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Sept m, Í946- R. LoRENzEN ETAL 2,407,308 METHOD AND APPARATUS FOR SECRET SIGNALING ' /llo \l Filed Jan. 1e, 1941 5 sheets-sheet 1 _à Esse-r" La/zeazsq ATTORN . Sept. l0, 1946. 2,407,308 R. LORENZEN ET AL METHOD AND APPARATUS FOR SECRET SIGNALING Filed Jan. 1e, '1941 ,N 7 5 Sheets-Sheet 2 Sept. w; 194s. 2,407,308 R. LORENZEN ETAL METHOD AND APPARATUS FOR SECRET` SIGNALING Filed Jan. 16, 1941 as 34 se AMPLIFIER ‘ DD# MoDuLAToR ` INTERMEDIATE -- MoDuL-ATING A 5 Sheets-Sheet 3 a1 AMPLIFIER -- MoouLA'roR oscILLA-roR A A ss do 35 AMPLIFIER ED- MoDuLAI'oR 4I 4e INTERMEDIATE A‘MPLIFIER -- MoouLATING -- MoouLAToR B oscILLAToR e osclLLAToR FI B 4a 47 CARRIER FREQUENCY FC 44 I FCÍ CFIAÍFSA: 4s FctrFxBtl-'SBJ 42 AMPLIFIER INTERMEDIATE DD- MoDuLA‘roR` . -- MoouLA‘rINs C - 49 4s _ MoouLA'roR oscILLAToR _ c C- `5o 5I ‘ ' Pci I: FIC-1» Fsc: AMPLIFIER s2 sa 54 - 4?“ Vs «C» - #s I» I» *og é’ ss Q~ g - 57 e Q» ‘9 4"? e? 6%* _ sa __ I@ Qvs f" Q4’.F è@ o“ ' En . , f R026* è» Fs f‘* - so A \ eI ss Q@ \ '_ìgv?c’ "' Oo”ftp? e" Qrç O o@è es »6' ofe9QWQèQ e4 e2 Q Qs? - 09s' " \ l QV '9. Q0 o@‘Y’ .è QQ’ es @QQ~ v YF*Q <9o e7 è F I S B se - A v» Q èQVQ&9 es . ¿ov‘50e .5S \ e «i A@ o?.èoÖVQQO E Q~ «6» _ » V '?Q @o , BY A0 oy' o@`k~ s@ YQ“QvQ6 o RBEQT‘LORENZE'” Flam); Spia sc_ - lIF sc R* INVEÀTFO ATTORNEY Sepî- l0, 1946. R. LoRENzl-:N ETAL METHOD AND APPARATUS FOR SECRET SIGNALING Filed Jan. 16, ~l94l 5 Sheets-Sheet 4 INVENTOR Egger L «WEA/25N @O B Y ., ATTORNEY. ’ Sept., M), w46. R. LORENZEN ET AL METHOD AND APPARATUS FOR SECRET SIGNALING Filed Jan. 1€, 1941 5 Sheets-Sheet 5 Patented Sept. 10, 1946 ¿M1308 UNITED STATES PATENT OFFICEv 2,407,308 METHOD AND APPARATUS ron SECRET SIGNALLNG Robert Lorenzen and Felix New York, N. Y. l Spiegel, Application January 16, 1941, Serial No. 374,790 2 Claims. (Cl. 179-15) The present invention relates to methods and apparatus for secret signaling. The disadvantages of present existing com municationg systems are: (l) the possibility of blanketing-out or jamming the audiofrequency signal modulation by a third party, thereby dis rupting communication service, and (2) the pos sibility of a third party intercepting signals that are desired to be kept secret. The need for new communication systems is to obviate the above mentioned disadvantages and shortcomings of present systems, for the present invention introduces a multiplicity of communication systems which can either be used alternately or in conjunction, whenever the need arises. Thus, if by remote chance one of the hereinafter mentioned systems should fall into the hands of a third party so that this third party discovers the technique employed in the new sys tem, it is merely necessary to adopt one of the manifold alternate systems. The possibility of employing a multiplicity of 2 operation of one of the manifold of communica tion systems herein described. One of the principal objects of the present in vention is the application of the new principle to radio communication systems. Another object of the invention is to sho-w the application of the new principle to'supersonic sig naling, i. e., its application to communication ysystems which employ ultra-audible waves in a 10 Imaterial medium as a means of c-ommunication. Stil1 another object of the present invention isV to show how the herein described principle may be applied to communication systems which em _ploy electromagnetic waves of a non-radio char 15 acter as the carrier of the transmitted signals. Typical of such systems are those which utilize a light-beam as the means of transmission, or infra-red rays as the carrier of the transmitted signals, or ultra-violet as the signal carrier. Another object of the invention is to show the application of the present system to those com munication systems which employ wired wireless, alternative communication systems is obviously of considerably greater advantage than would be i. e., where the signals are transmitted along the case if the number of communication systems 25 either a conductor or a dielectric guide. Another principal object of the present in vention is the simultaneous transmission of dif ferent signals when but. a single carrier fre quency is employed. blanketing-out or jamming the conventional eX Still another object of the invention is the si isting transmissions lwill leave the new system 30 multaneous transmission of the desired signals unaffected, despite the fact that the means em and false signals, soI that, although only the de ployed by the third party have elîectively par sired signals are received by the two parties be alyzed the yconventional existing means of com tween whom communication is established, any munication. By the employment of the new sys outside third party receives only the false sig tems, hereinafter to be described, the desired nals and is thereby deceived as to the real con communication is enabled to be continued with tent of the transmitted messages. out interruption or interference. Still another object of the invention concerns One of the objects of this invention is to show itself with a new method of scrambling signals were limited to three as at present, for if it is assumed that any one of the multiplicity of the new systems is employed, then any means for how an inñnitely large number of diiîerent com munication systems are made available instead so as to make the interception of transmitted messages impossible to any outside third party who is not informed both as to the method of 0f merely the present limited number of avail able systems, namely, three. Another object of the present invention is to show how uninterrupted communication may be maintained between two parties, despite the fact scrambling and the principles underlying these new communication systems. 45 The present invention will be described Iwith reference to the accompanying drawings, but it that a third part may, by the process of creating artificial noise and interference, cause the iam ming of conventional communication systems so will be realized that other application-5 and em bodiments lie within the scope of the invention, for it should be understood that the scope of the as to result in a complete disruption of commu present invention is so broad that only the gen 50 eral features are herein disclosed. Subsequent nication service. patent applications will describe the various spe Still another 'object `of this invention shows ciñc embodiments and give in more concrete how it i-s possible to maintain uninterrupted form the manifold applications and modifications communication between two parties even though of the principle herein described. some third party has discovered the principle of Fig. 1A represents the generalized set-up of a 2,407,3oe transmitter which employs multiple modulation,l while Fig. 1B represents a receiver which is ca pable of receiving such multiply-modulated transmissions. Fig. 2A represents a transmitter wherein only one intermediate-modulating-frequency is em ployed, while Fig. 2B represents a receiver which is capable of receiving such a doubly-modulated transmission. ' Fig. 3A represents a transmitter which is capa ble of simultaneously transmitting a number of different signals on a single carrier frequency, while Fig. 3B represents a receiver for such transmissions. Fig. 4A represents a transmitter whichV is capa ble of transmitting both the desired as wellV assv 4 ñrst intermediate oscillation frequency fn. The foregoing process continues, as indicated by the dashed lines, until the multiply-modulated re sulting signal is fed into .the amplifier-modulator 6, the output of which is employed to modulate the nth intermediate frequency oscillator l, whose oscillation frequency fin is some multiple of the (n-Dth intermediate frequency oscil lator. The output of the nth intermediate fre quency oscillator 1 goes to an amplifier-modu lator 8, which is employed to modulate the car rier frequency oscillator 9. The modulated out put- of- the carrier frequency oscillator 9 is then either directly, or after further amplification, fed , into a,V radiatorY Il), which in the case of radio transmission would consist of an antenna system, At the receiving station, as illustrated in Fig. 1B, false signals, while Fig. 4B represents a receiver the multiply-modulated signal is picked up by an for receiving the desired signals. tennai t which is connected to amplifier i2. This Fig. 5A represents a transmitter employing amplifier i2 is capable of amplifying the carrier 20 triple modulation in which the signals are frequency and should have an> amplifying band scrambled in such a manner that part of .the width capable of amplifying the accompanying scrambled signals modulate the first intermedi multiply-modulated signal. After suitable ampli ate-modulating frequency and the otherpart of fication.V by amplifier l2. the signal is fed to de the scrambled signals modulate-the second’inter modulator i3, which removes the carrierI fre mediate-modulating frequency. Fig. 5B repre 25 quency fc and leaves only the multiply-modulated sents a receiver for the reception of such signal jin. The output of demodulator I3 goes to scrambled transmission. amplifier if», which amplifies the signal at fre In the conventional communications system,.at quency jim and which possesses a band-width ca the transmitter a signal frequency modulates a carrier frequency, this latter being propagated 30 pable of amplifying the accompanying multiple modulation. The output of amplifier I4 goes to ’ through space, this, in turn, is received at are demodulator l5 which removes the nth inter ceiver, Where, after' suitable demodulation, the mediate modulating frequency, so that the out original signal frequency is obtained. AsY will put of demodulator ifa-consists of the multiply hereinafter be disclosed, the present conven modulated @L_-1) th intermediate modulating fre tional method is but a very special case of the quency. This signal is fed to amplifier I6, which. new general principle, which -concerns itself with means and methods for producing andY utilizingV superimposed and multiple modulation of signals. In order to reduce the complexity of description, ampliiies at the ('n-Dth intermediate modulat ing frequency` and which has an amplifying band width suitable for amplifying the accompanying the principles underlying multiple modulation 40 will first be discussed. Again, although later de scriptions will utilize various combinations of amplitude, frequency, and phase modulation, . further simplicity of description will at this time multiply-modulated signal. This process is re peated, as indicated by the dashed lilies, until be secured by making the two following assump Demodulator ißîremoves the second'intermediate modulating frequency, thereby leaving only the tions: (1). amplitude modulation is employed throughout, and (2) spurious modulation prod only thev multiply-modulated second intermediate being amplified by ampli frequency remains, this fier il, after which it is fed to demodulator I8; signal-modulated first intermediate-inodulatingA frequency, Tlieoutput of demodulator iS goes to amplifier lil, which is capa-ble of amplifying the -applicable .to other than itsemployment'in radio . :i first intermediate-modulating frequency and its ucts are disregarded. In addition, although it will shortly be seen that the new principle is transmission and reception, the preliminary de scription will restrict itself to its application to radio communication. Referring to Fig. 1A, which represents in block accompanying signal modulations. The output up of the signals fs. Signals from l go to the am quency. After sufficient amplification the'orig of amplifier IS goesto demodulator 20‘ which re moves the first intermediate-modulating frequen cy and leaves only the original signal frequency. diagram form a transnriitterv employing multiple SI1 ri‘he output of demodulator 20 then goes to ampli fier 2l which ampliiies theV original signal fre modulation, I represents either a source or pick inal signal frequency may be taken from the out put of amplifier 2l to actuate any suitable device, ployed to modulate an oscillator 3 which isv oscil lating at the frequency fn. Oscillator 3, which (if) such as, for example a loudspeaker or telephone shall be called the first intermediate-frequency receiver. Having explained the general principle of mul oscillator produces an oscillation which is some multiple, not necessarily integral, of the- fre tiple modulation, there will now be considered a quency of the signal frequency. If the signal simple, example of multiple modulation, namely, is comprised of a band of frequencies, as would when only a single intermediate modulating fre be the case when the signal consists of speech quency is employed. The symbol fs willv be used. or music, the ñrst intermediate frequency oscil to designate the signal frequency, which, for co i lator will have a frequency which is some mul venience, may consisty of those frequencies of tiple of. the highest signal frequency. The output which music or speech sounds are comprised. of intermediate frequency oscillator 3'feeds into The symbol fr will be used to represent- the inter the input of the amplifier-modulator 4, where mediate modulating frequency, which, in this case, pliñer-modulator 2', the output of which is em the signal-modulated fn frequency is amplified we may assume to be a fixed frequency of 100,000 and then employed to modulate the second in cycles. Similarly, the symbolfcshall‘ be used to termediate frequency oscillator 5, whose oscilla 75 designate theV carrier frequency, which, in this tion frequency fi2 is Ysome multiple of,- that of the 5 6 case, should preferably be greater than one mega cycle. carrier frequency by either amplitude, frequency, , or phase modulation. Under these conditions the number of permutations is nine, so that nine dif ferent communication systems result. This mayV Referring to Fig. 2A, which shows a block dia gram of the transmitter, the microphone 22 picks up the speech sounds which it is desired to trans mit. The microphone connects to the amplifier - be seen from the following table. modulator 23, which ñrst suitably ampliñes the signal frequency and then is employed to modu I late the intermediate-modulating frequency fr produced by the intermediate-frequency oscilla Method by sgr which interme modulate g. . s Inter“ diete-modulaff ing frequency lgîliegläe'nlllìglê' modulates the g eq y carrier frequency tor 24. In consequence, the resulting output is comprised of the intermediate modulating fre quency fr in conjunction with the sum and dif Amlliìlitude o. Do. ference sideband frequencies due to the signal frequency fs. This resulting output then goes to 15 IAmplitude requency Phase Frequency O. the amplifier-modulator 25, where, after suitable âmplitude v IeqlleIlCy Do. amplification, it is used to modulate the carrier frequency oscillator 2B which is oscillating at a frequency fc. As a result there is obtained an output which is comprised of the carrier fre L Phase Phase Do. Amplitude Frequency Do. Phase In a similar manner, when two intermediate quency in combination with the sum and differ ence sideband frequencies due to the complex of the signal frequency and the intermediate-modu modulating frequencies are employed, it will be seen that: (1) II‘he si-gnals may either amplitude modulate, frequency-modulate, or phase-modu late the ñrst intermediate-modulating frequency; (2) the first intermediate modulating frequency may either amplitude-modulate, frequency-mod lating frequency. After suitable amplification, if desired, the doubly modulated carrier is radi ated into space by means of the antenna 21. At the receiver, as shown in Fig. 2B, the doubly modulated carrier impinges upon antenna 28 and ulate, or phase-modulate the second interme is then amplified by amplifier 29. The output of diate-modulating frequency, and (3) the second amplifier 2S consists of the doubly-modulated ` carrier frequency and this is fed to the demodu lator 30 which removes the carrier frequency and intermediate-modulating frequency may either amplitude-modulate, frequency-modulate, or phase-modulate the carrier frequency. Accord leaves only the signal-modulated intermediate modulating frequency. This, in turn, is ampli twenty-seven, it is seen that twenty-seven differ- ~ fied by amplifier 3| and is then fed to the de modulator 32 which removes the intermediate when two intermediate modulating frequencies ingly, since the number of permutations lis ent possible communication systems are possible modulating frequency and leaves only the origi nal signal frequency fs. After suitable amplifica are utilized. tion by means of amplifier 33 the resulting sig nal frequency may be used to actuate a loud ing frequencies are employed, the resulting num ber of different communication systems is eighty v Similarly, when three intermediate-modulat speaker. one. In general, when n intermediate-modulating frequencies are employed the resulting number of different communication systems is 30H1). Since all of these different systems may be t’ simultaneously employed, the total number N of It is therefore seen that even when using such a simple set-up as the one just described, a con siderable degree of secrecy of message communi cation may be obtained. For, if in the attempt to intercept a message from the transmitter of Fig. 2B, an ordinary receiver were tuned to the carrier frequency fc, nothing would be heard for the re sulting demodulated frequency would be the in different communication systems, and including the conventional single modulation, which result is given by the expression - termediate-modulating frequency fr, and since N=31+32+33+341 . _ _ 3(1L-l-l) this was chosen to be about 100,000 cycles it is beyond the audible frequency range and would not, therefore, be heard. Only a receiver which where n represents the number of intermediate modulating frequencies. It is readily seen, there doubly demodulates the doubly-modulated car rier would be capable of properly receiving the transmitted message. fore, that the number of different communica tion systems which become available increases ' very rapidly as the number of intermediate modulating frequencies is increased. The rapid ity with which different communication systems become available is shown by the following chart. In a similar manner, two intermediate-modu lating frequencies may be employed to obtain a triply-modulated carrier, thereby making it still more diñîcult for the uninformed to intercept the GO transmitted message. It is unnecessary to de scribe such a system at this point, as this type will later be used when the description of super imposed modulation as used in conjunction with multiple modulation is described. At this point it will be well to examine the num ber of different communication systems which are possible as a result of the employment of multi ple modulation. When only one intermediate