US3879664A
Expired / Lapsed
US
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High speed digital communication receiver
Assignee: Sundstrand Corp
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Filing: 1973-05-07
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Granted: 1975-04-22
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Expires: 1993-05-07
Abstract
Abstract A high speed digital communications receiver is used in a diversity receiver system in which the predetection combiner of the receiver utilizes a forward adaptive filter equalizer, having a plurality of weighting sections, in each of the diversity channels for processing each of the received bandpass diversity signals prior to demodulation. The combined weighted output signal from the predetection combiner is then demodulated and the data therein appropriately reconstructed and an error signal generated. The error signal is modulated and limited for use in adaptive control circuitry which provides appropriate adaptive weighting signals for use in the processing of the received diversity signals at each of the forward filter equalizers. The unmodulated error signal is used in a backward adaptation control circuit for providing appropriate adaptive weighting signals for use in a single backward filter equalizer which suitably processes the reconstructed data to form a cancellation signal which is used to eliminate intersymbol interference and source correlation effects in the demodulated combined weighted output signal. A novel adaptive timing system is disclosed which permits the receiver clock to follow transmitter clock variations. Further, a novel automatic gain control system at the input IF receiver amplifiers is used to reduce the dynamic range requirements of the forward filter weight components.
Inventors
- 👤 Peter Monsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:01
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/01; H04L1/00; H04L1/02; H04L1/04; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03057; H04L7/00; H04L7/0016; H04L7/0033; H04L7/0037; H04L7/0004
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
210 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal prior to demodulation, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for demodulating said combined weighted output signal to produce a demodulated weighted output signal; means for quantizing said demodulated weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an unmodulated error signal; means for modulating said error signal; and means for processing said modulated error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers.
Claim 2
Dependent Claim
210 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal prior to demodulation, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for demodulating said combined weighted output signal to produce a demodulated weighted output signal; means for quantizing said demodulated weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an unmodulated error signal; means for modulating said error signal; and means for processing said modulated error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers.
Claim 3
Dependent Claim
210 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal prior to demodulation, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for demodulating said combined weighted output signal to produce a demodulated weighted output signal; means for quantizing said demodulated weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an unmodulated error signal; means for modulating said error signal; and means for processing said modulated error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers.
Claim 4
Dependent Claim
210 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal prior to demodulation, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for demodulating said combined weighted output signal to produce a demodulated weighted output signal; means for quantizing said demodulated weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an unmodulated error signal; means for modulating said error signal; and means for processing said modulated error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers.
Claim 5
Dependent Claim
28 words
A receiver in accordance with claim 1 and further including means for limiting said modulated error signal to supply a limited modulated error signal to said processing means.
Claim 6
Dependent Claim
48 words
A receiver in accordance with claim 1 and further including time gating means for producing a gating signal having a time interval less than the data symbol interval; and said quantizing means being responsive to said gating signs for processing said weighted output signal over said time interval.
Claim 7
Dependent Claim
75 words
A receiver in accordance with claim 1 and further including amplifying means in each of said diversity channels, each being responsive to the received signal in said channel; and automatic gain control means responsive to the amplified signals in each of said channels for providing a common gain control signal to each of said amplifying means to control the gain in each said amplifying means in accordance with the received signal having the greatest amplitude.
Claim 8
Dependent Claim
68 words
A receiver in accordance with claim 4 wherein said automatic gain control means includes a plurality of envelope detecting means, each responsive to the amplified signal from one of said amplifying means to produce a plurality of envelope detected signals; and means for comparing the amplitudes of said envelope detected signals and selecting the envelope detected signal having the greatest amplitude to produce said common gain control signal.
Claim 9
Dependent Claim
158 words
A receiver in accordance with claim 1 and further including a backward transversal filter equalizer for processing said quantized data output signal to produce a feedback cancellation signal, said backward filter equalizer comprising a plurality of weighting sections spaced at not more than the data symbol interval for providing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weights of the signals processed at each of said weighting sections; means for combining the weighted outputs from each of said weighting sections to produce a weighted feedback cancellation signal; means for combining said cancellation signal with said demodulated weighted output signal to eliminate intersymbol interference and source correlation effects from said demodulated weighted output signal; and means for processing said error signal and said quantized data output signal to produce feedback control signals for controlling the weights operative at each said weighting section of said backward filter equalizer.
Claim 10
Dependent Claim
75 words
A receiver in accordance with claim 6 and further including amplifying means in each of said diversity channels, each being responsive to the received signal in said channel; and automatic gain control means responsive to the amplified signals in each of said channels for providing a common gain control signal to each of said amplifying means to control the gain in each said amplifying means in accordance with the received signal having the greatest amplitude.
Claim 11
Dependent Claim
48 words
A receiver in accordance with claim 6 and further including time gating means for producing a gating signal having a time interval less than the data symbol interval; and said quantizing means being responsive to said gating signal for processing said weighted output signal over said time interval.
Claim 12
Dependent Claim
48 words
A receiver in accordance with claim 6 and further including adaptive timing means for establishing a timing signal the phase of which varies in accordance with timing variations in the received signal arising because of variations in the timing system of the transmitter which generates said received signals.
Claim 13
Dependent Claim
90 words
A receiver in accordance with claim 6 wherein said unmodulated error signal and said quantized data output signal each have cophased and quadrature components and said feedback control signals producing means comprises means for mixing the cophasal and quadrature components of said error signal with the cophasal and quadrature components of said quantized data output signal to produce a plurality of mixed signals; means for combining said mixed signals to produce said feedback control signals for controlling the weights operative at each said weighting section of said backward filter equalizer.
Claim 14
Dependent Claim
26 words
A receiver in accordacne with claim 10 and further including means for adjusting the amplitudes of the cophasal and quadrature components of said unmodulated error signal.
Claim 15
Dependent Claim
23 words
A receiver in accordance with claim 11 and further including means for filtering said combined mixed signals to provide smoothed feedback control signals.
Claim 16
Dependent Claim
53 words
A receiver in accordance with claim 10 and further including means for delaying the cophasal and quadrature components of said data output signal supplied to each of said mixers by a preselected amount to provide for correct alignment of said error components with said data output signal components at each of said mixers.
Claim 17
Dependent Claim
47 words
A receiver in accordance with claim 6 wherein said modulated error signal processing means comprises means for mixing said modulated error signal with the received signal at each of said weighting sections in each of said forward equalizers to produce mixed signals having cophasal and quadrature components.
Claim 18
Dependent Claim
52 words
A receiver in accordance with claim 14 said weighting means including means for filtering and adjusting the amplitudes of said mixed signals to produce a control signal having cophasal and quadrature components for controlling the weights of the cophasal and quadrature components of the received signal in each of said weighting sections.
Claim 19
Dependent Claim
44 words
A receiver in accordance with claim 15 and further including means for delaying the received signal supplied to each of said mixers by a preselected amount to provide for correct alignment of said error signal with said received signal at each of said mixers.
Claim 20
Dependent Claim
82 words
A receiver in accordance with claim 16 wherein said weighting means comprises modulator means in each of said weighting sections responsive to the control signal components supplied to said section and to the cophasal and quadrature components of the corresponding received signal in said section, said received signals being bandpass signals and said control signals being baseband signals, said modulating means modulating said received signal components with the said control signal components to produce said weighted signal having cophasal and quadrature components.
Claim 21
Dependent Claim
48 words
A receiver in accordance with claim 1 and further including adaptive timing means for establishing a timing signal the phase of which varies in accordance with timing variations in the received signal arising because of variations in the timing system of the transmitter which generates said received signals.
Claim 22
Dependent Claim
112 words
A receiver in accordance with claim 18 wherein said receiver is provided with a clock signal and said adaptive timing system comprises averaging means responsive to said unmodulated error signal for providing a signal representing the average of said unmodulated error signal over a time period which is longer than the time constant of said diversity channels; means for producing a difference signal effectively representing the derivative of said averaged error signals; control means responsive to said difference signal to produce a phase control signal; means responsive to said clock signal and to said phase control signal for shifting the phase of said clock signal to produce an adaptively controlled timing signal.
Claim 23
Dependent Claim
66 words
A receiver in accordance with claim 19 wherein said control means includes a first parallel path for providing a first signal which is the integral of said difference signal; a second parallel path for providing a second signal which is proportional to said difference signal; means for combining said first and second signals; and means responsive to said combined signal for providing said phase control signal.
Claim 24
Dependent Claim
51 words
A receiver in accordance with claim 20 and further including means responsive to said phase control signal for providing a signal which determines the sign of said difference signal; and means responsive to said sign determining signal and to said difference signal producing a difference signal having a correctly determined sign.
Claim 25
Dependent Claim
248 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for quantizing said combined weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an error signal; means for processing said error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers; amplifying means in each of said diversity channels, each being responsive to the received signal in said channel; and automatic gain control means responsive to the amplified signals in each of said channels for providing a common gain control signal to each of said amplifying means to control the gain in each said amplifying means in accordance with the received signal having the greatest amplitude.
Claim 26
Dependent Claim
248 words
A receiver for processing signals transmitted through a dispersive medium from a transmitter and received in a plurality of diversity channels, said receiver comprising a forward transversal filter equalizer in each of said channels for processing said received signals to produce a combined weighted output signal, each of said forward filter equalizers including at least one or more weighting sections spaced at not more than the data symbol interval for producing a plurality of weighted signals; a plurality of weighting means, one for each of said weighting sections, for controlling the weight of the signals processed at each of said weighting sections; means for combining the weighted signals from each of said weighting sections of all of said forward equalizers to produce a combined weighted output signal; means for quantizing said combined weighted output signal to produce a quantized data output signal; means responsive to said quantized data output signal for deriving an error signal; means for processing said error signal and said received signals to produce control signals for controlling the weights operative at each weighting section of each of said equalizers; amplifying means in each of said diversity channels, each being responsive to the received signal in said channel; and automatic gain control means responsive to the amplified signals in each of said channels for providing a common gain control signal to each of said amplifying means to control the gain in each said amplifying means in accordance with the received signal having the greatest amplitude.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |