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`Sept. 3, 1946. A. ALFORD 2,406,735. MULTISIGNAL RADIATING I SYSTEM Filed Jari. so, 1945 2 Sheets-Sheet l @__ ,, ATTORNEY ‘ Sept. 3, 1946. ` 2,406,735 A.' ALFORD MULTISIGNAL RADIATING SYSTEM Filed Jan. '3o. 1945 .w w 2 Sheets-Sheet 2 l . IN VEN TOR. 14A/DREW HLP-ORO BY ATToM 2,406,735 Patented Sept. 3, 1946 STAT ES PATENT OFFICE 2,406,735 MULTISIGNAL RADIATING SYSTEM Andrew Alford, New York, N. Y., assigner to Federal Telephone and Radio Corporation, Newark, N. JL, a corporation of Delaware Application January 30, 1943, Serial No. 474,094 13 Claims. (Cl. 250---9) 2 l This application is a continuation in part of my copending application, Serial No. 445,944, filed June 5, 1942. The present invention relates to systems for combining two or more signals and more partic ularly to such systems wherein at least one of said signals may be a course determining signal. It is an object of my invention to provide a system for interconnecting two modulated radio frequencysources to a common line or load with out substantial loss oi radio frequency power. 1t is a further object of my invention to pro vide an arrangement wherein two separate sources of modulated radio frequency may be interconnected to supply modulated energy to a common load in conjugate relation with a mini mum oi energy dissipation. It is a further object of my invention to provide a system for radiating directively signals defin ing a course line while at the same time radiat ing upon the same wavelength further signals such as signals representing speech and/or sig no effect at the output of the source of the beacon signals _and vice versa. 'I'his requires that the two sources while being both coupled to the single antenna means must nevertheless not be coupled to one another. In order to attain such con jugacy various types of so-called conjugate net works may be used, such networks including the well-known “Wheatstone” bridge, the hybrid coil arrangement commonly used in carrier telephony and other types of arrangements speciñcally de Signed for coupling two sources to a load without intel-coupling the two `sources to each other. One of the most practical forms of conjugate net work for use at high radio frequencies is the type disclosed in my United States Patent No. 2,147,809 issued February 21, 1939, for “High fre quency bridge circuit and high frequency re peaters”, wherein there is described a sort of bridge made up of four lengths of 2-wire trans mission lines connected together in a square closed loop with a transposition in one of the four sec tions so as to prevent the effective transfer of nals representing a further course line. More particularly it is an object to provide such a sys» power from any one corner of the square to the one common antenna element while one of the corners. corner diagonally opposite while still permitting tem wherein both signals shall be radiated from 25 transfer of power from any corner to the adjacent signals, preferably the course line-defining sig nal, is additionally radiated from further antenna A common characteristic of all known types of conjugate networks, whether of the preferred type just described or not, is that an impedance elements. It is a further object to provide such a system 30 simulating the impedance of the useful load must be connected to the conjugate network and when wherein voice signals may be radiated from an element of a directive array used for beacon pur poses while at the same time insuring that the mitted to the useful load. Accordingly, when the voice signals shall not react upon the output stage conjugate network of the preferred type or any so connected receives as much power as is trans delivering the beacon signals or vice versa. 35 other type is employed for coupling to a common load the energy from a ñrst signal source and t is a still further object of my invention to provide a system which shall simultaneously ra from a second signal source the required balanc diate directional signals for aiding navigation and ing resistor or dump which must be connected to other signals such as speech signals without any the conjugate network will receive as much energy interaction between the sources of the two signals 40 as the load thus requiring that the speech signal sources each generate twice the amount of power and without requiring that 50% of the power from each source shall be dissipated in so-called necessary for the load. It is an object of the present invention to over “clumps” or matching resistors. come the above disadvantage. It is a further When combining two signals (e. g., directive beacon signals and speech signals) for applica 45 object of the present invention to provide a sys tion to a single antenna element (or to a group tem which may radiate from a common antenna both speech signals and other signals with rea of antenna elements connected together so as to sonable emciency (i. e., without the dumping of act as a single antenna means) or other load, large amounts of power) while at the same time it is necessary that the connections be made so as to maintain approximate conjugacy between 50 maintaining the essential characteristics of the signals