Патент USA US2409459код для вставки
Patented Oct. 15, 1946 2,409,457 UNITEDl STATESl PÀTENT OFFICE4N George L. Usselman, Port JelïersomN. Y., assign ’ or to Radio Corporation of America, a corpo ration of Delaware Application February 21, 1944, serial No. 523,232 9 Claims. 1 (Cl. 179-1715) 2 . This application Concerns timing modulation capacitive branch on the other side of the said point at which the tank circuit is grounded. The cathode of Vl is grounded, and thus the connec tions are such as to operate’ the anode and grid at opposed radio frequency potentials to make use of regeneration in the production of oscillations systems and more exactly systems for generat ing wave energy and controlling or modulating the ¿timing of the generated wave energy as de sire . " Many systems for‘this purpose are known in the radio art, and the general object of this when the electrodes are provided with operating Y application is improved `wave Vgeneration and wave length control. ‘ î ` potentials. ` . The anode I4 and grid I6 are coupled in a ` A more speciñc object of the present inven 10 tion is to provide a more simplified and more efficient arrangement for generating wave en ergy and controlling the Wave length thereof, similar 4manner to the inductive branch LI of the tank circuit. This coupling includes direct ’current blocking and`~coupling condenser `-I8. Here again,- for reasons‘pointed out above in con which arrangement uses a relatively small num ber oi tubes and circuit elements. I nection with tube VI, oscillations are generated in the tube V2 Whenfoperating potentials are sup-' An additional object of this invention is an arrangement as described in thepreceding par plied tothe tube electrodes. _ ` " Anode potential is supplied to the tube‘Vl agraph such that theA generated wave energy is . through choking inductance CH and to the tube controlled as to timing through a considerable range without causing undue undesired amplitude V2 through a part of the inductance LI. Biasing potential Vis supplied to the control grids I0 and I6 byïv'irtue of current (due to‘grid rectifica modulation thereof. ` ` » ` ‘ ‘ ‘ The manner in which the Vabove objects and other objects, which, appear hereinafter, are at-.» tained will be >apparent from the description which follows and therefrom when read <in con-1 25 tion) in resistances Rl and R2 or the same sup nection with the attached drawing. both branches ofthe tuned circuit and at the same time ï‘ prevent split tuning of the tank cir cuit. That is‘to prevent the upper and the lower halves ofthe circuit `from tuning separately. , l .l ` Figs. 1 and` 2 each illustrate diagrammatically by‘circuit connections the essential elements of a timing modulation systemarranged in accord plemented by potentialfrom the source B. The purpose of resistor R3 'is to make it possible to provide an RL‘fF, ground for the> center pointfof ance with my invention. The two embodiments 30 The anodes of tubes VI and V2 are both con are substantially the same, except that in the 'em nected to `the tank circuit on the same side of bodiment of Fig. l triode tubes are used ingthe the ground connection, as are the grids of these circuits, Whereas in the embodiment >of Fig. 2 tubes, so that the tubes operate in parallel using multi-grid tubes-are used.- `In the embodiment the same tank circuit. ‘ oi Fig. 1 the control of thegtimîng of the gen 35 y'I'he oscillation generating tubes Vl and V2 also erated oscillations is by way of control grid elec have as a functionimodulation or control of the trodes, Wlfiereas` other grid electrodesare used for timing of the oscillations generated. The imped-` this purpose inFig.2. „ ance between the anode and cathode of tube VI In Fig. 1 of the drawing, the tank-.circuit com prising an inductive branch LI and a capacitive branch Ci,»C2,.C3, is connected in an oscilla f v f «j ` '„ isv connected‘across Cl and constitutes a variable resistance `tapped across this condenser Cl, which tion generating circuit-includinggtwo tubes Vl and V2. In `the embodiment shown, the tubes and determines in part the frequency of the oscil- ' may be considered as inl parallel in4 the oscil The tube V2 has its output impedance coupled lation generating circuits, and the arrangement is also such that each-of the tubesper se may is a portion of the total tank capacitive reactanoe. lations generated. _ 45 across a’ portion of the inductive branch Ll of the tank‘circuit so that this> tube output imped be considered as a separate generator having l ance constitutes avariable’resistance tapped as a tank circuit Ll, Cl, JC2,and C3... However, the tank circuit is common,„so ‘that `the tubes tapped across" al portion of the total tank induc-V across a part` ofA Ll which is equivalent to being 50 tive rèactance which also determines in part _the frequency' “of the 'oscillations generated. It is _known that if a resistance istapped across a portion of any reactance the total effective reac a coupling?` and blockingfoondensera I2f`tofthel 55 also produces a variation in the total reactance. operate .In theinarrangement, unison. the > anode l _ 8 of VI ` isg cou pled tothe capacitive leg at a point on one side of the point at which the tank circuit is grounded. The control grid VIll of this tube is coupled by tance is changed. A variation of this resistance1 2,409,457 4 3 Where the reactance is used in an oscillation gen capacitive reactance between the control grid 6 erator circuit as is the case here, this causes a and the cathode in tube VI. L3 serves a similar purpose in connection with tube V3. L4 is of a value such as to balance out the capacitive reac change in frequency of the oscillations generated. In my arrangement I have the variable re sistances, i. e., the outputs of V! and V2 tapped Cl tance between the anode and cathode of tube VI. across a portion of the reactance in each leg or Inductance L5 serves a similar purpose in the cir side of the parallely tuned tank circuit. 'I’hat is, cuits. of tube V2'. The advantage of cancelling the ‘tube capacities at thegoperating frequencies is that there remains only the resistive component one tube’s loutput is tapped acrossa portion of the capacitive reactance and the other tube’s output is tapped across a portion of the inductive' reactance of the tuned circuit. If bothpfthese vof the tube impedance which is the one I vary to produce the frequency modulation. The tube capacitive reactance does not vary and therefore lproduces no'useful modulation. It may cause dis tube resistances are alike and are tapped" across the same proportion of the totalgreactance of the two branches of the tank circuit, the :frequency to which the tank circuit is tuned is not changed. This is because the increase in capacitive reac tance is accompanied by a decrease in inductive reactance and vice versa, so that in general-the tuning of the circuit is unchanged. As long as these resistances remain equal, though they be 'tortio-n4 by lunbalancing the modulator circuit. Thereforeit is Wi'seito cancel it out. In the embodiment of Fig. 2, the control grids 8 and IB are biased by the potential drop in re sistances Rl and R2 caused by current flowing in the grid circuit due to grid rectification. The in 20 ductances L4 and L5y serve as anode direct cur varied, the tuning of the circuit remains un rent'Y supply circuits for the tubes VI and V2, changed. However, if _one resistance be changed, while the inductances L2’ and L3 supply the bias forexampleby changing the current in one tube, potentials to the grids of tubes VI and V2. In both embodiments the reference character or ifboth tube resistances be changed in oppo site=sense,.for example, by changing-the currents in both tubes in oppositesense, then the tuning BP has beenapplied to radio frequency bypassing condensers, the function and connection of which frequency of the tank circuit is changed. 'll-he arrangement including tubes Vi.- -andV2 and thejtank circuit is, as'stated above, an> oscil are so well. known in the art as> tol hardly need discussion herein. In Fig. 2, 24 and 25 are high frequency coupling and direct current blocking _lation generator. Since thetube output imped condensers. ances are connected» across portions of the tank reactance as explained.v in detail above, and are guency bypass condenser. 2`8- is a modulation potential fre _arranged for differential individual amplituue In both embodiments the connections between the tank- circuit andthe anode and grid of either modulation-*the timing of the oscillations gener ated is modulated and the arrangement is a timing point at which the tankcircuit is ground or neu modulation System, v » ' tube Vi, V2, maybe reversed with respect to the tral withoutl changing the operation of the fre quency'modulation. This is obvious because the , _» =If-thetubes Vl andVZ aresimilar andare _sym tube arrangements would still be such as to pro metrically tapped onzthe reactive legs the timing vide'r regeneration therein. The oscillator tubes modulation» »characteristic isV 5 symmetrical ' above and'k below ai mean carrier frequency. Both tubes 40 might then be considered as being `coupled dif~ Viaud; V2 deliver their generated energy to the ferentially tothe tank circuit. Same tank-circuit `and the fact that both ytubes In thepmodiñcation of. Fig. 2, a frequency shift of'255'kc. was. obtained at a carrier frequency of arediiïerentially modulated in amplitude assures that amplitudefmodulation is balancedfout of the 45 output signal'. „Y 3188 kc. I ». ¿the embodiment of Fig. 1, the tube output resistancesand currents are varied by differen claim: ` ' v Y Y 1. In a wave-generating and- Wavel length mod ulating system, a capacitive element and an in tiallyV varyingl the tube grid potentials. A change ingridpotential'in the positive direction increases ductive element, a `discharge device having an anode', aV control grid and acathode,y connections the .anode .current andthereby decreases the tube « resistance. The „effect of this on say the capaci regeneratively coupling the anode, control grid, tive'branchisrto increase thecapacity. The effect including atïleast a part of one of said elements and-cathode of `-said- device in ay circuit for the of this on the inductive branch is to decrease the production of oscillations,ïthe arrangement be inductance;v Conversely, a change inthe grid potential -in a lnegative direction decreases the ing ’such that a part at least of said one element is4 shunted by the impedance between the anode and-'cathode of said one device, a second electron discharge device having an anode, a'cathode and anodecurrent, therebyincreasing the tube output impedance. - Theeiîect of this on say the capaci tive 'branch is _to- ,decreasethe‘ capacity and on a control ' grid,` connections including at least theinductive ’branch -to_ increase ythe inductance. a part of the> other of said elements regenera This therefore. requires that the