US1482558A - Alternating-current signaling apparatus - Google Patents

Description

l 1,482,558 Feb 5 4 B. P. HAMILTON ALTERNATING CURRENT SIGNALING APPARATUS Filed Sept. 26 1919 3 Sheets-Sheet 1 INVENTOR.

BBHamz'lZb/z A TT RNEY v Feb. 5; 1924. 1,482,558

B. P. HAMILTON ALTERNATING CURRENT SIGNALING APPARATUS a4 Bag. 5

filler }NVENTOR.

BJ Ham z'lzan l A TORNEY.

Feb. 5 1924.

' B. P. HAMILTON ALTERNATING CURRENT SIGNALING APPARATUS Filed Sgpt. 26 1919 3 Sheets-Sheet 3 m an L :r

I INVENTOR. B]? Hamilton A TORNEY Patented Feb. 5, 1924,

umrsosrArEs PATENT OFFICE.

BAXTER. P. HAMILTON, OF BRO OKLYE, NEW YORK, ASSIGNOR TO .AIKERICAN TELE- IHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

ALTERNATING-CURRENT SIGNALING APPARATUS.

Application iiled September 26, 1919. Serial No. 326,554.

To all whom it wmy mm .Be it known that I, BAXTER P. 'H-AnrL'roN, residing at Brooklyn, in the county of Kings and State of New Yorlghave invented certainlmprovements in Alternating-Current Signaling Apparatus, of which the following is a specification.

This invention relates to transmission 7 systems' 'and more particularly to transmis- 10 sion systems inwhich Morse signals, telephone signals and carrier currents are simultaneously transmitted over acommon Circuit. T

One of the features of the invention resides'in the provision of means whereby the transmitting and receiving apparatus of a carrier channel'superposed on a composited telephone line may be rendered conjugate with respect to' each "other.

Another feature of the invention resides in the provision of, a iiltering arrangement, for separating the telephonic frequencies from the carrier and Morse frequencies.

A still further feature of the invention is the provision of a system of filters, so applied to the side circuits of a phantom system in which the side circuits are composited for Morse operation and are also utilized for transmitting carrier frequencies, that the filters in the side circuits act together to form similar filters in the phantom circuit. 7 v

' These features, together with other char acteristics of the invention more fully hereinafter appearing, may be fully understood from the following description when read in connection-withthe accompanying drawing, in :which Figures 1 to 5 inclusive illustrate circuit diagrams embodying five differarrangement of fil transmission. of Morse. signals. In order to superpose acarder c nnel upon the line. tuned bridges TB anu 'iB are associated 7 with the; line at the terminal station ductively coupled with the tunedlu ent forms of the invention, while Figure the purpose of utilizing the line for the plicable'not only to the arra emcnt is the transmitting circuit TC, including transmitting apparatus conventionally n1d cated as an alternating current generator and a transmitting key K. A receiving circuit, RC, is also inductively coupled with the tuned bridge TB, said receiving circuit including receiving apparatus conventionally indicated as an alternating current receiving relay RR. In order that the transmitting and receiving circuits'rnay be rendered conjugate with respect to each other; so that electrical disturbances in the one will not affect the other these circuits are coupledto each other and to an artificial line MN, through a balanced transformer 11'. Corresponding transmitting and receiving apparatus is associated with the tuned bridge TB at the station B, said apparatus being designated by the san'ie reference characters primed.

In order to prevent the Morse and carrier frequencies from'being transmitted to terminal telephone apparatus which may be associated with the jacks J and L filters FS and FS' are inserted in the telephone circuit between the terminal jacks and. the composite apparatus GK and UK as illustrated. ,These filters are of the general type illustrated and described in the Uj patcuts of George ,A. Campbell. Serial Nos. 1227,1l3aud 1.227.114; dated lllay 22. 1917, 'aud,'as described in s .d patents. earl) '-ousists of a plurality of sections, each section including seriesand shunt impedance ele 'ments. For the purposes of the present inventioi'i these shunt and series impedance elements are so designed that the filter freely transmits a band of frequencies extending over the voice range; while suppressing: carrier and Morse frequencies.

Where it is desired to utilize the trans mission line as the side circuit of a phan tom system. it may be provided. with phan tom coils PC aud PC. with phantom taps such as 12, '12. extending from the mid 'points of one ofthe windings of each of the phantom coils. to thephantoni circuit The complete phantom arrangement for a line. such as that of Figure 1. may be more clearly understood from the diagram shown in Figure 6.- which. it will be understood. is apa t of Figure 1. but to the modified arrangements shown in Figures 3, 4 and 5. In Figure 6. ML' andiw L' designate telephone lines connection of the relay RR at the station A is such that it is unaffected by energy trans mitted from the local transmitting apparatus, but is responsive to energy incoming from the line. The relay HR at the station B is of course connected in the same manner and is therefore unresponsive to energy transmitted by closing the key K at station B. The filters FSand FS, as beiiore, prevent the transmission of carrier current to the terminal telephone apparatus.

Still another modification is shown in I Figure 3, in which the main line ML is provided with composite apparatus (IX and GK, and broad band filters FS and FS, as before. It Will be understood, of course, that the filters FS and FS may be phantoined in the manner indicated in Figures 1 and 4. Tuned branches TB and TB are bridged across the line ML at stations A and B respectively, and these bridges are associated inductively through transformers 20 and 20 with carrier circuits CC and CC.

Each carrier circuit includes a differential relay as shown at DR and DR. The differential relay DR compriseswindings 30,31,

' 32 and 33, between the midpoints of which a transmitting apparatus conventionally indicated as a generator'G and transmitting key K is connected. A balancing network or artificial line MN is connected to windings relay is not energizedand consequently the One armature 34 thereof is not actuated.

half of the energy from the generator G is transmitted to the artificial line MN and the other half flows over the circuit CC through the transformer to the tuned bridge TB,

from which itis transmitted over the line ML and selected by the tuned bridge TB at the station B. The alternating current is then transmitted through the transformer 20 to the carrier circuit CC and as the current flows in series through the tour wind- "'ings of the difl'erential relay DR, said differential relay is actuated, so that the arm-a.- ture 34 operates. Transmission over the line ML may simultaneously take place in the opposite direction by actuatingthe key K.

Figure 4fillustrates a modification of the invention arranged to operate on a halt duplex basis. The arrangement of the coinposite sets GK. and CK. the filters FS and FS and the tuned bridges TB and TB are the same as described in connection with the previous figures. It will be understood, of

course, that the filters and FS may be arranged for phantom operation as described in connection with Figures 1 and 6. At station A the receiving circuit RC inductively coupled to the tuned bridge TB through a transtorn'ier arrangeu'ient comprising windings 40 and 41. The receiving circuit in cludes an alternating current receiving rc lay RR which in turn controls the local circuit of a relay 42, which controls the sound er S. The transmitting circuit TC is in ductively coupled with the tuned branch TB through an autotransformer arrangement comprising Winding 41. Said transmitting circuit includes an alternating cur rent generator G. Both the transmitting circuit TC and receiving circuit RC are controlled by the contacts of a relay 43 under the control of the sending key K. At the station B the arrangement of parts will in practice be identical with those at station A, but for simplicity the details of the receiving circuit R0 are not shown and in connection with the transmitting circuit TC only a sendin kev K and a enerator G are indicated in. series, the details or the con trolling arrangement being omitted.

The operation is as follows:

In transmitting from'station A to station B, the key K is actuated thereby energizing the relay 43, which attracts its armature 44. thereby opening contact 45 of the receiving circuit RC and at contact 46 completing the receiving circuit through a 12,000 ohm resistance 47. This resistance is Provided for the purpose of reducing the amount of local transmitting energy admitted to the receiving circuit RC through the transformer 40. 41, so as to prevent overloading the receiving relay RB. The armature 44 also closes the transmitting circuit TC at contact 48. so that alternating current energy from the generator Gr is transmitted through autotransformer winding 41. to the tuned bridge TB, said energy being then transmitted over the main line ML and selected by the tuned bridge TB at the receiving station B. This energy is then transmitted through the transformer comprising windings 40 and 41 to the receiving circuit RC.

