US1490958A - Frequency-control system - Google Patents

Description

April 22 '1924. 1,490,958

- R. BowN FREQUENCY CONTROL, SYSTEM Filed Nov. 23. 1921 ,amw 0/0000 (M000 5/0000 mlm (500000 1001; mmp500000- //tb%(.600 Ilia/10:11am

INVENTOR ATTOR N EY Patented Apr. 22, 1924.

UNITED STATES 1,490,955 PATENT OFFICE.

RALPH sown, or 'rnEEnoLn, NEW JERSEY, ASSIGNOB 'ro AMERICAN TELEPHONE AND "TELEGRAPH COMPANY, A CORPORATION ornnw YORK.

FREQUENCY-CONTROL SYSTEM.

Application filed November 23, 1921 Serial No. 517,280.

T all whom it may concern:

Be it known that I, RALPH BoWN, residing at' Freehold, .in the county of Monmouth and Stateof New Jerse have in- I vented certainlmprovements in requency- Control Systems, of which the followingis a specification. This invention relates to radio signaling and .more particularly to arrangements for controlling signaling frequencies used by different stations. Theradio signaling, where a large number of signaling stations are to signal simultaneously; it. is desirable thateach pairof 16 communicating stations signal at one or more radio, f equencies, difierin from. the frequencies. \ised by all'other pairs of communicatinglstationsin order to, acid interq ferencei (Furthermore, theyarious signal-r ing stations maybedivided up into groups or systems,- depending upon the cooperation ofseveral interests controlling the system. or group-. Since but one irequency spec;

- trum isavailable to all of the partie s inter.-.- 2b ested'f it isldesi ra ble. that the spectrum be dividednp and certain ranges .oifrequencies be assigned to each group. -The organizationoperating' a given group ofstations then have available. for signaling as many' 80' channels .as can be included. within therange assigns and these channels may be individual channels fgr} individual signaling, staitions, or aplurality-of channelsmay be as signed. to a station for multiplex signalingj 3 In order to'prevent the stations of a group from overlapping in their operation. the:

range ot fre uencies assigned. to another group, lt ls BSIIElblG'tl'lELl'i some means or ,method be provided for definitely. relating W the frequencies of the various groups with: reference to each other so that a shifting of the bandof frequencies utilized by one group will be accompanied'by a corresponding;

shifting of the frequenciesutilized by other: groups. It has heretofore. been proposed to accomplish this result by generating at.

a master station one or moredundamental frequencies whichmay he radiated to the itations of thevarious groups, or systems,- the various s1 naling frequencies to be used h the individual stations of the groups being derived from the energyof the rev neived. fundamental- .frequency or. frequen- ;-cie-s hya process-of' a-mplification and f re-- qucncy translation.

-suitable apparatus for -translating the mas- This method has the obvious disadvantage that the energy to be used for signaling at the various stations isv a-function of the energy received from the-master controlling station. Consequently atany time the amount of energy to'be radiated5forsignalmg purposes by a givenstation'will do end upon the, amount off-energy radiated rom the master station andz- .upon the loss .=,of energy in transmission from thejmaster stationto thesignaling station. In accordance with the resent invention it;.i s pro osed. to generate t e energy-to be used for signaling at eachsignaling jstation so'that the amount of energy to .be used .forasig'nalin will be independent of, the amount-Jo energy radiated at themasterstationuthe frequency of the energy-generated,however, being-con trolled and determined by the frequency radiated from the.masters tation.' In other words; the methodiis such that thecontrol; exercised by; thegmaster station. is one of frequency;..-,on ly and gthe amplitude; of. the. energy. controlled;v entirely; by. -.-the local signaling station.

The" inyention. may:

; v =-now be moremfully understood -from the a following ;description: when read in connection with the accompany; ingdrawings; which-Figured is. a sche-' matic. diagram; illustrating. broadly one metho of carrying out the inyention, Fig. 21. is-a diagram of a portion ofthe apparatus at: one of thesi aling .stationseschematically' indicated in ld i g-tl, and Fig. 3 isa series. ofcurves. illustrating the operation of the con trolling apparatus. .1 T-

- 1' Referring to Fig.1; designates a-mas-. ter control station at which apparatus mayo be provided to radiate.;-,afundamental .radio frequency'ofsay-150,000 fcyples,"which;is to be picked up by the various signaling sta-E tions and translated into-.- the-particular radio frequency usedfor intercommunication between, any pairof stations. Two pairs of intercommunicating stationsr1-2 and 3-4 are schematically illustrated in Fig. 1. each pairheing typicalaof a larger group and it being further understood that in actual practice more than-two stations; may intercommunicate at t is sarne frecpienc Each station may include an apparatus schematically indicated .by-R for receiving themes ter controlling .frequenoy, together with ter controlling frequency into a frequency or frequencies suitable for the exercise of control over the-particular frequency .to be locally generatedand used for-intercommun'ication. As shown schematically in Fig.- 1, separate apparatus maybe used iii-conjunction with the receiving apparatus R for controlling the frequency generated for the localtransmitter T andv thermal-receiver R. Where a heterodyne or homodyne system is not employed hoiv'vei it 'ivill be understood that noappar atuslis necessary. for

ergj of thedifi'reireefr'eduelfey ay be im firessed a cafe; device" which is sensitive to frquenqiel eages and jtlii 's dvicfm'ey be used to govem' the rreqaeny'ef 'theTf-loc'a1 generator.

Ifi'oi-derto ri dergtafid more ially'the naturef {cr che control mechanism; 'r'ffeiiee may be had tathe appsrawsiunstret d"in Fig. 2, the app'ziratusth olwn' in thisfi 'ure being typical o'ffthe"ifichanisnidocated 'at and interconnecting mint-s lt; and or points R and B, so far as this mechanism is concerned 1 with] frequency "control. The.

antenna 10' of Figf'2j nia-y be nay Well 'lznown type'o'f receiving -ai-nter'ina 'a'ndlha 's' associated therewith a 11 0f it iell known type""for' selectingthekofitfH frequency radiated from the distant" master station. -="'I his 'fi1ter"may' be, for example, atuu edcircuit or 'ab'a nd filterof' theGa'jnpbell type.

VVhef e'the' frequenc'y to be'us'd in signaling 'difi'ers"quit'e materially from the master frequencyit'is necessary to produce a harmonic of {the "ma's'ter'ifiequeiic'y'which will be closely related infthefrequency-"spec trum to the freqi'i'e'ney which"it"isidesiied"to generate. For this purpose the selected master frequencyfi's"impressed iipen'fa harmonic producer-I2 of fill-knofixfty'pef For example, "it is now well known that flthe distorting" action of a"racuuin tube-may be' us'e'tl' to piedu 'e'l mnoniejsbf a fundamental frequency applied tube, (le

sired harmonic may be selected by suitable selecting 'means.' Assuming that the apparatus illustrated is to be used for the control of the signaling frequency at the transmitter-T of station 1 the-harmonic pro 7 liitifi appifatusllff through a transformer 1'52" l'iI modulating apparatus as 'illu'stiaite 'd isof tli'e'duiilx vacuum tube type disclosed in Carson Patent 1343307, fissu ed Ilii'n' 115 -1 920. The local generator for sup- Tier" ireiuengy to transriiitte'i or receiver, as t "e' he, may comprise for examp le an oscillator of the i'xfell ilfi'ioit ii' 'V'aE iiiiI'fi" e, se. fr.eqii'e'iicy isgebngreliaby'm tng of asiiitabh atljii's'tablciipacitv' C. Ai'coiinec-t-iorj 16 eiare oscillator O to the comrri'on path of the.

vae iurh .tubemiodulator s o 'that the ql 'eiicy 'siljiplied the oscillator 0 may with "the" harmonic frequency .d erived ffbin' fhe'iceived' 'iiiaster frequency. Aspecitil form of tiiiied circuit arrangemarge-meattam-pris ng ewe-sharply tuned c'i'rc u-i't l7 a'nr.l '18. "One'of' these ti1ned c ir-, dense-associated with the input circuit of vieuiiiff'tiib l9 and 'tlie olther With the irlp'ut' circuit-"oi i a'c'iiii'in'tube 20. The 'yacuurn-"tubes ie end'eo ar oi'rhe'dtecmr type andjeafih' includes in its 'output circuit a winding 21 or '22 'oiaselenoid arrangement foF'adj'usti'ng the condenser or capacity C.