modulation or 60 tively coupling the anode, control grid and cath control potentials are.applied‘differentially ode of the seconddevice in a circuit for the pro In the embodiment illustrated; the control po ductionof oscillations of substantially the same tentials are A„supplied from source A through a frequency, the arrangement being such that the transformer'T differentially to the control grids. impedance between the anode and cathode of ~1The`embodiment of Fig. ’2 is essentially the same as ._tlieiembodiment of Fig. 1.V In Fig. 2, however, the tubes Vl and V2' have additional gri'dsîß .andîZiiito-_which themodulationis applied diiîerentially. .by-transformerfl‘. > ' These . grids are shown as _operating at positive potentials and may be considered screen grids. _ y - ' ' said.. second; device isin. shunt toa-part at least of said other-element, and a source of- modulat ing .potentialscoupled -diiîerentiallybetween cor responding electrodes-foffsaid devices.vvvv » 2. In a wave generating and wave vlength vmod ulating system, acapacitive elementand anin ductiveelement; a pair ofdischarge deviceseach The inductance coils L2', L3, L4 andL5 are usedtofbalance out or cancel the effect of capaci havingY an anode„a,controligrid, and a cathode, tive >reactance between» the tubeelectrodes. For » elements¿regeneratively*coupling the anodes„control grids, and cathodes of said devices in a re example, L2' compensates or cancels out the connections including at leastì afportion of said 2,409,457 5 generative circuit for the production of oscilla tions, the arrangement being such that a por tion of one of said elements is shunted by the impedance between the anode and cathode of one device, anda portion of the other of said elements iS shunted by the impedance between the anode and cathode ci the other device, and a source ci modulating potentials coupled difier entially between corresponding electrodes of said devices. p 3. In a wave generating and wave length mod ulating system, a capacitive element, an induc tive element in parallel with the capacitive ele~ ment, a pair of discharge devices each having an anode, a control grid, and a cathode, con nections including said elements regeneratively coupling the anodes, control grids, and cathodes of said devices in a regenerative circuit for the production of oscillations, the arrangement be 6 5. In a Wave generating and Wave length mod ulating system, a tank circuit having a capacitive branch and an inductive branch, a first discharge device having an anode, a control grid, and a cathode, connections coupling the anode and control grid of said device to spaced points on the capacitive branch of said circuit, and cou pling the cathode of said device to a point on the capacitive branch intermediate said spaced points, thereby coupling the impedance between the anode and cathode of said device -in shunt to capacity of said capacitive branch, a second electron discharge device having a cathode, an anode, and a control grid, connections coupling the anode and control grid of the second device to spaced points on the inductive branch of said tank circuit, and the cathode of the second_de vice to a point intermediate said spaced points on said inductive branch, the arrangement being ing such that a portion of one of said elements 20 such that the anode to cathode impedance of said second device is in shunt to inductance of is shunted by the impedance between the anode and cathode of one device, and a portion of the other of said elements is shunted by the imped ance between the anode and cathode of the other device, and a source of modulating potentials 25 coupled diiîerentially between corresponding electrodes of said devices. 4. In a signalling system, a capacitive element, said inductive branch and the said electrodes of both devices are regeneratively coupled by said tank circuit for the production of oscilla tions in said tank‘circuit and a source of mod ulating potentials coupled differentially between corresponding electrodes of said devices. 6. A system as recited in claim 1 wherein said corresponding electrodes are the control' grids of pacitive element, two discharge devices each hav 30 the ñrst and second discharge devices. ing an anode, a control grid, and a cathode,l 7. A system as recited in claim 2 wherein said connections including said parallel elements re discharge devices each include a screen grid elec-' generatively coupling `the anode, control grid, trode, and wherein said screen grid electrodes and cathode of each of said devices in an oscil are the corresponding electrodes to which the lation circuit for the production of oscillations, 35 source of modulating potentials is differentially the arrangement being such that a portion of one coupled. of said elements is shunted by the impedance 8. A system as recited in claim 5 wherein said between the anode and cathode of one device, corresponding electrodes of the devices are the and a portion of the other of said elements is control grids of the devices. shunted by the impedance between the anode 40 9. A system as recited in claim 5 wherein said and cathode of the other device, and a source devices each have an additional grid-like elec of modulating potentials coupled diiïerentially trode, and wherein said corresponding electrodes between corresponding electrodes of said de are said additional grid-like electrodes. an inductive element in parallel with the ca VÍCES. ‘ GEORGE L. USSESLMAN.