US1986623A - Signaling apparatus - Google Patents

Description

Jan- 1, 1935- J. w. CONKLIN ET AL 5 IGNALI NG APPARATUS 2 Sheets-Sheet 2 Filed March 21, 1931 Pg [m LE6 J4 INVENTORS J. W. CONKLIN J. L. m2

AfTbRNEY PatentedJan. 1,1935

'H- ?S ATE s @PATENrY FricE ini -gs. (01. 250 17 This invention relates to high frequency .signaling apparatus and especiallyto apparatus wherein thefrequency ofan electron discharge device oscillator is controlled. andstabilized by the use of transmissionfllines, long, relative to the workingwave length." i In general, it may be said that signalingsystems and especially transmitting systems comprise an oscillation generator; means to control. and stabilize thefrequency. of oscillations1gen-- erated thereby, an antenna, and a transmission linecoupling an output circuit .of the generator to the antenna. Heretofore, the frequency controlling and stabilizing; means have taken the form of piezo-electric crystals and theirassociated circuits, or intricate net-works of tuned oscillation circuits, which were costly bothas to i 1 initial installation and as to maintenance. An

object'of the present invention is, broadly, the simplification of and reduction in cost of such apparatus; and, a furtherand morespecific object of this invention is to utilize the transmissionline of the combinati'on referred to for frequency control and stabilization of the system.

That is, I according to thepresent invention,

the transmission line between the antenna and high frequency apparatus is used as part of a long'line frequency controlling system such as described by us in our copending application 'on a Frequency control system, Serial Number 363,- 660', filed May16, 1929; the copending application of Clarence WpHansell on-anYOscillator, Serial Number 400,489, filed October 18, 1929; or,.such as described .by us in our copending application on Frequency control systems, Serial Number 511,210, filed January 26, 1931. i

Systems such as described in the-copending applications have been found verysatisfactory for use in connection with oscillation generators of 'theelectrondischarge device type, long lines being coupled to the oscillators so that, there-is a shift in phase of energy on the lines with a shift in frequency materially enhanced by the length of line; for, the shift or change in phase 1 between the input and output ends of the line is directly proportional to the number of wave lengths contained on the line. "Consequently, by making the line a number] of wave lengths long, there is an augmented shiftin phase with a change in frequencyfwhich jshift may be used to pull the 'oscillatorjback into step at, a fre- [quency corresponding'tothat-for which the line is the correct humberof wave lerigthSkorhalf wavelengths, long; Moreover, as the line can be constructed and. designed to accommodate large amounts of 1 power, l it can be applied directly tozthe, "final: stagesof a power amplifier, thereby making the power amplifier itstown gen-'- erator, of oscillations and: eliminating the expensesjincident to,..andi theevils concomitant with the use of a" master, oscillator such as a crystal oscillator and a longx'chain-ofamplifiers and frequency multipliers for building the 'crystal oscillator-energy. :up to a desired frequency and: value or intensity-to operate: the power 10 amplifier. gThe lines for frequencyr control, asdisclosed in the copending applications, may haveonly traveling. ,waves thereon in which case ithe lines are, termed, ,aperiodic the ,lines may have 15 standing'wavesthereon' f or frequency controlling stabilization and withsuch wavesthereon they are termed fresonant; or, thelines may have both standing: and traveling waves thereon for frequency, control of the oscillation generator to which itis coup1ed.- 1,