free from the inñuence of any vacuum the two sources of signals (i. e., between the source of the beacon signals and the speech sig tubes, tuned circuits or other critical equipment used for supplying them. nal source). In other words, the connections More particularly, it is an object to provide should be made in such fashion that the varying voltage from the speech signal source shall have 55 such a system wherein the phase and amplitude almejas 3 4 of the beacon signals will be comparatively un aiTected by the changing of tubes or retuning of the circuits used for speech radiation and where 0 are the short transmission line sections 8a and 9a whose effective electrical lengths are arranged to be varied cyclically at the rate of 90 cycles per' second and 150 cycles per second, respectively, in such eiîects as shall be produced shall not tend to alter the directional pattern of the beacon signals. In brief, the present invention attains the above and other objects by applying the one set thus cyclically tuning these line sections to res-~ onance at the frequency of source li and then de~ tuning them again. As a result of such cyclical tuning and detuning of the coupled sections 8a, and 0a the transmission of energy along the of signals and other signals to a common antenna or other load via a conjugate circuit having a 10 transmission lines 8 and 9 is cyclically varied so that the currents arriving in the upper portions dump resistor and by arranging that both the of these lines 8 and 9 correspond to a` carrier signals applied to a common load comprise sub frequency equal to the frequency of source 4 stantial carrier components of roughly the same modulated with 90 cycles tone and 150 cycles orders of magnitude and of accurately related phases, these phases being so regulated that the amount of power dissipated in the dump is small compared to the amount of power usefully radi 15.' tone, respectively. . These tone modulated signals are then applied from lines 8 and 9 to the right and left corners of a combining bridge lil whose lower corner is con ated from the common antenna. The exact nature of >the invention may best be understood from the annexed sheet of draw ings in which: Fig. 1 is a schematic diagram of a system em bodying my invention and> adapted to radiate di rective beacon signals and speech signals; Fig. 2 is a similar diagram of another embodi ment of my invention wherein the two signals radiated are both directive beacon signals; Fig. 3 is a schematic diagram of a portion of a nected (through circuits more fully described 20 hereafter) to the central antenna element I while the upper corner of this bridge I9 is connected to the outer antenna elements 2 and 3. As shown, the connection from the upper corner of bridge I0 to antenna element 3 includes the transposition II while the corresponding con nection to antenna element 2 includes no such transposition thus insuring that the antenna ele ments 2 and 3 are excited in phase opposition to one another. circuit which maybe incorporated in the system It should be noted that because of the transpo of Fig. 2 in order to render the latter capable of 30 sition Ilia of bridge I0 the energy delivered to simultaneously radiating two separate beacon sig the outer antennae 2 and 3 contains no unmodu nals and one speech signal; and lated carrier component since this component is Fig. 4 illustrates two modulated sources con-V nected to a common load by a circuit incorporat ing my invention. e Referring more specifically to Fig. 1, I, 2 and 3 balanced out. Thus, the antenna 2, for exam ple, contains only the side bands corresponding to the 90 and 150 cycle signals (e. g., c-I-90, c-90, c-I-150 and c-150 where c is the carrier frequen cy). The antenna 3 contains the saine four are three antenna elements horizontally disposed in a straight line with the outer elements 2 and 3 components in opposite phase. The power de equally spaced from the center element I. Pref erably, each element is a loop of the type disclosed 40 livered from the lower corner of bridge I0, on the other hand, contains a very strong component of in Henney’s “Radio Engineering Handbook” 1941, carrier frequency c as well as of the four side at page 601 and more fully described in my United bands above described. States Patent No. 2,283,897, issued May 26, 1942,` Temporarily assuming that the lower corner of for “Antenna system,” being thus adapted to radiate substantially pure horizontally polarized p bridge I0 is directly connected to antenna I With out any intervening bridge structure and assum waves with substantially circular radiation pat ing that the electrical length of the path from terns for each individual loop. In order to di such lower corner of bridge I0 to antenna I is rectionally radiate beacon signals modulated with _ 90° longer than that of the path from the upper 150 _and 90 cycles, respectively, the circuit ar rangement shown in the left hand portion of Fig. 50 corner of bridge I0 to antenna 2, it will then be clear that the 90 cycle side band components ra 1 is provided, this arrangement being essentially diated from antenna I will add to the radiation like that shown in my copending United States of the corresponding side bands from antennae 2 application, Serial No. 300,166, ñled October 19, and 3 in that region toV the north side of the 1939, now Patent No. 2,307,184, issued January 5, 1943. 