Time-domain equalization for discrete multi-tone systems
First Claim
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1. A method for computing coefficients of an impulse shortening filter, the method comprising:
- comparing a digital signal received by a spectrally constrained impulse shortening filter and a reference signal and generating an error signal based on a difference between the reference signal and the digital signal; and
updating coefficients of the spectrally constrained impulse shortening filter based on the error signal.
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Abstract
A multiple carrier communication system includes a primary impulse shortening filter that receives an output signal of an analog to digital converter and accepts coefficients. A secondary impulse shortening filter receives the output signal of the analog to digital converter, outputs an output signal, and passes coefficients to the primary impulse shortening filter. A reference signal generator outputs a reference signal. A comparator compares the output signal and the reference signal and outputs a resulting error signal. An adaptive processor computes coefficients for the secondary impulse shortening filter based on the error signal.
231 Citations
22 Claims
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1. A method for computing coefficients of an impulse shortening filter, the method comprising:
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comparing a digital signal received by a spectrally constrained impulse shortening filter and a reference signal and generating an error signal based on a difference between the reference signal and the digital signal; and updating coefficients of the spectrally constrained impulse shortening filter based on the error signal. - View Dependent Claims (2, 3)
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4. A system for computing coefficients of an impulse shortening filter, the system comprising:
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a comparator configured to compare a digital signal received by a spectrally constrained impulse shortening filter and a reference signal and generate an error signal based on a difference between the reference signal and the digital signal; and an updater configured to determine coefficients for the spectrally constrained impulse shortening filter based on the error signal. - View Dependent Claims (5, 6)
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7. A method for adapting an impulse shortening filter, the method comprising:
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computing a reference signal by applying a digital signal to a spectrally constrained impulse shortening filter; delaying the digital signal applied to the spectrally constrained impulse shortening filter to produce a delayed digital signal; comparing the reference signal to the delayed digital signal and generating an error signal based on a difference between the reference signal and the delayed digital signal; and updating coefficients of the spectrally constrained impulse shortening filter in an adaptive processor based on the error signal. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A system for adapting an impulse shortening filter, the system comprising:
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a first computer configured to compute a reference signal by applying a digital signal to a spectrally constrained impulse shortening filter; a delayer configured to delay the digital signal applied to the spectrally constrained impulse shortening filter to produce a delayed digital signal; a comparator configured to compare the reference signal to the delayed digital signal and generate an error signal based on a difference between the reference signal and the delayed digital signal; and an updater configured to update coefficients of the spectrally constrained impulse shortening filter in an adaptive processor based on the error signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification