US3715665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Joint initial setting of attenuator coefficients and sampling time in automatic equalizers for synchronous data transmission systems
Assignee: AT&T Inc
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Filing: 1971-06-15
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Granted: 1973-02-06
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Expires: 1991-06-15
Abstract
Abstract Method and apparatus for rapid joint setting in synchronous data transmission systems of the parameters of sampling time and transversal equalizer tap gain coefficients utilizes auxiliary delay means for a preliminary correlation of samples of transmitted test pulses and reference test pulses to obtain a signal which after application to the transversal equalizer generates an output wave whose peak coincides with the optimum sampling instant. This effect is assured by inversely orthogonalizing the tap output signals from the transversal equalizer. Once the optimum sampling time is established the tap gains can be set in a single adjustment to provide an open data eye pattern.
Inventors
- 👤 R Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:49
CPC Classifications
H; H04; H04L; H04L7/00; H04L7/0054; H04L7/0058; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038; H04L7/04; H04L7/041; H04L7/043; H04L7/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
187 words
In combination with a receiver for a synchronous data transmission system in which variable attenuators connected to tops on an associated transversal equalizer having an output are adjusted by comparing actual received signals with predetermined reference signals at sampling times determined by a local timing generator, means for jointly establishing initial sampling instants and tap attenuator settings comprising means for correlating received signal samples with said predetermined reference signal to form compensated signals, means for applying said compensated signals to said transversal equalizer, a matrix of fixed resistive elements for operating on compensated signals appearing at taps on said equalizer to form control signals, each of said control signals including a weighted contribution from at least one of said taps, means for feeding said control signals to said variable attenuators for adjustment to proportional coefficient values, means for synchronizing said timing generator with the time of occurrence of the peak amplitude of the output of said equalizer after initial adjustment of said variable attenuators, and means under the control of said timing generator for gating said control signals to said variable attenuators to establish optimum settings therefor.
Claim 2
Dependent Claim
187 words
In combination with a receiver for a synchronous data transmission system in which variable attenuators connected to tops on an associated transversal equalizer having an output are adjusted by comparing actual received signals with predetermined reference signals at sampling times determined by a local timing generator, means for jointly establishing initial sampling instants and tap attenuator settings comprising means for correlating received signal samples with said predetermined reference signal to form compensated signals, means for applying said compensated signals to said transversal equalizer, a matrix of fixed resistive elements for operating on compensated signals appearing at taps on said equalizer to form control signals, each of said control signals including a weighted contribution from at least one of said taps, means for feeding said control signals to said variable attenuators for adjustment to proportional coefficient values, means for synchronizing said timing generator with the time of occurrence of the peak amplitude of the output of said equalizer after initial adjustment of said variable attenuators, and means under the control of said timing generator for gating said control signals to said variable attenuators to establish optimum settings therefor.
Claim 3
Dependent Claim
187 words
In combination with a receiver for a synchronous data transmission system in which variable attenuators connected to tops on an associated transversal equalizer having an output are adjusted by comparing actual received signals with predetermined reference signals at sampling times determined by a local timing generator, means for jointly establishing initial sampling instants and tap attenuator settings comprising means for correlating received signal samples with said predetermined reference signal to form compensated signals, means for applying said compensated signals to said transversal equalizer, a matrix of fixed resistive elements for operating on compensated signals appearing at taps on said equalizer to form control signals, each of said control signals including a weighted contribution from at least one of said taps, means for feeding said control signals to said variable attenuators for adjustment to proportional coefficient values, means for synchronizing said timing generator with the time of occurrence of the peak amplitude of the output of said equalizer after initial adjustment of said variable attenuators, and means under the control of said timing generator for gating said control signals to said variable attenuators to establish optimum settings therefor.
Claim 4
Dependent Claim
187 words
In combination with a receiver for a synchronous data transmission system in which variable attenuators connected to tops on an associated transversal equalizer having an output are adjusted by comparing actual received signals with predetermined reference signals at sampling times determined by a local timing generator, means for jointly establishing initial sampling instants and tap attenuator settings comprising means for correlating received signal samples with said predetermined reference signal to form compensated signals, means for applying said compensated signals to said transversal equalizer, a matrix of fixed resistive elements for operating on compensated signals appearing at taps on said equalizer to form control signals, each of said control signals including a weighted contribution from at least one of said taps, means for feeding said control signals to said variable attenuators for adjustment to proportional coefficient values, means for synchronizing said timing generator with the time of occurrence of the peak amplitude of the output of said equalizer after initial adjustment of said variable attenuators, and means under the control of said timing generator for gating said control signals to said variable attenuators to establish optimum settings therefor.
Claim 5
Dependent Claim
66 words
The combination defined in claim 1 in which said received signals possess an impulse response having more than one nonzero sample at synchronous sampling instants and said correlating means comprises means for multiplying each nonzero received signal sample by each corresponding reference signal value and means for combining all the products obtained at a given sampling instant by said multiplying means to form said compensated signals.
Claim 6
Dependent Claim
73 words
The combination defined in claim 1 in which said received signals possess an impulse response having two oppositely poled nonzero samples spaced in time by two sampling intervals and said correlating means comprises means for multiplying respective nonzero samples of said actual received signals by the factors plus and minus one and means for combining the two products obtained at a given sampling instant by said multiplying means to form said compensated signals.
Claim 7
Dependent Claim
47 words
The combination defined in claim 1 in which said matrix comprises a plurality of resistive weighting elements whose weighting coefficients are chosen with reference to the signal impulse response and amplitude characteristics of said transmission system to operate on said compensated signals to produce said control signals.
Claim 8
Dependent Claim
123 words
The combination defined in claim 1 in which the amplitude characteristic H(f) of said transmission system is single-sideband aNd proportional to sin pi f/f0, where f any frequency within the bandwidth of said system, f0 the bandwidth of said system; each element aij or an orthogonalization matrix of coefficients which operates on signals appearing at the taps on said equalizer to render them mutually orthogonal are proportional to where i row index of each matrix element, j column index of each matrix element; and each element of said matrix of fixed resistive elements has the coefficient value of the inverse of said orthogonalization matrix determined by replacing each element aij by its cofactor divided by the determinant value corresponding to said orthogonalization matrix.
Claim 9
Dependent Claim
29 words
The combination defined in claim 1 in which said synchronizing means comprises a peak detector producing a discrete output when the maximum value of an analog signal is measured.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |