US2405617A

US2405617A - Data transmission system

Info

Publication number: US2405617A
Application number: US469045A
Authority: US
Inventors: Fred J Singer
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1942-12-15
Filing date: 1942-12-15
Publication date: 1946-08-13
Anticipated expiration: 1963-08-13

Description

'10 Sheets-Sheet 1 F. J. SINGER DATA mmsmssron SYSTEM- Filed nec. 15. 1 942.

Aug. 13, 1946.

Augf 13, 1946. l F. J. SINGER DATA TRANSMISSION SYSTEM n ld nac. 1'5. 1942 Y 1o sheets-sheet 2 www w .mum m l 6A wi Aug. 13, 1946. F, J, SINGER' 2,405,617

DATA TRANSMISSION SYSTEM Y Filed nec. 15.11942 1o sheets-sheet s Aug. 13, 1946.

F. J. slNGER DATA TRANSMI S S ION SYS TEM Filed naci. 15. 1.942 -1o sheets-sheet 4 QL... aM-

ATTORNEY' ugu E3, 119460 F, J, SENGER 2,405,611

l DATA TRANSMISSION SYSTEM Filed Dec. 15.v 1942 1o sneetslsheet 5.

1' J. S/NGER BV I ATTORNEY Ug 13; 1945 F. J. SINGER DATA TRANSMISSION sYSLrE/xv Filed pee, 15, 1942 1o sheets-sheet e Ff J 5//V R By I I TmR/VEV F. J. SINGER DATA TRANSMISSION SYSTEM Aug. 13, 1946.

F'iled Deens, 1942 1o sheets-sheet 'I ATTORNEY F. J. SINGER F'iied Dec.- 15, 1942 1o sheets-sheet 8 DATA TRANSMISSION SYSTEM Aug. 13, 1946.'

Milli ZAGSE 7 Aug. 33, i946, F. .1. SINGER DATA TRANSMISSION lSYSTEM 1o sheets-sheet 9 Fled'Dec. 15, 1942 33, i946 F..J.s1NGER DATA TRANSMISSON SYSTEM www Filed Dec. 1S. 1942 lO Sheets-Sheet 1G Patented Aug. 13, 1946 UNITED STATES DATA TRANSMISSION SYSTEM Application December 15, 1942, Serial No. 469,045

7 Claims. l

This invention relates to data transmission or telemetric systems and more especially to such systems in which data observed at the observing station is translated into permutation code telegraph signals which are transmitted from the observing to the receiving station for retranslation.

In the particular embodiment disclosed herein, the invention is applied to the transmission of data defining the angle between the line of sight to a target and a base line. Two observing stations at the extremities of a base line of known lengths areemployed. Mechanism is provided ior measuring the angle between the base line and the line of sight to the target at each observing station. The size of the angle is eX- pressed in degrees and hundredths of a degree. The number expressing the angle is divided into two parts. A separate permutation code is assigned to each of the two parts. A group of permutation code signals, corresponding to the code defining one part of the number, such as the two right-hand digits of the number, is impressed simultaneously on a circuit connecting the observing and receiving stations. That is to say, the complete multielement permutation code signal is impressed on a circuit having as many separate transmitting elements as there are elements in the multielement permutation code employed. if, as herein, a six-element permutation code is employed for one portion of the number, a circuit capable of transmitting six signals simultaneously to denne the two right-hand digits of the number completely are transmitted simultaneously. Then the signal elements comprising the code defining the left-hand digits of the number are impressed on the same connecting circuit in the same manner. At the receiving station two separate independent receiving means are employed to receive the signals from each observing station. The invention includes means for insuring that the two separate observing and receiving systems are operated in synchronism.-

The base line of fixed known length and the two angles between the base line and the two lines of sight from the two observing stations to the target X the location of the target. The system is arranged to dene to the hundredths of a degree any angle within a {E-degree Zone but is capable of expansion. The particular 30-degree zone in which the line of sight is located is made known to the operators at the receiving station by means of some complementary facility such as by telephone or telegraph. Although the invention is applied hereinv to the measurement of angles, it may be employed for transmitting receiving data representing anything without limit.

An object of the invention is the improvement of data transmission systems.`

A more particular object of the invention is the improvement of data transmission systems in which permutation code telegraph signals are employed in transmitting the data between stations.

A still more particular object of this invention is the provision of a data transmission system arranged to rapidly transmit signals deiining multidigit numbers.

A feature of this invention is means for supplying all of the electric energy required for the operation of the system from the receiving station so that no means for producing electric energy is required at the observing station.

A further feature of this invention is the employment of means for generating telegraph signals in accordance with two completely independent permutation codes and in which signals in accordance with one or these codes define the two right-hand digits of a four-digit number representing observed data and signals in accordance with the second of these codes define the two left-hand digits of the number.

A further feature of this invention is an arrangement in which any of 4,096 numbers may be defined by permutation telegraph signals in accordance with two independent six-element codes but in which the apparatus is arranged for the actual transmission and translation of 3,000 of the possible 4,096 codes to identify any of 3,000 numbers which may represent any part of a 30- degree angle dened to the hundredths of a degree.

A further feature of this invention is an arrangement in which a change in the data to be transmitted is from one number to the next higher or next lower number and in which a corresponding change in the permutation code signals transmitted involves a change in but one element of each of the two multielement signal codes used to identify the number, which results in effecting changes in the transmitting and receiving apparatus with a minimum of signal transmission and readjustment.

A further feature of the invention is that all of the elements of a particular signal code com bination completely dening one portion of the multidigit number corresponding to the observed data are impressed on the circuit interconnecting the stations at one time and all of the elements 3 of a particular signal code combination completely defining another portion of the number are impressed on the circuit at a second time.

A further feature of the invention is that each set of data is entirely independent of previous data. That is, the system does not depend upon sequence nor history for information sent or decoded at a particular time, so that line hits or other disturbances will not result in errors in subsequently transmitted data.

These and other features of the invention will become apparent from the following description when read with reference to the associated drawings in which:

Fig. 1 is a schematic showing the general disposition of the major apparatus units of the entire system;

Fig. 2 shows two sets of transmitting cams which are mounted on the azimuth instrument at each observing station and on which the two codes corresponding to the two portions of a multidigit number representing the measured angle are set up at each observing station as well as the electrical contacts and wiring controlled by the cams at each station;

Fig. 3 shows two sets of relays on which t'he codes set up by the two sets of cams in Fig. 2 are impressed and a transfer relay for controlling the transmission of the data set up on each set of code relays to the receiving station at different times; y

Fig. 4 shows a set of six polar relays located at the receiving station for receiving the codes set up on the two sets of code relays per Fig. 3 at different times. It includes also a transfer relay for controlling the directing of the two different codes dening the two different portions of the multidigit number to two diierent selecting and marking circuits which translates the two codes;

Fig. 5 represents the left-hand portion and Fig.

- 6 the right-hand portion of a relay selecting and marking circuit used in translating the codes set up on the top set of cams in Fig. 2 to identify the position of the line of sight in the observed .S-degree zone to the nearest half degree;

Fig. 7 is a commutator including six segmented drums each comprising conducting and nonconducting segments and a set of brushes for controlling the application of battery and ground to various apparatus units in the transmitting and receiving mechanisms associated with each observing and receiving device to control the transmission and reception of the two sets of permutation code Signals used in denning any observed angle at each station in the proper time sequence;

Fig. 8 is a time sequence diagram for the commutator per Fig. 7 used in explaining the operation of the commutator;

Fig. 9 is the left-hand portion and Fig. 10 is the right-handportion of a circuit which is identical with the circuit per Fig. and Fig. 6. It is used to translate the codes set up on the bottom set of cams in Fig. 2 to fix the line of sight to the nearest hundredth of a degree by making the selection of a particular one of fifty possible onehundredths of a degree in each one-half degree zone. Since Fig. 9 and Fig. 1G are identical with Fig. 5 a'nd Fig. 6 and the manner in which they operate is the same as Fig. 5 and Fig. 6, the wiring of Fig. 9 and Fig. 10 is not shown in Vdetail as it is not necessary to an understanding of the invention which may be fully understood from 4 the description herein of the operation of Fig. 5 and Fig. 6

Fig. 11 is a chart showing the manner in which the set of six cam-controlled contacts in the upper portion of Fig. 2 operates to transmit 60 codes defining 60 one-half degree angles. In this chart there are six horizontal rows, one for each of the six cams. There are 60 vertical rows, one for each of the 60 diierent cam settings. Where a rectangle is cross-hatched, it indicates that the corresponding cam has a raised surface in that particular position and that its corresponding contact is closed;

Fig. 12 is a chart showing the manner in which the set of six cam-controlled contacts in the lower portion of Fig. 2 operates to transmit 50 codes defining 50 one-hundredth of a degree angles. In this chart, there are six horizontal rows, one for each of the six cams. There are 50 vertical rows, one for each of the 50 different cam settings. Where a rectangle is cross-hatched', itindicates that the corresponding cam has a, raised surface in that particular position and that its corresponding contact is closed;

Fig. 13 shows two code tables, one for half degrees and one for one-hundredths of a degree used in explaining the invention; and

Fig. 14 shows the manner in which Figs. 2, 3, 4, 5, 6, 7, 9 and 10 should be arranged each with relation to the other so that they may be properly interconnected into an operative system. The conductors extending to the margins of each of these gures interconnect to conductors in Corresponding positions on contiguous iigures.

In the system of numbering of the apparatus and wiring shown on these figures, apparatus and wiring in Fig. 2 will be numbered in the 200 series, apparatus and wiring in Fig. 3 will be numbered in the 300 series, etc.

Refer to Fig. 1. Fig. 1 shows in schematic form the general arrangement of the major apparatus units of a complete system comprising two observingstations and one main station or receiving station. It is to be understood that the observing stations are actually located at the extremities of a straight base line of ixed length passing through the receiving station. In Fig. l, the two observing stations are shown for convenience at the left of the iigure. At the upper left of the figure the main items of apparatus located at one station, labelled the A station, are shown. At the bottom left of the iigure the major apparatus units at a second station, the B station, are shown. Each of the observing stations is connected to the receiving station by eight conductors. Six of these conductors are used for transmitting simultaneously the six-element permutation code signals. The remaining two conductors are used for synchronizing and controlling transmission.

As indicated in the upper and lower left-hand portions of Fig. 1, at each of the stations there are cams mounted on the azimuth instrument. As the line of sight to a target changes, the cam settings are changed. On each azimuth instrument, as indicated in Fig. 2, there are two sets of cams. One set of cams sets up 60 codes to denne each of 60 one-half degree angles in a 30- degree zone. The other set of cams sets up 50 codes to define each of 50 one-hundredths of a degree in a half degree zone. At the main station there is a motor-driven synchronizing switch or commutator indicated by a rectangle in the middle of the right-hand portion of Fig. 1. The motor-driven synchronizing switch or commutator (l.) maintains 'the transmission v'and reception of the data for teach station in synchronism; (2) controls the operation of -a transfer relay at each observing Kstation which transfers the 'six code 'signal transmitting conductors, interconnecting .an vobserving station land the 'central station, lbetween two different sets of code registering relays at each observing station, which relays respond to 'the codes set upon the two Isets of cams, .so as to transmit `each Y"of the 'two co'des defining each multidigit number 'to the receiving station in the proper sequence; '(3) controls a second `transfer .relay individual to veach observing station but located .at vthe 'receiving station so as to direct the code signals defining the half degree information .and the 'hundredth .degree information to separate selecting and marking circuits in the receiving station for 'each observ- Aing station; (4) locks the 'code :information received by the selecting circuit for 'the half degree information and the hundredth degree information momentarily in 'the selecting and marking circuits associated with `each observing station at the receiving station.

Codes defining the particular half degree zone in which the line of sight to the targetfis located are impressed on 'the six code `transmission conductors connecting each observing station with the main station simultaneously. 'The code defining the half degree zone is impressed on a polar relay repeating circuit at 'the main station individual Yto each observing station. The code set up on each polar lrelay repeating circuit for a particular lone-half degree zone is impressed at the receiving station on Sa'n individual onehalf degree :selecting and marking circuit 'for each observing .station which translates the code and operates an indicator to show the number of the particular one-half degree zone involved at the main station. .After this information has been transmitted and' recorded at the 'main station, the code for the hundredth of a degree iny formation is transmitted 'from each observing station over the same six wires used to transmit the half degree information from each observing station to the receiving station. The hundredth of a degree information is set up at the receiving station on the same polar 'relay repeating circuit associated with each observing station used in receiving the one-half degree information. The polar relay repeating lcircuit transmits the code identifying the hundredth degree setting into an individual one-hundredth degree selecting and marking circuit for each observing station. marking circuit controls an indicator to indicate the particular one-hundredth degree setting for each station.

Refer to Fig. v2. Fig. 2 shows the two sets of permutation cams mounted on the azimuth instrument at an observing station. Fig. 2 also shows a Vernier 20| having 100 divisions. Each of the divisions represents one-hundredth degree. The Vernier is rigidly secured to a shaft 202. The shaft and Vernier are rotated by means of crank 203. The telescope on the azimuth instrument (not shown) is rotated through one degree for each revolution of crank 203 by means of gear 204 which is also rigidly secured to shaft 202.

Securely xed to shaft 202 is worm gear 22| which engages with spur gear 222. The ratio of gears 22| and 222 is such that gear 222 makes one-thirtieth of a revolution for each revolution of gear 22| and Vernier 20|. One-thirtieth of The hundredth degree selectingv and "f a revolution of gear 222 therefore corresponds to one degree change of azimuth and a complete revolution of gear 222 corresponds to a -degree change of azimuth. Gear 222 is securely xed to shaft 223.

Cams

224, 225, 226, 221, 228 and 229 are also securely fixed to shaft 223. Cams 224 to 229

control contacts

230, 22|, 232, 233, 234 and 235. The cuttings of cams 224 to 229 are arranged so that they set up 60 different combinations on. contacts 230 to 235 for each rotation of shaft 223, Each different setting of contacts 230 to 225 defines a diiferent half degree in a 30- deg'ree zone.

Rigidly secured to shaft 202 is gear 204 which engages gear 225 securely mounted on shaft 22S. The ratio of gears 204 and 225k is such that for each revolution of shaft 202, while gear 204 rotates once, gear 205 rotates twice turning shaft 226 through two revolutions. Securely fixed to shaft 265 are cams 227|, 208, 209, 2li), 2H, 2|2 and 2|3 whichcontrol contacts 2|4, 2|5, 2|6, 2||,

2i

8, 2|9 and 220. Since shaft 202 rotates twice for each rotation of the Vernier, shaft 226 makes one revolution for each fifty-hundredths degree change of azimuth. Cams 221 to 2|2 are so cut that during each revolution of shaft 206 the cams set up different combinations of settings of contacts 2|4 to 2|9. Each different combination of contact settings defines a different one-hundredth degree of azimuth.

Cam 2| 3 and contact 220 act as a switch to control the circuits associated with the one-half degree cams so that when the Vernier passes through 00 and 49 the one-half degree cam circuits are held open.

Refer to Fig. l1. The different settings of the contacts controlled by cams 224 to 220 are indicated in the chart of Fig. 11. Reference to the left-hand vertical column in the chart, per Fig. 1l, indicates the manner in which contacts 230 to associated with cams 22|@ to 220 are arranged the rst of the 5() different cam positions for the half degree zones which corresponds to the code for di) degree. The left-hand column of the chart indicates that for this condition contacts associated with

cams

225, 225, 223 and 229 are closed and that contacts associated with cams and 22? are open. The condition of contacts to 235 for each of the cam cuttings defining each of the half degree zones from 0.0 degree to 29.5 degrees is indicated in its respective vertical column in the chart per Fig. 11.

Refer to Fig. 12. The 50 vertical columns in 1.2 indicate the condition of contacts 2M to 2i@ associated with cams 2ii| to 2 I2, respectively. The left-hand vertical column in Fig. 12 shows thalr the contacts associated with

cams

207, 208, i and 2 l2 are closed in the first 0f the fifty cam positions which corresponds to the code for .Q0 degree or .50 degree for each degree setting, depending upon the particular half degree zone in which the line of sight is located.

Attention is particularly called to an important characteristic of the codes disclosed in Fig. 11 and 12. Reference to either of these iigures shows that the change in the cam settings and therefore, in the contacts which the cams control, involvesa change in but a single cam and therefore a single contact for each transition from one setting to the next higher or next lower setting.

This also illustrated in Fig. 13, Tables 1 and 2. Table 1 refers to the half degree cams; Table 2 refers to the hundredths of a degree cams.

Columns

1 and 4 of each of these tables show the number of the cams which are in position to close contacts for each code position.

Columns

2 and 5 of the tables show the half degree and hundredth degree information corresponding to the codes indicated in columns l and 4. In the selecting circuits, per Figs. 5 and 6 considered together and Figs. l9 and 10 considered together, the selecting relays are arranged in six vertical rows in each pairof figures, each row comprising two relays. For instance, there are three such vertical rows in Fig. 5,

rows

1, 2 and 3; and three in Fig. 6, rows Il, 5 and 6. The numbers in

columns

3 and 6 in code Tables l and 2, per Fig. 13, indicate the relay row position in Figs. 5 and 6 and Figs. 9 and 10 in which the selected lamp corresponding to the code in the nist and third columns and to the degree numbers in the second and fourth columns will be found. This will now be explained in more detail.

The code combination inthe top rectangle of column 1, Table 1, which pertains to half degrees is 2356. This indicates that the contacts associated with half degreecams 2,. 3, 5 and 6 will be closed for the 0.00 degree code as shown in the top rectangle of column 2 of Table l. The number 6 appearing in the top rectangle of the third column of Table 1 indicates that the lamp for the 0.00 half degree zone will be found connected to a relay in relay row position 6 which is shown' at the right of 6. Reference to Fig. 6 shows that the lamp corresponding to the 0.00 zone is connected to the upper of the two relays in position 0.

Reference to Table kl and Table 2 of Fig. 13 will disclose that there is a change in only one element in each code on transition to the next higher and next lower number.

