US2119196A - Type printing telegraph system with means for eliminating interference - Google Patents

Type printing telegraph system with means for eliminating interference Download PDF

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Publication number
US2119196A
US2119196A US724804A US72480434A US2119196A US 2119196 A US2119196 A US 2119196A US 724804 A US724804 A US 724804A US 72480434 A US72480434 A US 72480434A US 2119196 A US2119196 A US 2119196A
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Prior art keywords
signal
current
relay
interference
resting
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US724804A
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English (en)
Inventor
Bakker Arjen
Hendrik Cornelis Antoni Duuren
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RCA Corp
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RCA Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received

Definitions

  • the object of the invention is to provide a type printing telegraph system in which the unnoticed reproduction of signals or signal elements wrongly receivedd'may be avoided.
  • the signals are transmitted by means of double currente-that is to say the working elements of the signals are transmitted by means of Working or marking current and the resting elements by means' of resting or spacing current. Furthermore, in the receiving circuit an error-detecting device is provided whereby the presence of disturbing impulses or the dropping outcj signal elements is made recognizable.
  • the construction of the printing telegraph system so as to achieve the object of the invention results in 'a marked increase in traflic' trans'- an indicatingcircuit which renders the disturbed i ⁇ signals recognizable.
  • the invention may be employed in all known type printing telegraph systems. It has particular. advantages in two-way communication between two stations, and in systems in which, for
  • each cording to the invention employed for two-way communication between two stations.
  • Figures 5-9 relate to three constructional examples for systems in which the signals or signal elements are transmitted and received a plurality of ⁇ times.
  • the error-detecting device comprisesrtwo relays, one of which is acted upon by the working (marking) current and the other by the resting (spacing) current. of the transmitter.
  • the tongues of these relays co-operatein such a manner that when the reception'is not disturbed i rent impulse to be annulled, the' 'tongues both lie indirectly operating the ⁇ signal element is sent out several times by the modulated on a common carrier wave.
  • double current is ernployed.
  • a so-called double Wave transmitter or two signal frequencies are employed, which are In any case, the .working signal elements are transmitted with working current and the resting signal elements are transmitted with the resting current.
  • the two sources of current, which produce the Working current and the resting current, are shown at l andv 2, and 3 is the tonguel ot the transmitting relay.
  • This circuit arrangement of *the transmitting station is not essential for the invention.
  • both signal currents are rreceived, and are thereupon separated from one another by lknown means such as lters fi, E.
  • the resting current and the Working Acurrent are now fed to rectiers 6 and 1 respectively and these rectiers act upon relays 8 'and 9 respectively.
  • the tongues of these relays are applied against. the resting contact r when the, corresponding .rectier does not receive anysignal voltage,and
  • both relay tongues occup'y opposite positions when there is no disturbance in the reception.
  • the tongue of the relay 8 occupies the working position (w)
  • the tongue of the relay 9 occupiesrthe by a lead I0 to the printer apparatus.
  • Thefresting contact of the relay 8 and the working contact of the relay 9 are connected together and to an interference relay II,.while the working contact of the relay 8 and the resting contact of the relay 9 are both connected to a source of current I2.
  • One side of the relay II and one side of the i source oi current I2 are grounded.
  • the interference relay II receives current when the tongues of both relays 8 and 9 occupy the resting position r (interference through fading) or when they both occupy the working position w, (interference through an additional 'current impulse). In the event of undisturbed reception, on the other hand, the relay II does not receive any current.
  • the printing apparatus connected to the lead I0 receives working current when the relay is in the working position and the relay 9 is in the resting position. It.does not receive any current when the relay 8 is in the resting position and therelay 9 is in the working position, and t receives working current when both relays occ y the same position/(that is to say in the case oi' interference). In the last case. however, the received signal may beindicated as an error by means of the interference relay II, or in any other manner. 'I'his relay,.therefore, indicates erroneous signals with absolute certainty.
  • the interferencev relay .I I may act upon the printer in many diderent ways.
  • ablank or another interference signal such as a special printed sign. may be given.
  • the starting of the printer may .be prevented in systems in which the code signal is followed by a locally initiated printer-actuating impulse. The practical execution dependsV upon the particular telegraph apparatus employed, and is not an essential feature of the invention.
  • the occurrence of a wrong signal element may be rendered recognizable by the employment of means responsiveto such an-erroneous signal for intercepting the working 'or resting current as -supplied to the printer.
  • the printer will then function aswhen spacing"instead 'of printing erroneous characters. 'Ihis i'eature'is of considerable importance when using uniform length code signals in printing telegraph systems', as will be shown more clearly hereinafter.
  • Fig. 2 illustrates how the relays l and 9 may be so employed that. the .disturbed signal element is kept away from the printer. As will be seen from .this figure, the printer does not receive any current when the tongues of the relays 8 and a are bonn in the' resting position or both station A has been shown in the drawings.
  • the telegraph apparatus receives position, remains in this middle position, so that the telegraph apparatus does not receive any current.
  • the invention as used in two-way communication renders it possible to repeat the transmission of a certain signal by one of two stations, if this signal is not correctly received at the other station. If, therefore, a. signal is mutilated during transmission, it is repeated and if it is notl mutilated it will not be repeated.
  • this method is preferably carried out in such a manner that the reception of a mutilated signal results automatically in a warning signal being sent back, whereby the signal is repeated in the transmitting station, while the reception of an linterference-free signal results automatically in a monitoring signal being sent back, whereby the succeeding signals of a message are transmitted in regular course.
  • FIG. 4 will serve for explanation of the foregoing.
  • a constructional form of the system according to the invention is shown ldiagrammatically by way of example, it being assumed that each transmitted signal consists of ilve elements (5-unit code).
  • the two-way or cross trailic takes place between two stations 'A and B, .which are substantially constructed in the same way.
  • Each station has on the left hand side a receiving device and on the right hand side a transmitting device.
  • 'Ihe parts of the individual station are denoted by numbers, and will be distinguished from one another by the addition of the letter A or B.
  • AIB is the receiving apparatus of station A and BIB the receiving apparatus Iof station B.
  • the vertical strokes under the number I represent the4 nl oments at which a distributor (or any other equivalent device) connects the receiving device'of each station with the ytransmitter, say, through a radio communication channel
  • the vertical strokes under the number 2 represent the monents at which another distributor connects the transmitting device with the channel of communication.
  • the vertical strokes under the number 2 represent the monents at which another distributor connects the transmitting device with the channel of communication.
  • the transmitting distributor A2 of station A runs synchronously with the receiving distributor BI of station B, and the transmitting distributor B2 of station B runs synchronously with the receiving distributor AI of station A. Both distributors in each station may be coupled together mechanically. It is immaterial whether synchronism is obtained by means of distributors moving continuously or discontinuously.
  • the present instance an installation with chronisin of the distributors in the transmitting station andthe receiving station are sent out 't by the transmitting station B through distributor segments B3 and B4, and are received bythe receiving station A on segment A5.
  • the correction magnet ⁇ of station A is connected to a protective device A6.
  • the latter operates in the manneralready described in the foregoing and may be so constructed, for example, that if an interference occurs while the receiving distribuf tor brush is traversing segment A5, the correction magnet of station A will not operate. Premature correction is, therefore, avoided.
  • the ve elements of each signal are transmitted by station B on segments B26 to B30, and
  • a onsegments A1 to AII whence' they are transferred to the protective and signal storing device AI2.
  • the protective device servesv to ascertain whether one or-more of the five signal elements received has been disturbed. If none of the five elements is disturbed, the interference relay AI3 remains unenergized, and the actual telegraph recording apparatus AIS receivesastarting current impulse by way of the resting contact Alt of the relay ⁇ AI3 and a con tact of the distributor AI, which latter contact is not shown.
  • the telegraph apparatus AI then becomes operative.' receiving the signal elements stored up in AI2 and converting them into printing or recording or interpreting them in any other manner.
  • ⁇ a positive (spacing) current impulse is sent through segment AIB to station B by way of the tongue AIG of the polarized relay All and is received by B on segment BIS.
  • This,v current impulse is received by a device B20, which is also constructed as a protective device.
  • An interference relay B2I s connected to this device. If the spacing current impulse transmitted by A is received undisturbed, the interference relay B2I ⁇ is not energized, and consequently the transmitting apparatus B22 receives a starting current impulse by Way of a contact (not shown) .0f the corresponding distributor from the protective device B20 by way of the resting contact B23 of the interference relay B2i. The trans.- mitting apparatus B22 is thereby rendered operative.
  • the spacing contacts of the ve transmitting tongues of this apparatus are connected at B24 ,to the positive-terminal of a source of current, and the marking contacts of the tongues are connected through the spacing contact of the interference relay B2I to the negative terminal of a source of current.
  • the transmitting tongues are connected to voltages which correspond to the next signal, so that this signal is now transmitted at the moments B26 to B30.y
  • this signal is again received at the moments A'l to AII.
  • the process described in the foregoing is Vthus repeatedand the second signal is also printed and so on.
  • This relay like the interference relays 2
  • This marking current impulse is received on 'segment BIS by the protectivedevice B20 and signal, to repeat the signal which has already once been transmitted.
  • this request is received at the station 1B ⁇ on segment BIS, there being a possibility that, due to an interference, the warning signal transmitted by station A is not received correctly at station B. Since then it is ⁇ not possible to ascertain whether a repeat o has been requested or not, in this case for the sake of certainty no fresh signal is transmitted and also the old signal is not repeated. This may be effected for example, as follows:
  • the interference relay B2i If an interference is received at the moment BI9, the interference relay B2i is energized.
  • the starting circuit of the transmitting apparatus B22 is interrupted at B23,
  • the tongue B25 of the interference relay B2i connects the positive terminal of a source of current to the working contactsof the five transmitting tongues, so that on segments B26 -to B30, five spacing current impulses are transmitted.
  • the receiving apparatusfof station A does not respond to these five spacing impulses, since the latter correspond to the resting condition of the transmitter.
  • Station A could ascertain the disturbed Vreception of the warning impulse by the fact that five f spacing impulses are received from the station B.
  • a special signal from station B, in addition' to the five spacing impulses.
  • This signal is preferably transmitted on segment 3
  • the special signal consists of a negative current impulse (working. current impulse), which is transmitted by way of the resting. contact of the tongue B25.
  • this signal is received through segment A32 by a protective device A33 which shows in known manner whether .the signal received consists of a. resting current impulse, a working current impulse, or an interference.
  • the circuit oi'the relay All is connected to earth by a contact (not showniof the distributor by way of a contact (likewise not shown) within the device A33, and through the resting contact A34 of the relay A35.
  • The.contact within the device A33 interrupts the circuit, however. if the special signal consists of a (positive) resting current impulse.
  • the circuit is likewise broken,l if the relay A35 is energized, which only takes piace in the event of undisturbed reception of the tive resting units by the device All.
  • the, relay All can never be iniluenced by the fact that the signal received by Ail is or is not disturbed, if the special signal received by A33 consists of a positive or resting .current impulse.
  • the circuit of the relay A II is already interrupted within the device A33 itself so thatthe tongue A16 remains in the position which it had attained after recepvthe moment AIB retransmits the same warning signal in the form of a resting or working cur,v rent impulse by way of the tongue AIS. If this current impulse is now received in B by B20 undisturbed, the repetition of the previous signal or the transmission of a fresh signal can take place.
  • the signal to be received at the moments A1 to AI I is stored up and any disturbance of this signal is reported by the relay AI3.
  • the probability of the warning signals and the other special signals being transmitted undisturbed may, of course, be increased in different ways, for example, by multiple transmission of these signals, or by lengthening or shortening them. It is also possible, by such means, to reduce the possibility oi.' interference of the five elements of each signal.
  • the time distribution of the above-mentioned contact moments shown in the ligure, the proportion of their length and the number of these contact moments are therefore not essential. They may be varied without departing from the principle of the invention.
  • the devices 3, I2, 20 and 33 are not connnedto a definite form of construction. This already follows from the discussion of the protective devices shown in Figures 1, 2
  • a further possible means of combating interference in a type printing telegraph system according to the invention resides in the application of the known principle namely, that interference may be eliminated up to a certain extent by repeated transmission and reception of all signal elements and signals.
  • the repeating systems known for this pzrpose are generally only capable of combating interference of a certain character, that is to say, either interference due to additional current impulses, or interference due to the absence of current impulses.
  • the undisturbed reception of a ⁇ single transmission is sumcient in order to render possible the reproduction of the correct signal in the actual receiving apparatus because each interference is. indicated with absolute certainty. If none of the transmissions is received undisturbed this is also rendered recognizable with certainty in the receiving apparatus. The unnoticed reproduction of a wrong signal is therefore impossible.
  • Several constructional forms will be de- 'further to the telegraph apparatus, so that the latter is set in operation. If, however, none of the signals passed on by the protective device is undisturbed, an interference signal is supplied in any manner tothe telegraph apparatus, or the operation of thesaid apparatus is prevented.
  • the testing device must satisfy the condition of being able to ascertain and store the diierence .75
  • Relay circuits which are adapted to receive' and re-transmit the diie'rence between a positive current impulse, a negative ⁇ current impulse and zero current impulse, or between current impulses of different intensities', or between direct current and alternating current.
  • FIG. 5I is shown a testing device employing a distributor or any other equivalent device which is, driven synchronously, in rhythm with the repeated transmission," with the repeating device of the transmitter, which supplies successively a single contact.
  • the current impulses which are given by a protective device, not shown (for example according to Figure 2) and which may compriseapositive current, a negative current or zero current in order to give a resting signal, a working signal, or an interference signal, are supplied to the lead 25.
  • , 22 and 2,3 ⁇ are contacts of a distributor contact disc, contact drum. or the like
  • the construction of the distributor is of course optional, the only condition being that it shall operate synchronously with the ⁇ repeating system of the transmitter.
  • the rst current impulse givenby the protective device has the opportunity of charging or not charging a condenser 26.
  • the contact 22 doesthe same for the second current impulse and the contact 23 for the third current impulse. Sincethevthree current impulses belong to the same signal element, the condenser 26 may be charged only in a certain direction either positively or negatively, or. may
  • the condenser is hence charged certainly in the correct direction, ii an undisturbed signal element has been received at least'once by' the protective device. '-If this is not the case, the condenser is not charged.
  • the polarized relay'21 is applied to the resting y relay.
  • the condenser 26 When, after the repeated transmission of a definite signalelement, the condenser 26 has performed its action, it is in a position to receive the current impulses -oi a following signal element. limited to one signal element merely for the sake of simplicity, for example tothe firstsignal element of a signal. comprising five elements.
  • each signal element is transmitted twice.
  • 'I'he relay chains are closed one after the other by a distributor or an equivalent device, driven synchronously with the repeating device of the transmitting end, at moments in which the individual current impulses or zero current impulses, given by the protective device during the repeated transmission of the same signal ele-L' ment, arrive lat the testing device.
  • the relay this The explanation given above has been Y chains are constructed 'in such a manner thatv the two relays of the protective device are situl ated a polarized relay and a non-polarized relay.
  • the relay chains of the testing device each comprise a non-polarized relayfll witha holding contact 36, and in series therewith a polarized relay Il.l
  • of the distributor is closed at the moment at which the protective device operates on the iirst reception of thetwice transmitted signal element. If the reception is undisturbed, the protective device gives rise to a working current or aresting current and the nonpolarized relay is energized .and is kept energized bymeans of its holding contact 35.
  • the polarized relay 42 applies its tongue.- in accordance with the direction of the received current impulse, 'either to the resting contact or to the working contact, so that this current impulse is passed on by way of the contact' 31 of the non-polarized relay 4I to the second relay chain, whereby this second relay chain which was originally connected to the lead 35 by the contact 39 is disconnected from the protective device.
  • the contact 32 oi the distributor is closed, the non-polarized relay 43 is then ener-v gized and is maintained energized by way of the contact 38. while, by means of the polarized relay 44, a current impulse is supplied to the teleiirst relay chain will be ready to receive a new current impulse, whilst the telegraph apparatus graph apparatus.
  • the contacts 33 and 34 of the distributor have the object of short-circuiting the holding winding ⁇ of the relays 4
  • the protective device does not transmit any current impulse. In-this case, the non-polarized relay 4
  • Figure 'l shows a third construction of the testing device. This operates substantially in a mel chanical manner.
  • a perforated strip 51 on which the signals to be transmitted are iixed, is passed through three automatic transmitters Il, 52, B3 in succession. These transmitters are so connected to a distributor 59 that they' are connected in succession to the transmission channel.
  • the perforated strip runsthrough the three transmitters and the elements of each signal are transmitted automatically three times.
  • the time intervals between the successive transmissions are quite optional.
  • reperi'orators-M At the receiving end are three so-called reperi'orators-M, 55, I6. 'Ihese are located behind a distributor 0
  • a strip 50 the speed of which 'is ⁇ equal to that of the perforated strip 51 ⁇ of the transmitting station, is passed through the three reperforators.
  • a givensignal is transmitted on the first reception to the reperforator 54 and this reperforator nal element or, if one or more of the si elements are received disturbedydoesnotproduce periorations for these elements.
  • the 'I'his testing device also operates in such a manner that the receiving apparatus is set into operation when the protective' device passes on at least once a signal (or signal element) lwhich has not been mutilated byainterference.
  • the invention may also be employed in telegraph systems with repeated transmission of all signals, by combining a protective f device with two known repeating systems, one for the working current and the other for the resting current.
  • a. telegraph system of the characterdescribed a receiver for receiving working and resting current impulses, and a protective device associated with said receiver for protecting the reassociated with said receiver for protecting the receiver against unnoticed reproduction of false 2,119,196 signal elements
  • said protecting device compris- A l ing two relays, the armatures oi' which are shiftable to working and resting positions, yone of said ⁇ relays being controlled by working current and the other being controlled by resting current, said relays nbeing operable in the event of undisturbed reception so that the amature of one relay is in working position andthe armature of the other in resting position, and so that in the event of interference both relay armatures are in the same position, and means operable upon the armature of one relay being in the working position and that of the other relay being in the resting position for passing the signal elements to the receiving apparatus and when both armatures are in the same position for rendering th interference recognizable.
  • a receiver for receiving working and resting current impulses, and a protective device associated with said receiver for protecting the receiver. against unnoticed reproduction of false signalelements, said protecting device comprising a relay having two windings and an armature movable to working and resting positions, ⁇
  • one or said windings being controlledby working current 'and the other winding being controlled by resting current, said windings being.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
US724804A 1933-05-09 1934-05-09 Type printing telegraph system with means for eliminating interference Expired - Lifetime US2119196A (en)

