US1657498A - Radio signaling system - Google Patents

Radio signaling system Download PDF

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Publication number
US1657498A
US1657498A US646903A US64690323A US1657498A US 1657498 A US1657498 A US 1657498A US 646903 A US646903 A US 646903A US 64690323 A US64690323 A US 64690323A US 1657498 A US1657498 A US 1657498A
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US
United States
Prior art keywords
relay
armature
circuit
contact
station
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
US646903A
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English (en)
Inventor
Charles S Demarest
Milton L Almquist
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.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
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 American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US646903A priority Critical patent/US1657498A/en
Priority to DEI24804D priority patent/DE510815C/de
Priority to FR582886D priority patent/FR582886A/fr
Application granted granted Critical
Publication of US1657498A publication Critical patent/US1657498A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/022—Selective call receivers
    • H04W88/025—Selective call decoders
    • H04W88/028—Selective call decoders using pulse address codes

Definitions

  • This invention relates to signaling systems and particularly to means for selectively signaling one of a plurality of stations c onstituting a high frequency communication 5 system.
  • a. high frequency communication system comprising a primary or centralstation and a plurality of secondary stations
  • the primary station should be able to call any secondary station without, at the same time signaling all of the other secondar stations.
  • A represents a primary station
  • 'B represents oiie of a plurality of secondary stations.
  • These stations taken together might, for example, represent a shipto-shore systemr of wireless telephone conrI munication, in which A represents the shore station and B, B1 and B2 represent a plurality of ship stations which are arranged to communicate either with the primary station or through the primary station with a telephone subscriber connected therewith.
  • the rectangle 1 represents either a sub-y scribers telephone or telegraph yset or the switchboard terminal equipment in a local telephone control oiiice.
  • 1 represents a subscribers telephone set which is connected by the line 2 with the primary radio station A, the connection being effected by the hybrid coil 3 comprising a plurality of windings 4 and 4.
  • this hybrid coil is a line balancing network 5 designed and adjusted to balance the line circuit 2.
  • Connected with the hybrid coil is the transmitting path 6 of the primary station, the conductors of which are connected with the outer contactsof the relay the inner contacts of which are connected with a source of'low frequency signaling current.
  • the relay 7 is controlled by current from the source of potential 9, the application of which is in turn controlled by a selector 'key 10.
  • This key may be of any well known type, but ⁇ is preferably of that type used in train dispatching telephone systems such as is disclosed in the patent to' J. C. Field, No. 1,343,256, dated June 15, 1920.
  • the rotation of thiskey will lift the arm ⁇ 11, thereby grounding the conductor 13 through its u per contact 12 and similarly opening the said contact whenever the arm again drops back into one of the notches of the selector key.
  • the key shown - is designed to transmit a certain code of impulses.
  • Thek armatures of the relay 7 are connected with ⁇ thev input side of the low frequency amplifier 1li, the output of which is connected with a radio transmitter 15.
  • the output side of this transmitter is in turn connected with the transmitting antenna 16.
  • This radio transmitter may be of any well known type, having a source of high ⁇ frequency carrier current and means for modulating this carrier current by the 135 cycle signaling current or by the voice currents imposed thereon.
  • This transmitter may also have any 'number of vstages of either audio or radio frequency amplification or both, for effecting the amplification of the currents.
  • the receiving ybranch of station A comprises an antenna 17 connected with a radio receiver 18 which may be of any well knowntype, embodying a detector and possibly one or more stages of radio frequency amplification.
  • the output side of this radio receiver is shown connected with a low frequency amplifier 19. This amplifier could be made part of the receiver 18 itself.
  • the output of the low frequency amplier 19 is connected with the windings 4 of the hybrid coil 3.
  • the secondary station B which typi# i cal ⁇ of all Isecondary stations of the system, comprises a receiving antenna 21 connected with a radio receiver 22, which may be of any well known t-ype, comprising a sui-tableV connected With the subscribers telephone re DCver 26 shown as supported by the switchhook which, of course, is its normal positionwhen the subscriber is not talking.
  • the outer eontactsof relay 23 are conn .With the primary ⁇ ivinding 27 ot the transformer 28 Which is especially designed to transmit a low frequency current, ier leX- ample, of the order of 135 ⁇ cycles.
  • the armature 32 of this relay which is grounded is designed to vibrate freely at the resonant frequency.
  • the contact point oi. the relay is connected through the resistance 33 to a circuit consisting of tivo parallel branches, one ot Which includes the Winding of the relay ⁇ 34, and a resistance l35, and the other a condenser 36. These parallel branches fare connected With a source of potential 37.
  • the circuit containing' the elements 34, 35 and 36 isso designed that during the time in which the armature 32 is eff its contact, the/condenser 36 will dischargey through this closed circuit and Will tend tomaint-ain the armature 39 ot therelay 34 in this closed position.
  • the left-hand contact el' relay 3ft r is connected with a grounded source ot potential 38.
  • the right-hand contact is connected with a selectively operated circuit centrolling device 40, ⁇ (shown Within the ydotted lines) this connection being grounded at the point 511.
  • the armature 39 is also connected with the other terminal of this device, the said connection including a condenser 56.
  • This selectively operated circuit eontrolling device 40' ispret'erably of the type shown in the patentto J. C. Field, No. 1,343,256, dateddune 15, 1920. For the sake of simplicity, it-
  • The'princip'al elements or this A preferred selector are the windings 41 which control an armature 42 which isdcsigned to rotate an annular element 4ta which carries a grounded contact s6. This contact is intended to engage the contact L17 Whenever the element 4,4 has been moved ⁇ through the proper distance whichwill beA effected by the proper actuation otl the ratchet 43 by means of the armature L12.
  • the positioning ottl the plus controls'the responsiveness of a particular selector-5to ⁇ a particular code of impulses.
  • the operation ot' this selector Will be referred to herein in onlyn general way inasinuch as a full detailed description is to be found inthe said patent to Field.
  • the contact i7 is connected 'with the windings of relay 48 with which also is connected the grounded source ot potential This source is also connected with the armature ot thesaid relay in such manner that when the relay is op erated current will tloiv therefrom.through the signal device 50.
  • the transmitting path of station B comprises in its simplest term, a transmitter 51 connected with a radio transmitter 52 which may be ot' any Well known type, Vcomprising a suitable source of high frequency currents, a modu ⁇ lat-ing device and preferably -one or more stages of radio or audio frequencyamplitication, or both.
  • This radio transmitter is connected with the transmitting antenna
  • the sections of antennae marked B, and B... are intended' to represent symbolically other secondary stations ot the system, haring similar equipment to station B.
  • the method oi operating the system as follows. It the operator at station A desires to call the subscriber at station B in order to establish communication with such subscriber, he will actuate the proper selector key to send out the required code of impulses for operating the selector equipment at station B. It this selector key is 10 it will be rotated at uniform speed so as to open and close contact 12 a definite number of times, the said impulses being grouped in a manner which will be more fully described later.
  • condenser 36 discharges through the closed circuit containing also the winding of relay 34 and resistance 35 and the direction of fiow of current from the condenser through the said winding will be such as to maintain the armature 39 upon its left-hand contact during the interval of time'in which the armature 32 is off its contact. It will be seen therefore that as long as the impulse is being transmitted from station A, the armature of relay 31 will vibrate at the rate of 135 times per second, but the armature of relay 34 will be moved to its left-'hand contact as soon as the said impulse is received at station B, and will remain upon that contact point as long as the impulse continues to be received, regardless of the movement of the armature 32 in response to the yfrequency of the said impulse.
  • the relay 31 will cease to oper- -ate and relay 34 ⁇ will be deenergized allowing its ari'nat-ure 39 to .drop back.
  • This will opent-he circuit from the source 38 and the condenser 56 will then discharger and current will flow through the windings 41 to ground at 54;
  • the mechanism'associated with the armature 42 is so arranged that the effect of this impulse is to move the rotating member 44 in the direction of the arrow, namely, the same direction in which the impulse from the source 38 moved vthe said member.
  • the movable contact 46 By applying the correct number of impulses the movable contact 46 will be brought into such position as to touch they fixed contact 47, thereby groundingthe relay 48 and causing it to operate.
  • v Uponthis operation current will iow from the source 49 over lits armature and inner contact to the signal device 50 which may be any form of visual or audible signal., such as in lamp or bell or similar device.
  • the arrangement shown in Fig. 2 is a modification of that shown in Fig. 1.
  • the antenna 21 may be connected in any well known manner such as by the transformer 100 with a radio receiving circuit here shown -as comprising a detector 101 and an audio ⁇ frequency amplifier 108.
  • the antenna circuit is tuned by condenser 125 to the frequency ofv the carrier of the transmitting station;'the secondary of transformer 100 is tuned by condenser 126.
  • the input circuit of the detector contains the grid condenser 102 and the grid leak 103.
  • Connected with the filament is a source of potential 104 and means for varying the current.
  • Connected with the plate circuit of the detector is a source of potential 105. This circuit is connected with the amplifier circuit by the transformer 107.
  • the plate circuit also contains a jack 106 which is adapted to receive the plug 114.
  • This jack is so arranged that the plate circuit will be effectively connected with the amplifier circuity when the plug 114 is not inserted in the said jack; and alternative arrangement of the jack is shown by theldotted lilies designated 106 representing a bridged connection of the jack.
  • the amplifier circuit contains sources of potential 109, 110 and 111, and also a jack 112 which is adapted to receive the plug 113 whereby the receiver 26 may be connected with the output side of the amplifier.
  • the plug 114 is connected With the cord 116 with which is also connected another plug 115, which may be inserted in the jack 117. As an alternative to be used with jack 106, it may be inserted in jack 119 or 120.
  • the circuit with which the jacks 117, 119 and 120 are connected may be designated the signal receiving circuit.
  • This circuit contains an amplifying tube 123 having associated therewith an input transformer 121 ⁇ and an output transformer 28.
  • the other elements of this arrangement Which arey the same as in Fig. 1, have been given theV same designating numbers., The arrangement of Fig.
  • FIG. 2 differs principally from Fig. ⁇ 1 in having an additional relay 122 controlled by relay 34 so as to reverse the polarity of the potential applied to the controlling circuit of the selector containing the condenser 56 and the windings of the magnet 41 whenever relay 34 operates or releases.
  • This 10W frequency current will be amplified by the amplifier 123 and the resultant amplifiedy current will be impressed upon the circuit of the relay 31 which is tuned to 135 cycles.
  • the armature 32 of this relay will vibrate at the rate of135 times per second so long as the impulse continues to be received by the antenna ⁇ 21.
  • current Will flow from battery 37, over conductors and 61, thence, through the winding 34 and condenser 36 in parallel, thence through the contact of the armature 32 and conductor 62, to the opposite pole of battery 37. This will energize relay 34 and cause its armature 39 to touch itsV contact.
  • bat teries are connected in series aiding manner.
  • Thewvinding 41 will be energized and the armature 42 actuated.
  • the rotating element 44 of the selector 40 will be stepped around Va predetermined distance by the operation of the armature 42 in the manner .fully Adescribed in the patent to Field.
  • the armature 32 Will stop vibrating, thereby releasing relays 34 and 122. lVhen the armatures 124 ⁇ and 124 drop back, an impulse'lof opposite polarity ,Will be transmitted through the Winding 41 which will assist the impulse stored up in the condenser '56.
  • the selector' 40 is arranged so that the rotating member l44 will be stepped around through the same distance and in the same direction as etfected by the first impulse although the direction of flow of current in the circuit of the windings 41 is different in the two cases.
  • the suhscriber Upon the receipt of this signal, the suhscriber will opera-te key 118. This ⁇ effectively disconnects the signal receiving circuit from the radio receiver of which detector 101 forms a part. By the closing of the upper contact of key 118, the plate circuit of the detector 101 is effectively connected :through the transformer 107 to the speech frequency amplifier 108. Since the plug 113 will normally be inserted in jack 112,