Before beginningr the description of the detailed operation of the system a further explanation of the function of the commutator, per Fig. 7, and its relation to the various circuits will be givenin order to facilitate an understanding of the detailed description to follow.

The raised surfaces Aon the peripheries of cams 224 to 223 in Fig. 2 will supply battery transmitted from the commutator at the receiving station over one of the two control conductors through such of contacts 230 to 235 as are operated to the windings of corresponding relays in relay group 302 to 33'! in Fig. 3. For each cam contact which is closed a corresponding relay in the group of relays 302 to 301 will be operated and locked. When contacts 2M to 2|9 are operated in accordance with a particular code, a corresponding relay in the groupmc relays'300 to 3M will be operated and locked. interconnecting each observing station with the receiving station there are six transmission conductors, such as 3|6 to 32|, and two control conductors. 322 and 323. The transmission conductors are terminated on individual armatures of transfer relay 3io. The armatures of the two sets of code relays are connected to opposing contacts associated with each of the six armatures of transfer relay 3|5. The same six transmission conductors 3|6 to 32| are used to transmit and the same six receiving relays 40| to 400 at the receiving station are used to receive both the code signal impulses for the half degree and the hundredth degree settings for one observing station. Corresponding transmission conductors and receiving relays function for the second station. It is necessary in order to fiX the position of the target that the angles between the line of sight and the base line at each observing station be measured and the corresponding code signal impulses be transmitted simultaneously. Further, it is necessary to insure that the half degree 8 code impulses and the hundredth code impulses 'oe transmitted from each observing station to the receiving station in proper sequence.

This is performed in large part by the commutator, per Fig. 7. This commutator supplies either battery or ground, as required, at proper intervals to control the switching of relay 3|5 in Fig; 3 so as to connect the six conductors 3|6 to 32| either to the contacts of relays 302 to 301 for the transmission of the half degree code information, or to the contacts of relays 309 to 3M for the transmission of the hundredth degree information. After the codes for either the half degree information or the hundredth degree information are set up on relays 40| to 405 individual to each observing station, the commutator controls transfer relay 401 at the receiving station to direct the code` information to the proper group `of selecting and marking relays. It has been explained that there are two different selecting and marking Vcircuits associated with each observing station, one for the half degree information and the other for the hundredth degree information. As this information is set up at different times on relays 40| to 406 in Fig. 4 at the receiving station, itV

is necessary to route it at the proper time to either the selecting and marking circuit for the half degree information or to the selecting and marking circuit for the hundredth degree in"- formation. Relay 401 controls the connection ofFigs. 5 and 6 which taken together constitute the selecting and marking circuit for the half degree information, or of Figs. 9 and 10 which taken together constitute the selecting and marking circuit for the one-hundredth degree information to the code receiving Vrelays 40| to 40B.k When Figs. 5 and 6 are connected through transfer relay 407 to the code receiving relays 40| to 406 in Fig. 4, relays corresponding to the particular code set up on the code receiving re!- lays will be operated in Fig. 5 and Fig. 6 to make a selection yof a particular indicator which in the present embodiment is a lamp. Some one of 60 lamps in Figs. 5 and 6 is lighted to indicate a particular half degree zone in the Sli-degree range, When Figs. 9 and l0 are connected through transfer relay 401 to code receiving relays 40| to 406. a group of relays in Figs. 9 and l0, corresponding to the code'set up on relays 40| to 006 in Fig. 4, will be operated to make a selection of some one of 50 lamps. The lighted lamp in Fig. 9 or 10 will indicate the particular ftieth division on which the line of sight is located in the half degree zone shown by the lighted lamp in Fig. 5 or 6, thus determining the line of sight to the nearest hundredth of a degree.

The time of operation of the transfer relays for both stations iscontrolled simultaneously by the commutator in Fig. '7. The commutator also locks thevarious code and selecting relays momentarily to maintain their registrations for necessary intervals and to achieve one of the important objectives of this invention, to prevent unnecessary operation of relays on transitions.

The means by which the whole system is held in synchronism and the time sequence of operations may be understood from reference to Figs. 7 and 8.

Fig. 7 represents a commutator having six segmented rings '|00 to '|05 and twelve brushes '|06 to The segmented rings are shown in the developed condition. The rings are rotated in unison by a motor (not shown). As the six rines rotate each engages e eerl'espoedirlg pair of; stationary conducting brushes which Vare insulated each from the other. Thus, brushes '106 and '10'1 engage rings '160. Brushes '108 and '1119 engage rings llhetc. Ground H9 is' connected to brushes lill, 'H5 and lll'. Battery '118 is connected to brushes 129, 1li and tls. Each of the segmented rings comprises conducting and insulating segments. The conducting segments are represented by plain rectangles; the insulating segments are 'represented' by shaded rectangles. As the rings are rotated, when a conducting segment is presented to its corresponding pair of brushes, batt/ery or ground is transmitted from' one of the pair' o f brushes through the conducting segment and the other of the pair of brushes to Various items of apparatus at each of the A and B transmitting Stations to insure their operation in synchronism and to control the', order of transmission of the codes for the half degree and hundredth degree information from each observing station land their reception by the crresponding selecting and marking circuit for each station in the proper seqilenceY Attention is especially called to the fact that the single six-ring commutator, per Fig. 7, controis the operation of the transmitting mid receiving apparatus for both the A and B stations. The six time-control conductors '121 to '126, in Fig. 7, are shown connected to various items of apparatus in the dilerent figures which are assumed to serve the A station. These same six conductors are extended to a bracket inFig. 7 marked To corresponding apparatus for B station to indicate that they also serve the B station simultaneously.v Fig, 8 is a time sequence diagram for Fig. 7. It indicates times when the battery or ground connection, as the ease may be, is applied through the conducting segments of the rings, per Fig. 7, to the transmitting and receiving apparatus of stations A and B to maintain Synchronism and the proper order of transmission and reception of the half degree and hundredth degree information The time cycle is represented as starting at the lefthand margin of Figi. 8 marked Start of cycle and ending at the right-hand margin of Fig. 3 marked End of cycle. The time or a `full cycle is equal to the time for one complete rotation of the commutator, per Fig. 7, which is of the order of one one-twentieth of a second. It is pointed out that the line of sight -to the target may change more slowly than one one-hundredth .of a degree per one-twentieth of a second and may even remain stationary, in both of which cases the azimuth setting and corresponding .codes will remain unchanged while the code impulses are repeated and the indicator settings willremain unchanged during a corresponding interval, although they will be checked Vonce each cycle, or once each rotation of the commiltaters- Ifime in 8 is measured from left to right. The direction of rotation of the commutator rings is represented by the arrow in Fig. 7. The brushes Yare shown in the middle of Fig. -7 rather than -at the start of cycle position for convenience.