modulating fre quency is employed it will be seen that: (1) The Number of available com frequencies systems modulating munication 0 1 2 3 4 3 12 39 120 363 5 ad infinitum 1, 092 ad infinitum This enormous number of possible communi cation systems is to be contrasted with the small signals may modulate the intermediate-modulat ing frequency by means either of amplitude, fre quency, or phase modulation, and (2) the inter mediate-modulating frequency can modulate the. Number of intermediate- num-ber, namely three, which have hitherto been 75 available. It is well to remember, however, that while the w i 3B; Considering. the first ofi these receivers, an tenna 43 connects to amplifier 49 which amplifies the carrier frequency. Afterv suitable amplifica tion the complex signal is demodulated by de modulator` 50",. thereby eliminating the carrier.' The: output' of the demodulator willi contain all employment'of an ever-increasing.` number ofi in' termediate-modulating frequencies, and conse; quently an ever-increasing number of different communication systems, is theoretically capable of indefinite extensionr there are, nevertheless, practical limitations. Which..mitigate against such indefinite extension. This practical limitation is dependent upon the amountv of frequency band width available, for, asthe‘number ofV intermedi ate modulating frequencies ar‘eiincreased, so, like wise, is the necessity for an increased frequency band-width. of the intermediate-modulating frequencies and' their accompanying modulations. Accordingly; a band-pass-ñlter 5i isinserted-in the» output cir‘ This band-pass ñlt'er should beV operative at frequency fm, namely, at> the frequency of the intermediate-modulating oscillator 361 of the‘transmitter, and' it shouldï have a'Í pass-band suflifciently Wide as to pass' the origi inalï` signals of frequency fsA without undue' at- Y tenuation. The output ofthe band-pass- filter 10 cuit. of’ demodulator 50. Consequently, as more and more intermediate-modulating frequencies are em ployed the higher must the frequency of the car rier become: in. order to maintain the frequency band-width required at some given percentage of the carrier frequency». The intermediate-modulating frequency f1 is not restricted toV any single frequency and may Will' then contain intermediate-modulatingi fre quency‘ fm- which has been modulated byî the original signal frequency fsa. This is-then- am p‘liñed' by amplifier 52- and then demod'ulatedí by assume» various values, such as ffl, frz, frs», etc. 20 demodulator 534 so that the intermediate-modu for any- given carrier frequency- f¢,.the same lating frequency fla» is» removed. The> remaining (or different) station may employy the intermedi signalv frequency fs». is thenA amplified by ampli ate-modulating frequencies- frl, frz, T13, etc., to fier Sli, the output of whichY goes to` any suitableI modulate the carrier. Since, in this event, band device, as for example, a loud speaker or ear» pass filters would be employed .to prevent any 25 phones; interaction or interference. of the various inter The operation cf the second- receiver is similar mediate-modulating frequencies, it is seen that to that just described. Antenna 55 receivesthe the-«simultaneous- transmission of diverse signals complex of’ signals radiated by transmitting an may be transmitted- and received although but a tenna 41 and this is fed tothe amplifier 56- which 30 single given carrier frequency is employed. amplifies at the carrier frequency, after> which A typicalV example.V of a transmitter which en demodulator 51 removes the carrierY frequency. ables the simultaneous- transmission of different Since in this case it is desired'Y to receive the sig signals when. but a single` carrier frequency is nal frequency fsa the band-pass filter-5B' operates employed is illustrated. in Fig. 3A. For simplicity of> description only one intermediate-modulating> 35 at' frequency fm corresponding to frequency fm of' oscillator 40 in thetransmitter. frequency is used, as the extension of the-method. Itis now possible‘to' examine how this'neW com so asi to employ twoor. more intermediate-modu munication system may be utilized so that the lating, frequencies is` obvious. The microphone regular transmission ofv unimportant’ signals 34 picks up the speechV` signals. fs». at point A and which employv the customary direct modulation these are fed to the amplifier-modulator 35. The 4.0 may be simultaneously transmitted in conjunction intermediate-modulating oscillator 36, whose os with multiply-modulated signals containing the cillation> frequency fm may, for example, be essential information, in order to deceive- any 100,000 cycles, is modulated» by amplifier-modu-` third party who may the attempt' to> inter lator 35. This modulated output then goes to cept. the desired signals'. Atypical transmitter' for. performing. this function is shown in Fig. 4A. amplifier-modulator 31, which', in turn, modulates the-carrier frequency oscillator'ßt. The doubly modulatedwave- is thenfedinto the' antenna 41. The desired signals fs are picked up by micro In a similar manner, microphone 33- picks up the speech signals fsB at point B and are then 1D', and' are then employed' to modulate theinter phone ES', are' amplified' by ampliñ'er-mod'ulatorv mediate-modulating frequency oscillator 1|'. The frequency of' oscillation fr of the intermediate modulating frequency oscillator 1|' may be any suitable value, as. for example,> 100,000 cycles.. suitably amplified` by means of amplifier-modu lator 39. The intermediate-modulating oscillator has a frequency fm which is different from that of intermediate-modulating oscillator 36, and it The' modulated' output of intermediate-modulat'- , may be assumed, for example, that the inter ing frequency oscillator 1'I‘ is fed'to' the. amplifier modulator 12, which latter is> used" to modulate mediate-modulatingv frequency fm is 200,000 cycles. Amplifier-modulator'then causes this- re sulting. signal to` modulate. the' carrier frequency oscillator.y The microphone 42, the amplifier-modulator 43, the intermediate-modulating oscillator All, and `the amplifier-modulator 45 operate in a similar manner. Again the' frequency fic of in the-carrier’frequency oscillator 13, and these sig nals are radiated' into" space via antenna 16. Si GO multaneously with the' preceding, the falsesignals Fs are rpicked'up by’ microphone 14', are amplified bythe amplifier-modulator 15*y which latter also modulates the` carrier frequency oscillator 1.3',~ termediate-modulating oscillator Ml is different from that of the intermediate-modulating oscil lators 36 and 40, so'that, for example, the oscilla tion frequency fic of intermediate-modulating oscillator 44 may be. 300,000 cycles. . after which these false signals are. also’ radiated It is, of course,.not necessary that the single carrier frequency oscillator 43 be employed. In ff.- Will receive only the false signals since itwill be unresponsive tov the intermediate-modulating frequency fr.' stead, separate carrier frequency oscillators may be used; the carrier frequencies of the separate int'o‘sp'ace via the antenna 161. It is therefore seen thatthe radiati'ons'em’ana‘t ingfrorrrantenna'16` consist of‘the' desired'Í signals andJ the; false signals; A> conventional receiver' which is tuned to` receive the carrier frequency In" order. to 'receive' the, desired ‘signals Yav receiver oscillators being the same or‘diñerent'as desired. Returning tothe preceding case, the complex of Waves radiated by transmitting antenna. 41 of the type shown in FigAB‘ may be employed. Antenna 11 picks up> the signal" radiated from‘ arepicked upby» antennas d'8, 55, and 62 of`Fig. antenna- 16'. This doubly-modulatecl-- signal is“ ` 9 2,407,308 amplified by amplifier 78. The demodulator 79 removes the carrier frequency so that the output of demodulator 'I9 contains the desired signal modulated intermediate-modulating frequency and the false signals. The band-pass filter 89 permits only the signal-modulated intermediate modulating frequency to pass through, so that the output of band-pass filter Già does not contain the false signals. After further amplification by means of amplifier SI the signal-modulated inter lator 82 which removes the intermediate-modu lating frequency and leaves only the original de sired signals. After further amplification by am pliñer 89 the desired signals may be utilized to actuate any suitable device, as, for example, a loudspeaker or earphones. ri‘Ühe signaling system just described is not lim ited merely to the use of a single intermediate modulating frequency, but may employ multiple- f modulation using any number of intermediate modulating frequencies, as desired. the separately scrambled portions of the scram bled signals modulate difierent intermediate modulating frequencies. One of the manifold of transmitters for accomplishing this purpose is shown in Fig. 5A. The desired signal fs is picked up by microphone 34, these signals then being suitably amplified by means of amplifier 85. From here the signals go to a Scrambler 86 which breaks the signals up in any desired manner. One portion of these scrambled signals feeds into the amplifier-modulator 8l while the other portion of these scrambled signals feeds into the amplifier modulator 89. That portion which Went to am plifier-modulator 81 is utilized to modulate the first intermediate-modulating frequency oscillator 88, the output of which also goes to amplifier modulator 89. Amplifier-modulator 89 