More specifically, in thecaseof an aperiodic 1 long line frequency control system, the line is used to couple input and output circuits of an electronjdi'scharge' device. oscillator and is terminated at the output end of the line'orthe input side wof :the device with 1 an impedance equalgin, value1to thev surge impedance of the line, whereby reflections with their accompanying standing waves on the line are prevented. The line. ismade of .such. a length that at a desired frequency, the potentials applied to the input circuit from the output circuit of the device are of correct phase, for the production of oscillations 'at ,only the frequency: for which the CAD , line'contains the correct number 'of whole half wave lengths. The aperiodic line and its action are more fully disclosedainuour "copending application Serial Numberf5363,660, filed May 16,1929 a f In the resonant long line frequency control system, the line, coupled to the oscillator;is either short circuited or open ended so. that standing waves are produced thereon. Frequency controllingactionof this system may beattributed 'to the fact that the'st'anding waves on theflinexpull the oscillator. into steptherewith, and, as the standing wavesare determined in length by the length of the line, it is clear that with a suitably" designed' line', "invariable in length, ithe frequency-{of oscillations gen erated will maintainedyery constant. 'Ifhe action and structural organization "of such a sysa tem is more" fully disclosed in the jcopending application of Clarence 'W. Hansell referred to hereinabove.

In our copending application Serial Number 511,210, filed January 26, 1931, we have described a system wherein both standing waves and traveling waves on the line are used for frequency control, the line producing a phase shift with aashift inmscillator frequency proportional to the number of "waves on the line. However,

in this system, in order to get a maximum I :Gand 8 may be varied by means of the U-shaped adjustable slides 10.

phase shift in energy between the input endof the line and output end of the line, it is necessary to place a reactor at the input-end crane line to introduce a 90 degree, phase rshift sothat the line may be fed at ateuneen axnnu x r voltage nodal point. Ref erence isgmadelto our copending application, Serial Number 511,210,

filed January 26, 1931, for ammo-complete -de= scription of the combination long line; forefree-g quency control and for a more complete descriptibn of its structurezand action.

,..itiis:a fiUI'IbhEI'mObjGCt of the present invention: to, sutilizei lthe. transmission line coupling the antenna JOf a highdrequency system" to "high frequency apparatus :as quart of one of the long line: frequency icontrolling systems hereinabove referred to for. stabilization and control of cs- 7 cillations generatedxby'the roscillating system or oscillator in'mthe high- 'freque'ncy apparatus, wherebyr'ithe entire :system is materially sirn-' plified.

Moreover, certain types f directional antennae,="-such. asdescribed by Nils E. Lindenblad in hislcopen'ding application; SeriaYNumber 304,-

445, .filed Sept. 1, 1928,- and Philip 8'. Carter in Lcopending application Serial- Number 460,- 46 7, filed J-une '11; 1-930, cOmpriSe -conductorS, long, relative to theoworking wave length, the conductors having standing waves'thereom It is a further object of the present" inventionto combine such antennae systems-with an-oscillation generator and the transmission line coupling the Jgenerator 'andthe antenna systems in order to v use "both the antenna and transmission line as part of aiilong line :system for frequency controlling and stabilizing the oscillationsgeneratedmbyra generator in the high frequencyap paratus coupled .to the antenna system-thereby still further increasing the-frequency constancy of ".the: apparatus .as-ta whole as simpli fying still further-thexenti-re signaling system. Although-ithas been-zattempted to define the present invention ithe appended'claims, it

mayehowe-ver, be best understood as to its structuraljbrgani-zation' and referring "to Figure :1 illustratesa liigh'frequency system utiiizingia transmission line between the anmethod' of operation by 'theaccompanying drawings wheretenna and high frequency apparatus as part bff an aperiodic long line frequency 'control system," Figure :2-iillustnates a similar system wherein the transmissionElzine is :used -.as part of a resonant frequency controlling-scheme, :and,

Eigu-re i1 1 illustrates; a 'tran'smission system wherein the transmission line coupling high frequency apparatus to an antenna has :both stande ingrand traveling @waves ,thereon which are used to frequency control an oscillator of the high frequency apparatus coupled to the antenna.

eferring .t.o .Eigune 1,,.-high, frequency :apparatus is ,cou'plednto a radiating, antenna ,4 thr gh;- the me i ransmissi n l es which, according to this invention, is used, as shown, to aperiodically control the frequency of oscillations generated by the high frequency system or apparatus 2. The output end of transmission line 6 not only feeds antenna 4, but through another transmission line 8, runs parallel to and supported by the same supports for line 6,; feeds the tunable input circuit .1 2 -of pushpull connected screen 1 grid electron discharge devices l4, 16. The length of the combined lines cause sustained oscillation generation at a frequency roughly determined by the tuning of the input * andoutput circuits 12, 22 and 24 for electron discharge device 14, 16 and 18, 20, and accurately fixed by the lines 6, 8.

1 That 15,101 accuratepfrequency control, feed back other than that along the transmission lines is prevented by; suitably shielding the cirwits, and, by, as already indicated, using screen grid'ztubes or bylsuitably neutralizing the devices as disclosed in our copending application Serial Number 499,642, filed December 3, 1930. -:;By suitably adjusting the lengthsof the lines bysliders 10 so that the.lines are, a suitable whole number-of jhalf wave lengths longat the desired frequency .of operation, the lines 6, 8 will feed energyto the-input circuit 12 at correct phase :condition relative tomthe high frequency output potentials on theanodes of tubes 14, 16 only:for-a frequency corresponding to that for which the linesfi, 8 ,havebeen .made a whole number of half wave lengths long.

As the .lines may be a whole number of half wave lengths long for-a number of frequencies, tuningof, theltunable circuits '12, 22, 24 associated with the electron discharge :devices to aipproximatelythe desired frequency will cause those circuits to oiferhigh impedances to energy of other frequencies. Consequently, the/entire system will oscillate only at that frequency for which'the lines' area correct number of half wavelengths "long-andfor which the tunable circuits are tuned to approximately the correct value. L In order .to'prevent reflections, the lines are terminated by suitableimpedances in the form of resistances .26, 28- equal in value to the surge impedances of ,thelines. Biasing of thej tubes may be accomplished by condenser and resist-.- ance arrangements such as grid .leak and condenser arrangements 30; 3.2, or, biasing potential'gmay be supplied, -.as ,done in connection with tubes'.18,x20,througha-suitable lead 34. Modulationsmay be introduced tot-he: screen grids of tubes 14 and 16" by the action .of modulation transformer 36 supplied from a suitable amplifier 38 and transmitter 40 =with-modulating potentials; This modulating arrangement may be replaced by other desirable schemes such as the one described more fully hereinafter in connectioniwithfEigure 3.' j

To prevent the application of anode potentials-of tubes 18,, 20 to the control'electrodes' or usual grids of. tubes, 14,. 16,..blocking condensers 42, 44 are 'inserted inflthe transmission line 6 which are made-sufficiently large so that they do .notint-roduce any appreciable phase change currents from outp,utcircuit 24, However, hem-id, cond se 2 :4 o e. any ph se I change thisimay readily beacompensatedfor by a suitable? adjustmentof. i'sliders 10. v r By'the use :ofntransmission linel6 and line 8, ani exceptionally long line may readily be 1 had which, for frequency control :offers the. :decided advantage that: r for; a i shift in oscillation freque'ncy; there is i a shift "in :phase between the input and "output endswofl-the line proportional 'to the'number' ofwave lengths contained in the line or feed' back=conductors. Consequently, any slight shift 'in frequencyds accompanied by a large phase change resulting in the rapid return to the desired {frequencyland therefore predetermined frequency A The inventin"described inFigure 1 maynot only be used in anape'riodic frequency control system, but, the transmission line coupling high frequency apparatus andan antenna may also be used in aresonantilong line frequency controlling system. Moreo'ver, certain types of ram tennae" comprising conductors which are long, relative to i the working wave length, having standingwaves' thereon, may he used in combination with 'the long line frequency control system to "give added stability to the oscillating ystem. if, T11, m