  • the receiver 26 will thereupon be effectively connected ⁇ with the antenna 21 and accordingly the speech signals received by antenna 2l will be heard by the subscriber at the receiver 26.
  • the operation of the key 118 also serves to open the locking circuit of eliy 66, thereby stopping the ringing of the By inserting the plug 114 in jack 106',
  • the detector 101 will be connected with the input side of the ampliiier 123, whereas, if the plug 115 is inserted in jack 120, the detector will be connected directly with the resonant circuit of relay 31, thereby cutting out the amplifier 123.
  • a selective signaling system has been shown in Figs. 1 and 2, as described heretofore, the arrangements there shown may be readily made non-selective by a simple i'nodiication of the apparatus at the central and the secondary stations.
  • the selector key 10 may be replaced by any simple type of key whereby the circuit of relay 7 might be opened and closed.
  • the selector 40 may be disconnected from the right-hand contact and armature 39 of the relay 34E. This armature may then he directly connected with any slow acting relay, the winding of which should be grounded.
  • the armature of such relay may be arranged to control a signal, such as 50.
  • relay 7 will be operated, and a carrier current modulated by 135 cycle signaling current will be transmitted from the antenna 16. This current will be demodulated by the radio receiver 22, and the 135 cycle component will operate the relay 31, which will in turn control relay 34 in the manner fully described heretofore.
  • This relay when energized, will connect the source of potential 38 with the slow acting relay mentioned above, which in turn will control the signal 50.
  • Figs. 1 and 2 has been described as a one-way signaling system, viz., from station A to B, B1 and B2, it is to be understood that it is not so limited but may be readily adapted for two-way signaling.
  • the selective transmitting apparatus such as is shown in the transmitting branch of station A, codey signaling impulses may rbe sent out from the various secondary stations.
  • a low frequency signahng circuit such as isshown in the receiving path of station B and having a plurality of selectors connected therewith, the code impulses transmitted from the secondary stations will be received, thereby not only enabling the secondary stations to signal the operator at the central station, but also to indicate the number of the calling station.
  • a radio communication system for the transfer of messages and. calling signals, consisting of a series of impulses grouped in accordance with a predetermined code
  • a radio communication system for the transfer of messages and calling signals consisting of a series of impulses grouped in accordance with a predetermined code
  • a code selective switching means responsive to the said slow acting relay, an indicating device connected with the said selective switching means, and means to connect the said radio receiver with either the speech receiving circuit or the said signal receiving circuit.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
US646903A 1923-06-21 1923-06-21 Radio signaling system Expired - Lifetime US1657498A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US646903A US1657498A (en) 1923-06-21 1923-06-21 Radio signaling system
DEI24804D DE510815C (de) 1923-06-21 1924-05-18 Anordnung zum wahlweisen Anruf von durch Hochfrequenz miteinander verbundenen Stationen
FR582886D FR582886A (it) 1923-06-21 1924-06-11

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US646903A US1657498A (en) 1923-06-21 1923-06-21 Radio signaling system

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US1657498A true US1657498A (en) 1928-01-31

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US646903A Expired - Lifetime US1657498A (en) 1923-06-21 1923-06-21 Radio signaling system

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DE (1) DE510815C (it)
FR (1) FR582886A (it)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431018A (en) * 1943-03-26 1947-11-18 Ibm Sound detection system and apparatus
US2554591A (en) * 1945-03-01 1951-05-29 Bell Telephone Labor Inc Radio paging system for vehicles

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE745321C (de) * 1936-11-20 1944-03-21 Lorenz C Ag Anordnung zur Nachrichtenuebermittlung mittels hochfrequenter Wechselstroeme, vorzugsweise ueber Leitungen
DE878517C (de) * 1949-04-24 1953-06-05 Siemens Ag Verfahren zur Ruf- und Wahlzeichenuebermittlung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431018A (en) * 1943-03-26 1947-11-18 Ibm Sound detection system and apparatus
US2554591A (en) * 1945-03-01 1951-05-29 Bell Telephone Labor Inc Radio paging system for vehicles

Also Published As

Publication number Publication date
DE510815C (de) 1930-10-24
FR582886A (it) 1924-12-30

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