55‘ course line WE while tending to oppose such ra diation on the south side of such line. The rea Bríeily, this arrangement comprises the com son for this is that the 90 cycle side bands must mon source li whose output after passing the pass through one transposition in traveling from power amplifier 5 is applied to the lower> corner transmission line 8 to antenna 2 while encounter of a bridge (i. This bridgerß is of the type de scribed in the above-mentioned United States 60 ing noY transpositions but only a 90° greater length of line when traveling from transmission patent, No. 2,147,809, the transposition 6a being line 8 to antenna I. Accordingly, the radiation arranged in the upper right hand arm thereof of the 90 cycle side bands from antenna 2 will and a balancing dissipating impedance -I sub stantially simulating the loutput impedance of be 90° retarded with respect to the corresponding the amplifier 5 being connected to the upper cornerof the bridge so as to be essentially con jugate to the amplifier 5. A 2-Wire transmission line 8 is connected to the right corner of bridge 6 anda similar line 9 is connected to the left hand corner thereof so that energy is delivered to each of these lines from the ampliiier 5 although substantially no energy is delivered from this radiations from antenna I. At the same time the corresponding radiations from antenna 3 will be 90? advanced compared to those from antenna I because of transposition II. While the radi 1 ations from antennae 2 and 3 exactly cancel along 70`the course line WE, the vectorial combination of the> 90 cycle side 'bands from these antennae 2 and 3 will yieid a resultant at any other given ampliñer to the balancing impedance 'I because point in space by reason of the difference in path length from the two antennae to such given point. of the effect of the transposition 6a. Loosely coupled to the transmission lines 8 and North of the course line WE, the radiations from 2,406,735 5 6r, antenna. 2 will arrive in a shorter time than those from antenna 3 thus effectively advancing the phase of the radiations from 2 and retarding the phase of those from 3 with respect to the phase of radiations from antenna I. Therefore, the re panying these speech signals` is dependent upon sulting radiation from antennae 2 and 3 com bined will be in phase with the corresponding ra diation from antenna I at anyv point north of the course line. Conversely, the 150 cycle radi ation from the antenna 2 will be 90° advanced in phase with respect to the corresponding radiation from antennaV |. The resultant 150 cycle side band radiation from antennae 2 and 3 will' tend the characteristics of ampliñer 2| and thus can be varied due to adjusting the tuned circuits of this ampliñer or even by virtue of changes in the tube characteristics thereof.v The phase shifter 22 is. provided to take care of these- variations in phase andV is intended to be setv so that the phases of the carrier components in the speech signals io and in the beacon signals are alike at the points where these signals are applied to the right and left corners of bridge 23’, respectively. If this phase relationship is attained and if the magni tudes of the carrier components of the two sig to add to the corresponding radiation from an nals are alike, it will then follow that no carrier tenna | in the region south of the course line 15 frequency energy will be dissipated in impedance WE while subtracting therefrom in the region 24> because of the effect of transposition 23a. north of this course line. Even if the carrier power from speech ampliñer The aparatus so far described corresponds to 2| be assumed to be only half as great in ampli that disclosed in detail in the above-identified tude as the carrier power from the bottom of bridge I0 (so that the corresponding voltages are application, Serial No. 300,166, a detailed under standing of the operation of such arrangement in the ratio of .707i to 1) it can readily be seen being desirable for full appreciation of the pres that the voltage at the 'upper corner of bridge ent invention. 23 will correspond to l-I-.707 (i. e., to 1.707) while The further apparatus 20--25 is associated with at the lower corner- it will correspond to 1'-.707 the apparatus already described for the purpose 25 (i. e., to .293). rIïhe corresponding powers will of applying speech signals to antenna I simulta .be proportional to (1.70.7)2V and (.293)2 respec neously With the beacon signals heretofore de tively, being thus in the ratio> of 2.9' to: .086, i». e„ scribed. Such additional apparatus essentially about 34 to 1. Thus, when the carrier compo comprises a speech source 20 (illustrated as a nent from amplifier 2| is only half asV great as telephone transmitter but preferably comprising 30 the corresponding power from. bridge I0 it still a microphone and suitable audio amplifier stages) appears that the power dissipated in dump 241 is connected to modulate an R-F ampliñer 2| which less than 3% of the carrier power usefully radi is excited in parallel with the ampliñer 5 from ated from antenna I. the carrier source 4. The speech modulated out With respect to the side bands of the speech put of. amplifier 2| which is preferably of the 35 signals and the beacon signals it is true that sub same order of magnitude as the output of ampliiier stantially 50% dissipation occurs in impedance 24 5 is transmitted through phase shifter 22 to the but in most cases the average side band power right-hand corner of conjugate bridge network is considerably smaller than the average carrier 23, which is preferably of the type described in power and therefore the total amount of wastage the above-mentioned United States Patent No. 40 is a comparatively small percentage of the total energy usefully radiated from antenna I. 2,147,809. As shown in the drawings, the upper corner of One great advantage of the arrangement in the bridge 23 is connected to antenna | and the Fig. 1 is that phase variations introduced in the left hand corner thereof receives the proper bea amplifiers 5 and> 2| (by virtue of the adjusting con signals from the lower apex of combining of the associated tuned circuits or variations in bridge it' earlier described. Thus, both the speech modulated signals from amplifier 2| and the combined carrier and four side bands of the the tube characteristics thereof) do not alter either ythe position of the course line defined by the beacon signal or the shape of the radiation beacon signals from combining bridge I0 are pattern in respect to relative strengths of the transmitted via bridge 23 to antenna I. In order 50 150 and 90 cycle signals at. anyY points in space. to insure conjugacy between the speech signals It is also true that if .the phases of the carrier from ampliñer 2! and the beacon signals from components delivered by the ampliñers 5 and 2| the lower corner of bridge I0, bridge 23 is bal vary in opposite sense by a considerable number anced by means of transposition 23a and a bal of degrees a substantial dissipation of power in ancing dissipating impedance 24 whose impedance 55 impedance 24 will result since the carrier com as viewed from bridge 23 is equal to that of the ponents arriving at the right and left corners of antenna element I as viewed from this same bridge 23 will no longer be in phase. Such a bridge, A radio frequency voltmeter 25 is con result, however, is by no means as serious as a nected across the line between the lower corner of distortion of a beacon radiation pattern. Fur bridge 23 and the impedance 24 for a purpose thermore, the dissipation of energy in the dump 6O 24 is constantly indicated bythe meter 25 and hereafter to be described. it should be noted that the signals from mod therefore any person adjusting the tuned circuits ulated ampliner 2| and the beacon signals from associated with either amplifier 5 or 2|A will be the lower corner of combining bridge I0 are not immediately apprised of any incorrect phase re lationship. only of the same wavelength but both contain a It should be observed that even if a very large substantial component of carrier frequency de difference in phase exists between the carrier rived from the common source 4. 1n the case of components from` amplifiers 2| and 5 the side the beacon signals this carrier frequency compo band components of the beacon signal radiated nent has a phase dependent upon the character istics of power ampliñer 5 and this phase may 70 from antenna | willstill be properly phased with respect to the> corresponding side band compo vary due to adjusting of the tuned circuits of nents of the beacon signal radiated from anten this amplifier or even, to some extent, due to nae 2v and 3. Also, these side bandA components the two variations in the tube characteristics will be properly phased with respect. to the por thereof. In the case of speech signals from am pliñer 2| also the phase` of the carrier accom 75 tionA ofv the carrier'. component which. is derived 2,406,7354 7 8 from amplifier 5. If, therefore, the two carrier beacon signals comprises the power amplifier |05; the two transmission lines |68 and |09 with their components supplied by amplifiers 5 and 2| are modulating equipments |0811 and I09a; the bridge of equal magnitude, then a phase shift as much |05 for transmitting the power to these lines |08, as 60° between the phases of the carrier com |09 from the ampliñer |05; such bridge being ponents supplied from the >two Iampliñers will re provided with a transposition lßEa and a balanc sult in a phase shift of only 30° between the re ing impedance |01 in order to prevent the modu sulting combined carrier radiated from antenna lator of |00a of channel |09 from reacting on the I and the beacon side bands. Such a phase shift channel |08 or vice versa; the combining bridge will not alter the beacon pattern at all (in viewL of the fact ythat the side band components in the 102 I I0 with its transposition I Illa and the antennae |02 and |03. All of this equipment operates es several antennae are properly phased) but instead sentially like the correspondingly numbered will only decrease the efficiency of demodulation equipment in Fig. l (the number |08 being con at the receiver by decreasing the amount of use sidered as corresponding to the number 8, etc.). ful carrier component available for demodulating The side antennae |02 and |03 are fed anti the signals. This effect is not :at all serious un less the phase relationship between the carriers phasally with the four side bands corresponding becomes as great as 180°, in which case the re to a 1020-cycle modulation and a 1300-cycle sultant carrier being 90° to the side bands would not be useful for producing demodulation in the modulation, these side bands having the frequen cies c-l-lOZO, c-1020, c-l~1300, and c-1300. The receivers. It is clear, however, that the phase _ central antenna I’ is fed from the lower corner of shifts of the amplifiers are not likely to equal 180° especially with the constant check provided bridge I IIla with .appropriate signals having a strong carrier component and also including the by meter 25. With respect to the speech frequencies the tennae |02 and |03. .The bridge 23’ combines the shifting of the carrier with reference to the side bands is also somewhat undesirable since it tends to'produce harmonic distortion. Such distortion is unimportant if the percentage modulation is small. In the system shown, moreover, half the carrier component isderived from amplifier 2| and therefore does not shift. - Thus a phase shift of 60° between the two car rier components would only shift the combined carrier by 30° with respect to the speech side bands. YThese two factors (i. e., the effect of low modulation percentages in preventing distortion and the fact that only half the phase shift be tween carriers appears as a phase shift between the combined carrier and the side bands) both tend to reduce the amount of distortion encoun tered in practice. Thus, as a practical matter, under ordinary conditions with a modulation per centage around 80% a phase shift as large as 50° between the two carriers will not produce an intolerable percentage of harmonic distortion in the speech signal. » . >Although the invention has so far been de scribed as used for radiating speech signals and beacon signals from one common antenna ele ment (e. g., antenna element I of the array I, 2, 3), the invention is also capable of other uses. Thus, for example, it may be used for radiating two separate beacon signals from a common an tenna, such an arrangement being illustrated in Fig. 2. ' Referring more particularly to Fig..2 the com ponents I’, 2', 3', II', 5', 8'., 6a', l', 8', 8a', 9', 9a', I0', Illa' -and II' correspond exactly to the elements of Fig. 1 having corresponding unprimed designations. These elements together constitute same four side bands which are radiated from an _ signals from the lower corner of bridge ||0 with those from the lower corner of bridge I0'. Each of these signals to be combined contains a sub stantial carrier component and these components are ofthe same order of magnitude (i. e. the ratioof the powers is less than 10:1). The phases of the carrier components arriving at the left hand and right hand corners of bridge 23’ should be alike and this condition may be attained by adjusting the tuned output circuits of amplifiers 5’ and |05 to produce the desired phase relation. In case a more convenient adjustment is desired, a phase shifter may be provided just ahead of amplifier 5' or |55 or immediately following either or both of these ampliñers. The meter 25’ will serve to show when the desired phase condition is reached, since this meter will read Zero or a minimum when the carrier components arriving at the left and right corners of bridge 23' are in phase. In the system of Fig. 2, an east-west Ul course line is defined by the equality of the 150 cycle modulated signals and the 90 cycle modu lated signals, while a north-south course line is defined by the equality of the 1020 cycle modu lated signals and the 1300 cycle modulated sig nals. For properly generating the beacon pat terns to define these course lines, antennae 2' and 3' and |02 and |03 should be fed in phase quadra ture with respect to the central antenna I’. «Ac cordingly, the electrical length of the path from the upper corner of bridge I0’ to antenna 2' may be 90° shorter than the length of the path from the lower corner of bridge IIJ' to antenna I'. Similarly, the length of the electrical path from the upper corner of bridge III) to antenna |03 may be 90° shorter than the length of the path a beacon defining a west-east course line exactly 60 from the lower corner of bridge I I0 to antenna I'. as described in connection with Fig. 1. These relationships may be satisfied by suitably The bridge 23’ with its transposition 23a and choosing the lengths of the transmission lines. If desired, however, phase-shifter equipment can be its dump 2li' and its meter 25' serve, as in thev case of Fig. 1, to transmit to the central antenna 65 inserted between Vthe upperl corner of bridge I0' I’ not only the appropriate beacon signals (con and the antenna array and other phase-shifting sisting of a carrier component and four side band equipment may be inserted between the upper components having the frequencies c+ 150, c-150, corner of bridge | I0 and the antenna array. Such c+90 and 0_90, respectively), but also an ad phasing equipment, if provided, would be adjusted ditional independent set of signals based upon 70 for initially aligning up the courses and would the same carrier frequency. In the case of Fig. 2A thereafter not be disturbed. such additional independent Set of signals is as lfit is desired to combine more than two signals sumed to be another set of beacon signals rather y upon >a common antenna, this may be done by than a speech channel as in Fig. 1. extending the principle of the present invention. The equipment _for providing the additional. 