In tl-iiez 'seiasgumed, wlierleth' harmonic frequency is 500,000 c \'cles and the freqiie'ncy generated-b the oscillator 'O is 510,000 cj clesl', 2i beatfrequency of 10,000 cycles wiltappear in the output circuit of the modifier-3r M. The tuned circuits 1? and 18":11'6 "so adjusted that the resonance peak of thepnejWil-l correspond to :1 treueen-c5 lower than 10,000 cycles and the resonance peak of the other will correspond td'ii"fiquncydii'gher than l0 .000"cycles. as il'liisfiat'ed by the cur'ves 23iand 24 of Fig. In these curves'the' 'v'ertical dotted line corresponds the normal beat frequen'oi of 10.000 cycles and atthis' frcqiwncy the curves of the two tuned circuits' 17 and 1S mferlap qiiallfi 'ti thgit the same amount of ci'ii'ient'wil'l be' s'el c'te d into'each of these tundhfircl'iits, and hy fednseqenee the same auiouiit of direct current-Twill flow in each of'th'ejc'oi-ls" 21 'zi'n'df22f Under these circumsta'r'ic'es'"t'h' plunger of thefsoleno id will occupy an intermediate position and the capacity C will be set so that the desired frequency of 510,000 cycles will be generated by the oscillator and supplied over the circuit 25 to the radio transmitter or receiver, as the case may be.

If, however, the master control frequency varies so thatits frequency becomes lower for example, the harmonic frequency supplied bythe modulator M will be lower and the beat frequency appearing in the output cireuitof the modulator-will be greater than 10,000 cycles. This will cause the current flowing through one or the other of the oscillator O. It will thus be seen that the automatic governing apparatus operates to maintain afrequency difl'eren'cesubstantially constantso that I the freq11'ency"'s1ipplied over the circuit'j25 'will vary a up and down asthejfundaniehtal frequency varies up and down; If, 'now,' 'similar apparatusbe; provided at each station itwjll be seen that the signalingfrequencies generated will vary at allstations in the same'directio'n atthe same time, and by proportionate-amounts.

It will be not'edjthat the'dontrol arrange ment described is of "such-character that thecontrol exercisedgovei'fthe condenser 'o'r" "ca Y pacity C is entirelyindependen iwf th'e amonntf 'ofenergy" ''received" by I the" I antenna" 10Lan'd is" proportionate to the yariation p'f the "master" frequency or "harmonic thereof" from the: predetermined standard; The energy locally generated is' therefore at" "all -tinies quaiititatively controllable at the station.-

*In thepreviousdescription the operation ofii the apparatus has been described for the case in which the incoming master frequency 1 changes and the 'freq1'1ency generated by the'j oscllla'tor'O is changed correspondingly. It 1 is "obvious; howev'en that if the j incoming master frequency remains cons-tant-andffor any reason the frequency"ofthe oscillator 0' should vary, the capacity 'Cfwill be'ad j justed 'to bring the fr'eque'ncybf the osci1 lator' back to normal as the changed 'fre-" quency from the"'os"c illator 0 will pass through the circuit 16 to beat with the master frequency in themodulator M.

It will be obvious that'the' general'prin ciples here disclosed may be embodied in many other organizations widely "different" from those illustrated without departing from the'spirit of the invention as defined in the following claims.

What is claimed is:

1. ln a radio system in which a plurality of radio stations are divided into groups of inter-communicating stations, each group having assigned to it a definite frequency 7 range which shall not interfere with the frequency range assigned to any other group, the method of controlling the fre-' quencies used in the various groups for signaling, which consists in generating at a 7 master station a fundamental frequency, transmitting said frequency to the stations of the various groups, generating at said station energy to be used for signaling, and controlling: bythe fundamental frequency Bl) received at each station the frequency of the locally generated ener y without controlling the amplitude of t e energy.

