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US4635276A Expired / Lapsed US ⏱️ 0.0 years remaining

Asynchronous and non-data decision directed equalizer adjustment

Assignee: Nokia Bell Labs
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Filing: 1985-07-25
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Granted: 1987-01-06
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Expires: 2005-07-25
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Abstract

Abstract Equalizers, which provide distortion compensation for a modulated carrier signal having a time-varying signal envelope, are adjusted at selected times in response to the signal envelope and the data signals regenerated therefrom. Each selected time corresponds to a time when the signal envelope has a preselected value. Advantageously, the disclosed equalizer adjustment is unaffected by loss of receiver synchronization to the modulated carrier signal and is applicable to a variety of communications systems and modulation formats.

Inventors

  • 👤 Peter D. Karabinis

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 06:11
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/002; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038; H04L7/00; H04L7/0079; H04L7/0083

Claims Analysis

Total Claims: 18
Claim 1
Independent Claim 110 words
Apparatus for adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said apparatus comprising means for extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, means for forming a predetermined combination of said data signals, first means for comparing said combination of data signals to a threshold, and means responsive to said comparing means for generating an equalizer adjustment signal from said data signals and said combination of data signals.
Claim 2
Dependent Claim 110 words
Apparatus for adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said apparatus comprising means for extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, means for forming a predetermined combination of said data signals, first means for comparing said combination of data signals to a threshold, and means responsive to said comparing means for generating an equalizer adjustment signal from said data signals and said combination of data signals.
Claim 3
Dependent Claim 21 words
The apparatus of claim 1 wherein said generating means includes second means for comparing each data signal to an associated threshold.
Claim 4
Dependent Claim 18 words
The apparatus of claim 1 wherein said second comparing means also compares said combination to a corresponding threshold.
Claim 5
Dependent Claim 25 words
The apparatus of claim 3 wherein said data signals and said combination each has an algebraic sign which is determined by said second comparing means.
Claim 6
Dependent Claim 24 words
The apparatus of claim 4 wherein said equalizer adjustment signal is a function of the algebraic signs of said data signals and said combination.
Claim 7
Dependent Claim 16 words
The apparatus of claim 1 wherein said threshold utilized by said first comparing means is adjustable.
Claim 8
Dependent Claim 26 words
The apparatus of claim 6 wherein said first comparing means varies said adjustable threshold in response to the comparison of said combination to said adjustable threshold.
Claim 9
Dependent Claim 23 words
The apparatus of claim 6 wherein said first comparing means produces a pulse each time the adjustable threshold is less than said combination.
Claim 10
Dependent Claim 37 words
The apparatus of claim 8 wherein said adjustable threshold is varied in response to a comparison of the number of pulses in a given time interval to a statistically expected number of pulses in said time interval.
Claim 11
Dependent Claim 34 words
The apparatus of claim 9 wherein each of said data signals has a plurality of signal levels and said statistically expected number of pulses is formed using a uniform probability for said signal levels.
Claim 12
Dependent Claim 19 words
The apparatus of claim 1 wherein said forming means multiplies each data signal by itself to form respective products.
Claim 13
Dependent Claim 13 words
The apparatus of claim 11 wherein said forming means sums the respective products.
Claim 14
Dependent Claim 17 words
The apparatus of claim 12 wherein said forming means determines a square root of the respective products.
Claim 15
Dependent Claim 108 words
Apparatus for compensating for distortion in a modulated carrier signal having a time-varying signal envelope, said apparatus comprising means for demodulating said carrier signal to form data signals individually, each of said data signals being a component of said signal envelope, equalizer means for receiving said data signals and providing distortion compensation, said equalizer means having tap-weight coefficients which affect the compensation provided, means for forming a preselected combination of said data signals, means for comparing said combination to a threshold, and means responsive to said comparing means for forming an equalizer adjustment signal from said data signals and said combination, said adjustment signal altering said tap-weight coefficients.
Claim 16
Dependent Claim 108 words
Apparatus for compensating for distortion in a modulated carrier signal having a time-varying signal envelope, said apparatus comprising means for demodulating said carrier signal to form data signals individually, each of said data signals being a component of said signal envelope, equalizer means for receiving said data signals and providing distortion compensation, said equalizer means having tap-weight coefficients which affect the compensation provided, means for forming a preselected combination of said data signals, means for comparing said combination to a threshold, and means responsive to said comparing means for forming an equalizer adjustment signal from said data signals and said combination, said adjustment signal altering said tap-weight coefficients.
Claim 17
Independent Claim 109 words
A method of adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said method comprising the steps of extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, forming a preselected combination of said data signals, determining when said combination has at least a preselected value, and forming said equalizer adjustment signal in response to said data signals and said combination when the latter has at least said preselected value.
Claim 18
Independent Claim 109 words
A method of adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said method comprising the steps of extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, forming a preselected combination of said data signals, determining when said combination has at least a preselected value, and forming said equalizer adjustment signal in response to said data signals and said combination when the latter has at least said preselected value.

References Cited (Backward Citations)

US3843942A Cited
US3890572A Cited
US4097806A Cited
US4227152A Cited
US4343041A Cited
US4545060A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-01-05 1990-07-07 1991-01-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-01-05 1994-07-07 1995-01-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-01-05 1998-07-07 1999-01-06 $7700.00 Window Closed / Lapsed

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