Commutatcr ist applies ground intermittently voyer .conductors 12.4 in Fig. 7, and i524 in Fig. 4 .to each ,of the make contacts of Apolar relays `lilll -to we `at `the receiving station, which relays -receive the permutation code signals from .the Aobserving station.

momentary locking of the six relays 369 to 314 on which the codes for the hundredth degrees are set up by cams 201 to 212.

Commutator '102 supplies battery over conductorsl in Fig. 7, and425 in Fig. 4, to the windof transfer relay 1101 which controls the directing of the signal impulses for the halfy degree and hundredths degree codes, set up on relays !lll to litt in Fig. 4, to their proper selecting and marking circuits, that is, either to Figs. 5 and 6 which serve for the half degree codes or to Figs. 9 and 10 which serve for the hundredth degree codes.

Commutator 7e3 supplies batt ry intermittently over conductor `'122 in Fig. 7, conductor 422 in Fig. 4, and conductor 322 in Fig. 3, to the winding of transfer relay 315 at observing station A. Relay 315 switches the six code transmission conductors alternately from the half degree code relays r30| to 33'1 to the hundredth degree code relays 3118 to 3l3 so that signal impulses in accordance with the half'degree codes and'hundredth degree codes may be'transmitted from the observing station to the receiving station in their proper order.

.Ccmmutator '104 supplies ground intermittently over conductor 12d in Figli and conductor 921 in Fig. 9 to the locking armatures and windings of the six pairs of selecting relays for the hundredth degree lamps in Figs. 9 and 10. `rlhe details of the connection of conductor 92! to .the locking pathsof the six pairs of relays are not shown. The details are identical, however, with the connections of the locking paths for the siX pairs of *corresponding selecting relays for the half degree lamps in Figs. 5 and 6.

'Commutator '1&5 supplies ground intermittently over conductor '125 in Fig. 7,'condu`cto`r 626 in Fig. 4, conductor 52.6 in Fig. 5, and conductor 626 in Fig. 6 tothe locking armatures and windings f the -five :pairs of selecting relays -for the vhair" degree 'lamps in Figsl Y5 and "6,

Fig. 8 shows al time sequence diagram of operation for both halves of the system. Sections Sill! to 805 of Fig. 8 are time diagrams which relate to rings '190 to TG5 in Fig'. 7 and the apparatus units controlled thereby. Section elle relatesto the time of collection of the one-hundredth ydegree and one-half degree information at the A and B stations and to the times of the reception of the data at the central station.

Detailed operation The operation of the system will now be described for `the case in which the A observing station azimuth instrument is at 29.05 degrees. Since the B observing station arrangements are identical with those of station A, the operation of vthe B station part of the system will not be described. It is apparent, however, that veven vthough `the method of collecting, transmitting and translating data .for both halves of the complete .system is identical, the angular positions of the instruments at the two stations would normally be quite different. i r Starting at the beginning of the time cycle .of the motor-driven synchronizing Switch, Figsj'? 11 and 8, and assuming that the position of theV azimuth instrument at the A station is at 29.05 degrees, a circuit may be traced from battery 113 in Fig. 7 through brush 100, the conducting segment of ring 10|, brush 108, conductor 123, conductor 423 in Fig. 4 and conductor 323 in Fig. 3 to parallel branches formed by conductors 335 and 303. The upper branch 335 extends also to parallel branches 331 and 338. Branch 361 continues through the Winding of relay 30| to ground. Relay 30| is slow to operate. During the interval before it operates, the branch through conductor 353 extends through break contact 324 of relay 30| through conductor 339 which connects vto conductor 231 in Fig. 2 and the `circuit extends through contact 220 which is closed, conductor 238, conductor 310 and conductor 245. Conductor 245 is connected in parallel to the armatures actuated by the half degree cams.

Reference to Fig. 13, Table 1,

columns

4 and 5, second line from the bottom, indicates that the code for 29 degrees on the halfdegree cams is 1256.

Contacts

230, 23|, 234 and 235 will therefore be closed. The closure of contactl 230 establishes a circuit through

conductor

23,3, conductor 31| and the winding of relay 302 to groiinijoperating relay 302. The closure of contact 23| establishes a circuit through conductor 240, conductor 312 and the winding of relay 303 to ground; operating relay 303. The closure of contact 234 establishes a circuit through conductor243, conductor 315 and the winding of relay 303 to ground, operating relay 303. The closure of contact 235 establishes a circuit through conductor 244, conductor 316 and the winding of relay 301 to ground, operating relay 301.

Simultaneously with the operation of the half degree code relays the hundredth degree code relays are operated over the branch of the circuit connected to conductor 368. Conductor 36S extends to parallel branches 311 and 310. Branch 311 extends through the winding oi relay 308 to ground but relay 303 is also a slow-tooperate relay. While it remains released a circuit may be traced through conductor 318, break contact 333 of relay 308, conductor 319, which connects to conductor 23S in Fig. 2 to the armatures of the hundredth degree cams in parallel.

Reference to Fig. 13, Table 2,`

columns

1 and 2, sixth line from the top, indicates that the code corresponding to five-hundredths is 123456. Contacts 2|4 to 2|0, inclusive, will therefore all be closed. Closure of these contacts establishes circuits through conductors 230to 235 which connect to conductors 330 to 335, respectively, each of which extends to ground through the winding of a relay in the 303 to 3 |11 group, operating each of these relays.

When relay 30| operates, the battery supplied from the commutator circuit heretofore traced is connected through conductor 368 and make contact 325 of relay 30| to the left-hand armatures and make locking contacts of operated

relays

302, 303, 30S and 301 to maintain the code for 29 degrees on these relays. After relay 308 operates, battery is supplied through conductor 310 and make contact 340 of relay 308 to the lefthand armatures and locking make Contact of of each of relays 309 to 3I4, locking each of these relays to 'maintain the code for live-hundredths of a degree,

During the interval that thedata is being set up on the coding relays, per Fig. 3, atthe A station, relay 3|5 at that station is released because Cil thecircuitto battery through Ycommutator 103, Fig. 4, is open. Y This is indicated by the shaded rectangle at the left-hand end of commutator ring 103 as Well as by the time sequence diagram of Fig. 8. With relay 3|3 released, the right-hand armatures of the group of relays 302- to 301 are connected tothe break contacts of relay 315. Those of relays 302 to 301 which have been operated, namely, relays 302, 303,- 300 and 301,V will connect ground through their righthand armatures and the corresponding make contacts of relay 3|5, namely,

contacts

353, 355, 332 and 364 to conductors 3|6, 3|1, 320 and 32|. These circuits are extended to the receiving station Where they connect to`conductors 4I6, 4|1, 420 and 42| which extend through the top windings of polar receiving relays 40|, 402, 405 and 400 to battery in each instance. -Polar relays 40| to 406are-biased by obvious circuits extending through their bottom windings which maintain their respective armatures actuated toward the left when no current flows in their top windings. When the circuit through their top windings is energized, the armatures are actuated toward the right to engage their contacts. The armatures of relays 403 and M14-remain actuated-t0 the left. v f n l f At this time, however, the coded information setv up on the group of relays 40| to 406 is not transferred to the corresponding relays of the selecting and marking` circuits for one-half degrees, per Fig. 5 and Fig. 6, because ground `is disconnected by means of the insulating segment shown at the left of ring '|00 in Fig. '-from the circuit which may be traced from ground 1|3 through brush 101, insulating segment of ring 100, brush 100, conductor '|24Y and conductor 424 tothe contacts of relays 40| to 400 in parallel.

The coded data that was set up during the previous cycle of the synchronizing switch is, therefore, maintained on the relays, per Figs. 5 and 6, at this time.

After the coded data for 29.05 degrees has been collected on the relay register circuit, per Fig. 3, and concurrent with the completion of the operfation of relays 30| and 308 in Fig. 3, synchronizing switch 1 moves to a position Where commutators 102 and 103 apply battery, respectively, to the-transfer relays, such as 401, corresponding to each observing station and to the transfer relay, such as SI5, at each observing station. The circuit for relay 401 may be traced from battery 118,through brush 1H, conducting segment of ring 102, brush 1|0, conductor 125, conductor 425, and the Winding of relay 401 to ground, operating relay 401. The circuit for

relay

'operation of relay 3|5 transfers the six code transmission conductors 3|0 to 32| to the make

contacts

354, 350, 358, 359, 36| and 363 which connect to the right-hand armatures of relays 30S to 3|4 and the circuits are extended through

contacts

342, 344, 340, 348, 350 and 352 to ground. In this case impulses are transmitted over each of conductors 3| 3 to 32| and all relays 40| to 40S operate.

4Simultaneously with the operation of relays 40| to 406 in Fig. 4 the, synchronizing switch movesjto position where commutator 104 removes ground from' the locking circuits of the relays which were operated forthe previous onehundredth degree code in Figs. 9 and l0, thus enabling those relays to release and break down the hundredth degree code which had been set up by the previous cycle of the synchronizing switch. On the previous cycle the relays in Figs. 9 and 10 which had been operated in accordance with the code were locked over a circuit which extends from ground H9, through brush N5, conducting segment or" ring m4, brush H4, conductor 42H, conductor 92h and conductor |925 which extends through a locking circuit of each of the operated relays in Figs. 9 and 10. The locking circuits on Figs. 9 and 10 are not shown in detail but they are identical with the locking circuits connected to conductor 526 in Fig. 5 which corresponds to conductor 92| in Fig. 9, and conductor 626 in Fig. 6 which corresponds to conductor E62! in Fig. 10.

As the relays in Figs. 9 to l0 start to release, the synchronizing switch, per Fig. 7, moves to position where commutator ring '66 applies ground to the make contacts of relays 49! to 495 in Fig. 4. llipplication of these grounds closes paths from the respectively operated relays 45! to 405 to their corresponding relays in Figs. 9 and 10. Since each of relays 461 to 455 is operated, each of the relays in Figs. 9 and 10 will also be operated.v Operation of all of the relays in Figs. 9 and 10 establishes a local circuit in these figures to light the .65 lamp which indicates that the line of sight of the azimuth instrument at observing station A is at .05 degree. After the relays in Figs. 9 and 10 have had time to fully operate, cominutator 'Hifi-applies ground to the locking circuits of the relays and they, therefore, remain operated throughout the rest of the cycle of the synchronizing switch and the .G5-degree indication is maintained. These circuits will not be traced at this time as Figs. 9 and v10 are not shown in detail. The detailed operation` of these circuits to perform this function will be understood from the detailed description of the operation of the selective circuits per Figs. 5 and 6 hereunder.

Shortly after the locking path is established through commutator ring 104 of the synchronizing switch to the operated relays of Figs. 9 and l to maintain the registration for the K55-degree code, commutator 199 again removes ground from the make contacts of relays 40! to 455 in Fig. 4. This ground is removed in time to insure that when battery is removed from transfer relays SI in Fig. 3 and 457 in Fig. 4 and relays 451 to 496 in Fig. 4 take up new positions for the one-half degree code, there will be no false code set up on the one-half degree or one one-hundredth degree selecting circuits per Figs. 5 and 6 and Figs. 9 and 10.

After the removal of the ground from the make contacts of relays 40d to 406 in Fig. 4, commutator ring 792 in Fig. '7 removes ground from transfer relay 453i in Fig. 4 and shortly thereafter cominutator ring 753 removes ground from transfer relay 3i5 in Fig. 3 and these relays release. As soon as transfer relays 45'! and 3&5 are re* leased the 29-degree code set up on the half degree code relays, per Fig. 3, is transmitted to the receiving station and relays 136i, 492, 495 and 465 operate.

Later after suiilcient time has elapsed to insure the complete release of transfer relays SI5 in Fig. 3 and 49? in Fig. 4 and the operation of relays 45t, 492, 405 and 495 in Fig. 4, commutator 95 removes ground from the locking circuits of the one-half degree selecting circuit, per Figs,'5

.operated in accordance with the previous code attempt to release. Those of the operated relays which do not receive ground from the make contacts of the polar relays in Fig. 4 release; those that do receive ground from the make contacts of the polar relays in Fig. 4 remain operated. If the code which isreceived by the polar relays requires the operation of relays in Figs. 5 and 6 in addition to such of the relays as are maintained operated, such relays will receive ground and will be operated. Y For the ZQ-degree code the relays in positions l and 2 in 5 and in positions 5 6 in Fig, 6 operate, as the half degree code for 29 degrees, as has been explained, is 1256. Relays 59E, 592, 553, and 554 in Fig. 5 and. relays 659, 545, 5H and 5l2 in Fig. 6, therefore, operate. This will now be explained in lmore detail.

When transfer relays. SI5 and 46'! are released and the conducting segment of commutator ring ldd is in engagement with brushes 705 and lill., a circuit may be traced from ground 'H 9 through brush l5?, conductingsegment of ring 15.9, brush 05, conductor '124, and conductor 424 in Fig. 4, to the right-hand contacts of the polar relays 40! to v456 in parallel. In the case of relays del, 452, 455, and 406 circuits are closed through their armatures and

conductors

427, 428, 438 and 432, respectively, through contacts 435, 434, 437 and 435, respectively, through conductors 445, 446, 449 and 450, respectively, through conductors 545,

545, 549 and 559, respectively, each of which con-A nects in parallel to the windings of a -pair of rei, lays in Fig. 5 or Fig. 6. Conductor 545 connects through the windings of relays i and 592 in parallel to battery. Conductor 545 connects through the windings of relays 553 and 554 in parallel to battery. Conductor 549 connects to conductor 549 in Fig. 6 which extends through the windings of relays 609 and 6l@ in parallel to battery. Conductor 550 connects to conductor 650 which extends through the windings of relays Ell and 6l2 in parallel to battery. All of these relays operate. A circuit may then be traced from battery 65| through resistance 652, con ductor 653, contact 654, conductor 555, contact 655 and conductor 557 which connects to conductor 557 in Fig. 5. The circuit continues through contact 558, conductor 559, contact 559, co ductor E, contact 552 and conductor`55 which connects to conductor 653 in Fig. 6. The circuit continues through contact 554 and conductor 655 and is terminated at a point marked 29.00 which represents a circuit extending through the filament of a lamp to ground. The lamp lights to provide an indication that the line of sight of the azimuth instrument is in the 29.00 half degree zone.

If the relays in Figs. 5 and 6 are assumed to be operated in accordance with any of the code combinations for any of the sixty diierent half degree settings indicated in Fig. 13, Table l, a circuit may be traced from battery 65| through make contacts on relays in positions corresponding to the particular code in Figs. 5 and 6 and through break contacts on relays in other positions to numbers corresponding to those shown in

columns

2 and 5 of the table which represent corresponding indicating lamps in each instance.

After registration of the 25a-degree setting on the half degree selector circuit, commutator locks these relays momentarily over a circuit which may be traced from ground 'H9 through brush 'l l?, conducting segment of ring 105, brush 15 116, conductor 126, conductor 425 in Fig. 4, conductor 526 in Fig. 5, and conductor 626 in Fig. `G which connect to

parallel branches

564, 565, E55 and 651. Branchr564 extends through operated contacts 556 and582 and the windings of relays 552 and 58! in parallel to battery. Branch 565 extends through make contacts 551 and 583 to the windings ofY relays 504 and 503 in parallel to battery. Branch extends through make contacts 668 and 516 and the windings of relays Bill and 659 in parallel to battery. Branch 661 extends through make contacts 659 and 611 and the windings of relays SI2 and 6H in parallel to battery. Relays 55E, 502, 593, 504, 609, BID, 6H and SI2 will be locked to maintain the Ztl-degree code until commutator ring 105 interposes its insulating segment between its associated brushes.

Soon after the relays for the ZQ-degree code are locked in the operated position ground is removed from the make contacts of the polar relays in Fig. 4 when the insulating segment of ring 150 is interposed between brushes 155 and 101.

Finally the cycle is completed when the insulating segment of commutator ring is interposed between brushes i138 and 109 vto disconnect battery from the locking circuits of the half degree and hundredth degree code relays in Fig, 3, permitting these relays to release. The apparatus associated with stations A and B is then prepared to register and record the new position of the teleending at 49 correspond to those shown for the ,Y

half degrees in Table ,1, starting at the code for 0.50 degree and ending at the code for 25.00 degrees. The code for five-hundredths degree, shown in Table 2, is 123456. rIhis corresponds to the code for 3.05 in Table l. A circuit corresponding to the circuit for the uve-hundredth degree code in

Figsl

9 and 10 may, therefore, be traced, by way of example, in Figs. 5 and 6. The circuit extends from ground through battery 55! in Fig. 6, resistance 552, conductor 515, contact 6H, conductor 612, Contact 513, conductor 551, contact E14, conductor S which connects to conductor 515 in Fig. 5, contact 516, conductor 511, contact 518, conductor 519 and contact 580 to conductor 58! which is terminated in a symbol for the 3.00-degrce lamp. In Fig. 9 the conductor corresponding to conductor 58i would be terminated in the symbol 5 corresponding to the ve hundredths of -a degree lamp, as indicated in the sixth line,

columns

1 and 2 oi rFable 2 and as shownv for contact S85 of relay 952 of Fig,` 9.