then mod ulates the second intermediate-modulating fre quency oscillator 90. In other Words, the second intermediate-modulating frequency oscillator 90 so that the second intermediate-modulating fre quency is removed. The output of demodulator líiâ‘ then goes to amplifier i?I, as did also one portion of the desorambled signals coming from descrambler 98. After suitable amplification by amplifier I EI, demodulator IGZ removes the first intermediate-modulating frequency, so that the l() original signal now appears in the output of the mediate-modulating frequency goes to demodu There will now be described a typical method whereby the desired signals are scrambled so that flcation by means of amplifier 99 the doubly-mod ulated portion is demodulated by demodulator |09, demodulator. After suitable amplification by means of amplifier IGS, the output of this ampli îier may be utilized to aetuate any suitable device, such as, for example, a loudspeaker or earphones. The principle herein described is not limited in its scope merely to radio transmission and recep tion, for the principle of multiple-modulation may be utilized in conjunction with supersonic signal ing, to Wired Wireless, as well as to signaling by means of other non-radio electromagnetic radia tions, such as light-beam signaling, infrared sig naling, and ultraviolet signaling. Thus, in supersonic signaling, if IU in Fig. 1A, 27 in Fig. 2A, s1 in Fig. 3A, 'I6 in Fig. 4A, and 94 in Fig. 5A represent supersonic output sources, the transmitters described in these various fig ures may be employed to transmit multiply modulated supersonic waves. Similarly, if I I in Fig. 1B, 28 in Fig. 2B, 48, 55, and 62 in Fig. 3B, 'I1 in Fig. 4B, and 95 in Fig. 5B consist of super sonic pickup devices, the various receivers de scribed in these various figures may be employed to receive multiply-modulated supersonic waves. In a similar manner, a third party who at tempted to intercept the signals of multiply modulated light-beam, infrared beams, or'ultra violet beams would receive the false transmis sions if such were transmitted, but would not, for the reasons already given, be able to intercept 40 the real signals which it Was desired to transmit. The principle herein described, together with the various systems evolving from this principle is not, of course, limited in scope to the double sideband transmissions which were used for illus is modulated both by a portion of the scrambled 45 trative purposes only, but may utilize the various signals and by the signal-modulated first inter other forms of transmission technique as, for mediate-modulating frequency. The output of oscillator 9€! consisting of the superimposed mod ulations then goes to amplifier-modulator 9|, which latter modulates the carrier frequency oscillator 92. After further amplification, if de sired, by means of amplifier 93 the scrambled complex of triply-modulated and doubly-modu lated Waves are radiated into space by means of antenna 94. Although for the sake of simplicity it has not been shown, it is obvious that the sys tem just described can be used in conjunction With the transmission of false signals. The reconversion of the original desired signals example, single-sideband transmission, asym metric-sideband transmission, suppression of the carrier at the transmitter, as Well as the other transmission techniques known to the art. We claim: 1. A radio signaling system including a trans mitter and a receiver, and in which the trans mitter is provided with a pickup device and a carrier frequency oscillator, and interposed mod ulators and companion oscillators employing am plitude, phase, and frequency modulations; and in which the receiver is provided with a receiving element and a translating device, and interposed is accomplished by means of a receiver of the 60 modulators and oscillators for receiving from the type shown in Fig. 5B. Antenna 95 picks up the compleXly-modulated carrier which is then am plified by means of amplifier 96. The process of demodulation by means of demodulator 91 re receiving element such amplitude, phase, and frequency modulations as originated in the trans mitter and delivering same to the translating element. moves the carrier, the output of the demodulator 65 2. A radio signaling system as claimed in claim then going to the descrambler 98. Descrambler l, wherein the number of oscillators and their 98 is arranged to act in synchronism with the companion amplitude, phase, and frequency Scrambler 86 of the transmitter, and is so ad modulators are arrangeable in a selected se justed that the doubly-modulated portion goes quence. to amplifier 99, While the single-modulated por 70 ROBERT LORENZEN. tion goes to amplifier IUI. After suitable ampli FELIX SPIEGEL.