Patent US3835259A successfully refreshed from Google Patents.
US3835259A
Expired / Lapsed
US
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Time division conference hybrid circuit
Assignee: AT&T Inc
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Filing: 1973-03-22
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Granted: 1974-09-10
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Expires: 1993-03-22
Abstract
Abstract In a time division communication system a conference connection among a plurality of stations is established utilizing station associated hybrid circuits connected to an incoming common bus and an outgoing common bus in an assigned conference time slot. It is required that each station receive the outgoing signals of the other conferenced stations but not its own outgoing signal while only the station''s own outgoing signal is applied to the outgoing bus in the assigned time slot. Each hybrid circuit stores the sum of the conferenced signals received from the incoming bus in the assigned time slot. The associated station''s own outgoing signal in the stored conference signal is canceled by a signal derived from the station outgoing signal in a first difference amplifier so that only the signals from the other conferenced stations are applied to the associated station. The other conferenced station outgoing signals appearing at the associated station are prevented from returning to the outgoing bus through cancellation of said other station signals by a signal derived from the first amplifier output in a second difference amplifier whereby only the associated station''s own outgoing signal is applied to the outgoing bus in the assigned time slot. A portion of the associated path outgoing signal from the second amplifier is applied to the hybrid storage capacitor in the interval between successive distinct time slots so that the storage capacitor includes the instantaneous value of the associated path outgoing signal for improved cancellation.
Inventors
- 👤 D Medill
- 👤 P Vachon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:42
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
339 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles comprising a plurality of communication paths, an incoming time division bus, an outgoing time division bus, each communication path having an associated circuit connected to said communication path and selectively connectible to said incoming and outgoing buses, means for exchanging signals among a plurality of selected communication paths comprising means for connecting said incoming bus and said outgoing bus to each selected communication path in a distinct time slot, means connected between said incoming and outgoing buses for producing a signal corresponding to the sum of the selected communication path outgoing signals appearing on said outgoing bus in said distinct time slot, and means for applying said produced signal to said incoming bus in said distinct time slot, each communication path circuit comprising means for storing a sample of said produced signal received from said incoming bus in said distinct time slot, first and second amplifying means each having first and second inputs and an output, said first amplifying means first input being connected to said storing means, said first amplifying means second input being connected to said second amplifying means output, means for coupling said first amplifying means output to said communication path, said second amplifying means first input being connected to said communication path, said second amplifying means second input being connected to said first amplifying means output, means for coupling said second amplifying means output to said outgoing bus in said distinct time slot, said first amplifying means comprising means for canceling the communication path outgoing signal portion of said produced signal from said storage means with said second amplifying means output signal, said second amplifying means comprising means for canceling the portion of the produced signal coupled to said communication path with the first amplifying means output signal, wherein the improvement compriSes means connected between said second amplifying means output and said storing means for directly coupling a portion of said second amplifying means output signal to said storing means.
Claim 2
Dependent Claim
339 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles comprising a plurality of communication paths, an incoming time division bus, an outgoing time division bus, each communication path having an associated circuit connected to said communication path and selectively connectible to said incoming and outgoing buses, means for exchanging signals among a plurality of selected communication paths comprising means for connecting said incoming bus and said outgoing bus to each selected communication path in a distinct time slot, means connected between said incoming and outgoing buses for producing a signal corresponding to the sum of the selected communication path outgoing signals appearing on said outgoing bus in said distinct time slot, and means for applying said produced signal to said incoming bus in said distinct time slot, each communication path circuit comprising means for storing a sample of said produced signal received from said incoming bus in said distinct time slot, first and second amplifying means each having first and second inputs and an output, said first amplifying means first input being connected to said storing means, said first amplifying means second input being connected to said second amplifying means output, means for coupling said first amplifying means output to said communication path, said second amplifying means first input being connected to said communication path, said second amplifying means second input being connected to said first amplifying means output, means for coupling said second amplifying means output to said outgoing bus in said distinct time slot, said first amplifying means comprising means for canceling the communication path outgoing signal portion of said produced signal from said storage means with said second amplifying means output signal, said second amplifying means comprising means for canceling the portion of the produced signal coupled to said communication path with the first amplifying means output signal, wherein the improvement compriSes means connected between said second amplifying means output and said storing means for directly coupling a portion of said second amplifying means output signal to said storing means.
Claim 3
Dependent Claim
52 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles according to claim 1 wherein said means for directly coupling a portion of said second amplifying means output to said storing means comprises an impedance network connected between said second amplifying means output and said storing means.
Claim 4
Dependent Claim
46 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles according to claim 2 wherein said impedance network comprises a capacitor having a first terminal connected to said second amplifying means output and a second terminal connected to said storing means.
Claim 5
Dependent Claim
387 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles comprising a plurality of lines, an incoming bus, an outgoing bus, each line having an associated circuit connected to said line and connectible to said incoming and outgoing buses, means for exchanging signals among a plurality of selected lines comprising means for connecting said incoming bus and said outgoing bus to each selected line circuit in a distinct time slot, a summing amplifier connected from said outgoing bus to said incoming bus for producing a signal proportional to the sum of said selected line outgoing signals appearing on said outgoing bus in said distinct time slot, and means for applying said produced signal to said incoming bus in said distinct time slot, each line circuit comprising a storage capacitor for storing a sample of said produced signal in said distinct time slot and first and second operational amplifiers each having a positive input, a negative input and an output, means for coupling said produced signal from said storage capacitor to said first operational amplifier positive input, means for coupling the second operational amplifier output to the first operational amplifier negative input, said first operational amplifier comprising means for subtracting a signal proportional to the signal appearing at the output of said second operational amplifier from a signal proportional to said produced signal appearing on said storage capacitor whereby the signals from the other selected lines are transferred to said associated line, means for coupling the signal appearing on said associated line to said second operational amplifier positive input, means for coupling the signal appearing on the first operational amplifier output to the second operational amplifier negative input, and means for coupling the second operational amplifier to said outgoing bus in said distinct time slot, said second operational amplifier comprising means for subtracting a signal proportional to the signal on said first operational amplifier output from a signal proportional to the signal appearing on said associated line whereby the outgoing signal from said associated line is transferred to said outgoing bus in said distinct time slot, wherein the improvement comprises impedance means connected between said second operational amplifier output and said storage capacitor for applying a portion of the signal appearing at the output of said second operational amplifier to said storage capacitor.
Claim 6
Dependent Claim
387 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles comprising a plurality of lines, an incoming bus, an outgoing bus, each line having an associated circuit connected to said line and connectible to said incoming and outgoing buses, means for exchanging signals among a plurality of selected lines comprising means for connecting said incoming bus and said outgoing bus to each selected line circuit in a distinct time slot, a summing amplifier connected from said outgoing bus to said incoming bus for producing a signal proportional to the sum of said selected line outgoing signals appearing on said outgoing bus in said distinct time slot, and means for applying said produced signal to said incoming bus in said distinct time slot, each line circuit comprising a storage capacitor for storing a sample of said produced signal in said distinct time slot and first and second operational amplifiers each having a positive input, a negative input and an output, means for coupling said produced signal from said storage capacitor to said first operational amplifier positive input, means for coupling the second operational amplifier output to the first operational amplifier negative input, said first operational amplifier comprising means for subtracting a signal proportional to the signal appearing at the output of said second operational amplifier from a signal proportional to said produced signal appearing on said storage capacitor whereby the signals from the other selected lines are transferred to said associated line, means for coupling the signal appearing on said associated line to said second operational amplifier positive input, means for coupling the signal appearing on the first operational amplifier output to the second operational amplifier negative input, and means for coupling the second operational amplifier to said outgoing bus in said distinct time slot, said second operational amplifier comprising means for subtracting a signal proportional to the signal on said first operational amplifier output from a signal proportional to the signal appearing on said associated line whereby the outgoing signal from said associated line is transferred to said outgoing bus in said distinct time slot, wherein the improvement comprises impedance means connected between said second operational amplifier output and said storage capacitor for applying a portion of the signal appearing at the output of said second operational amplifier to said storage capacitor.
Claim 7
Dependent Claim
47 words
A time division communication system wherein a plurality of time slots occurs in repetitive cycles according to claim 4 wherein said impedance means comprises a capacitor having a first terminal connected to the output of said second operational amplifier and second terminal connected to said storage capacitor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |