US1921961A - Apparatus for connecting alpha source of acoustic waves with several listeners for alpha suitable time - Google Patents

Description

Aug. 8, 1933. M BAZE 1,921,961

APPARATUS FOR CONNECTING A SOURCE OF ACOUSTIC WAVES WITH SEVERAL LISTENERS FOR A SUITABLE TIME Filed June 5, 1951 2 Sheets-Sheet l W I Q""""H f" km) 1m) 1 5w 1mm LAW I: I o

12 JVVEI UE y QZU MZ Aug. 8, 1933. BAZE 1,921,961

APPARATUS FOR CONNECTING A SOURCE OF ACOUSTIC WAVES WITH SEVERAL LISTENERS FOR A SUITABLE TIME Filed June 5, 1931 2 Sheets-Sheet 2 19L" I1 l Patented Aug. 8 1933 APPARATUS ZFQR QQNNECTIING A SOURCE 0F ACRUUSTEC WAVES i l/11TH SEVERAL FOP-s A SUITABLE TIME Societ e, Paris, France, assignor'to Holding e Anonyme, Luxembnrg, Gral d-ii) chy oi Luxcmburg Application June 5, 1931, Serial No. 542,362, and in France June 7, 1931 8 @ialms.

The present invention relates to an arrangement enabling the use of a State or private telephone system for the transmission of acoustic waves, with a single microphone transmitter, to a certain number of subscribers at a time, and in which the listeners will have no connection with one another, and hence cannot interfere with the listening or make it impossible.

For this purpose, the said arrangement comprises a device for amplifying th waves of the acoustic source, in whose circuit are comprised various p 'imaries of transformers corresponding to the number of listeners in question, and each of said primaries acts upon a secondary connected with a subscribers line.

This connection is made automatically by a relay, after the central telephone employee has placed the subscriber in the circuit, said relay cooperating with other relays in order to operate the devices for the control of the number, quality, duration, and distribution of the communications.

In such conditions, if for instance the transformers have the ratio of l to 1, with the use of 100 transformers, the ratio of transformation, which is 100: 1 with reference to the source acoustic waves, is only 1: 100 as concerns a subscriber who speaks, and thus the energy transmitted is practically null, and this subscriber cannot be heard by the other listeners, and in addition the impedance of the circuit comprising the primary oi the transformers, is increased by the resistance of the filament-plate space of the last amplifying valve in use.

The accompanying drawings show by way of example an embodiment of the invention.

Fig. 1 is a diagrammatic view of the arrangement of the transformers.

Fig. 2 shows the details of the controlling relays used for each subscriber.

Fig. 3 shows the amplifier.

Referring to Figure l, the telephone wires 1, 2 of each subscribed may be connected, by the transmitter, respectively with th wires 3, 4, connected to the contacts 5, 6; said contacts, as will be further disclosed, are automatically brought against the two ends of the wires of a secondary winding of a transformer 8.

All of the primary windings 9 of said transformers are connected together and also connected by wires 11l2 with an amplifying device A provided with microphone transmitter 10, for instance, which is spoken into by a speaker.

It is thus observed that as long as the contacts '56 close the circuit, the corresponding subscriber will hear the speaking.

In order to regulate the time of the listening and to provide for its proper control, th arrangement shown in Figure 2 is employed; the poles (rill. lit-4) indicated correspond to the poles of the battery of the telephone central.

To the wires 3-4 are connected the respective ends of the winding 11 of a relay 12, with a condenser 13 interposed, and thus when the subscrlber is connected to the wires 3 l, the alternating current for the call, which is sent by the central, will energize the said relay.

Thus the contact 14 is attracted, and the circuit of the winding 15 of a relay connected to the negative pole will be closed at the same time that the winding 28 of relay 12 is energized, said contact 1 being connected with a contact 17 to the positive pole which is in contact at this time. When the relay is is thus energized, the contact 18 is attracted, and it closes the circuit of the winding 19 of a relay 20, which gives an impulse to the meter 21 for the communications. At the same time, the relay 12 attracts the contact 22 connected to the positive pole, and the electric, current starts a clockwork device 23 which is adapted to move contact 24 (connected to the negative pole) toward the left, immediately upon being started, and to bring it back to its initial position after a predetermined interval of time. Consequently, as soon as clockwork device 23 has been started the winding 25 of a relay 26, connected to the negative pole, which was shortcircuited by said contact 24, is now energized, and it attracts the contacts 2'? and 17. It should be understood that the clock work mechanism 23 may be substituted by a mechanism similar to the mechanism employed in the automatic telephone system of the rotary type, more specifically, the type of telephone employing a continuously rotating shaft and electro-magnetic contacts intermittently engageable for making and breaking the circuit.

When the contact 27 is attracted, the circuit of the second winding 29 of the relay 26, conn cted to the positive pole, is now closed at the contact 25, at the same time as the circuit of a pilot lamp 30 which locates the line in operation.

At the same time, since the circuit is broken at 1'2, the windings 28 and 15 cease to be energized, and the contact 22 breaks the circuit for the windings 23-25 which are thus out of action; but since the winding 29 carries current, it holds down the contacts 27 and 17, as Well as the contacts 5 and 6- by which the secondary 7 is connected to the line.

In these conditions, as the primary carries the modulated current, the subscriber making the call will receive the musical waves or others. After three minutes, for instance, according as the apparatus is regulated, the clockwork 23 will bring contact 24 back to its initial position and consequently cut off the current flowing through winding 29 of relay 26, thus returning the arrangement to the inoperative position.

The speaker or phonograph are stationed before a single microphone transmitter 10 (Fig. 3) comprised in the plate circuit of a two-electrode valve 31, so as to prevent all distortion arising from the use of devices such as self-induction or capacity; said microphone thus imparts a difference of potential to a device for amplifying musical frequency, which may comprise two double-grid valves 3233 and a three-grid valve 34. The valve filaments are supplied by a 4-volt battery 35, the plates of the valves 3233 by a 120- volt battery, and the plate of the valve 34 by a 200 volt battery 37. The plate of the valve 31 is supplied at volts by a battery 38.

The speaker is enabled to observe at each instant the quality and the power of the transmitted waves, by means of telephone listener 39 which is branched upon the transmission line by means of a transformer 11, 12.

The speaker is further advised that a subscriber has made a call, by the deflection of a mini-ampere meter 41. For this purpose, the return of all the valves 30 (Fig. 2) to the battery takes place bymeans of an ammeter shunt 42.

The difference of potential at the ends of this shunt is transmitted by a line to a milli-ampere meter 41 mounted on the speakers desk. The meter 41 is, of course, of conventional construction and does not need any further description. One communication is indicated by a deflection of the pointer by a scale-division, two communications by two divisions, and so on.

Obviously the aforesaid arrangement can be used for a wide variety of purposes, and for instance for the voice of a speaker, for the broadcasting, over a wire, of received radio communications or the broadcasting of communications which are not in normal connection with the apparatus, and the like.

The installation may employ the city lines, or interurban or private lines, and it can be used for advertising, news, transmission of orders, or the like.

I claim:

1. In an ordinary telephonic system including a plurality of subscribers lines each connected with a subscribers station provided with an ordinary telephone set respectively, a transmission distributing station in said telephonic system adapted to be called in the ordinary way from any of the subscribers stations and comprising in combination, a microphone, electric amplifying means connected with said microphone, an output circuit for said amplifyin means, a plurality of transformers having their primary windings in serted in. serie in said circuit, and means for connecting the subscribers lines with the secondary windings of said transformers respectively.

2. In an ordinary telephonic system including a plurality of subscribers lines each connected with a subscribers station provided with an or dinary telephonic set respectively, a transmission distributing station in said system adapted to be called in the ordinary way from any of the subscribers stations and comprising in combination, a microphone, electric amplifying means connected with said microphone an output circuit for said amplifying means, a plurality of transformers having their primary windings inserted in series in said circuit, a plurality of call circuits for said subscribers lines, means, connected with said call circuits, for establishing connections between said lines and the secondary windings of said transformers respectively, and means for cutting off said connections a predetermined time after they have been established.

3. In an ordinary telephonic system including a plurality of subscribers lines each connected with a subscribers station provided with an ordinary telephone set respectively, a transmission distributing station adapted to be called in the ordinary way from any of the subscribers stations, comprising in combination, a microphone, electric amplifying means connected with said microphone, an output circuit for said amplifying means, a plurality of transformers having their primary windings inserted in series in said circuit, a plurality of call circuits for said subscribers lines respectively, a relay for each subscribers line adapted to connect said line with the secondary of one of said transformers, a clockwork device for controlling said relay, and a second relay connected to the call circuit of the subscribers line for starting said clockwork device, whereby the first mentioned relay connects the subscribers line with the secondary winding of one of the transformers when a call is made in said line, and cuts off the connection a predetermined time thereafter.

4. In an ordinary telephonic system including a plurality of subscribers lines each connected with a subscribers station provided with an ordinary telephone set respectively, a transmission distributing station adapted to be called in the ordinary way from any of the subscribers stations, comprising in combination, a microphone, electric amplifying means connected with said microphone, an output circuit for said amplifying means, a telephone receiver coupled with said circuit whereby the quality and the power of the emission can be tested, a plurality of transformers having their primary windings inserted in series in said circuit, and means for connecting said subscribers lines with the secondary windings of said transformers respectively.

5. A transmission distributing station according to claim 1 in which the electric amplifying means are connected to the microphone through a two electrodes valve in the plate circuit of which said microphone is inserted.

6. A transmission distributing station according to claim 1 in which there is provided a two electrodes valve in the plate circuit of which said microphone is inserted, for connecting said microphone to said electric amplifying means, said amplifying means including two two-grid valves and a three-grids valve.

'7. A transmission distributing station according to claim 3, further comprising a lamp, a circuit for said lamp, and means, operatively connected with the first relay and with said clockwork device for closing the last mentioned circuit when the clockwork device is started.

8. A transmission distributing station according to claim 3, further comprising a counter, relay for operating said counter, and means, operatively connected with the first mentioned relay, for operating the third mentioned relay every time said first mentioned relay is energized.

MAXIME BAZE.

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