US2435035A - Simultaneous plural frequency start-stop telegraph system - Google Patents

Simultaneous plural frequency start-stop telegraph system Download PDF

Info

Publication number
US2435035A
US2435035A US473885A US47388543A US2435035A US 2435035 A US2435035 A US 2435035A US 473885 A US473885 A US 473885A US 47388543 A US47388543 A US 47388543A US 2435035 A US2435035 A US 2435035A
Authority
US
United States
Prior art keywords
code
character
relays
signal
contact
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US473885A
Other languages
English (en)
Inventor
Devaux Lucien
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Priority claimed from GB305544A external-priority patent/GB576352A/en
Application granted granted Critical
Publication of US2435035A publication Critical patent/US2435035A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes

Definitions

  • the present invention printing telegraphs and particularly systems adapted for transmission of messages, by means of radio;
  • An object. of the present invention is the reduction or elimination of parasitic disturbances in the transmission of code signals. by means: of. a printing telegram
  • Garbl-ing'of' code signals dueto-para sitic influences is. appreciably reducectby lengthening the duration of the signals" while using alow resonance frequency having a. large time constant.
  • a disadvantage; of this arrangement resides: in the fact that lengthening of the duration or the signals brings about an unacceptable slowedown in-tra-nsmission.
  • the system is adapted to operate at a, speed of seven characters per second. or approximately 140 milli-seconds for each character, the transmission of various frequencies, including the: starting signal. and the: code; signal, will; last 150' milli-seconds.
  • the signals are separated by filters and act upon the respective relays which register the combinations of the code; Durin the next period of. 14:0: milk-seconds, which i relates to systems for.
  • the total time allotted for the transmission and printing of a character is 420 mint-seconds, of which 280 milli-se'conds are used for the transmission of a second and third.
  • the signals of the code are sent in permutations of 5 in the present embodiment of the invention which contemplates a code of five elements, the intensity of each signal being Such that the total of five signals produces maximum modulation of the sending station.
  • 5 the intensity of the modulation ranging from 0 to the maximum, according to the number of the marking signals of the code. Due-to this arrangement, it would become impossible to use devices for attenuating parasitic influences such as for instance limiting means.
  • the present invention overcomes this drawback by sending a code signal not just by direct transmission of a frequency, but by variation of this frequency which is being transmitted continuously.
  • the transmitter is modulated by the combined code frequencies fl, f2, f3, f4, and I5, for; instance.
  • the sending of a marking signal consists in causing a slight variation of the corresponding frequency in a fractional amount thereof, for instance. by slightly increasing the capacity of the resonant circuit relating thereto; Frequency f l becomesfl-Afl for the sending of the first code signal etc.
  • the transmitter is modulated at the frequency f6 and the sending of the starting signal is produced by varying the frequency from JSto Iii-M6.
  • the modulation of the transmitter by means of frequencies it to f6 may be produced by any known method, for instance by means of simple modulation while transmitting a carrier and two lateral bands. or, preferably, by means of modulation without carrier while sending a single lateral band, or by means of frequency modulation etc.
  • the frequencies assigned to the code signals should preferably be contained in an octave in order to avoid intermodulation frequencies.
  • the code signals the harmonics II, I3, I5, I I, and I9 of such basic frequency as may be desired. For instance, 50 cycles per second would give the following frequencies: 550, 650, 750, 850 and 950.
  • this invention also provides for the determination of each frequency in such manner that the spacing between two adjacent frequencies is a constant fraction of one of the two frequencies; with a spacing of approximately 15% of the lowest frequency, the following values are obtained:' 550, 628, 722, 830 and 955.
  • the frequency of the starting signal which'is sentalone may be of any desired value but the same is preferably superior to the highest signalling frequency in order to prevent the harmonics from falling Within the range of the code signal frequencies. In the example given above, this frequency could for instance be 1100 cycles per second.
  • the factor which characterizes the variation of frequencies for producing marking signals is made as small as possible in order not to render separation of frequencies difficult. With resonant circuits of good quality one may use a factor of 0.02.
  • the invention also provides means for producing the transmission of frequencies according to the method described above and uses a radio transmitter controlled by a printing telegraph transmitter. Moreover, the present invention uses the various frequencies obtained from the output of a radio receiver in order to operate a printing telegraph receiver.
  • Fig. l is a schematic view of a printing telegraph transmitter
  • Fig. 2 shows schematically a printing telegraph receiver, designed for cooperation with radio receiving apparatus.
  • Fig. 1 illustrates the transmitter comprising five key bars I, 2, 3, 4, 5, whose movement is controlled by keys such as 6, I, 8, and 9. Transmitting keyboards of this type are well known in the printing telegraph art, for example, the present Teletype and Creed keyboards.
  • the connection between the keys and the bars is conventional and not shown in the drawing.
  • shaft I When a key is depressed, shaft I is connected by a clutch, not shown, to motor t l and performs one revolution and is then stopped in well known manner by the disengaging of the clutch members.
  • Shaft Ill carries two cams I2, I3 which operate contact springs I4 and I5, respectively.
  • a sixth oscillator 05 is connected to contact I4 and to one contact of spring I5. It will be noted from the shape of cams I2 and I3 that the duration of the start signal occupies about one third of the rotarycycle of shaft III while the remainder of the cycle, that is, during the time cam I3 holds contact lever I5 against its upper contact, is used for the simultaneous transmission of the frequencies assigned to the particular character being trans-- mitted. In rest position, oscillator 06 operates alone, one of its circuits being closed by contact I5a. Thus a frequency I6 is produced and the transmitter sends a modulated wave at this frequency.
  • each of these frequencies depends upon the position of bars I to 5, that is to say opening and clos ing contacts I6 to 20 which, when closed, cause the frequency of the corresponding oscillator to change from f to f-Af.
  • the five frequencies transmitted thus depend upon the position of the bars I to 5, or in other words, upon the combination of the code corresponding to the letter to be transmitted.
  • the transmitter keyboard mechanism is simpler than that used in conventional start stop systems in that no distributor is required for sending the selecting impulses in succession, because the selecting impulses are transmitted simultaneously after the start signal has been sent.
  • Cams l2 and I3 serve to separate and time the transmission of the start impulse and the selecting impulses.
  • FIG. 2 An example of a receiving circuit is schematically shown in Fig. 2.
  • the invention contemplates the use of a start stop receiving printer preferably of the kind known in the art as a single magnet printer wherein one magnet serves as a start magnet and also responds to selecting impulses received after the start impulse to control the operation of a mechanical selector.
  • the printer is a clutch whose driving and dt'iven members are normally disengaged tinder lQQRiiXQl of :the start :magnet 1 armature.
  • the :start magnet operates :releasing the shafit 'Which'inakes 0118 revolution and then ntops yon engaging the startmagnet :armae ture.
  • Theshaft remains stationaryiuntilreleased when the :start signal :for the :next :character is received.
  • the power :shait usually carries 101' drives ca :mechanical distributor arrangement vimich cooperatesmithzthe.startmagnetawhen the latter is receivingzselectingsimpulsesto controlithe selecting mechanism of the printer. .
  • This unechanism allao'f which, however, :have ithezsame vgeneral principle :of operation.
  • printer rmotor 1k! is.
  • cams 2-9 and an required to :controlathe ifirstimpulse are :shown, :the impulses stored n .a .'g11OuD of :relays :-are :sent one at ;a time to magnet ':24 via ⁇ a second distributor .arran'gement including cam 12.4 and :a series :of contacts "which separate the impulses and sends them properly itimedtto magnet 12 ,l, so that the flatter operates :at just the right time :to contnol the respective mechanical selectors withinithezprinter.
  • Shaft '25 carries thr cams :28, '29,, .30 acting :uDQn certain contact spring des ribed below.
  • Fig. 2 shows a idirect tconnecticn with relay- 49, however, in order to p reserye the full .ef ficienc y of the inesona nt circuits 43, .44,';prov-ision is also made for inse itionpf a tube, During the waiting-period, the ifirequcncyjfi .is received and the resonant ciecuit 43 .is excited more than circuit 44.
  • the current i polarized relay .49 has such a direction that the v atter :opens .its contact.
  • ireqns c tit-1M6 is .-.rcc d ci cu is re .ex itediand rel y 1& h c i t rs y ecutent inhnpcs te dit ct cn. o s h co t 1 shc ld be me ed thatth r a r n em n c cc netoth pre ent e n i ha ns tivezat all t o;parasitic influences. 'If-such-occur, they are reduced by the first resonant circuit and act 'uponicircuit .43 and .44 with equal inten itras a re t. the e ay 11 not affected attain.
  • ⁇ Ehecontactof relay 4-9 isconnectedtotheelectmmaenei :24 by m a s o :sp in c n t 50 ch. is actu ted by the ra e p r ion 1 c 24.
  • Circuits are as little dam ed as; pos sib.1e :and each of them permits the apesis fed by resistances 51 and connected across con denser 58 to the exciting windings 59 and 60 of. the two resonant circuits GI and 62.
  • has a resonance for a frequency slightly higher than fl and circuit 62 has a resonance for a frequency slightly lower than fl -Afl The two circuits are.
  • the first-code signal is a spacing signal
  • the frequency fl is received and the contact of relay 6'! is open.
  • the signal is a marking signal, the frequency f
  • the contact of relay 6'! is connected to the contact terminals of springs 68, 69 which are actuated by cam 29.
  • circuits including tube 56, relays 61, 10 and 12 as well as cams 29 and 30 and the contacts operated thereby are only for the reception, storage and retransmission of the first impulse to the printer.
  • each cam 29 has associated with it a relay HI and a relay 12. These relays are for the purpose of storing received impulses.
  • Cams 29 which control the operation of relays 10 or 12 depending on which half cycle of shaft 25 is effective, all have the same angular position on shaft 25, because immediately on receipt of a start signal shaft 25 starts to move and-either contact H or 8! closes an operating circuit for the group of-relays- Ill or 12 and immediately thereafter cams 29 close either contact 68 or 69 which causes either relay group ill or "to store simultaneously any impulses registered by any operated relay 61 leavingthe latter ready to register the simultaneously transmitted code impulses which follow immediately after the start impulse which initiated the operation'just described.
  • shaft 25 moves an appreciable distance before the transmission of the long start impulse has terminated, and therefore relays 61 are ready for a new'oode combination before the expiration of the start impulse.
  • the respective cams 30 are mounted on shaft 25 in the-same angular position, the effective length of the cams and their angular position on the shaft being such that the respective wires from contacts 14 or leading to contacts 15, I6, l7, l8 and 19 of cam 24 which control the operation of magnet 2
  • the relay circuits will now be described in more detail. While the shaft 25 makes a half revolution upon rotation of shaft 22, spring 68 closes its contact and the registering relay ill is connected to contact 68.
  • relay I0 is likewise operatedfrom battery, contact H, winding of relay lll, contact 68, armature of relay 6! to ground, and it becomes locked by its grounded tongue to battery at the spring contact H which is closed due to rotation of cam 28.
  • contact 68 is open but relay 10 remains in the position where it finds itself as a result of the operation or non-operation of relay 61.
  • relay 6'! is connected to a registering relay 12 of a second group of five relays, only one of which is shown by means of springs 59 disposed on the other side of cam 29.
  • the contact of relay ill is connected by means of spring 14, which is operated by cam 35, to the first spring I5 of the distributor which in turn is actuated by cam 24.
  • the indication registered by relay i0 is transmitted to the electromagnet 2
  • the invention operates as follows:
  • Synchronism of the transmitter and receiver motors is maintained by the well known start stop system.
  • the transmitting station is arranged to send out an unusually long start impulse preceding the code combinations of each character which are sent out as a group of modulated frequencies simultaneously after the transmission of the start pulse.
  • the relatively long start impulse and the still longer interval'used to transmit simultaneously the frequencies corresponding to the selecting impulses permits the use of efficient filter arrangements at the receiving station that effectively eliminate parasitic frequencies.
  • the selecting frequencies are separated by filters/and immediately on reception operate a combination of relays 61 of which there are five, according to the marking and spacing elements of the characters transmitted.
  • a line signal having the characteristics just described is not adapted to operate any of the standard start stop printers, so accordingly, means are provided at the receiver to alter the received signals so that only a relatively short start signal is sent to the printer followed by suitably timed selecting impulses which are transmitted to the printer in succession.
  • a storing arrangement is'necessary, which in the present embodiment consists of two groups of storing relays 70' and 12 respectively.
  • the combination as set up on relays 6'! is transferred to relays lll or 12 depending on the position of shaft 25.
  • start. impulse for a second character cams 30,103; means of contacts M or 80, depending on which halt cycle of. shaft 25 iseflective, connects the contacts of any operated relays H1 or 12 to the wires extending. from the contact levers of contacts '15, 1.6, 1'], T8.
  • the stationary contacts: associated with the respective contactlevers are connected to the windings Li of the common start and selecting magnet of the printer. It will-be understood thatthe printer shaft, notshown, and shaft 22 driven therefrom. start to rotate when the start signal releases the printer clutch. As soon as the start magnet has released these shafts, contact 50 of cam 24 opens, irrespective of the length of the startsignal, or whether-it has terminated or not, and-cam 24 proceeds to send to magnet 2
  • An alternating-currentstart-stop printing telegraph system comprising a group of continuously operating wave signal producers corresponding respectively to code signals and start signals, means for modulating and" transmitting first a wave for a start signal and thereafter the waves all at one time fora given code character, so that each of said transmission prolonged beyondsingle signal ti-me butwithin substantially thetime of code charactertransmission bysignal sequence, in combination with a receiver andrecorder comprising devices for translating the received signals pertaining to a given code character to a printed record thereof during a plurality of time periods of operation and means by which such devices are successively controlled by the start signals of succeeding code characters.
  • An alternating current start-stop printing telegraph system comprising a group of continu-, ously operating wave signal producers corresponding respectively to code signalsand start signals, means for modulating and successively transmitting first a wave-for a start signal and thereafter the waves all at onetime for a given code character, so that each of said transmissions is prolonged beyond single signal time but within substantially the time of code character transmission by'signal'sequence, means for receiving and recording code character signals successively transmitted as aforesaid, ,comprising means including on or more sets of storing relays and responsive to receptio'noia start signal 110 to: registerslmultaneously thecodesignals of. the; transmittedcharacter corresponding to that start.
  • A. telegraph systemv according: .to claim 1 whereinthe waveproducers continuously operate. toprodnce waveirequencies assigned respectively to: the component signals. and means by whlchthe waveszso produced are transmitted in the absenceof: marking and starting signals.
  • a telegraph system according toclaim 4 wherein the receiver translating devices com.- pri-se selective circuits of low damping and freguency. gijcriminating circuits of high efficiency'.
  • the receiver translating devices vcomprise-selective circuits otlow dampin and electronic discharge amplitudelim-iters, whereby to redu para it d turbances in transmission.
  • 1.0-- e esrap syste ac ordin to claim .4 hete nth c iver tran latin ev es comprise selecti e ci cu ts. of low dampi an l ni discharge amplitude limiters and wherein the irequency dis i minating circuits are of high cf.- fiQ nG v 1 1.
  • each character of the message corresponds to a code symbol and each code symbol is composed of a predetermined number of code signals, a plurality of signal bars, the number of the latter being the same as the largest number of signals contained in any one symbol of the code, a contact associated with each of said bars, a plurality of frequency'modulating circuits, each one of said circuits being connected to one of said contacts, operating means associated with and adapted to operate said bars to open and close said circuits, a radio transmitter, all said circuits being connected to said transmitter; an extra modulating circuit connected to said transmitter, make-and-break contacts, connecting means interconnecting said modulating circuits among each other and connecting the same to said malre-and-break contacts, the latter being also connected to said extra modulating circuit, a control contact connected to the latter, and control means associated with said operating means and said control and malre-and-brealr contacts, whereby, upon actuation of said operating means, said control means
  • control means comprises a pair of cams for actuating said contacts
  • means for simultaneously registering the code elements of a transmitted character a set of storing relays, means responsive to the start signal of the next following character for transferring the code elements of the first mentioned character to said set of storing relays thereby making said registering means available to register the code elements of said next following character, a' start stop printer, and means responsive to the start signal preceding the transmission of the code elements of a third character for transferring the code elements of the first mentioned character one at a time from said storing relays to said printer, thereby causing th printing of the first mentioned character after the printing operation has been initiated by the start signal of the third character.
  • a printer having a single magnet responsive to start signals followed by successively transmitted selecting impulses, a plurality of registering relays,means 12 for separating said diiferent frequencies and simultaneously operating a combination of said relays thereby, whereby said relays are positioned in'accordance with the marking and spacing units of the code character, means responsive to the receipt of a second start impulse for transferring the code elements registered by said relays to a set of storing relays, and means responsive to a third start signal preceding the transmission of the frequencies for a third character for transmitting the impulses of the first mentioned character one at a time to said printer magnet after said magnet has been actuated by said third start signal whereby said printer prints the first mentioned character.
  • a printer having a single magnet responsive to start signals followed by successiveiy transmitted, selecting impulses, registering relay means, a plurality of filter means each connected to a relay of said relay means, said filter means being adapted to separate the simultaneously transmitted frequencies and pass the respective frequencies to predetermined ones of said relays whereby the latter are operated in combinations corresponding to the code elements of the received character, a plurality of storing relays, means responsive to the receipt of a second start frequency preceding the frequencies corresponding to the code elements Of a second character for transferring the code elements of the first mentioned character recorded by said registering relays to a set of corresponding storing relays, and -means operable in response to a third start signal preceding the reception of the frequencies for a third character for transmitting impulses one-at a time from the operated ones of said storing relays to
  • a telegraph system according to claim 17 wherein said means for transmitting impulses one at a time to said printer comprises a distributor,
  • a telegraph system as claimed in claim 17 wherein sa d means for transmitting impulses one at a time to said printer comprises a distributor having a rotary shaft driven from the printer power shaft.
  • said means 101 transmitting impulses one at a time to said printer comprises a distributor having a rotary shaft driven from and at the same rate as the printer power shaft, and wherein the means for transferring the code combinations from the registering relays to the storing relays comprises a second distributor having a rotary shaft driven from the printer power shaft.
  • a telegraph system as claimed in claim 17 'whereinsalid means for transmitting impulses one at a time to said printer comprises a distributor having a rotary shaft driven from and at the same rate as the printer power shaft, and wherein said storing relays comprise two independent sets of storing relays, a second distributor having a rotary shaft driven from said printer power shaft at one half the speed of said power shaft, said second distributor being adapted to connect the respective sets of storing relays to the contacts of said registering relays alternately, whereby each storing relay set stores only alternate letters, and circuit means controlled by said second distributor for connecting the contacts of the respective sets of storing relays alternately to the contacts of the first mentioned distributor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
US473885A 1942-01-31 1943-01-28 Simultaneous plural frequency start-stop telegraph system Expired - Lifetime US2435035A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR2435035X 1942-01-31
GB305544A GB576352A (en) 1944-02-18 1944-02-18 Printing telegraph system

Publications (1)

Publication Number Publication Date
US2435035A true US2435035A (en) 1948-01-27

Family

ID=32178828

Family Applications (1)

Application Number Title Priority Date Filing Date
US473885A Expired - Lifetime US2435035A (en) 1942-01-31 1943-01-28 Simultaneous plural frequency start-stop telegraph system

Country Status (2)

Country Link
US (1) US2435035A (fr)
FR (2) FR54621E (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3009988A (en) * 1955-11-16 1961-11-21 Smith Coroua Marchant Inc Communications equipment
US3022375A (en) * 1955-09-22 1962-02-20 Bell Telephone Labor Inc Synchronizing start-stop digital transmission system
US3288919A (en) * 1962-12-10 1966-11-29 Bell Telephone Labor Inc Data transmission system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1521722A (en) * 1974-07-24 1978-08-16 Singer Co Frequency-shift digital data link system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1599445A (en) * 1924-09-17 1926-09-14 American Telephone & Telegraph Alternating-current printing-telegraph system
US1661962A (en) * 1928-03-06 Trimbw
US1960021A (en) * 1929-09-27 1934-05-22 Western Electric Co Printing telegraph system and apparatus
US1975486A (en) * 1931-07-02 1934-10-02 Adolph A Thomas Electric transmitting and receiving apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1661962A (en) * 1928-03-06 Trimbw
US1599445A (en) * 1924-09-17 1926-09-14 American Telephone & Telegraph Alternating-current printing-telegraph system
US1960021A (en) * 1929-09-27 1934-05-22 Western Electric Co Printing telegraph system and apparatus
US1975486A (en) * 1931-07-02 1934-10-02 Adolph A Thomas Electric transmitting and receiving apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3022375A (en) * 1955-09-22 1962-02-20 Bell Telephone Labor Inc Synchronizing start-stop digital transmission system
US3009988A (en) * 1955-11-16 1961-11-21 Smith Coroua Marchant Inc Communications equipment
US3288919A (en) * 1962-12-10 1966-11-29 Bell Telephone Labor Inc Data transmission system

Also Published As

Publication number Publication date
FR960675A (fr) 1950-04-22
FR54621E (fr) 1950-07-07

Similar Documents

Publication Publication Date Title
US2046328A (en) Facsimile printing telegraph system and apparatus
US2435035A (en) Simultaneous plural frequency start-stop telegraph system
US3363238A (en) Electronic convertor and control means
US2495705A (en) Multiple frequency telegraph system
US2052677A (en) Telegraph system and apparatus
US1821110A (en) Selecting and printing mechanism
US1703152A (en) Selective system and apparatus
US1975486A (en) Electric transmitting and receiving apparatus
US2613267A (en) Printing telegraph system
US2193213A (en) Printing apparatus
US2360580A (en) Telegraph system and printing apparatus
US1793700A (en) Signaling system and apparatus therefor
US1873206A (en) Selective system and apparatus
US2010505A (en) Time division multiplex system
US1821109A (en) Selective system and apparatus
US1612101A (en) Radio signaling system
US3084219A (en) Printing telegraph selectrive signaling system
US2083160A (en) Telegraph printer system
US2802048A (en) Selecting and printing apparatus
US2658943A (en) Printing telegraph system
US1884743A (en) Single magnet reperforator
Harrison Developments in machine telegraph systems and methods of operation
US2361115A (en) Keyboard operated code transmitter
US1821164A (en) Printing telegraphs
US1948364A (en) Telegraph system