 of the energy goes into the spark, and the intense oscillation in the storage element and spark cir S. N. 432,009. The members 39 to 32 provide aux cuit above mentioned interferes with the func iliary spark gaps 33 and 34 in shunt with the load tioning of the circuits of the multivibrator 21 resistor 6. The auxiliary spark gap members may included in the triggering or spark initiation pore be of smaller diameter than that of the main spark gap members II to I3 and the length of 70 tion of the system. The damping resistance 38 e?ectively prevents this interference. the gaps 33 and 34 may be less than that of the In a practical application of our present inven main gaps I4 and I5. The gaps 33 and 34 are preferably equal in length and are shunted re tion the charging circuit was powered from a 400 spectively by equal impedances constituted by cycle alternating current source, "A pulse of 125 capacitances 35 and 36 for apportioning the ini 75 amperes at 32 kilovolts which had a duration of ‘2,405,070 5 6 approximately one microsecond repeated 400 times per second, and of a substantially improved wave form as shown in Fig. 2, closely approxi mating the desired square wave form, was applied to the load 6. The value of resistance 38 ranged from 12.5 to 50 ohms. The value of load resist of said pulse to cause said voltage to drop abruptly whereby said voltage pulse becomes of substan tially exactly rectangular wave form. ance 6 was 250 ohms; capacitors 35 and 36 were .pulse at the initiation thereof rising abruptly of approximately 15 micromicrofarads each; the value of resistance 31 was 25,000 ohms; the spark from its minimum to its maximum value, then re from said maximum to said minimum value 2. The combination with means to produce a voltage pulse across a load, the voltage of said maining at maximum for a short time interval, gap members 30 to 32 were one inch in diameter 10 and thereafter dropping to its' minimum value and were provided, as in the main spark members during a relatively short time interval, of means H to l3, with airblast means (not shown) to re to cause said voltage to drop to said minimum move ionization products from the gaps after value abruptly a predetermined time interval ?ring. after said initiation whereby said voltage pulse It Was found, as the charging voltage was ?rst becomes of substantially exactly rectangular wave applied at a relatively low value and then in spark gap members providing two spark gaps in creased, that the spark gaps “! and I5 of the series, the pair being in shunt with said load and main switching means ?rst ?red alone giving, means to change the apportionment of the volt across load 6, the usual pulse having a wave form ages between said gaps. the terminating or lagging edge of which was 20 3. The combination with means to produce a slightly sloped. As a particular charging voltage voltage pulse across a load, the value of said volt was passed, however, the spark gaps 33 and 34 of age at the termination of said pulse dropping the auxiliary switching means began to ?re ir from its maximum to its minimum during a short regularly in a transition range and then regu; time interval, of means to terminate said pulse larly, clipping the lagging edge of the pulse to 25 abruptly comprising three spark gap members give the desired substantially rectangular form providing two spark gaps in series, the pair being illustrated in Fig. 2. Further increase of charg in shunt with said load, and means to change the ing voltage shortened the pulse duration until the apportionment of the voltages between said gaps limit of the main gaps l4 and I5 was reached. comprising a resistance in shunt with one of said The voltage at which clipping began, as well as gaps. the pulse duration at a given voltage, was con 4. The combination with a capacitive device trollable by suitable variation of resistance 31 and adapted to produce a voltage pulse approaching capacitances 35 and 36, and variation of the a rectangular wave form, a load, switch means length of gaps 33 and 34. adapted to connect said device to said load pro— The system illustrated in Fig. 1 embodying our 35 viding two spark gaps in series with said device invention has been described as powered from and said load, and means to change suddenly the an alternating current source, However, instead of the alternating current source a direct current apportionment of the voltages between said spark gaps to initiate the discharge of said pulse source may be employed to charge the capacitive through said load, of means to short circuit said storage element I as described in the above-men 40 load a predetermined short interval of time after tioned copending application, S. N. 432,009, said initiation of said pulse discharge to cause and in this case the multivibrator 21, together abrupt termination of said pulse thereby to pro with any initial or primary timing device con duce a pulse approaching substantially closer nected thereto, may be utilized as a timing means than said ?rst-named pulse to an exactly rec to control the positive pulsing of the control tangular wave form, said last-named means com electrode of the space discharge device 24. Fur prising auxiliary switch means providing two ther, instead of changing the initial apportion spark gaps in series, the pair being in shunt with ment of the voltages across the main spark gaps said load, two capacitances connected respective l4 and 15 by reducing close to zero the initial po ly in shunt with said last named spark gaps, and tential on spark gap member l2, the change may 50 means including a resistance in shunt with one be accomplished, as described in the above-men of said last-named spark gaps to change progres tioned copending application, by impressing a sively the apportionment of the voltages there voltage pulse on member 5 from the inductance between. 23, arranged to be raversed periodically by cur In combination, a capacitive device adapted rent from the space discharge device 24 having a 55 to 5.produce a voltage pulse approaching a rectan pulse timing means associated therewith which gular wave form, a load, switch means adapted to may include the multivibrator 21 together with connect said device to said load providing two any primary or initial timing device associated main spark gaps in series with said device and therewith. said load, means to change suddenly the appor Our invention has been described herein in a 60 tionment of the voltages between said gaps to in particular embodiment for purposes of illustra itiate the discharge of said pulse through said tion. It is to be understood, however, that the load, means to short circuit said load a short in invention is susceptible of various changes and terval after said initiation comprising auxiliary modi?cations and that by the appended claims switch means providing two auxiliary spark gaps we intend to cover any such modi?cations as fall in series, the pair being in shunt with said load, within the true spirit and scope of our invention. means to change the apportionment of the volt What we claim as new and desire to secure by ages between said auxiliary spark gaps, an oscil Letters Patent of the United States, is: lator circuit comprising said capacitive device 1. The combination with means to produce and said main and auxiliary spark gaps, and a re across a load a voltage pulse approaching rec 70 sistance connected in series in said circuit to tangular wave form, the voltage of said pulse damp oscillation therein tending to occur upon dropping from its maximum to its minimum value sparking in said gaps. during a relatively short time interval, of spark LEWI TONKS. gap switching means to short circuit said load a predetermined time interval after the initiation 76 MILTON DAVIS.