Thus, in Figure -T'there is disclosed an an tenna system comprising a numberx iof linear v conductors 50;"long, 'relative:to the working wave length, arranged in physically parallel fashion I but staggered so'that radiation occurspredominantly inthe plalne 'hfthe conductors in the direction of the arrow,'?-making a predetermined angle {with the ccncuctorsMrhe construction and action ;of'y'this antenna are more fully described the copending-applicationi of Nils E. Lindenbladalready referred to and, therefore,

i need notherebegone into ingreaterfdetail. 4A}

- In thenorrnalcons'truction of such a signaling system an impedance matching circuit-52 is insertedin the transmission line 54 but, in accordance with the presentinventidn, this impedance matching device; is omitte'd, the standing waves on the *conductors 50- beingallowed to make themselves manifest 9 the transmission lines 54-having -therein lengtlr adjusting means in i the formofu shape sliders 56.

As a consequence of the foregoing construction, by suitably adjusting the overall length of the antenna andtransmission line, standing waves ontheline 'willpull thepushpull connected oscillation generator 58 into step therewith, the frequency of oscillations of the-oscillation generator being initially "roughly or approximately adjusted to a; desired valueby adjustment of the tunable, circuits 60 after which the action of linef54= and antenna 50 will maintain accurate frequency control. i

For regenerative action, the electron discharge devices of oscillatoror generator 58 are designed so as to have sufiicient interelectrode capacity to get the desired feed back, or, ,anyof the other known means inthe art may be used for this purpose. Modulation may be accomplished by applying signal potentials to the anodes of oscillators 58 through the action of a modulation transformer 62.

From another aspect it may be said that the.

frequency controlling action of the system shown in Figure 2 is attributable to the fact that there is a phase shiftbetween the incoming and refiected waves on the line 54 of a value; proportional to the numberxof waves contained onthe antenna and transmission line. Thisphase shift production of oscillations of a constant, desired,

between the I incoming and reflected -:waves produces a desiredrz'stabilizingz effect and, by: using the transmission lineand antennaforithispurpose, a high "degree of'zfrequency stabilityfimay be obtainedlrwithout the addition of apparatus a ,ductorswand: along the. bisector ofartherajngle formed: by the conductors. 1: a-The direction of maximum radiation 1 is indicated by the arrow;

The-jantennaiscoupled; to an, oscillator: '72

through 'i a' transmission. line 17 4'; and small reactors, here in the form of condensers T16, introduce a 90 degree phase change-in energy from the output circuit of oscillator1f72 '1 fed into theuline; 74.

.Modulating potentialsfroin arsuitable source 90 may be used, as showhi;tdccontrolythe flow of current to ,electronac discharge rdevicegflz in seriesziwith 'theezoutput c'irc'uiton whichwthere is placed a resistance 94 and source of ,unidirec tional: potential 965;, Variationhin current. fiow through the fresistance 94 will cause potential variationscat the upperiijend g'thereofgnext to radio frequency. choke ,coil: 98xthereby varying the plate potential on theanodes oft the: push.- pull connected system. 72 shown; and'in turn causing modulation ofthe' output thereof. This modulatingscheme, of course,\-;may besubstitutedcin and =forthetarrangement described in connection withl 'igure l if desiredr." 1 After the relectron discharge'devices of oscillator 72 are suitably neutralized by adjustment of neutralizing condenser=78,- feed back is established thrbughtransmis'sion line '74 andftransmission line 80 having U-shaped sliders-82 therein f or length adjustment jthrough large condensers 84 -tdthetur1ab1e input Circuit 86. y

Condensers 84 should be chosen sufliciently large so that there is no appreciable change in energy fed back and are addedfor the purpose of preventing application of anode potentials to the grids of the devices forming oscillator 72 should one of the relatively small condensers '76 break down.