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GB13504/33A GB419526A (en) 1933-05-09 1933-05-09 Improvements in type-printing telegraph systems with means for eliminating interference

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US2119196A true US2119196A (en) 1938-05-31

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DE (1) DE692899C (ru)
GB (1) GB419526A (ru)
NL (1) NL40443C (ru)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE868918C (de) * 1939-05-04 1953-03-02 Staatsbedrijf Der Posterijen Drucktelegrafensystem mit Gegenverkehr, insbesondere fuer drahtlose UEbertragung
DE945038C (de) * 1943-04-28 1956-07-12 Sadir Carpentier Fa Telegraphisches UEbertragungsverfahren
US2900447A (en) * 1953-09-24 1959-08-18 Siemens Ag Apparatus for correcting the effects of disturbances in telegraphic communication
US2928897A (en) * 1955-03-02 1960-03-15 Philips Corp System for the radiographic transmission of telegrams

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE767832C (de) * 1938-01-14 1953-10-19 Siemens App Befehlsuebermittlungsanlage, bei der fuer jeden zu uebertragenden Befehl durch den Geber die gleiche Anzahl von Stromstoessen uebertragen wird
BE513064A (ru) * 1951-07-24

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE868918C (de) * 1939-05-04 1953-03-02 Staatsbedrijf Der Posterijen Drucktelegrafensystem mit Gegenverkehr, insbesondere fuer drahtlose UEbertragung
DE945038C (de) * 1943-04-28 1956-07-12 Sadir Carpentier Fa Telegraphisches UEbertragungsverfahren
US2900447A (en) * 1953-09-24 1959-08-18 Siemens Ag Apparatus for correcting the effects of disturbances in telegraphic communication
US2928897A (en) * 1955-03-02 1960-03-15 Philips Corp System for the radiographic transmission of telegrams

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GB419526A (en) 1934-11-09
NL40443C (ru)
DE692899C (de) 1940-06-28

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