US1933100A - Process for the secret transmission of vibrated modulated currents - Google Patents

Description

Oct. 31, 1933. J D|EUX 1,933,100

PROCESS FOR THE SECRET TRANSMISSION OF VIBRATED MODULATED CURRENTS Filed March 17, 1931 2 Sheets-Sheet l I P r I T T2. -o 0- o Oct. 31, 1933. J. 'DIEUX 1,933,100

PROCESS FOR THE SECRET TRANSMISSION OF VIBRATED MQDULATED CURRENTS Filed March 1'7, 1931 2 Sheets-Sheet 2 11/167 zfw Patented Get. 31, 1933 issait PROCESS FOR THE SECRET TRANSMISSION OF VIBRATED MODULATED CURRENTS Y Jean Dieux, Paris, France Application March 17, 1931, Serial No. 523,224,

and in France May22, 1930 a The purpose of the present invention is to effect secret transmission of oscillated, modulated currents free from interference. V

More particularly it has for its object the transmission through different media of sub sidiary or elementary electric currents resulting from the splitting up of an initial electric cur rent-this transmission being succeeded by a .synthesis or recombination of the elementary currents, whereby the originalstored.

' It will be understood that, as the transmission media are different and the subsidiary currents current is reare electrically differentiated, the latter will not be aifected by the same interferences at the same time and that the final recombination of the subsidiary elementary currents will restore the initial current, but not the interference effects .which neutralize themselves. Moreover, each subsidiary current is only a part of the initial current and if it is intercepted, does not allow of the latter being restored.

The transmission of the elementary, sub

.sidiary currents through diiferent media thus enables the end: in view to be attained, that is to say ther secret gtransmission of an oscillated, modulated current free from interferences.

The present invention relates to aprocess-comprising a transmission of'oscillated, modulated currents, effected by the splitting up ofthese currents, a differentiation of the resulting subsidiary currents, the transmission through various media, the recombination or synthesis of .these subsidiary currents, characterized in that the resulting subsidiary currents are differentiated before transmission, by subjecting them to variations of equal amplitudes or intensities" but of opposite sign and by recombination of the .saidsubsidiary currents after transmission by *subjecting them to variations which are'thereverse of those" to which they were subjected before transmission. h According to'one'form of the process, the elements of the oscillated, modulated currents proceeding from an'auxiliary source are added to or subtracted from, and after transmission these elementary or subsidiary currents are recombined by adding to *them oscillated, modulated currents'the reverse of those added before transmission.

According to one'method of carrying out the above process use is made, before and after transmission, of one singlesource or of two identical auxiliary sources of oscillated; modulatedf currents, the said currents being symmetrically 'Fig. 1 represents a general view of the transmission installation, according to the invention.

Fig. ZrepreSents a transmission system utilizing intermediary record discs as hereinafter described. a Fig. 3 represents diagrammatically the apparatus employedin the case of transmission by phonographic record discs.

Figs. 4 and 5 are two diagrammatic views of" an alternative form of the invention.

The arrangementshown in Fig. 1 comprises an amplifying and analyzing multiplate valve L1 comprising a filament F1, a grid G1 and two plates P1, P1. The circuit of the vibrated modulated current to be transmitted is connected to,

the grid G1 of valve L1, andthis vibrated modu s5 lated current thus gives' rise to two amplified currents (one in each plate circuit) which can be considered as subsidiary elements of the initial vibrated modulated current. The variation of the characteristics of each plate circuit permits in some manner the control of the division.

Each of these subsidiary elementary currents can be formed either by asingle frequency band or by several frequency bands of the initial vibrated modulated current. a V

Each plate P1, P1 is connected to a distinct transmission medium C1, 02'. Each transmission 7 medium is thus utilized in a continuous manner and always by the same subsidiary element. The

two transmission mediums are entirely identical,

but distinct from each other. They can be either distant from each other, or near each other; They can, for example, consist of 7 1. Conductors (transmission by wires) 2. Ether (wireless transmission) 3. Phonograph discs.

The arrangement, accordin'gto Fig. '1, alsoinw eludes an amplifying and synthetizing valve 7 which comprises a filament F2, two grids Gz and Gzand a plate P2.

The grids G2 and G2 are respectively connected to transmission mediums C1, C2, while the plate P2 is connected to the utilizing circuit.

The vibrated modulated currents arriving at 5 the grids G2 and (312' produce. in the plate cirthe other positively on the elementary or subsidiary oscillated, modulated currents, fiowing in the two circuits of the plates P1 and P2. This commutator may be regarded as a double detector which splits up a symmetric, oscillated, modulated current proceeding from a source S1 and sends into one of the plate circuits the positive part of this current and the corresponding negative part into the other plate circuit. 2 After transmission and before the recombina tion of the currents, a commutator C2 sends into the gridcircuits, oscillated, modulated currents, opposed to each other, and the reverse of those added to each circuit before transmission. The

commutator C2 may, for instance, be fed by a source S2 similar to source S1 or even by the same source, provided the valves L1, L2 are in proximity to each other, but the commutator C2 -;should function in opposite phase to that of commutator C1.

The elementary or subsidiary currents are thus restored, after transmission, to their original form.

The vibrated or oscillating modulated currents of differentiation can, for instance, be produced by the'superposition in one and the same circuit of S1 S2, and V 2. A modulating current of well-known characteristics coming from a source T1 T2.

The interferences towhich the currents may have been subjected during transmission-have been different for each transmission medium and the final recombination or synthesis either re-' duces the effects of the interferences or even suppresses them altogther. r This purely electrical method of differentiation may be extended. to the case where the transmission media are phonograph discs.

In this arrangement there are used, in the case of a duplex transmission, two phonograph discs -rotating with the same linear speed, the differentiation being produced not by mechanical action but by an electric effect in the circuits .of the.

recording instruments S1, S2.

The installation in this case, Fig. 2, consists of :a valve L1 similar to that described above, the plates P1, P1 of which are connected respectively torecording instruments S1, $2, the commutator C1 producing the differentiation in the circuits of the subsidiary currents. The recorders S1, S2

= ngrave the surfaces of the discs D1, D2 with the same linear speed V1.

The recorders S1, S2 are then replaced on the discs D1, D2 by electric pick-ups or reproducers L1, L2 connected to the grids of the valve L2, the

-; commutator C2 acting as in the previously de-.

1. A vibrated or oscillating current of regular amplitude and frequency coming from a source scribed arrangement on the subsidiary currents, before recombination of these currents is effected. I

The valve is connected to an output circuit such as the loud-speaker H. P., or to a recording device cutting a final masterrecord.

The intermediary discs D1, D2 are free to rotate throughout the reproducing phase, at a linear speed different from that with which they'rotated during the engraving phase, but their respective speeds remain in every case equal to each other at any moment.

'A convenient method of driving the discs D1, and D2 is shown diagrammatically in Fig. 3 and consists insupporting the discs on vertical shafts P1, P2 driven from the same driving shaft through themedium of gearing R1 R2, these gears being driven by motor M.

According to a further alternative form of the invention (Fig. 4) the multiplate valve which functions as an amplifier and splits up the initial electric current is replaced-by two or more ordinary amplifiers A1, A2, fed respectively by one or more microphones M1, M2 each circuit A1, A2 thus receiving thediiferentiated sound elements. emitted by source S. I

When this arrangement is adopted, it is possible to differentiate the oscillated, modulated currents by combined action on the amplifiers. Thus for example, two amplifiers A1 A2 of different characteristics may be employed, one producing attenuation, augmentation or suppression of certain frequency bands of the oscillated, modulated current traversing the circuit, while in the other, on the contrary, the corresponding frequency bands in the second elementary or subsidiary modulated current may be simultaneously augmented, attenuated or restored.

The elementary currents thus transformed by the amplifiers A1, A2, act on two recording instruments S1 S2 which engrave the sounds on the discs D1 D2. These discs D1 D2 then actuate two electric pick-ups or reproducers L1 L2, whichgive rise to the separate currents in amplifiers A2 A4, the recombination of these currents being effected by 1 a single recording instrument Se which engraves a single master surface G as indicated diagrammatically in Fig. 5.

What I claim as my invention and desire to secure by Letters Patent is:

1. The process for the transmission'of oscillated, modulated currents, which consists in dividing these currents, differentiating the subsidiary currents so produced, adding tothe subsidiary currents elements of oscillated, modulated current proceeding from an auxiliary source, transmitting through difierent media the difierentiated sub sidiary currents, adding to each subsidiary current oscillated, modulated currents the reverse of those which were added to them before transmis sion, and finally, effecting the recombination of the subsidiary currents.

2. The process for the transmission of oscillated, modulated currents, which consists in dividing these currents, differentiating the subsidiary currents so produced, adding to the subsidiary currents elements of oscillated, modulated current obtained by a previous commutation of an auxiliary current, transmitting through different media the differentiated subsidiary currents, adding to each subsidiary current oscillated, modulated currents obtained by the commutation of the auxiliary current, of opposite phase tothat obtained 3. In a system for the transmission of oscillated,

modulated currents, a valve having several anodes, a grid and filament joined to the circuit producing the current to be transmitted, a second valve having several grids, an anode and filament both connected with the circuit for utilizing the transmitted current, means connecting the anodes or" said first valve to the grids of the said second valve, a source of oscillated, modulated current, a commutator symmetrically dividing the oscillated, modulated current from the single source and causing each portion of this current to act upon each of the subsidiary currents before transmission, a second source similar in all respects to said first source and a second commutator similar to said first commutator but functioning in phase opposite to that of the latter and symmetrically dividing the current of said second source, and causing each portion of the current to act upon each of the subsidiary currents after transmission.

4. In a system for the transmission of oscillated, modulated currents, a valve having several anodes, the grid and filament both connected to the circuit supplying the current to be transmitted, a second valve having several grids, a plate and a filament both connected with the circuit for utilizing the transmitted current, transmission media consisting of two phonographic discs rotating with the same linear speed, means allowing the subsidiary currents produced by splitting up of the initial current to undergo variations of equal amplitude but of opposite sign before their transmission, and means allowing the subsidiary currents, after transmission, to undergo variations the reverse of those they underwent before transmission.

5. The process for the transmission of vibrated, modulated currents, which consists in dividing ferent variations of frequency and amplitude,-

transmitting said differentiated subsidiary ourrents through different media, imparting to said subsidiari, currents variations the reverse of those to which they were subjected before transmission and, finally, combining said several reconstituted subsidiary currents. I

6. The process for the transmission of vibrated modulated currents, which consists in dividing the vibrated modulated current to be transmitted into several distinct and uninterrupted subsidiary currents, differentiating said subsidiary currents by amplifying them with diiferent amplifying intensitiesand by modifying certain frequency bands, transmitting said differentiated subsidiary currents through different media, subjecting said subsidiary currents after transmission to variations the reverse of those which they were subjected to before transmission by amplification and modification of certain frequency bands, and, finally, combining said various subsidiary currents.

7. The process for the transmission of vibrated modulated currents which consists in dividing the vibrated modulated current to be transmitted into several distinct and uninterrupted subsidiary cur-- to which they were subjected prior to transmission and, finally, recombining said difierent subsidiary currents.

JEAN DIEUX.

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