Patent US2200932A successfully refreshed from Google Patents.
EP0334549A2
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Method and apparatus for wideband transmission of digital signals between a telephone central office and customer premises
Assignee: AT&T Inc
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Filing: 1989-03-16
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Granted: —
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Expires: 2009-03-16
Abstract
Abstract In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multi-dimensional, passband signal illustratively at 480 kb/s and 1.544 Mb/s. In accordance with a feature of the invention, the passband signal is a so-called carrierless amplitude modulation/phase modulation signal. A trellis code or other code that provides coding gain can be used in conjunction with maximum likelihood sequence estimation, also referred to as Viterbi decoding, at the receiver to provide enhanced receiver noise immunity.
Inventors
- 👤 Richard Dennis Gitlin
- 👤 Sailesh Krishna Rao
- 👤 Jean-Jacques Werner
- 👤 Nicholas Zervos
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 22:48
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/3405; H04L27/3416; H04L27/3427; H04L27/3438; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4917; H04L25/4919; H04L25/4921
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
77 words
A data communication method comprising the steps of generating an outbound passband signal representing a stream of outbound data bits, applying said output passband signal to a telephone local loop, receiving over said telephone local loop an inbound passband signal representing a stream of inbound data bits, and recovering said inbound data bits from said inbound passband signal, at least one of said inbound or outbound bit streams being at a rate of at least 160 kb/s.
Claim 2
Dependent Claim
77 words
A data communication method comprising the steps of generating an outbound passband signal representing a stream of outbound data bits, applying said output passband signal to a telephone local loop, receiving over said telephone local loop an inbound passband signal representing a stream of inbound data bits, and recovering said inbound data bits from said inbound passband signal, at least one of said inbound or outbound bit streams being at a rate of at least 160 kb/s.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein at least one of said bit streams is at a rate of at least 480 kb/s.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein at least one bit streams is at a rate of at least 1.544 Mb/s.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said outbound passband signal is a carrierless amplitude-and-phase modulated signal.
Claim 6
Dependent Claim
45 words
The method of claim 1 wherein said outbound passband signal is a signal representing a stream of channel symbols selected from a predetermined signal constellation, said channel symbols being selected as a function of a trellis coded version of said stream of outbound data bits.
Claim 7
Dependent Claim
60 words
The method of claim 1 wherein said telephone local loop is a two-wire loop, wherein said inbound passband signal includes echos of said outbound passband signal and wherein said method comprises the further steps of generating a replica of said echos, and subtracting said replica from said inbound passband signal prior to the recovery of said inbound data bits therefrom.
Claim 8
Dependent Claim
85 words
The method of claim 6 wherein said inbound passband signal represents said inbound data in a stream of channel symbols selected from a predetermined signal constellation, said channel symbols being selected as a function of a trellis coded version of said stream of inbound data bits, and wherein said recovering step includes the steps of adaptively equalizing said inbound passband signal, recovering said stream of channel symbols by Viterbi decoding the resulting equalized signal, and recovering said inbound data bits from the recovered channel symbols.
Claim 9
Dependent Claim
179 words
A network termination comprising transmitter means for generating an outbound passband signal representing a stream of channel symbols selected from a predetermined signal constellation, said channel symbols being selected as a function of a trellis coded version of a stream of outbound data bits, means for applying said output passband signal to a two-wire telephone local loop, means for receiving an inbound passband signal representing a stream of inbound channel symbols selected from said predetermined signal constellation, said channel symbols having been selected as a function of a trellis coded version of a stream of inbound data bits, said inbound passband signal including echos of said outbound passband signal, means for generating an adaptively equalized version of said inbound passband signal from which said replica has been subtracted, means for recovering said stream of inbound channel symbols by Viterbi decoding the resulting equalized signal, and means for recovering said inbound data bits from the recovered inbound channel symbols, at least one of said inbound or outbound streams of data bits being at a rate of at least 160 kb/s.
Claim 10
Dependent Claim
179 words
A network termination comprising transmitter means for generating an outbound passband signal representing a stream of channel symbols selected from a predetermined signal constellation, said channel symbols being selected as a function of a trellis coded version of a stream of outbound data bits, means for applying said output passband signal to a two-wire telephone local loop, means for receiving an inbound passband signal representing a stream of inbound channel symbols selected from said predetermined signal constellation, said channel symbols having been selected as a function of a trellis coded version of a stream of inbound data bits, said inbound passband signal including echos of said outbound passband signal, means for generating an adaptively equalized version of said inbound passband signal from which said replica has been subtracted, means for recovering said stream of inbound channel symbols by Viterbi decoding the resulting equalized signal, and means for recovering said inbound data bits from the recovered inbound channel symbols, at least one of said inbound or outbound streams of data bits being at a rate of at least 160 kb/s.
Claim 11
Dependent Claim
20 words
The invention of claim 8 wherein each of said outbound and inbound passband signals is a carrierless amplitude-and-phase modulated signal.
Claim 12
Dependent Claim
22 words
The invention of claim 8 wherein at least one of said bit streams is at a rate of at least 480 kb/s.
Claim 13
Dependent Claim
22 words
The invention of claim 8 wherein at least one of said bit streams is at a rate of at least 1.544 Mb/s.
References Cited (Backward Citations)
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