Patent ID: 6975689

Claim:
A receiver apparatus for digital signals of a prescribed baud rate transmitted by respective amplitude-modulated radio-frequency carriers through a medium subject to multipath distortion, said receiver apparatus comprising: a receiver front-end connected for responding to any selected one of said digital signals transmitted by respective amplitude-modulated radio-frequency carriers through said medium subject to multipath distortion, to generate an amplitude-modulated intermediate-frequency carrier that is amplitude modulated in accordance with said selected one of said digital signals and any multipath distortion thereof; demodulator and oversampling analog-to-digital conversion circuitry connected to receive said amplitude-modulated intermediate-frequency carrier from said receiver front-end and to supply a digital baseband signal at an oversampling rate higher than said prescribed baud rate; an analyzer filter for generating the discrete Fourier transforms of successive portions of said digital baseband signal, said analyzer filter connected to receive said digital baseband signal from said demodulator and oversampling analog-to-digital conversion circuitry; a bank of multipliers for multiplying the terms of each said discrete Fourier transform of said digital baseband signal, term by term, by respective ones of a set of adaptive weighting coefficients to generate a set of products describing the discrete Fourier transform of an equalizer response to said digital baseband signal; apparatus for generating, in response to the discrete Fourier transforms of successive portions of said digital baseband signal that provide a sampling window moving through a succession of different positions in each of successive data fields, said set of adaptive weighting coefficients for use by said bank of multipliers; a synthesizer filter connected for receiving said set of products from said bank of multipliers and for generating therefrom said equalizer response as the inverse discrete Fourier transform of said discrete Fourier transform of said equalizer response described by said set of products; a decimation filter connected for re-sampling said equalizer response supplied from said synthesizer filter to generate as a decimation filter response an equalized digital baseband signal re-sampled at said prescribed baud rate; and decoding apparatus connected for decoding said decimation filter response to recover a data stream.