The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 13, 2003
Filed:
Oct. 29, 1998
Qin Zhang, Bensalem, PA (US);
Shlomo Ovadia, Yardley, PA (US);
General Instruments Corporation, Horsham, PA (US);
Abstract
The performance of a multiphase and/or multiple amplitude receiver, such as a 64/256 quadrature amplitude modulation (QAM) receiver, is improved in the presence of single and multiple echoes. A moving window adaptive decision feedback equalizer (DFE) is provided according to the adaptive equation C (k+1)=C (k)−&Dgr;·W(k)·E (k)·X (k), where &Dgr; (delta) is the step size, C (k) is the tap value of tap n for the k symbol, E (k) is the error output at the symbol k, X (k) is the received signal for pre-cursor taps (FFE) and past decision output for post-cursor taps (DFE), and W(k) is the sliding window function at symbol k. In the adaptation process, some coefficients are fixed while other taps are being adapted. In particular, the adaptation is focused on a group of taps which correspond to received echoes. By only adjusting these taps, no interference or noise is introduced to the decision making device in the digital receiver and therefore, the effect of noise and echoes on the adaptation control is substantially reduced.