US2819340A

US2819340A - Voice operated intercommunication system

Info

Publication number: US2819340A
Application number: US392776A
Authority: US
Inventors: Stanley S Brody
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-11-17
Filing date: 1953-11-17
Publication date: 1958-01-07
Anticipated expiration: 1975-01-07

Description

Jan. 7, 1958 s. s. BRODY 1 VOICE OPERATED INTERCOMMUNICATIDN SYSTEM Filed Nbv. 17, 1953 STANLEY. 5. 535m ATTORNEYS VOICE OPERATED INTERCONIMUNICATION SYSTEM Stanley S. Brody, Brooklyn, N. Y.

Application November 17, 1953, Serial No. 392,776

Claims. (01. 119 1 ,1

--(GrantetLunder Title 35, U. Code (1.952), sec. 266) operational restrictions upon the manufacturers and users of. theequipment. One of themajor. defects of an intercommunication system'is-. the .well known effect of feed back with "the resultant "high :pitchi noise. 'All conventional intercommunication systems contain a microphone, an-"amplifier and 4a speaker;r:. 'Il1e audible energy that impinges uponthe microphone, is converted into electrical energyA The'electrical energy atz'the output of the micro phone" is theninserted': into an amplifier'to increase the level of the electrical energy to a new value without any alteration'in thetype or the graphic form of the energy wave.- l-lhe outputof the amplifier is then-fed to a speaker where the electrical energy is converted back into the original form of audible energyat an increase in energy level. If the output of the speaker were to be inserted into the microphone, the new output would be at a greater energy level. The cycle 'of increasing the energy input and greater speaker output would continue until the amplifier reached saturation. The end result of the above type of feedback and saturation is a loud high pitch tone that emits from the speaker.

Feedback will occur whenever the speaker and the microphone of a system are in close proximity to each other. The energy wave from the speaker can cause feedback by entering the microphone directly or indirectly. Numerous methods-have been devised to counteract the objectional effect of feedback. They usually encompass complicated, expensive and sensitive equipment and circuit arrangements that result in high initial costs, high failure rate and-increased maintenance costs. Many of the devised methods decrease, rather than eliminate, the possibility of feedback.

One of the common methods that is utilized to eliminate the possibility of feedback is the use of a talk-listen key thatis operated by the user to conform withthe act being performed. The operation of a talk-listen key is objectional in that the user must develop a certain amount of coordination to carry on a conversation. This type of intercommunication system requires the use of v the operators hand thus preventing him from doing all but the most elementary duties while talking into the interto the input of an amplifier and, through a relay, to the output of theother amplifier. A difierential relay that is connected to the output of each amplifier through a rectifier, determines the transducer that shall perform as a speaker and the transducer that shall perform as a microphone. At any particular instant during the operation, one amplifier will be operating into a transducer that functions as a speaker while the output of the other amplifier will be grounded to prevent feedback and will be disconnected from all transducers.

To operate, the user talks into one of the transducers. A differential relay that is triggered by the output of the activated amplifier, automatically connects the second transducer to the output of the activated amplifier, grounds the output of the other amplifier and removes the transducer from the output of the grounded amplifier. The differential relay is of the quick-make, slow-break type so that the operating amplifier will remain opera tive during the short pauses that are common to normal speech.

It is a general object of the present invention to provide an intercommunication systemthatis completely free of the effect offeedback. T

It is another object to present an intercommunication system wherein the switching is performed automatically.

An additional object is to provide an intercommunication system that will allowa two-way conversation without requiring the user to manuallyoperate any control device. w Other objects and many of the attendant advantages of this invention willbe readily appreciatedasthe same becomes better understood by reference to the following :detailed description when considered .in'connection with the accompanying drawings wherein; v Fig. 1 is a block and schematic diagram of the invention wherein the switching is performed .by three relays, one of which is a diiferential relay and Fig. 2 is a block and schematic diagram of a modified form of the invention wherein the switching is performed by two relays. Y

Referring to Fig. 1, permament magnet speakers or transducers 2 and 4 are of conventional-design and construction well known in the art. The amplifiers 6 and-8 are also of conventional design.

' Each speaker or transducer 2 and 4 is capable of operation either as a transmitter or as a receiver. Such speakers are old in the art. The voice coil of each speaker is connected to the input of a corresponding amplifier 6 or 8, respectively. The outputs of amplifiers 6 and 8 are each connected to a corresponding speaker through the normally open contacts of the

relays

10 and 12, respectively. The

relays

10 and 12 connect the appropriate transducer to the output of the proper amplifier at the required instant. The output of the amplifier 6 is also connected to operate one side 13 of a differential relay 14, through a rectifier 16. The dif-. ferential relay is of the normally open type. The output of the amplifier 6 is also connected directly to ground 3 through the normally open contacts 20 of side 15 of the differential relay 14. The output of the amplifier 8 is connected to operate the other side 15 of the relay 14 through a similar rectifier unit. The output of the amplifier 8 .is also connected directly to ground 3 through the normally open contacts 18 of theside 13 of the relay 14. The circuits of the coilsof the

relays

10 and 12 are completed when connected to ground through another pair of normally'open contacts 22 and Mrespectively of the relay 14.