It is to be noted that the line 80 is not terminated by a correct surge impedance to prevent reflections. Consequently, standing waves are set upon transmission line 80 whichare enhanced by the standing waves on the antenna conductors 70. Oscillations will ensue at a frequency roughly determined by the tuning of the input and output circuits and accurately determined by the length of transmission lines 74 and 80. t i

In order to get a maximum phase shift between the; input and output ends of the transmissionlines forming thefeed back circuit, it

is desirable to feed transmission lines '74 at a voltage nodalor current maximum point. However, this will necessitate a line a whole number of half wavelengths long plus or minus a quarter of a wavelength as disclosed more fully in our copending application, Serial Number, 511,-

210, flledJanuary 26, 1931. Consequently, to

compensate ilter: the imndesii'ed 1 nuarter' :rwave lengthrmi line; mactorsxllfiiin the form of small condensersniiayeabeen inserted whichiproduce a sausage-Jermain energy .iieduinto the: lines. Therefore, at anies'ired irequencyg'th'ezphase re-. lationship' of inputzand ioutputpotentials. for the electron discharge devices; forming :theoscilla tor 72 will ipe-icorrectzandisin the event of a shift in oscillation frequencm'ftherewill be afzshiftain phase .of energy 'fediliack-pver the. lines to the inpirt side of the :oscillatoraincreased by an amount directlyxpmoportional. to the number .;of

halfi wave." lengths; on-':the: transmission lines. This shift .in vphase willtcounteract avchange :in

, trequencyizbringing=ti1e=osdiiiatonback to that her of 'shalfiwavetiengfthsilong.

fiereizagaininithisiisystem, iorcirequency control, :apparatus 'that wvould of necessity be required is used, .:and, -.1the2 line :80 ."M'rhich may. be madezt parallel etransmission linen at a relatit/elyimmor: cost, is the ronly addition required, thereby"resultingv in" a. system: extremely stable inire'quency and "inexpensive. As twill ib'eiapparentito: those skilled in the art, many iminormchanges iinxithis. invention may be frequency tor-whichithe-liner is the: correctinum made: 'Cons'equently tthe.inventionis notto be limited byithe described. but solely by the scopeofi thetiappendedlclaims. Having thus described-bur invention, what We v In: highlfrequency signaling" apparatus, an:electron dischargerdevice oscillator, an antennascomprising alplurali-ty of conductors, long, relative to the operating Wave length, a transmission line, many-haliffwaye. lengths long connected betweenisaid 2 oscillatorrand said antenna forsfeeding oscillatory energy from said oscilla tor to said antenna, the overall length of said antenna: and transmission linebeing adjusted so that manyzstanding waves atthe desired operating frequencyare set up thereonewhereby said standing'zwayes upon said antenna. and transmission f-linezcontrol and stabilize the frequency of oscillation of said electron discharge device oscillator.

1-2. In signaling apparatus utilizing alternating electrical currents, the combination of, high frelation; generator end-of .said line to ground;

whereby energy; fed ,irom' said transmission line to said .conductonandback: to said oscillation generator maintains the-frequency of operation of saidzoscillation generator substantially constant 3. In signaling apparatus-utilizing undulatory electrical currents, the-combination of high frequency apparatus including-1 a multi-electrode oscillation generator, a tuned circuit tuned approximately to. a desired frequency of operation coupled" to the outputv electrodes of said gene'raton; an antenna, and a transmission line coupling saidantenna to said tuned output circuit; said transmission line being adjusted in length so as tobe substantially a whole number of half wavelengths long at 5 a desired operating frequency and acting toiifreduency control and stabilize the frequency of oscillations generated by said oscillation, generator. Y a 4; Infiapparatus for highfrequency electrical currents, "a ,pair of pushpull connected. electron dischargedevices, a-tuned circuit connected; to theoutput electrodes ofsaiddevices, means for establishing feedback from the output circuit of said- ,device to the input circuit of said devices whereby oscillations. are generated at a JAM-ES Wl ,C N-

JAMES L.- FINCH.

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