Attention is especially called to the fact that in the invention herein the entire multidigit number is defined for each cycle of operation. Notwithstanding the half degree azimuth zone may not change, the half degree code is transmitted once for each time the hundredth degree information is transmitted. The reason for this is to minimize the seriousness of trouble conditions such as hits aiiecting a code for any setting, particularly a half degree setting. If the setting for the half degree zone, were to remain unchanged, after having been once transmitted, while the line of sight of the azimuth instrument remained in a particular half degree zone, a transient trouble condition causing an erroneous halidegree setting would be much more serious than is the case when the entire half-degree and hundredth degree position is dened once per cycle andthe frequency of transmission is relatively substantially high as in the arrangement herein. The system practically proof against the effect of random hits as the effect ci a hit would be so transient that it would be wiped out by the eiect of the following cycle of operation practically before it could become apparent to the eye.

This is particularly important, as it eliminates practically the only vdiiculty inherent in permutation code data transmission systems so that full advantage may be taken of their characteristic superiority over other presently known systems, namely, that the received information is not seriously affected, as are present systems which depend upon balancing arrangements of impedance or voltage, by variations in line impedance due to changes in temperature and Weather conditions.

What is claimed is:

1. A data transmission or communication system having a plurality of data stations connected to a central station, instrumentalities in said system for collecting complementary data simultaneously, said instrumentalities comprising a transmitter for transmitting synchronized impulses from said central station to said data stations, and control means at each of said data stations, responsive to the reception of said synchronizing impulses, for controlling the simultaneous transmission of all of the elements of a rst and a second combination of multielement permutation code signals from each of said data stations to said central station at a rst and a second time respectively, to define a first and a second portion of a multidigit number correspending to a measurement at each of said data stations.

2. A data transmission or communicating system, a plurality of dat-a stations and a central station in said system, a transmitter at said central station, means connected to said transmitter for transmitting first synchronizing impulses from said central station to said data stations, control means at said data stations, responsive to the reception of said impulses, for controlling the instantaneous and simultaneous transmission of all of the elements of multielement permutation code signal combinations from each of said data stations to said central station, means at said central station for transmitting second synchronizing impulses to said data stations, and means at said data stations, responsive to the reception of said second impulses, for controlling the order of transmission of said permutation code signal combinations from said data stations to said central station.

3. In a data transmission system, an observing station, a first means thereat for establishing simultaneously first permutations of two electrical conditions to completely dene a rst portion, comprising two digits, of a multidigit number, a receiving station, a group of polar receiving relays at said receiving station, a multiconductor transmission circuit interconnecting said stations, means at said observing station for impressing first signals in accordance with said first permutations simultaneously on said circuit at a first time, a second means at said observing station for establishing simultaneously second permutations of two electrical conditions to completely denne a second portion, comprising two digits, of said multidigit number, means for impressing second signals in accordance with said second permutations simultaneously on said circuit at a second time and other means at said receiving station, responsive to the reception of said first and said second signals, for operating said relays in conformity with said rst and second permutations.

4. In a data transmission system, an observing station, a receiving station, a transmission circuit interconnecting said stations, means at said observing station for impressing simultaneously on said circuit at a rst time permutation signals in accordance with a iirst multielement code to completely dene at least two digits forming a rst portion of a multidigit number, means at said observing station for impressing simultaneously on said circuit at a second time permutation signals in accordance with a second multielement code, completely independent of said first code, to completely define at least two digits forming a second portion of said multidigit number, a single measuring device, at said observing station, for controlling both of said means, and means at said observing station for transmitting signals in accordance with said second code once for each time signals in accordance with said first code are transmitted so as to minimize the adverse effect caused by trouble conditions while said signals are being transmitted.

5. In a data transmission system, an observing station, a single measuring device at said station, a plurality of separate groups of electrical contacts controlled by said measuring device, means connected to said device for translating a measurement made by said device, expressible as a multidigit number, into a plurality of separate multielement permutation code combinations, in accordance with separate multielement permutation codes, means for adjusting all of the contacts in each of said groups of contacts simultaneously in accordance with said combinations, in response to said measurement, a single multichannel transmission circuit having a separate channel for each element in said codes connecting said station with a receiving station, means for impressing signals in accordance with all of said elements of one of said code combinations on said channels simultaneously at a first time to completely define a first group of two digits in said number, and means for impressing signals in accordance with all of said elements of another of said code combinations on said channels simultaneously at a second time to completely define another group of two digits in said number.

6. In a telemetric system, means for adjusting a measuring device to measure a quantity at an observing station in terms of a, multidigit number having more than three digits, means for translating said measurement simultaneously into a 18 plurality of combinations of permutative settings of a plurality of groups of electrical contacts in accordance with a plurality of separate multielement permutation codes, to define each separate portion of said number, at least one of whichl portions has more than one digit, in response to said measurement, means for translating said plurality of permutative settings of said plurality of groups of electrical contacts into a plurality of separate code combinations of electrical signal elements, means for impressing each of said signal elements of each particular one of said code combinations simultaneously on a separate transmission channel in a single multichannel circuit interconnecting said observing station with a receiving station, and means for impressing said separate combinations on said circuit in sequence.

7. In a data transmission system, a rst and a second observing station, a measuring instrument at each of said stations, means connected to each of said instruments for making measurements in an ordered numerical sequence, means connected to each of said instruments for translating each measurement by said instruments simultaneously into a first and a second six element permutation code signal combination, each combination corresponding to two consecutive digits of a four digit number defining each of said measurements, a receiving station, six individual conducting channels of a single transmission circuit interconnecting each of said observing stations individually with said receiving station, a synchronizing device at said receiving station, means connected to said synchronizing device for controlling each of said circuits simultaneously so as to impress on said channels simultaneously at a first time at said observing stations all six of the elements of a signal combination corresponding to the two right-hand digits of said four digit number dening a measurement at each observing station, means connected to said synchronizing device for controlling said circuits simultaneously so as to impress on said channels simultaneously at a second time at said observing stations all six of the elements of a signal combination corresponding to the two left-hand digits of said four digit number defining said measurement at each observing station, and means for impressing said combinations corresponding to said left-hand digits on said channels once for each time said combinations corresponding to said right-hand digits are impressed on said channels to minimize the effect of errors due to hits during transmission.

FRED J. SINGER.