Each transducer is connected To operate this invention, the amplifiers 6 and 8 .are turned on. -The transducers 2 and.4 are conveniently located at the desired locations that are usually known as stations. When the apparatus onstation. is in the.

facts of relays 10, '12 and 14' are "open? "At'the instant somebody speaks into the transducer or transmitter and receiver}, the intelligence is .con v e rted into electrical energy fand amplifiedbythe amplifier output of the amplifier 6 actuates the side our the relay 14 through the action of the rectifieri16. The closing of the

contacts

18 and 22 of the" relay 1,4 grounds the output of the amplifier Sand actuates' the relay 10. f The closing of the contacts of the relay connects the output of the amplifier 6 to the other transducer 4. "At this instant, the direction of intelligence is from transducer 2 to transducer 4 through amplifier 6. 'At this point the output of the amplifier 8 is grounded, thus preventing feedback and making the transducer 4 completely serviant to the transducer, 2. The transducer '2 is not connected to the output of the amplifier 8 because -relay 12 is open at this time, but performs as a'mici'ophone for the amplifier 6. The relay 14 is of the q uicki'make, slow'break type so that the transducer Twill retain control during the short pauses that occur during'nor'mal conversion. The transducer 4 can never gain controlwhile' the transducer 2 has controL- The "contacts 18 a'r'1d22 of the relay 14 andthe contacts o'f' the relay 10 o'penwhen the flow of intelligence into the speaker 2' stops for a time interval that is equal to or greater than the drop-out time of the relay 14. When this condition occurs, the transducer 2 can regain control, or the transducer 4 can take control and make the speaker 2 the serviant transducer. The relay 12 and-sideof m'ereiay' '14 o per'ate in the same sequence and' ma'nner as thei'elay 10'andside 13 operate.

The form of invention shown in Fig. 1 may be constructed in a'modified form, "such as shown in Fig. 2. For example,-'the relay' 14' mayhe'in the form of two separate relays 113' and} 115 an the" quick-make-slowbreak type instead of one differential t ype of relay. The

relays

10 and 12 maybe eliminatedby adding another set of normally open contacts llqa'nd 112 to the

relays

113 and 115. 1lfiis 'also obvioiis thaf'one'of the amplifiers 6 or 8 may b e in-sea from the circuit by the utilization of thefproper s'v'vitcfin {not shown).

Obviouslymany modificatioiis and "variations of the present invention are possible in the light of the above teachings. 'i lt therefore'to' be understood that 'within the scope ot the appended claims'ithe invention may be practiced otherwise' thanspecifically described.

What is claimed is: p

l. A voice operatedintercommunication'system"comprising aplurality of transducers 'of the' transmitting and receiving type, a plurality-"of amplifiers connected to said transducers, means connected to the output sides of said'amplifiers to ground the outputs of all but one of the amplifiers to prevent signal generation'feedback and means to connect the transducers 'ofthegrounded amplifiers to the output of the ungrounded amplifier, said grounding means and said transducer-connection means being actuated by the output of the ungrounded amplifier to form a communication circuit comprising the transducer which receives the voice energy, the ungrounded amplifier and 'thetransducers which are connected to the output of the ungrounded amplifier.

2. A voice operated intercommunication system having a sending and a receiving station comprising a first and a second transducer of the transmitting and receiving type, a first amplifier coupled to receive a signal from mid transducers, a second amplifier coupled to receive a signal from said transducers, a ground, and means tothe output of'said first amplifier when said first transducer is receiving voice energy. 1

3. A voice operated intercommunication system having a sending and a receiving station comprising a first transducer of the transmitting and receiving type to generate a signal, a second transducer of the transmitting and receiving type, a first amplifier coupled to receive the signal from said first transducer, a second amplifier coupled to receive a signal from said second transducer, a ground, and a relay coupling the output from said first amplifier to said second transducer and the output of said second amplifier to said ground when said first transducer is receiving voice energy, and coupling the output from said second amplifier to said first trans ducer and the output of said first amplifier to ground when said second transducer is receiving voice energy, so that speaking into either of said transducers automatically forms a communication circuit comprising the energy-receiving transducer operating as a microphone, its associated amplifier and the other transducer operating as a speaker.

4. A voice operated intercommunication system having a sending and a receiving station comprising a first transducer of the transmitting and receiving type, a first amplifier coupled to said transducer to generate an amplified signal, a second transducer of the transmitting and receiving type, a second amplifier coupled to said second transducer to generate an amplified signal, first and second rectifiers coupled to receive such amplified signals and to convert a portion of such signals to direct current, a ground, and switching means coupled to said first and second transducers and amplifiers, said first and second rectifiers and said ground, said switching means being selectively actuated by the output of either one of said amplifiers, Whose associated transducer is receiving voice energy, to ground the output of the other amplifier and to form a communication circuit comprising the energyreceiving transducer operating as a microphone, its associated amplifier and the other transducer operating as a speaker.

5. A voice operated intercommunication system having a sending and a receiving station comprising a first transducer of the transmitting and receiving type, a first amplifier coupled to said transducer to generate an amplified signal, a second transducer of the transmitting and receiving type, a second amplifier coupled to said second transducer to generate an amplified signal, first and second rectifiers coupled to receive such amplified signals and to convert a portion of such signals to direct current, a ground, and a difierential relay coupled to said first and second transducers and amplifiers, said first and second rectifiers and said ground, said difierential relay being selectively actuated by the output of either one of said amplifiers, whose associated transducer is receiving voice energy, to ground the output of the other amplifier and to form a communication circuit comprising the energy-receiving transducer operating as a microphone, its associated amplifier and the other transducer operating as a speaker.

6. A voice operated intercommunication system having a sending and a receiving station comprising a first transducer ofthe transmitting and receiving type, a first amplifier coupled to said transducer to generate an amplified signal, a second transducer of the transmitting and receiving type, a second amplifier coupled to said second transducer to generate an amplified signal, first and second rectifiers coupled to receive such amplified signals and to convert a portion of such signal to direct current, a ground, a difierential relay coupled to said first and second amplifiers and to said ground to selectively feed the outputs of said amplifiers to ground and means coupled to said differential relay to feed the outputs of said amplifiers to said transducers, said last-named means being actuated by operation of said difierential relay which, in turn, is actuated by the output-of either one of said amplifiers whose associated transducer is receiving voice energy, so that speaking into either of said transducers automatically forms a communication circuit comprising the energy-receiving transducer operating as a microphone, its associated amplifier, and the other transducer operating as a speaker, while grounding the output of the other amplifier.

7. A voice operated intercommunication system having a sending and a receiving station comprising a first transducer of the transmitting and receiving type to generate a signal, a first amplifier coupled to said first transducer to receive the generated signal, a first rectifier coupled to the output of said first amplifier to convert a portion of the output signal to direct current, a second transducer of the transmitting and receiving type, a second amplifier coupled to said second transducer, a second rectifier connected to the output of said second amplifier to convert a portion of the output signal to direct current, a ground, a first relay having a coil connected to receive a direct current from said first rectifier and having two sets of normally open contacts, one set connected between the output of said first amplifier and said second transducer and the other set connected between the output of said second amplifier and ground, and a second relay having a coil connected to receive direct current from said second rectifier and having two sets of normally open contacts, one set connected between the output of said second amplifier and said first transducer and the other set connected between the output of said first amplifier and ground, so that speaking into either of said transducers actuates the relay whose coil is connected to the rectifier which receives the output signal of the amplifier associated with the energy-receiving transducer, whereby the output of the other amplifier is grounded and a communication circuit is formed comprising the energy-receiving transducer operating as a microphone, its associated amplifier and the other transducer operating as a speaker.

8. A voice operated intercommunication system having a sending and a receiving station comprising a first amplifier, a first transducer of the transmitting and receiving type coupled to said first amplifier to generate and feed a signal to said first amplifier, a rectifier coupled to the output of said first amplifier to convert a portion of the output signal to direct current, a second amplifier, a second transducer of the transmitting and receiving type coupled to said second amplifier to generate and feed a signal to said first amplifier, a rectifier coupled to the output of said second amplifier to convert a portion of the output signal to direct current, a ground, a differential relay having a pair of coils each connected to one said rectifier and to ground and having two sets of normally open contacts, a second relay having a coil connected to one of the sets of contacts on said differential relay and having a set of normally open contacts connected between one of said transducers and the output of its non-associated amplifier, a third relay having a coil connected to the other of the sets of contacts on said differential relay and having a set of normally open contacts connected between the other of said transducers and the output of its non-associated amplifier, said differential relay being actuated by the output signal from one of said amplifiers whose associated transducer is receiving voice energy, t e actuation of said differential relay in turn actuating said second and third relays, so that speaking into either of said transducers automatically forms a communication circuit comprising the energyreceiving transducer operating as a microphone, its asso ciated amplifier and the other transducer operating as a speaker, while grounding the output of the other amplifier.

9. A voice-operated intercommunication system comprising in combination: at least two transducers of the transmitting and receiving type; at least two amplifiers, each connected to a diiferent one of said transducers; and switching means connected to said amplifiers and said transducers for selectively disabling one of said amplifiers when the transducer associated with the other said amplifier is receiving voice energy and for connecting the non-utilized transducer at that time to the output of the non-disabled amplifier, said switching means being actuated by output signals from the amplifier whose associated transducer is receiving voice energy.

10. A voice-operated intercommunication system comprising, in combination: at least two transducers of the 'transmitting and receiving type; at least two amplifiers,

each connected to a difierent one of said transducers; and switching means connected to said amplifiers and said transducers for selectively grounding the output of one of said amplifiers when the transducer associated with the other said amplifier is receiving voice energy and for connecting the non-utilized transducer at that time to the output of the ungrounded amplifier, said switching means being actuated by output signals from the amplifier whose associated transducer is receiving voice energy.

References Cited in the file of this patent UNITED STATES PATENTS 2,102,903 Levique Dec. 21, 1937 2,424,069 Tschumi July 15, 1947 2,477,275 Tschumi July 26, 1949 2,545,489 Levy Mar. 20, 1951