2. In a radio system in which a lurality of radio stations are divided into 55 groups of intercommunicating stations, each group having assigned to it a. definite frequency range which'sh'all not interfere with the frequency range assigned to any other group,'the method of controlling the frequencies used in thevarious groups for signaling which consists in generating at', a master station'a fundamental frequency-, transmitting said frequency to the stations" of the various groups, deriving from the received fundamental frequency otherj fifequencies at the several stations,'-"generating atsa'id' stations! energy 'to' be used for signaling, and controlling 'by' means of the derived frequencies the frequency of the locally generated energyfwithont' control ling' thei'amplitude thereofm j 3. 'In a radio system in"'which" a plur'al-' ity" of fradio'" stations are divided into groups i of interconimunicating stations, each group having assign'edfto it a definite frequencyf rangve which shall' not interfere with'fthe' frequency (range "assigned ft'o' any othei groum' the fmetho'd of controlling the frequencies used in'the various gr'oup's forsignalingyvhich consists' in generating at a In'a.'ster"station a fundamental frequency. transmitting said frequency to the "stat ions of-",the' various groups; generating-locally a freqfiency'tobe used' for's igpalin'g, produc- 116 ing a det'e'rminin frequency which is 1 a Q function of the difference 'het'weenthe fundamental" "frequency'{and the locally generated frequency, and-controlling the frequency of, said locally generated'frequency 120 in accordancewith said determining freuency without controlling the amplitude ter'eoff'j f 4. The methodof preventingrelative frequency changes between a plurality'of separate radio channels of con'im1.1nication involvinga plurality of radio stations. which consists in transmitting acontrol frequency to 'eac-h'of theradio' swims: involved; generating at each station energy to be used in no si -rnaling, and controlling the frequency of the locally generatedenergyin accordance with the control frequency without controlling the amplitude of the energy.

5, The method of preventing relative fre- 1 quency changes between a plurality of sepa amplitude, thereof. a

derivedrrfrequency Without. controllingrithe 6. The method of preventing-relativeifre i quency changps between a plurality; oflsepal rate; radiate anne'ls ofrcommunication volv'ingaa plurality ofz-radio stationsf-Ivhich consists in transmittinglwcontroltfreqnency toiea'chf of the radi stations.-inyo;lwed;; gencrating-'1- at; ea ch 1 radio- Station; a; local; quency; t'oebe; ?.usede;forssignaling,. producing tion vof-nthe difference between, the locally; generatedfrequency and the; 'centroli; :,r-: q1 1e.11 y,.-,andv c ntrolling the! frequency; vlof= said locally; generated fr"equency- ,in accords ance with said determining frequency withr.

out controlling they amplitude ;th er'eof:, 7; The method ofgfixing frequency ref;- lation between a. plurality of non intercom municating radio stationsqwhich cQnsists,in

transmitting toeach of saidstations a-cpntrol frequency-,i-generating'f at each station; energy to be used .in 'si nalin", and con trolling the frequency of--the ally generated energy in accordance with-the,--.con-,

trol frequency without controlling theam plitude of the energy;

8. The method of fixing frequency relation between a plurality of nonsintercommunicating radio stations whichconsistsjn transmitting to each of said stations a con-' trol frequency, deriving at each radiotsta e tion a frequency from the control frequency, generating at each station local energy to be used for signaling, and controllin the frequency of said local energy in accor ance' with the derived frequency without controlling the amplitude thereof.

v9. The method of fixing frequencyrelation between a plurality of non-intercommunicating radio stations which consists in tr'ansmittingto each of said stations a con trol frequency, generatil-ig at each radio 1-;.

tion a local frequency to be used for signal-' ing. producing 5 a determining frequency which is a function ,of the difference between the loca-llygenerated frequency andthe con--- trol frequency, and controlling the fre--- quency of said locally generated frequency, in accordance with said determining fregenerated! frequencyeto; produce a-- difference frequency,-;-and controlling. by said difi'er ence frequency; ,the frequency of: said :locally genenatedifrequehcy without controlling the mplitude'thereof, 5-. .ff 1'1.{-;-lI;i1 :flraYdiosystentdnwvhich a plurality Qi radio) stationsmre I divided into T cups of :Qmrnunicatingdstations; eac hav gvass g' ed to iitl-iaidefini e q ncy tangent-hit h shall-notintenferewith the. he. qiiencyemng z-as igneddto an ,;o'therou he method 1%reontrallingietimafreqlgnci s in; *thfin fiifiql h groups for. sign i g, wh hmn s singenerating=at a-masterf 's'taime-a (maamennaaquenm r nsmittin aidzinequeney tql-the stations-9f the Various gr0upsgenerat n it-said ationenergy-'-= th ;b is d1 fe signml n' [and Whose/8 p tude: is independent-pf; e fundamental fre quench-and .i Ql ztroll-ingaby the fundamental frequency (received at-each -station the fre qnency iofj the locallyjgenerated energy. 1 12.3 ln a radio system-m which a-gplur'ality ofr-adio stations-ate, divided into groups of rcemmuniaa ng i: sta iq "each g p having assigned; .to; {it a" definite frequency ra gecwh ch shall not interfere with-thefrequency rangoA-assigned to anyother group, the-:methOd of-- controlling the frequencies used in the various groups for signaling which consists -in generating at 4 a master stationa fundamental frequency, transmitting said frequencyto the stations of the various groups, deriving from the received fundamental frequency other- .frequencies alt-the several stations, generating atusa-id" stations-energy to'beused for signaling and whose amplitude is independent of the fundamental frequency. and controlling by means ofthe derived-frequencies the frequency of the locally generated energy -18J'I11 a radio system inwhichaplrwality of radio stations redivided into groups of inter-communicating stations, each group haying'assigned to it a definite frequency range which shall not interfere with the frequency range assigned to any other group, thejmethod ofcontrolling the frequenoie'sused in the/various groups for signaling which consists in generating at a master, station a fundamental frequency, transmitting-said frequency to the stations of the various groups, generating locally a frequency to be used for signaling and whose amplitude is independent of the fundamental frequency, producing a determinin frequency which is a function of the di erence between the fundamental frequency and the locally generated frequency, and controlling the frequency of said locally generated frequency in accordance with said determining frequency.

14:. The method of preventing relative frequencychanges between a plurality of separate radio channels of communication involving a plurality of radio stations, which consists in transmitting a control frequency to each of the radio stations involved, generatin at each station energy to be used in signa ing and whose amplitude is independent of the control frequency, and controlling the frequenc of the locally generated energy in accor ance with the control fre uency.

15. T e method of preventing relative frequency changes between a plurality of separate radio channels of communication involving a plurality of radio stations, which consists in transmitting a control freuency to each of the radio stations involved, derivin at each radio station a frequency from t e control frequency, generating at each station local energy to .be used for signalingandwhose amplitude is independent of the'icontrol frequency, and controlling the frequency of said local energy in accordance with the derivedlfrequency. 16. The.'method of'pi'eventingrelative frequency changes 'jbetween-a .plurality of separatefradio channels} of ommunication involving a plurality Qor fadio stations,

which consists in transmitting a- 'fcontrol frequency to each of' the zradio stations involved, generating at each" radio station a local frequency to be used for signaling and whose amplitude is independent of the control frequency 'j producing a determining frequencywhich is a function of the difference between the locally generated frequen- *'="-',cy-' andi the control frequency, and controlling the frequency of said locally generated frequency in accordance with said determining fre uency.

17. e method of fixing frequency relation' between a plurality of non-intercommunicating radio stations which consists in transmitting to each of said stations a control frequency, generating at each station energy to be used in signaling and whose amplitude is independent of the control frequency, and controlling the frequency of the locally generated energy in accordance with the control frequency.

18. The method of fixing frequency re-. lation between a plurality of non-intercominunicating radio stations which consists in transmitting to each of said stations a control frequency, deriving at each radio station a frequency from the control frequency, generating at each station local energy to be used for signaling and whose amplitude is independent of the control frequency, and controlling the frequency of said local energy in accordance with the derived frequency.

19. The method of fixing frequency relation between a plurality of non-intercom mfunicating radio stations which consists in transmitting to each of said stations a control frequency, generating at each radio station a local frequency to be used for signaling and whose amplitude is independent of the control frequency, producing a determining frequency which is a function of the difference between the locally gener ated frequency and the control frequency,

and controlling the frequency of said locally generated frequency in accordance with said determining fre uency.

20. The method 0 fixing the frequency relations between a plurality of non-inter-,

communicating radio stations which con- 'sists in transmitting to each of said stations a control frequency, producing a harmonic of the control frequency at each signaling station, locally generating at each station a frequency to be used for signaling and whose amplitude is independent ofthe control frequency, modulating the harmonic frequency with the locally generated fre quency to produce a difference frequency, and controlling by said difference frequen cy the frequency of said locally generated frequency.- i

In testimony whereof, I have signed my name to this specification this 22nd day of November, 1921.

RALPH BOW'N.

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