US1612101A - Radio signaling system - Google Patents

Description

Dec. 28 1926. v 1 1,612,101

I H. J. J. Mp2 R. DE'BELLESCIZE RADIO SIGNALING SYSTEM Filed Au ust'zs, 1921 4 Sheets-Sheet 1.

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H. J. J. M. DE R. DE BELLESCIZE RADIO SIGNALING SYSTEM Filed August 29, 1921 4 Sheets-Sheet 2 6 I ALTERNATOR H. J. J. M. DE R. DE BELLESCIZE Dec. 28 1926.

RADIO SIGNALING SYSTEM Filed August 29, 1921 4 Sheet s-Sheet 3 H. J. J. M. DE R. DE BELLESCIZE RADIO SIGNALING SYSTEM .Filed August 29, 1921 4 Sheets-Sheet 4 Slum/Mu H.J.J. .DeR.DeBELLE5C|ZE 3 his QZA Patented Dec. 28, 1926.

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I i it 'lti earner HENRI JEAN J'QSEZPH IlIABIE DE REG-HAULID DE BELLESCEZE, O1 PAEI$, FRANCE.

RADIO SEEENALING SYSTEM.

Application filed August 29, 1921, Serial No. 496,536, and in France January 22, 1920.

(GRANTED UNDER THE PROVISEQNS '1 THE ACT 0F MARCH 3, 1921, 41 STAT. L, 1313.)

The present invention relates to secret ra dio telegraphic transmission and the objects of the invention are as follows:

To apply to wireless telegraphy a signaling system based on aprinciple to be hereinatter set forth and that has been known for titty years as applied to telegraphy through wires in the Baudot apparatus.

At the sending station, a certain number a of keys are successively and in a certain determined order connected with a rotating distributor so as to make possible the sending ct signals by means of these keys. I

At the receiving sta ion, there is another rotating distributor which is synchronous with the first mentioned distributor. The receiving distributor connects successively n registering apparatuses with the receiving circuit, and this occurs exactly at the time when this circuit receiv the corresponding signals from the sending station.

Due to the selecting operation effected by the distrilnitors an exact correspondence, two by two, is obtained between the 92 keys oi the sending station and the n registers of the receiving station. In this manner, a signal sent by a certain key is received by a certain register, and only by this register.

A further object of the invention is:

To arrange the sending and receiving devices provided in accordance with the above system in such a manner that, the radiotclegraphic signals that are sent out cannot be deciphered by any other station than the desired receiving station.

The invention will be more clearly understood by a brief reference to the Baudot system as applied to a radio-telegraphic installation. After this arrangement has been explained the modification of the apparatus for insuring the secrecy of the transmission will be readily understood.

In the following description and the accompanying drawings, two arrangements are shown to illustrate the invention. These arrangements dilier in the details of the ra diotelegraphic transmitting and receiving devices.

Figs. 1, 1. 1 and 1 show a radiotelegraphic sending station and a corresponding receiving station constructed in accordance with the principle of the Baudot apparatus.

2 and 2 show the same arrangement modified in a manner to prevent deciphering by other than the desired receiving station.

Figs. 3 and 3 are front and side views of a device for regulating the synchronism ot the sending and receiving apparatus of a secret signaling system, no special signal being necessary for effecting the regulation.

Fig. a shows a modified receiving arrange ment.

The Baudot system is adapted to a radiotelegraphic system in the following manner:

The important parts of the sending station (Fig. 1) are arranged in the following manner:

The distributor D L is composed of a plate or cylinder D the periphery of which is divided into a certain number of seg ments 22 in the present case, that are insulated from each other. Twenty of these segments (02:20) are connected to a corresponding number of keys divided into groups of five (Fig. 1 shows one of these groups M M By means of thisarrangement, tour simultaneous telegrams may be sent. Each telegram utilizes the five keys of one and the same group. The two last segments 21 and 22 serve for maintaining the synchronisn'i. lhe manner in which this is accomplished will be set forth more in detail.

The brush L rotates at a constant speed,

Each group of keys is arranged in a keyboard of five keys that may be manipulated by an operator. The time at the disposal of the operator for the sending of a character is equivalent to the time required for the brush to traverse the other segments. In the present case this will be 17/22 part of the circumference. hen a key is once depressed, it is maintained in this positionby means or" an electromagnet (not shown) until the wiper passes over the five segments of this group and picks up the signal prepared by the adjustment of the keyboard.

The sending station comprises also anoscillation generator G. By short-circuiting a portion of the seli induction coil of the antenna this generator will alternately send out two waves, one w rking wave when the contact N is open, and a second normal wave when N is closed. This or any other similar arrangement (e. g. the utilization of two musical tones by means of the Lepel system) is not absolutely indispensable, but it has certain advantages which will be hereinafter set forth.

Upon the energization of the electromagnet 1-1,, the Contact N is opened and the working wave is sent out. The operation of. the electromagnet H has exactly the opposite elfect. By examining the circuit arrangement it will be seen that the electromagnet H, is energized when the wiper L engages a segment connected with a key actuated by the operator. The electromagnet H is energized when the wiper engages a segment that is connected with a key in its normal position. v

If, for example, the operator desires to send out a signal represented by the co1nbination M M normal, M M, M actuated, while the wiper is passing over the corresponding segments, waves of equal duration will be sent out, and will follow each other in the following combination; normal, work ing, normal, working, working.

The circuits are arranged in such a man ner that, when the wiper engages the seg ment 21, a working wave is sent out, and when it engages segment 22, a normal wave is sent.

The receiving station (Fig. 1) is an ranged in the following manner:

The receiver proper comprises two resonators R, and R, that actuate through the agency of indicator relays a common armature J The resonator R, is tuned to the frequency (wave length or musical tone) corresponding to the working wave, and the resonator R is tuned to the frequency cor responding to the normal wave. If the resonators R and R are operated respectively at the normal and working wave length, a detector, preferably, will be utilized in each local circuit, as shown in Figure 1 It" the resonators R, and R are operated at lower frequencies or musical tones, the latter will be obtained in any well known manner; for example, by means of a vave oscillator adapted to give audible beat frequencies in R, and R as shown in Figure 1". In this manner, the contact of armature J is closed when the sending station sends out a worln ing wave, and it is open when a normal wave is sent. This difierential arrangement may be variously modified, and it is notabsolutely essential. However, the arrange ment utilizing musical tone frequencies for R, and R, has great advantages. On one hand, it makes the receiver unresponsive to dampened disturbances which affect the resonators R, and R in identically the same manner; and on the other hand, it makes possible to increase the sensitiveness and the speed in obviating the necessity of pro viding a restoring spring for armature J.

The distributor D L at the receiving station is like the one provided at the sending station. However, the speed or rotation of wiper L, is regulated to a value slightly higher than that of wiper L It the angular displacement between these. two wipers gets to be such that, the wiper is in engagement with the segment 22' at a time when the wiper L is still in engagement with the segment 21 and causes the sending of a working wave, the electromagnetic regulator B becomes energized (circuit: contact J closed, battery 1 wiper L segment 22, elect: omagnet B) and, by means of a mechanism not shown in the drawing, slowsdown the rotation of wiper L, of the distributor at the receiving station. In this manner, it the two *ipers are out of tune, there is a tendency to establish the synchronism, whereby the two wipers L and L, are always in engagement with corresponding segments.

A group of five electromagnetic receivers E, E shown in Fig. 1 is provided for each group 01 five sending keys (e. g. M to One of these receiving magnets will be energized and caused to attract its armature at the instant the wiper L engages the corresponding segment, whenever the sending station is radiating the working wave. In other words, if the operator at the sending station depresses the correspond ing key, one of these magnets will become energized. In this manner, when the wiper L traverses the live segments of the group, the armatures K K reproduce the co1nbination determined by the five lreys.

The balance of the Baudot apparatus is adaptable to radiotelegraphy without any modification. The operation is as follows:

During the time required for wiper L, to traverse the 17 other segments, the arma tures oi the magnets K K, remain in the positions they acquired. A translating disc is connected with the wiper L, and carries suitably arranged projections and grooves. By means of these projections and grooves, the lovers C C called also selectors, are actuated and perform movements successively to reproduce all the combinations of the Baudot alphabet. At the moment when the position of the selectors coincides with that of the armatures of the receiving magnets, the printing magnet F becomes energized, and by attracting its armature, presses the paper ribbon against the type-wheel. This wheel is fixedly secured to the wiper L and presents always that character with respect to the paper, the corresponding combination of which is reproduced by the selectors.

In accordance with the present invention, the secrecy of the communications is secured by destroying the regularity or periodicity of the signals by means of which they might be deeiphered. Such periodicity lll or regularity may be found in the periodic ity of the synchronism controlling impulses, in the succession of the signals in the alter nating order of the characters in the dit- 't'erent telegrams, and in each character the order of the signals of which it is composed.

The arrangements provided in accordance with the present invention tor insuring the secrecy are as follows:

(a) The synchronism controlling inunilscs are eliminated. Due to this elimination, itis necessary to control the regulating of the apparatus by means of signals of which the telegrams themselves are con'iposed.

This is accomplished in accordance with the following principle:

The instant when the indicator J (Figs. 1 2 3 is actuated in response to the attraction by resonators B R, is entirely dependent on the position of the wiper L, serving the sending distributor, because its movement depends on this wiper. At this same time, the position of wiper L, serving the receiving distributor, must be fixed with precision. Thus, through the agency oi the movement performed by the indicator J, the relative positions of the two distributors are regulated. If L lags, the indicator 5 must send to it an advancing impulse, and vice versa.

An embodiment of this principle is illustrated in Figs. 3 and 3 An insulating disc 0 is rigidly connected with, and is driven by the wiper serving the receiving distributor. Conducting segments are provided on the periphery of this disc. The number of these segments is 2%, double the number of segments provided on the distributor D The segments are insulated from each other, and are alternately connected with two wipers Q and Q lVhen the indicator J changes its position, a contact V is suddenly pressed against the disc O. The contact is retracted as soon as the indicator J reaches the position opposite to its initial position.

Depending on the common position occu pied by the wiper L of the receiving dictributor and the disc O, the contact V closes the circuit of battery P, either through the agency of wiper Q, or through the agency of wiper Q The other ends of these two wipers are connected with two opposed windings Y, and Y One of these windings is provided in a manner to slow down the movement of the wiper L of the distributor, and the other winding to speed up the movement. As shown in Figs. 3 and 3 these windings pro vide an additional energization for the driving motor X of the wiper L When the distributor is slightly lagging and closes e. g. the circuit Y the field of the motor de creased and its movement accelerated. The additional inductors Y and Y, are shunted by means of large condensers I so as to at tenua-te the breaking sparks and to increase the quantity of electricity stored in response to the sudden closure of the contact V. If the regulators of the driving motors at the two stations are sensitive and well regulated, the corrections, that are repeated upon each movement of the indicator J, might be very slight.

The contact V may be controlled in a plurality oit dill'erent wa Fig. 3 illustrates an anchor escapement controlling a camwheel S, controlled in turn by a spring, not shown.

The positioning of the disc 0 with relation to the distributor L is determined by means of a preliminary adjustment. adjustment is made once for all to take into account the angular displacements due to the time constants of the different circuits and the mechanical apparatus.

(2)) Elimination of all apparent corre- This spondence between the order in which. the

a Hertzian signals sent out by the distributor really follow each other, and the order in which these signals ought to arrive to form, for direct reading, the 12/5 characters appertaining to a/5 different telegrams.

The distributors D,, L, and D L autoally transmit to each receiving magnet the impulse sent out under the control of the corresponding key, and thus it is not necessary to send the signals in the same order in which they will be ready. One of the main features of the present invention is the ad; ntation of this arrangement to Wireless telegraphy. All. we need to do is, to connect each key and each receiving magnet armature (Figs. 2 and 2) with the shaft of an interrupter having a terminals which in turn are connected with 11 segments of the corre sponding sending or receiving distributor. In accordance with a previous understand ing between the operators at the sending and receiving station, any segment may represent a lrey and a corresponding armature. It should be understood, however, that one and the same segment cannot represent at the same time a plurality of keys or armatures, and each armature must be connected to a segment the order number or' which is the same as that oi the corresponding key. In order to make possible the operations necess for the sending and the transcribing, only n-|-1n/5 segments (i. e. 30+14::17, in the present case) are reserved for each group tra isinitting or receiving the same telegram; As shown in Fig. 2, the first group might occupy the segments 1, l7 and any other three segniionts between 1 and 17; and so forth for the other groups.

This arrangement makes impossible the success of any deci ncring method, because it a third person intercepts the Hertzian signals, the alphabet may be changed as often Hill as it is desired and the characters of which the telegrams are composed may be arbitrarily mixed up. Furthermormthe momentary stopping of a group of keys is hardly noticeable, and the risk of discovery is lessened.

By setting aside any segment for any key or receiving magnet armature, it becomes necessary to make important modifications in the Baudot apparatus. As a matter of fact, the operator at the sending station, and the transcribing wheel at the receiving station have no more the time necessary for preparing the character to'be sent or for transcribing the character received. This disadvantage is remedied in the following manner (Figs. 2 and 2 The sending station comprises a timing device between each key and the corresponding contact. The arrangement is provioed in such a manner that, during almost an entire revolution of the distributor (in the present case, exactly 15/20 of a revolution), the keys combined at will do not interfere with a character that is being transmitted, actuate the contacts at the end of the revolution, and cause the sending out of the signal representing the character registered during the revolution that follows. In the following, a detailed description will be given of the mechanism for the group of live keys shown in the drawings and adapted to be connected with terminals 1 to 17.

I The electromagnets 1V are energized while the wiper L, traverses the segments 20, 1, 2 17. These magnetsmaintain their contacts in a position determined by the character to be sent. The attracted force of these .electromagnets is calculated in such a manner that it always overcomes the springs r 7",. When engaging segment 3, the wiper L, causes the actuation of an audible signal, whereby the operator will be informed that he has to register on the keyboard the next character. The actuated keys cause the armatures T to stick to the electromagnets U, which are energized between segments 3 and 20, inclusive, and the action of which over coming the action of the sorings r, and r maintain the armature in the position into which it has been moved. Due to this movement, the springs are put under tension and they will have a tendency to turn the contact K in a clockwise direction. The keys that are left in their normal position, leave the armature T at a distance from the electromagnet U. The springs 1', and r are adjusted in such a manner that they will under these circumstances have a tendency to turn the contact K in a counter clockwise direction. When the wiper L, engages the terminals 18 and 19, the contacts K are released by the deenergized magnets N and are un der the exclusive control of the springs. Yi'hen the wiper reaches the terminal 20, the

contacts are arrested in their new position.

The sending of the signal registered on the keyboard begins now. When the wiper engages the terminals 1 and 2, the electromagnets U release their armatures, and there abut against the keys that are in normal position. And so on and so forth.

An identical arrangement is shown at the receiving station (Fig. 2 and operates in the same manner. If the indicator J is actuated by a working signal at the time when the distributor L, passes over the corresponding terminal each one of the magnets E, will become energized. The armature T in question is then attracted and a magnet (U, U,) will be energized while the wiper L, of the distributor traverses terminals 1 to 19 to maintain the armature in its actuated position. At the end of one revolution. the aiuiatures T reproduce the combination transmitted by the sending station. While the wioer passes ov r terminal 18, the magnets ll are deenergized and release the armatures K, K These armatures in turn reproduce the same combination and are maintained in their position during almost an entire revolution of the distributor, by means of magnets VJ which are again energized. Vvhile these armatures are thus maintained in their position, the desired character is printed under the control of the selectors and the type-wheel in the same manner as in the usual Baudot apparatus in above explained manner.

This receiving arrangement could be considerably simplified. In each group, the give timing arrangements, the armatures of the receiving magnets, the selectors and the transcribing wheel could be replaced by five electromagnets which impress directly on the type-wheel additional movements which are respectively proportional. to 1, 2, 4, S and 16.

The circuit arrangement of such system is illustrated in Fig. 4. The give magnets a, b, 0, cl. 0 attract armatures the displacements of which are proportional to 1, 2, 4, 8 and 16. These armatures carry pulleys a 6,, 0,, (Z 6,. A thread f passes overthese pulleys. One end of this thread is attached at g, and the other end is turned around the drum h, of the typewheel h. All the numbers 1 to 81, inclusive, may be obtained by adding 1, 2, 4;, 8 and 16 to the combinations. By energizing one or a plurality of the magnets a, b, 0, cl, e, the type-wheel 72, may be rotated to an extent in proportion with any of the numbers of the series 1 to 31, i. e. may be operated to impress on the paper any one of the characters carried thereby.

Having now described myv invention, what I claim is:

1. In a radio signaling system, the combination of a transmitting system comprising a plurality of groups of keys, the keys of each of said groups being adapted to be set in accordance with a code for indicating a character, an oscillation generator adapted to radiate impulses of two differentfrequency characteristics, means for automatically causing said generator to successively radiate either of said impulses in accordance with the position of said keys, means at the receiving station for selectively receiving said impulses, and means for selecting the impulses of each group.

2. In a radio signaling system, the combination of a transmitting system comprising a plurality of groups of keys, the keys of each group being adapted to be differently set in either of two positions in accordance with a code for indicating a character, an oscillation generator adapted to radiate impulses of two different kinds in accordance with the position of said keys, means for predetermining the order in which the impulses are transmitted, means at the receiving station for selectively receiving the two kinds of impulses, and means for selectively indicating the impulses of the groups.

3. In a radio signaling system, the combination of a sending station having a distributor, a rotatable wiper cooperating therewith, a plurality of segments, a plurality of keys connected to said segments and divided into a plurality of equal groups, an oscillation generator adapted to radiate two kinds of impulses depending on the position of each key when the wiper of the distributor passes over the corresponding segment, and a receiving station having a distributor, a wiper adapted to rotate in synchronism with the first mentioned wiper, a plurality of segments and a plurality of -electromagnets connected therewith corresponding to the keys and grouped in the same manner.

a. In a radio signaling system, the combination of a sending station having a distributor, a rotatable wiper cooperating therewith, a plurality of segments, a plurality of keys connected to said segments and divided int-o a plurality of equal groups, an oscillation generator adapted to radiate two kinds of impulses depending on the position of each key when the wiper of the distributor passes over the corresponding segment and a receiving station having a distributor, a wiper adapted to rotate in synchronism with the first mentioned wiper, a plurality of segments and a plurality of electromagnets connected therewith corresponding to the keys and grouped in the same manner, a motor for driving the last mentioned means, and means for controlling the speed of said motor in accordance with the signal impulses received.

HENRI JEAN JOSEPH MARIE de REGNAULD de BELLESCIZE.

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