US1666154A - Distribution of programs over wires - Google Patents

Description

v 1,666,154 J. F. TOOMEY DISTRIBUTION OF PROGRAMS OVER WIRES April 17, 1928. I

Filed July 12.1924

IN VEN TOR JZ 150W Patented Apr. 17, 1928 I z ,1; a

TELEGRAPH COMPANY, A CORPORATION or NEW" YORK.

"DISTRIBUTIONYVOIF rRoeRAMs OVER WIRES,

' Application filed Julyllz,1924..SriaiNo.725,G43. f" v This invention relates to the distribution of programs over More lines, andmore particularly to an amplifying arrangement to:

be vused in connection with such systems.

In a system for thedistribution of music,

news, entertainment, etc, over wire trans mission lines, it 1s customary to establlsh a connection from the studio or other point at .which the program originates. over a trunk to a central ofiice from Whl Ch' branch trunks extend to points in local areas, such as I apartment houses At each apartment house or other'local area branches extend from each distributingtrunkto thereceiving equipment located at the subscribers premises. Atveach distributing point, such, for example, as the central station, or the p I p from battery, over the switch 13,"-thr0,ugh

local distributing point, such as an'apartment house, it is desirableto provide amtributing trunk or subscribers branch.

' rAt such distributing points ,it-is not-21 up its armature in series with the high re ways convenient to have an attendant on Y duty-to maintain the amplifying equipment.

may be .substituted forthe'regular equip ment without interruptingthe service there by enabling a trouble man to rectity the.

ditficulty at his convenience.

-The invention ,will now bev moreiully :un-L

derstood from the following description wheniread in connection Wlth tllfl accom I panyingdrawing, thefigure of which illustrates an'amplifying arrangement embodying the principles of the invention.

Referring to the-drawing, T may be taken torepresent a trunk extendingfrom astud-io' to a distributing P011113 or a trunk extending from a centraltdistributing point to a local distributing point such as an apartnent house- Atthe apartment house, am-

plifying equipment. is provided comprising two amplifying stages, the first stage comprising preferably a ,single tube amplifier and the second stage comprisingpreterably a push-pull amplifier. Atube is PIOVldGCl as the normal amplifier for the first vstage,

' and an auxiliary tube 10": is adapted to be switched in the circuit in the event that the tube 10;should fail. 1 Similarly, tubes 11 and 1 2,normally function as. the amplifiers V thatthe switching of an auxiliary tube will be under, the control of a marginal relayin we I circuit with the filament of the regular tube, thev relay being so arranged that it-will ,au vtomatica lly disconnect theregular" tube and the 24 volt ba y;

relay 19 to point 20. 'From-pointf20 the cir- I v 'of th e second stage pushepull combination, auxiliary tubes 11. and 12 being provided JOHN F. rooMEY, on NEW YoRig-iv. Y nssxenoRao AMERICAN TELEPHONE Ann" to be substituted in the case of failure ofthe regular tubes. The circuits "are so arranged substitute an auxiliary tube in case the filament of the regular tube should burnout. v

Further -detailsof the apparatus willfnow i be clear from 'the'description the opera tion, which is asfollowsr I 1 l/Vhenever it is desired to place the'eircuit' in condition for transmission, .a 'sw'itch13 will be closedlthereby completing a circuit;

marginalrelay l l, over the ring side'of the trunk T, through the high resistance windl,

ingot the relay 15,, andfback over the tip 'side of thetrunkT; to ground. The relay 15 is energizedover the circuit above traced. 1 The relay. 14 being marginal doesnot pull contact, throughthewinding oifl'relay- G to V thereby-energizing the, 1 I s5 p relay G. Relay in turn "completes a cit cuit' from the 24 volt,battery over itsgfront contact, through impedance. coil 16 and're- I sistan'ce'l'? to the point 18, thence in parallel over the left hand back contact of marginal t and outer right-hand back contact ofrela'y' relay19, through the filament ofjtubefl2 19 to point 20, and from ,thei point "18 through the energizing wind ng of marginal ouit extends to. point121and'then'ce in parallel :over'the' outer right-handback Contact ,i

of] marginal relay 22, through the filament and from the point2l through the energizof tube 11, and "overfthe left-hand back con- 1' tact of marginalrelay 22 to'the point 23',

23. From point the circuitextendsjtopoint 24 and. thencein' parallel over the left hand back contact of marginal relay} 25, through the filament of the tube 10, outer right-hand *backcontact'of relay 25to point;

10c ing winding of marginal relay 22, to point put circuits 7 of the amplifiers. therefore flows from the plate of the first traced that the circuit extends through the filament of each normal tube in parallel with the operating winding of the marginal relay. Suiiicient current flows through the filaments of each of the normal tubes 10, 11 and 12 so that the filaments glow and each filament shunts the energizing winding of the corresponding relay to such an extent that an insuliicient amount of current flows through the marginal relay to cause its energization.

As soon as I the filaments of the tubes begin to glow, the space current flows in the outstage tube 10, through the primary winding of transformer 28, through the winding of the relay I to the 350 volt source of space current, thereby energizing the relay 1. Similarly, current flows in parallel from the plates of the tubes 11 and 12 of the second stage amplifier to the midpoint of the primary winding of the transformer 29 and thence through the winding of the relay L to the 350 volt plate source. Relays I and L, upon being energized, complete a circuit from ground over the front contact of relay L and over the front contact of relay l through the left-hand winding of relay H to the 24c volt battery thereby energizing relay H and looking it up through its righthand winding and over-its right-hand front contact to ground over the front contact of relay 15. A relay '30 is connected in the lead which extends to the 350 volt plate source so that as soon as'current flows to the plate circuits of the amplifying equipment the relay 30 is energized and completes a shunt circuit through the low resistance Winding of the relay 15, said shunt circuit extending over the back contact of the relay F. The closing of the low resistance shunt circuit increases the current flow over the trunk T thereby energizing relay 1 1 which completes a circuit for the lamp31 to indicate that the circuit is in operative condition. Transmission may now take place in the regular manner.

In case'the350 open the low resistance shunt winding of the relay 15, thereby 'causing'the marginal relay let to be deenergized. When the armature of the relay 14 falls OK, the lamp 31 will be extinguished, thereby indicating that there is trouble on the circuit. In the event the tube 10 should fail by reason of burning out its filament, the current through the left-hand winding of the marginal relay 25 will be increased owing to the opening of the shunt path about said winding. Marginal relay 24: will thereby be energized and will be locked up over a circuit from the 2 1 volt battery, over the front contact of relay Gr, through the right-hand locking Current the marginal volt power source shouldv fail, the relay 30 will be deenergized and winding of relay 25 and over its inner righthand front contact and through the lefthand winding of relay F to ground over restoring key li. At its outer front contacts relayzf) substitutes the filament circuit of the auxiliary tube 10 for the filament circuit of the tube 10 so'that the tube 10 at once functions, and transmission may proceed as before- 'lhe relay F, upon being energized, opens the low resistance shunt winding of the relay 15 to cause the signal lamp at 31 to be extinguished thereby indicating trouble upon the circuit, so that an attendant may substitute a new tube for the tube 10. Upon replacing the tube 10, the

attendant opens the key K thereby releasing the relay i and unlocking the marginal relay 25 which is restored to normal and agaln connects the filament'of the tube 10' in circuit, softhatthe tube 10 now functions as the amplifier. The releasing of the relay F again closes the circuitthrouglr the low resistance shunt winding of the relay 1'5 and causes the signal lamp 31 to again glow. A. similar action takes place in case the filaments of either of the tubes 11 or 12 should burn out.

1n the event that plate current should fail to flow through the relay I for any reason, its armature in falling off will complete a circuit from ground, over the front contact of relay L and back contact of relay l, frontv contact of lock up relay H and through the winding of the relay F to the 2s volt battery. Similarly, if the space currents should fail to flow through the winding of the relay L, a circuit will be completed from ground, over the back contact of relay L, front contact of relay H, and through the right-hand winding of relay F to battery. In every case the relay F will be energized thereby opening the low resistance shunt of the relay 15 and causing the lamp 81 to indicate trouble on the line. When the circuit is no longer to be used for transmission, the switch 13 will be opened thereby 'deenergizing marginal relay ll and relay 15. Relay 15 opens the locking circuit of relay H and also opens the circuit of relay G so that all of the apparatus is restored to normal. a

lit will be obvious that the general prm ciples herein disclosed-may be embodied in many organizations widely difierent from those illustrated without departing from the spirit of the inventionas defined in the following claims.

What is claim-ed'is: I i 1. In a transmission circuit, an amplifier comprising a normal vacuum tube and circuits therefor, a spare vacuum tube, a mar ginal relay supplied with current from the filament current supply-circuit of said normal vacuum tube, and means controlled by said relay whereby when said filament burns cuits therefor, a spare vacuum'tub'e, a current supply circuit for energizing the fila- .ment of said normal tube, a marginal relay connected 1n parallel with. said filament,-sa1d'marg1nal relay remaining deenergized while current flows throughsaid filament and adapted to be energized'when the filament burns out, and means controlled by said marginal relay for switching said spare tube into theamplifier circuit in place of the normal tube. v

3. In a transmission circuit, a multi-staget spare tube'therefor.

fication, a marginal relay connected in shunt with the filament of each normal tube, said plifier comprising a normal tube and cir cuitsthere'for for each stage of am'plifica tion, aspare tube for each stage of ampIi-H marginal relay being deenergized as long as current, fiowsthrough the filament but being energized when the -filament-burns out, and switching means controlled by each' marginal relay for disconnecting the corresponding normal tube and .substituting'the In testimony whereof, I have signedmy July, 1924. I JOHN F. TO'OMEY.

[a name to thisspecificationthis 11th day of

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