GB2082875A - Conference bridge circuit arrangements - Google Patents

Conference bridge circuit arrangements Download PDF

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Publication number
GB2082875A
GB2082875A GB8126375A GB8126375A GB2082875A GB 2082875 A GB2082875 A GB 2082875A GB 8126375 A GB8126375 A GB 8126375A GB 8126375 A GB8126375 A GB 8126375A GB 2082875 A GB2082875 A GB 2082875A
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GB
United Kingdom
Prior art keywords
signals
coded
serial
circuit arrangement
bridge circuit
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.)
Granted
Application number
GB8126375A
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GB2082875B (en
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General Electric Co PLC
Original Assignee
General Electric Co PLC
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 General Electric Co PLC filed Critical General Electric Co PLC
Priority to GB8126375A priority Critical patent/GB2082875B/en
Publication of GB2082875A publication Critical patent/GB2082875A/en
Application granted granted Critical
Publication of GB2082875B publication Critical patent/GB2082875B/en
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
    • H04B14/04—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using pulse code modulation
    • H04B14/046—Systems or methods for reducing noise or bandwidth
    • H04B14/048—Non linear compression or expansion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
    • H04M3/561—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities by multiplexing

Abstract

In a conference bridge circuit arrangement for interconnecting a plurality of telephone sets of a P.C.M. telephone system the coded signal values to be applied to the receiver of any one of the telephone sets are derived by serial addition 10, 11 of coded signal values from the transmitters of all of the plurality of telephone sets followed by serial subtraction 13-16 of at least a proportion of the coded signal value from the transmitter of the respective telephone set. <IMAGE>

Description

SPECIFICATION Conference bridge circuit arrangements The present invention relates to conference bridge circuit arrangements.
In particular but not exclusively the invention relates to conference bridge circuit arrangements of integrated circuit form.
According to the present invention in a conference bridge circuit arrangement for interconnecting a plurality of telephone sets in a pulse code modulation telephone system composite signal values to be applied to the receiver of any one of said telephone sets are derived by serial addition of pulse coded signal values from the transmitters of all of said plurality of telephone sets and by serial subtraction from the resultant of at least a proportion of signal values from the transmitter of said one of said telephone sets.
In a telephone system in which the speech signals are compression-law coded, for example in accordance with the CCITT A-law code, there may be provided means to derive linear binary coded signals from said compression-law coded signals for said serial addition and subtraction and means subsequently to derive compression-law coded signals from said composite signal values. The conference bridge circuit arrangement may utilise integrated circuits.
A conference bridge circuit arrangement for a pulse code modulation telephone system, the circuit arrangement being in accordance with the present invention, will now be described by way of example with reference to the accompanying drawing, which shows the circuit arrangement schematically.
Referring to the drawing, which shows a four party conference circuit arrangement, compression-law coded speech signals from the transmitters of the four telephone subscriber's sets, received in serial form over paths 1 to 4, are converted to serial linear binary coded form in respective circuits 5 to 8. All four serial linear coded signals added together by means of serial adder circuits 9, 10 and 1 and the linear coded signals representing the sum of all the speech signals from the four parties, on path 12, are applied to circuits 13 to 1 6 where the respective linear coded signals from the transmitters, or linear coded signals representing a fraction of these signals, are subtracted from the sum signals to provide linear coded signals for the respective receiver circuits of the four subscriber's sets.If the whole of the respective coded signals are subtracted in the circuits 1 3 to 1 6 each party will hear only speech signals from the other three, whereas if only a fraction of the respective coded signals are subtracted each party will be provided with a degree of side-tone.
The signals from the circuits 13 to 16 are passed in serial mode to respective stores 1 7 to 20, from which they are applied, again in serial mode but in reverse order, to respective circuits 21 to 24 for conversion from linear binary code to compression-law code for the receiver circuits of the respective subscriber's sets. The use of serial mode greatly reduces the number of conductors required to interconnect the circuits 5 to 24, a factor of some importance if the circuit arrangement is to be produced in integratedcircuit form.
1. A conference bridge circuit arrangement for interconnecting a plurality of telephone sets in a pulse code modulation telephone system wherein composition signal values to be applied to the receiver of any one of said telephone sets are derived by serial addition of pulse coded signal values from the transmitters of all of said plurality of telephone sets and by serial subtraction from the resultant of at least a proportion of signal values from the transmitter of said one of said telephone sets.
2. A conference bridge circuit arrangement in accordance with Claim 1 wherein the speech signals are compression-law coded.
3. A conference bridge circuit arrangement in accordance with Claim 1 wherein the speech signals are compression-law coded in accordance with the CCITT A-law code.
4. A conference bridge circuit arrangement in accordance with Claim 2 or Claim 3 wherein there are provided means to derive linear binary coded signals from said compression-law coded signals for said serial addition and subtraction and means subsequently to derive compression-law coded signals from said composite signal values.
5. A conference bridge circuit arrangement substantially as hereinbefore described with reference to the accompanying drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Conference bridge circuit arrangements The present invention relates to conference bridge circuit arrangements. In particular but not exclusively the invention relates to conference bridge circuit arrangements of integrated circuit form. According to the present invention in a conference bridge circuit arrangement for interconnecting a plurality of telephone sets in a pulse code modulation telephone system composite signal values to be applied to the receiver of any one of said telephone sets are derived by serial addition of pulse coded signal values from the transmitters of all of said plurality of telephone sets and by serial subtraction from the resultant of at least a proportion of signal values from the transmitter of said one of said telephone sets. In a telephone system in which the speech signals are compression-law coded, for example in accordance with the CCITT A-law code, there may be provided means to derive linear binary coded signals from said compression-law coded signals for said serial addition and subtraction and means subsequently to derive compression-law coded signals from said composite signal values. The conference bridge circuit arrangement may utilise integrated circuits. A conference bridge circuit arrangement for a pulse code modulation telephone system, the circuit arrangement being in accordance with the present invention, will now be described by way of example with reference to the accompanying drawing, which shows the circuit arrangement schematically. Referring to the drawing, which shows a four party conference circuit arrangement, compression-law coded speech signals from the transmitters of the four telephone subscriber's sets, received in serial form over paths 1 to 4, are converted to serial linear binary coded form in respective circuits 5 to 8. All four serial linear coded signals added together by means of serial adder circuits 9, 10 and 1 and the linear coded signals representing the sum of all the speech signals from the four parties, on path 12, are applied to circuits 13 to 1 6 where the respective linear coded signals from the transmitters, or linear coded signals representing a fraction of these signals, are subtracted from the sum signals to provide linear coded signals for the respective receiver circuits of the four subscriber's sets.If the whole of the respective coded signals are subtracted in the circuits 1 3 to 1 6 each party will hear only speech signals from the other three, whereas if only a fraction of the respective coded signals are subtracted each party will be provided with a degree of side-tone. The signals from the circuits 13 to 16 are passed in serial mode to respective stores 1 7 to 20, from which they are applied, again in serial mode but in reverse order, to respective circuits 21 to 24 for conversion from linear binary code to compression-law code for the receiver circuits of the respective subscriber's sets. The use of serial mode greatly reduces the number of conductors required to interconnect the circuits 5 to 24, a factor of some importance if the circuit arrangement is to be produced in integratedcircuit form. CLAIMS
1. A conference bridge circuit arrangement for interconnecting a plurality of telephone sets in a pulse code modulation telephone system wherein composition signal values to be applied to the receiver of any one of said telephone sets are derived by serial addition of pulse coded signal values from the transmitters of all of said plurality of telephone sets and by serial subtraction from the resultant of at least a proportion of signal values from the transmitter of said one of said telephone sets.
2. A conference bridge circuit arrangement in accordance with Claim 1 wherein the speech signals are compression-law coded.
3. A conference bridge circuit arrangement in accordance with Claim 1 wherein the speech signals are compression-law coded in accordance with the CCITT A-law code.
4. A conference bridge circuit arrangement in accordance with Claim 2 or Claim 3 wherein there are provided means to derive linear binary coded signals from said compression-law coded signals for said serial addition and subtraction and means subsequently to derive compression-law coded signals from said composite signal values.
5. A conference bridge circuit arrangement substantially as hereinbefore described with reference to the accompanying drawing.
GB8126375A 1980-08-29 1981-08-28 Conference bridge circuit arrangements Expired GB2082875B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8126375A GB2082875B (en) 1980-08-29 1981-08-28 Conference bridge circuit arrangements

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8028037 1980-08-29
GB8126375A GB2082875B (en) 1980-08-29 1981-08-28 Conference bridge circuit arrangements

Publications (2)

Publication Number Publication Date
GB2082875A true GB2082875A (en) 1982-03-10
GB2082875B GB2082875B (en) 1984-08-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8126375A Expired GB2082875B (en) 1980-08-29 1981-08-28 Conference bridge circuit arrangements

Country Status (1)

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GB (1) GB2082875B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754258A (en) * 1985-03-01 1988-06-28 Kabushiki Kaisha Toshiba Integrated digital circuit for processing speech signal
EP0317463A1 (en) * 1987-11-20 1989-05-24 Societe Prescom Sarl Conference arrangement circuit for a plurality of participants in telecommunication systems
EP0358981A2 (en) * 1988-09-07 1990-03-21 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754258A (en) * 1985-03-01 1988-06-28 Kabushiki Kaisha Toshiba Integrated digital circuit for processing speech signal
EP0317463A1 (en) * 1987-11-20 1989-05-24 Societe Prescom Sarl Conference arrangement circuit for a plurality of participants in telecommunication systems
FR2623677A1 (en) * 1987-11-20 1989-05-26 Prescom Sarl CIRCUIT FOR CONFERENCE OF A PLURALITY OF PARTICIPANTS IN TELECOMMUNICATIONS SYSTEMS
US4975902A (en) * 1987-11-20 1990-12-04 Societe Prescom Circuit for putting in conference a plurality of participants in telecommunication systems
AU609213B2 (en) * 1987-11-20 1991-04-26 Societe Prescom Sarl Circuit for putting in conference a plurality of subscribers participating in telecommunication systems
EP0358981A2 (en) * 1988-09-07 1990-03-21 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange
EP0358981A3 (en) * 1988-09-07 1990-07-18 Siemens Aktiengesellschaft Circuit for setting up conference connections in a digital time multiplexed telecommunication exchange

Also Published As

Publication number Publication date
GB2082875B (en) 1984-08-15

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee