Receiver employing correlation technique for canceling cross-talk between in-phase and quadrature channels prior to decoding
First Claim
1. A receiver comprising:
- A) an analog-to-digital converter for converting an encoded, quadrature-modulated, analog communication signal into in-phase and quadrature digital signals having cross-talk components;
B) an attenuator coupled to said analog-to-digital converter for subtracting a first feedback signal from said in-phase digital signal to produce a cross-talk-attenuated in-phase digital signals, and for subtracting a second feedback signal from said quadrature digital signal to produce a cross-talk-attenuated quadrature digital signal;
C) a decoder coupled to said attenuator for decoding said cross-talk-attenuated in-phase and quadrature digital signals to generate respective first and second data output signals; and
D) a feedback arrangement including a recoder coupled to said decoder for producing first and second recoded signals from said respective first and second data output signals, and feedback-signal-generating means coupled to said analog-to digital converter, said attenuator, and said recoder, for generating said feedback signals in response to said in-phase and quadrature digital signals, said cross-talk-attenuated in-phase and quadrature digital signals, and said first and second recoded signals.
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Abstract
A receiver suitable for use in a radio-telephone system for recovering data from encoded, quadrature-modulated communication signals employs a feedback arrangement for suppressing cross-talk between the receiver'"'"'s in-phase and quadrature channels to improve data recovery rates during decoding. The receiver converts in-coming analog communication signals into in-phase and quadrature digital signals, which may have cross-talk components. The receiver has an attenuator for subtracting feedback signals from the in-phase and quadrature digital signals to produce cross-talk-attenuated in-phase and quadrature digital signals, a decoder for decoding the cross-talk-attenuated in-phase and quadrature digital signals to generate first and second data output signals, and the above-mentioned feedback arrangement, which preferably employs a recoder and cross-correlation techniques, for generating the feedback signals.
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Citations
14 Claims
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1. A receiver comprising:
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A) an analog-to-digital converter for converting an encoded, quadrature-modulated, analog communication signal into in-phase and quadrature digital signals having cross-talk components; B) an attenuator coupled to said analog-to-digital converter for subtracting a first feedback signal from said in-phase digital signal to produce a cross-talk-attenuated in-phase digital signals, and for subtracting a second feedback signal from said quadrature digital signal to produce a cross-talk-attenuated quadrature digital signal; C) a decoder coupled to said attenuator for decoding said cross-talk-attenuated in-phase and quadrature digital signals to generate respective first and second data output signals; and D) a feedback arrangement including a recoder coupled to said decoder for producing first and second recoded signals from said respective first and second data output signals, and feedback-signal-generating means coupled to said analog-to digital converter, said attenuator, and said recoder, for generating said feedback signals in response to said in-phase and quadrature digital signals, said cross-talk-attenuated in-phase and quadrature digital signals, and said first and second recoded signals. - View Dependent Claims (2, 3, 4)
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5. A receiver for recovering data from encoded, quadrature-modulated communication signals, comprising:
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A) supplying means for supplying in-phase and quadrature digital signals each having cross-talk components; B) first attenuating means coupled to said supplying means for attenuating said cross-talk components of said in-phase and quadrature digital signals by subtracting first and second cross-talk-attenuating feedback signals from said in-phase and quadrature digital signals to produce a cross-talk-attenuated in-phase and quadrature digital signals, respectively; C) decoding means for decoding said cross-talk-attenuated in-phase and quadrature digital signals to generate respective first and second data output signals, and for applying said first and second data output signals to at least one output line; and D) feedback means coupled to said attenuating means and said decoding means for generating said cross-talk-attenuating feedback signals; and E) wherein said feedback means includes 1) recoding means coupled to said decoding means for re-encoding said first and second data output signals to produce first and second recoded signals; and 2) feedback-signal-generating means coupled to said supplying means, decoding means and recoding means and responsive to said in-phase and quadrature digital signals, said cross-talk-attenuating in-phase and quadrature digital signals, and said first and second recoded signals, for generating said cross-talk-attenuating feedback signals. - View Dependent Claims (6, 7, 8)
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9. A receiver for recovering data from encoded, quadrature-modulated communication signals, comprising:
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A) supplying means for supplying in-phase and quadrature digital signals each having cross-talk components; B) attenuating means coupled to said supplying means for attenuating said cross-talk components of said in-phase and quadrature digital signals by subtracting an in-phase cross-talk-attenuating feedback signal rom said in-phase digital signal to produce a cross-talk-attenuated in-phase digital signal, and by subtracting a quadrature cross-talk-attenuating feedback signal from said quadrature digital signal to produce a cross-talk-attenuated quadrature digital signal; C) decoding means for decoding said cross-talk-attenuated in-phase digital signals to generate an in-phase data output signal, for decoding said cross-talk-attenuated quadrature digital signal to generate a quadrature data output signal, and for applying said data output signals to at least one output line; and D) feedback means coupled to said attenuating means and said decoding means for generating said cross-talk-attenuating feedback signals, said feedback means including 1) recoding means coupled to said decoding means for re-encoding said in-phase data output signal to produce an in-phase recoded signals, and for re-encoding said quadrature data output signal to produce a quadrature recoded signal; and 2) feedback-signal-generating means coupled to said supplying means, decoding means and recoding means, for generating said in-phase cross-talk-attenuating feedback signal in response to said quadrature digital signal, said cross-talk-attenuated in-phase digital signal, and said quadrature recoded signal, and for generating said quadrature cross-talk-attenuating feedback signal in response to said in-phase digital signal, said cross-talk-attenuated quadrature digital signal, and said in-phase recoded signal. - View Dependent Claims (10, 11, 12)
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13. A receiver for recovering data from encoded, quadrature-modulated communication signals, comprising:
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A) frequency-converting means for providing baseband in-phase and quadrature analog signals; B) means coupled to said frequency-converting means for converting said baseband in-phase and quadrature analog signals into corresponding in-phase and quadrature digital signals; C) decoding means coupled to said converting means for decoding first and second cross-talk-attenuated in-phase and quadrature digital signals to generate corresponding first and second data output signals, and for applying said first and second data output signals to corresponding first and second output lines; D) recoding means coupled to said decoding means for re-encoding said first and second data output signals to produce corresponding first and second recoded signals; and E) cross-talk equalizer means coupled to said converting means, decoding means and recoding means for attenuating cross-talk in said in-phase and quadrature digital signals, said cross-talk equalizer means comprising 1) cross-talk correlator means for generating first and second correlation factors indicative of the correlation of said in-phase and quadrature digital signals with respect to said second and first recoded signals, respectively; 2) means for combining said first and second correlation factors with said quadrature and in-phase digital signals to produce first and second feedback signals, respectively; and 3) attenuating means coupled to said converting means;
combining means, and said decoding means, for subtracting said first and second feedback signals from said in-phase and quadrature digital signals to produce said cross-talk-attenuated in-phase and quadrature digital signals, respectively. - View Dependent Claims (14)
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Specification