EP0669740A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Modem adapted to digital subscriber lines
Assignee: AT&T Inc
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Filing: 1994-12-14
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Granted: —
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Expires: 2014-12-14
Abstract
Abstract The present invention is a quantization-level-sampling (QLS) modem which includes means for separately equalizing each loop of an end-to-end digital telephone system network connection by employing a plurality of transmitter filters and a plurality of receiver filters in such a way that, in the direction of transmission from modem to central office, the voltage samples seen by the coder/decoder stations are equivalent to the network quantization levels transmitted by the modem, and in the direction of transmission from central office to modem, the voltage samples seen by the modem are equivalent to the network quantization levels encoded by the coder/decoder stations. The invention also includes a QLS modem communications system which includes the aforesaid digital telephone system network and a plurality of QLS modems. In preferred embodiments, an adaptation service unit within the telephone system network assists in the determination of the settings of the transmitter and receiver filters.
Inventors
- 👤 Ender Ayanoglu
- 👤 Glenn David Golden
- 👤 Raymond K. Jones
- 👤 James Emery Mazo
- 👤 David Goodwin Shaw
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 16:41
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4917; H04L25/4927
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
112 words
A high speed modem, which comprises: a modem having a transmitter component and a receiver component for transmitting and receiving signals through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: transmitting means within said transmitter component for transmitting data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based telephone system network; and, receiving means within said receiver component for receiving data having a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based telephone system network.
Claim 2
Dependent Claim
112 words
A high speed modem, which comprises: a modem having a transmitter component and a receiver component for transmitting and receiving signals through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: transmitting means within said transmitter component for transmitting data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based telephone system network; and, receiving means within said receiver component for receiving data having a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based telephone system network.
Claim 3
Dependent Claim
38 words
The modem of claim 1, wherein said transmitting means includes a plurality of separate transmitter filters for transmitting separate signal symbols and wherein said receiving means includes a plurality of separate receiver filters for receiving separate signal symbols.
Claim 4
Dependent Claim
97 words
A high speed modem, which comprises: a modem having at least one of a transmitter component and a receiver component for transmitting and for receiving signals respectively through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: at least one of said transmitter component and said receiver component having means to operate on data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network.
Claim 5
Dependent Claim
97 words
A high speed modem, which comprises: a modem having at least one of a transmitter component and a receiver component for transmitting and for receiving signals respectively through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: at least one of said transmitter component and said receiver component having means to operate on data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network.
Claim 6
Dependent Claim
44 words
The modem of claim 3, wherein said transmitter component includes transmitting means having a plurality of separate transmitter filters for transmitting separate signal symbols and wherein said receiver component includes receiving means having a plurality of separate receiver filters for receiving separate signal symbols.
Claim 7
Dependent Claim
24 words
The modem of claim 2 or 4,wherein said transmitting means includes six separate transmitter filters and said receiving means includes six separate receiver filters.
Claim 8
Dependent Claim
19 words
The modem of claim 1 or 3,wherein said channel symbol alphabet is equivalent to u-law transmission system quantizing levels.
Claim 9
Dependent Claim
57 words
The modem of claim 2 or 4,wherein said transmitting filters and said receiving filters are adaptively determined so as to transmit and receive signals which pass at least substantially close to predetermined points equivalent to predetermined quantizing levels at concise times, at least some of said concise times coinciding with sampling times of said telephone system network.
Claim 10
Dependent Claim
23 words
The modem of claim 2 or 4, wherein each of said transmitter filters and receiver filters are adapted to operate at 1 kilosymbol/second.
Claim 11
Dependent Claim
184 words
A high speed modem communications system, which comprises: (a) a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, and includes a plurality of coder/decoder stations for analog to digital and digital to analog conversion and a switched digital network for movement of digital signals among said plurality of coder/decoder stations; and, (b) a plurality of modems, each such modem having a transmitter component and a receiver component for transmitting and receiving signals through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: transmitting means within said transmitter component for transmitting data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network; and, receiving means within said receiver component for receiving data having a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network.
Claim 12
Dependent Claim
184 words
A high speed modem communications system, which comprises: (a) a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, and includes a plurality of coder/decoder stations for analog to digital and digital to analog conversion and a switched digital network for movement of digital signals among said plurality of coder/decoder stations; and, (b) a plurality of modems, each such modem having a transmitter component and a receiver component for transmitting and receiving signals through a telephone system network which utilizes a transmission system wherein conversion of analog to digital signals and digital to analog signals is based on a known quantizing rule with predetermined quantizing levels, said modem including: transmitting means within said transmitter component for transmitting data with a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network; and, receiving means within said receiver component for receiving data having a channel symbol alphabet which is equivalent to predetermined quantizing levels of a quantizing-rule-based system network.
Claim 13
Dependent Claim
26 words
The communications system of claim 9, which further includes timing means for each modem to synchronize said modem with the timing of said telephone system network.
Claim 14
Dependent Claim
78 words
The communications system of claim 9, wherein said telephone system network includes at least one adaptation service unit having central circuitry and an equalization filter, said adaptation service unit being adapted to receive a training initiation signal from any of said plurality of modems, identify any interference related to said initiation signal, feed back to an initiating modem adaptation signals to adjust and equalize at least one of said transmitting means and said receiving means to minimize interference.
Claim 15
Dependent Claim
28 words
The communications system of claim 9, wherein said telephone system network operates at 64 kilobits per second and has 48 kilobits per second available for modem transmission data.
Claim 16
Dependent Claim
17 words
The communication system of claim 9 or 12, wherein said transmission system is a u-law transmission system.
Claim 17
Dependent Claim
18 words
The communications system of claim 13, wherein said modems each have six transmitter filters and six receiver filters.
References Cited (Backward Citations)
No citation records indexed.
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