US5659581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modem receiver pre-emphasis
Assignee: Smart Link Ltd
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Filing: 1994-12-13
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Granted: 1997-08-19
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Expires: 2014-12-13
Abstract
Abstract A echo-canceling modem uses pre-emphasis in both the transmitter and receiver sections. In particular, the receiver section of the modem processes a received signal with a pre-emphasis filter before performing echo cancellation on the received signal. The receiver pre-emphasis filter is identical to the transmitter pre-emphasis filter, i.e., the pre-emphasis added in the receiver is the same as the pre-emphasis added in the transmitter.
Inventors
- 👤 William Lewis Betts
- 👤 Keith Alan Souders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:21
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/01; H04B; H04B3/00; H04B3/02; H04B3/20; H04B3/23
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
115 words
An improved data communications equipment apparatus for receiving a data signal, the apparatus comprising a receiver including an echo canceler means for processing an echo-corrupted signal to provide an echo-canceled signal, and an equalizer means for processing the echo-canceled signal to compensate for intersymbol interference present in the received data signal, wherein the improvement comprises: pre-emphasis means located in the receiver for processing the received data signal to provide the echo-corrupted signal, said pre-emphasis means for receiving a predefined signal, and for evaluating said predefined signal in order to determine a spectral response of a communications channel and to set said pre-emphasis means to an inverse value of a portion of the determined spectral response.
Claim 2
Dependent Claim
115 words
An improved data communications equipment apparatus for receiving a data signal, the apparatus comprising a receiver including an echo canceler means for processing an echo-corrupted signal to provide an echo-canceled signal, and an equalizer means for processing the echo-canceled signal to compensate for intersymbol interference present in the received data signal, wherein the improvement comprises: pre-emphasis means located in the receiver for processing the received data signal to provide the echo-corrupted signal, said pre-emphasis means for receiving a predefined signal, and for evaluating said predefined signal in order to determine a spectral response of a communications channel and to set said pre-emphasis means to an inverse value of a portion of the determined spectral response.
Claim 3
Dependent Claim
37 words
The apparatus of claim 1 wherein the receiver means further comprises: echo-canceler means for processing the pre-emphasized signal to provide an echo-canceled signal; and equalizer means for processing the echo-canceled signal to compensate for the intersymbol interference.
Claim 4
Dependent Claim
87 words
Data communications equipment apparatus comprising: receiver means for receiving a data signal from a communications channel; means located in the receiver means for pre-emphasizing the received data signal to provide a pre-emphasized signal, said means for receiving a predefined signal, and for evaluating said predefined signal in order to determine a spectral response of a communications channel and to set said means to an inverse value of a portion of the determined spectral response; and receiver means for equalizing the pre-emphasized signal to compensate for intersymbol interference.
Claim 5
Dependent Claim
87 words
Data communications equipment apparatus comprising: receiver means for receiving a data signal from a communications channel; means located in the receiver means for pre-emphasizing the received data signal to provide a pre-emphasized signal, said means for receiving a predefined signal, and for evaluating said predefined signal in order to determine a spectral response of a communications channel and to set said means to an inverse value of a portion of the determined spectral response; and receiver means for equalizing the pre-emphasized signal to compensate for intersymbol interference.
Claim 6
Independent Claim
70 words
A method for use in data communications equipment having a receive pre-emphasis section, the method comprising the steps of: receiving a pre-defined signal over a communications channel from a far-end data communications equipment; evaluating the received pre-defined signal to determine a spectral response of the communications channel; and setting a receive pre-emphasis filter of the data communications equipment to an inverse value of a portion of the determined spectral response.
Claim 7
Independent Claim
70 words
A method for use in data communications equipment having a receive pre-emphasis section, the method comprising the steps of: receiving a pre-defined signal over a communications channel from a far-end data communications equipment; evaluating the received pre-defined signal to determine a spectral response of the communications channel; and setting a receive pre-emphasis filter of the data communications equipment to an inverse value of a portion of the determined spectral response.
Claim 8
Dependent Claim
31 words
The method of claim 4 wherein the setting step sets filter coefficients of the receive pre-emphasis filter to a set of values representative of the portion of the determined spectral response.
Claim 9
Independent Claim
99 words
A method for use in data communications equipment having a receive pre-emphasis section, the method comprising the steps of: receiving a predefined signal over a communications channel from a far-end data communications equipment; evaluating the received predefined signal to determine a spectral response of the communications channel; setting a receive pre-emphasis filter of the data communications equipment to an inverse value of a portion of the determined spectral response; and sending the remaining portion of the determined spectral response to the far-end data communications equipment for use in a far-end transmit pre-emphasis filter of the far-end data communications equipment.
Claim 10
Independent Claim
99 words
A method for use in data communications equipment having a receive pre-emphasis section, the method comprising the steps of: receiving a predefined signal over a communications channel from a far-end data communications equipment; evaluating the received predefined signal to determine a spectral response of the communications channel; setting a receive pre-emphasis filter of the data communications equipment to an inverse value of a portion of the determined spectral response; and sending the remaining portion of the determined spectral response to the far-end data communications equipment for use in a far-end transmit pre-emphasis filter of the far-end data communications equipment.
Claim 11
Dependent Claim
25 words
The method of claim 6 wherein the sending step sends a set of filter coefficients representative of the remaining portion of the determined spectral response.
References Cited (Backward Citations)
US5008903A
Cited
US5280473A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-18 | 2001-02-17 | 2001-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-18 | 2005-02-17 | 2005-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-18 | 2009-02-17 | 2009-08-19 | $7700.00 | Window Closed / Lapsed |