Should the operator at station B desire to break in while the operator at station A is speaking, the sending key K at station B will be actuated, thereby transmitting alter nating current to the tuned branch TB over the line ML to the tuned branch TB at sta tion A. It will be noted that as the operator at A is manipulating the key K, the relay BR will be energized when the key is closed and de-energized each time the key is opened, thereby causing the actuation of the sounder S through the relay 42.. When the alternating current from the distant station is transmitted from the tuned branch TB through the transformer 40, 41 to the receiving circuit RC in response to the actuation of the key K, at the station B, as just described,.

the relay BR will not release when the key .I\ is released, so that the operator at A. will at-once observe that the sounder is not responding to the signals transmitted by the hev K at station B desires, for some reason, to transmit a message. The operator at A will then permit the key K to remain open, so

that the circuit RC will remain closed over.

the contact 15, the resistance of the receiving circuit RC being); thus rendered sufficiently low so that signals from the distant station will actuate the receivlng'relay RR.

An arrangement somewhat similar to that of Figure 4 is illustrated in Figure 5, except that in this case an improved means for amplifying and detecting the received alternating current is illustrated. The tuned branches, the composite set and the filter ar rangement are the same inthis case as in those previously describedythc filters, asbefore, being arranged for phantom operation as described in connection \viththe Figures 1 and 6. The sending apparatus at the station A is schematically indicated as comprising a circuit TC" .Lincludini: a transmitting key. K and an alternating current generator G. It will be understood, however, that this sci'iding circuit will in practice be identical with: that shown at station A of Figure e. The receiving apparatus at station A is not-illustrated, but will be identical with that hereinafter described at station. Ii. The sending apparatus at sta tion B is not illustrated, but, as in the case of station A, will he identical to that illustrated in Figure 4; The receiving apparatus at StationB comprises a receiving circuit RC connected to the input ot a-three-element vacuum tube amplifier VA, the output of which is connectedthrough a trans former to the input circuit of a threeelement vacuum tube detectorVD',in whose output circuit is arranged a receiving relay 35R and, if desired. an ammeter.

The operation of this circuit is as follows:

Upon actuating the key K alternating car riier currents from the generator'G are transmitted to the tuned branch. TB and thence over the main line 1WD to the tuned branch TB from which they aretransmitted to the receiving-circuit RC and impressed upon the amplifier V A. After amplificatiom the amplified alternating currents are impressed upon thedetector VD which operates to 'de tect the signals in a well-known manner, so as to actuate the receiving rcla v RR.

It will be obvious that the general principles herein disclosed maybe embodied .in many other organizations widely different from those illustratechwithout departing from the spirit of the invention as defined in the following claims:

and will understand that the operator;v

-. paratu s conjugate. Withrespect toieach other.

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What is claimed is: 1.In a signal ng system, a transmission circuit, a tuned bridge across said ault;

transmitting and receivingapparatus, as-

soci ated with said transmission ,circuit only through said bridge, and -means,for.maintaming SfllClt. ansinittmg and receivury ap- 2'. In a signaling system a;

circuit, a tuned bridge across said circuit,

transmitting and receiving apparatus associated with said transmission circuit only through said tunedbridge, and means for renderingsaid transmitting. and receiving apparatus conjugate with respect to each other, said means comprising an artificial line associated with said transmitting and receiving apparatus. i

3. In a signalingsystem, atransmission circuit, atuned bridge .acro. saiclciipiritf transmitting and receiving apparatus associated with 1 said transmission circuit, by being inductively, coupled-l to;said-b1: idge only. and means for rendering said{transmitting and receiving apparatus conjugate I with respect to each other.

e. In a s gnallng system, a transmission circuit, tuned bridge across said circuit,

.tr ansmittingand receiving apparatus assoc1ated with said transmission circuit by being inductively coupled to said tuned bridge only, and means for renderingcsaid t l-ansmitting andreceiving apparatus conjugate with respect to. each other, said means comprising an artificial line associated with.

said transmitting and receiving apparatus.

; 5;- In a signaling systema telephone .transmission line including telephone sets. composite apparatus associated .therewith for superposmg .Morse signals thereon, atuned bridge across said line. transmitting; and re ce ving apparatus associated with' said br dge, and means for rendering saidtransmittingand receiving apparatus conjugate with respect to eachv other. i i

6. In a signaling system. a telephone transmission line 'including telephone sets, composite apparatus. for superposingMorse sig na ls on said line. a tuned bridge across said line, transmitting a nd receiving; apparatus associated with said line, and .rneans for rendering said transmitting andreceiving ap}paratusconjugate with respect to ,-ea-ch ot er.

7 In a signalingsystern, a telephone transmission line including telephone sets, composite apparatus for superposing Morse signals on said line, a tuned bridge across said line, transmitting and receiving apparatus inductively coupled to said tuned bridge, and means for rendering said transmitting and receiving apparatus conjugate with respect to each other.

9. In a signaling system, a telephone transmission line, terminal telephone apparatus associated therewith, composite apparatus associated with said line for superposing Morse signals thereon, a tuned bridge across said line, transmitting and receiving apparatus associated with said bridge, means for rendering said transmitting and receiving apparatus conjugate with respect to each other, and broad band filters between the terminal telephone apparatus and said composite apparatus, and a tuned bridge for freely transmitting telephone frequencies, while suppressing Morse signals and carrier frequencies.

10. In a signaling system, a telephone transmission line, terminal telephone apparatus associated with said transmission line, composite apparatus associated with said line for superposing Morse signals thereon, a tuned bridge across said line, carrier current transmitting and receiving apparatus associated with .said bridge, and broad band filters included in said line, between said terminal telephone apparatus and said composite apparatus and the tuned bridge, for freely transmitting telephonic frequencies, while suppressing Morse signals and carrier frequencies.

11. In a signaling system, a pair of telephone side circuit transmission lines, terminal telephone apparatus associated with said lines, composite apparatus associated with said side circuits for super-posing Morse signals thereon, carrier current appa ratus associated with said side circuits, phantom connectionswhereby said side circuits together constitute a phantom transmission line, broad band filters in said side circuits between the terminal telephone ap paratus and said composite apparatus and carrier apparatus for freely transmitting telephonic frequencies, while suppressing Morse signals and carrier frequencies, and phantom connections between the corresponding filters in the two side circuits, whereby the two side circuit filters constitute a filter in the phantom circuit for freely transmitting telephonic frequencies while suppressing carrier and Morse frequencies.

12. In a signaling system, a transmission line, a tuned bridge across said line, a transmitting circuit and a receiving circuit, each associated with said transmision circuit by being inductively coupled with said tuned bridge only, an artificial line and inductive connections between said transmitting and receiving circuits and said artificial line, whereby said transmitting and receiving circuits are rendered conjugate with respect to each other.

13. In a signaling system, a transmission line, a tuned bridge across said line, a circuit inductively coupled with said tuned bridge, said circuit including a receiving relay having balanced windings, transmitting apparatus connected to mid-points of said windings, and an artificial line associated with said receiving relay and transmitting apparatus.

14. In a signaling system, a telephone transmission line including telephone sets, composite apparatus associated therewith for superposing Morse signals upon said transmission line, a tuned circuit bridged across said line, and a receiving circuit associated with said tuned bridge, said receiving circuit including vacuum tube amplifier for amplifying received signals, and a vacuum tube detector for detecting received signals.

In testimony whereof, I have signed my name to this specification this 25th day of September 1919.

BAXTER P. HAMILTON.

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