75 Fig. 3 illustrates how Fig. 2 could be modified to A2,406,735 ,9. 10 -embody such a system, the circuit of Fig. 3 being intended to be substituted for the rectangle 5D age incurred with the ordinary conjugate circuit arrangements, without controlling the phases of in Fig. 2. As will be shown by comparing Fig. 3 with the right hand portion of Fig. l, the ampli the carriers). In respect to phasing, also a ‘con siderable latitude is permissible. Thus if the vfier 22! which is modulated by speech source 220 5 two carrier components to be combined are equal feeds its speech modulated output to bridge 223 in power, a phase divergence Of as much as 30% in essentially the same way that amplifier 2l causes the dissipation of only .about 61/2% of the fed its output to bridge 23 in Fig. l. In the sys total power while even a phase divergence as tem of Fig. 2 as modified by Fig. 3, the additional large as 60° >causes the dissipation of only about input which is combined with the speech signals 10 25% of the total power. in bridge 223, arrives from the lower corner of Although the invention has been particularly bridge I I0 and in order to minimize losses in the described for combining two signals one of which dump 224, the phases of the arriving carrier com is a beacon signal, it can also be used for com ponents may be adiusted by adjusting the tuned bining two signals of any type, for example, output tank of amplifier HB5 of modulated ampli -iier 221, or both. If desired, however, a phase shi‘fter'may be included before or after either or both of these amplifiers. The output from bridge 223 'is applied to the right hand corner of bridge 23’ where it is combined with output from the lower corner of bridge l0’. Preferably, the ampli tudes of the carrier components arriving at the upper and lower corners of bridge 223 (from amplifier 22K! and the lower corner of bridge I I0) should be approximately equal in magnitude and should each be approximately half the amplitude of the carrier components delivered from _ the lower corner of bridge lil’. Thus, the combined carrier delivered from the left corner of bridge 223 -will be of substantially the same amplitude as the carrier delivered from the lower corner of bridge l0’ and therefore substantially no dissipation of vcarrier energy will occur in the dump 24’. In the circuits of Figs. 1, 2 and 3 a circuit ac cording to my invention has been shown for com bining beacon signals and speech signals. The circuit is useful, however, for combining modu lated radio frequency energy from any two sources. In Fig. 4 is shown a ñrst source of carrier modu lated signal '60H and a second source of modu lated signal 402. These sources are of the same radio frequency but carry thereon different signal energies. The modulations may be of any de 15 phase and amplitude modulated signals vemploy ing the same carrier or telegraph and telephone signalsY based' on the same carrier. For` convenience, the illustrated embodiments of the invention show the modulation as effected at audio-frequencies (i. c. by audible -frequency tone modulators producing ‘power tones of 90 cycles, 150 cycles, 1020 cycles or 1300 cycles, or by speech frequency >modulating equipment. It should be understood, however, that the modu lation may be performed at `super-'audible or sub audible frequencies and may lconsist of or include the process of 'keying in A-N rhythm >or other rhythm. Thus, the expression “modulation” as used in the appended claims should `be inter preted in its broader sense to include `all modifi cations of the amplitude, phase, or frequency of the carrier by any of the commonly used proc esses ordinarily referred to >as modulation or keying. Although certain >embodiments of the inven tion have been shown and described for purposes of illustration, it will be understood that varia tions, adaptations and modifications thereof oc curring to one skilled in the art may be made without departing from the scope of `the inven tion as defined bythe appended claims. What is claimed is: 1. A `system for simultaneously applying two Vsignals on the same carrier lfrequency wavelength sired type, for example, they may be intermediate 45 to a common useful load which comprises a 'first carriers modulated with signals to be applied to a signaling means for producing 'a iirst side band component and a first carrier component, second signaling means for producing a second side band transposition 405. A balancing dissipating net component and a second carrier component, work 406 is coupled to the bridge terminal opposed `50 common load means, a balancing dissipating ele to load line 403 and is proportioned to match the ment simulating the impedance of said common ’impedance of the load. Thus, two sources are load means, a balanced network connected to interconnected so as to have no reaction one on transfer energy from said first and secon-d sig the other, and yet relatively wide variations in naling means to said common load means and amplitude and phasing of the signals may be per .55 with a relative phase reversal to said balancing multiplex line 423. Sources Ml, 402 are applied to the opposed d'iagonals of bridge 404, having a mitted without destroying the substantial advan element while maintaining substantial conjugacy tages of the system. between said first and second signaling means, If desired, 450|, 402 or both, may include `arn and carrier synchronizing means for maintain plitude and phase adjusting means so that ad ing said first and second carrier -components at justment may be made until minimum lcurrent 60 the same frequency and in a predetermined is applied to dissipating network 4835 as indi phase relation such as to minimize the absorption cated in meter li111. of carrier energy in said balancing element. Although it is preferred that the two carrier 2. A system for simultaneously applying two components to be combined ‘in any one of the signals on the same given carrier frequency bridges (e. g. 23. 23', 223 or 404) are preferably wavelength to a common useful load which com oophas‘ial and oi’ equal magnitudes, very wide prises a iirst signaling means for producing a departures from this condition may be tolerated first side band component and `a first carrier while still giving surprisingly'small losses in the component of said given wavelength, second sig dum-p balancing resistor. Thus, for example, a naling means for producing a second side band 4:1 power ratio will result in a dissipation of component and a second carrier component of only 10% of the total power; 90% of this `power said given wavelength, common useful loa-d being transmitted to the useful load. Even a means, a balancing element simulating the im 10:1 power ratio results in wasting only about pedance of said load means, a, balanced network 21% of the total power (which is a very sub connected to transfer energy from said iirst and stantial improvement over the 50% power Wast 75 second signaling means to said common useful Y 2,406,735 12 11 load connection, means in said bridge for Yproduc load> and with a relative phase reversal to said ing a phase reversal of energy from one of said sources intermediate the connection points of said source and said dissipating network to the said balancing element while maintaining substantial conjugacy between said iirst Iand second signaling means, and means for adjusting the phases of said first and second carrier components thereof y5 bridge and means for maintaining energy sup plied from said sources to said bridge substan as measured at the input to said balancing'ele ment substantially into opposition. tially in phase coincidence whereby carrier fre p quency energy is substantially balanced out at 3. A system for simultaneously applying to a common useful load two signals on the same car the input of said dissipating'network and substan rier frequency wavelength which comprises ñrst 10 tially only side band energy is dissipated in said signaling means for producing a ñrst side band network. ` ` 8. A system in accordance with claim 7 wherein each of said sources comprise independent ampli fier arrangements and said means for maintain nent, said carrier components being of the same 15 ing energyY applied from said sources to said bridge substantially in the same phase comprising a radio frequency, a dissipating balancingelernent phase shifting network for adjusting ’in phase simulating the impedance of said common load, energy from one of said modulated sources with a balanced network connected to transfer energy respect to energy from the other of said sources. from said ñrst and second signaling means to 9. A system for simultaneously applying car said common load and with a relative phase re 20 rier energy of the same frequency but modulated versal to said balancing element while main component and a first carrier component, a sec ond signaling means for producing a second side band component and a second carrier compo with different characteristic signals to a common taining substantial conjugacy between said ñrst radiating means, said signals each comprising a and second signaling means, carrier synchro carrier frequency component and respective side nizing means controlling said ñrst and further signaling means to maintain the phases of said 25 band components comprisingV a balanced four arm bridge circuit, means for coupling saidV radi carrier components substantially opposite as ating means to a ñrst point on said bridge, a dis measured at the terminals of said balancing sipating network means for coupling said Ydissi pating network to a second point diagonally oppo 4. A system according to claim 3 wherein said ñrst and second signaling means are adjusted to 30 site said first point, means Yfor applying carrier and said band components from each of said transmit to said balanced network carrier com sources to ’respectively opposite terminal points ponents of substantially the same Iorder of power. of said bridge to supply carrier frequency energy 5. A system according toY claim 3 wherein said element. ‘ ‘ Y first and second signaling means are adjusted to transmit to said balanced network carrier com ponents, the ratio of whose powers _is less >than 3 to 1. ' ' ' » l and side band frequency energy from both sources 35 to said common radiating means, and means for maintaining energy from both said sources 'over said network to said dissipating network in such ' phase relationship that said carrier components 6. A system for simultaneously applying to> a from the respective sources are substantially in phase opposition whereby substantially no car rier frequency energy Vis dissipated in said net common load two signals on the same carrier fre quency wavelength which comprises ñrst signal ing means for producing a ñrst side band com ponent and a first carrier component, second sig work, said side band components both being ap plied to said network for dissipation. 10. The method for simultaneously applying naling means for producing a second side band component and a second carrier component, a dissipating balancing element simulating the im 45 two signals on the same‘wavelength to a common useful load over a’balancing network designed to pedance of said common load, a balanced network connected to transfer energy from said first and second signaling means to said common load and maintain conjugate relation between said signals - which comprises producing a first carrier compo nent at said wavelength and an associated ñrst with a relative phase reversal to said balancing element while maintaining substantial' conjugacy » side band component, producing a second carrier between said first and second signaling means, carrier synchronizing means controlling said first and second signaling means to maintain the fre quency of the carrier components identical and the phases of said carrier components within 60° component at said wavelength and a second asso of being opposite. ’ ' ciated carriercomponent, applying said ñrst car rier component, said first side band component, said second carrier component and said second carrier side band component to said load over said network in such phase relation that said car ' riers are substantially in phase coincidence in said load and applying said components over said network to said dissipating network in such phase '7. A system for simultaneously applying two signals on the same common carrier frequency to a common load comprising a ñrst source of modu lated energy having a carrier componentof said common frequency and side band components, a second source of modulated energy having a s'ec ond carrier component of said common frequency relation that the ñrst and second carrier com ponents are substantially in phase opposition at the inputin said dissipating network whereby substantially only side band energy is dissipate in said dissipating'network. and other side band energy, a dissipating ele- Y Y 1l. The method in accordance with claim 10 ment simulating the impedance of said common 65 the further step comprising adjusting the rela load, a balanced bridge having four diagonally arranged points, >means for applying energy from tive phase in said first and second carrier com ponents to maintain the desired phase relationship said ñrst modulated energy source and said sec ond modulated energy source to opposite diagonal therebetween atV said load and said balancing points of said'bridge, means for coupling said 70 load to another of said diagonal points to receive carrier frequency energy and side band frequency ' energy from both said sources, means for cou network.` . ' ' ` ` l2. A system for simultaneously radiating course indicating signals and voice signals simul taneously from the same antenna system on the pling said dissipating network to the other'Y said same carrier frequency comprising a ñrst’car point on said bridge diagonally opposite to. said 75 rier frequency source, means for modulating en 2,406,735 13 14 ergy from said carrier frequency source with and means in said balancing networks for main beacon signals, means for applying said signal modulated energy only to certain of said antenna taining carrier frequency energy from both of said sources substantially in phase coincidence at units, a second carrier frequency source, means said common antenna and substantially in phase for voice modulating said second carrier fre opposition at said dissipating network. quency, a balancing network, a common antenna 13. An arrangement in accordance with claim 12 further comprising means for shifting the phase of said voice modulated carrier energy be fore application to said balancing network to unit cooperatively arranged with respect to said certain antenna units, means for applying modu lated energy from said course indicating source and from said voice modulated source over said 10 assure proper phase relation of said carrier energy at said antenna and at said dissípating network. balancing network to said common antenna and for supplying energy from said sources over said balancing network to said dissipating network ANDRE‘N' ALFORD.