Pulse or digital communications – Receivers – Interference or noise reduction
Reexamination Certificate
2006-07-11
2006-07-11
Tran, Khanh (Department: 2631)
Pulse or digital communications
Receivers
Interference or noise reduction
C375S232000
Reexamination Certificate
active
07076010
ABSTRACT:
The current invention provides a method and apparatus for time domain equalization in an XDSL modem. A received communication channel is analyzed to determine the highest frequency component thereof. Typically, there is an inverse relationship between the length of a subscriber line and the highest frequency component over which communications can be supported. In response to the frequency determination, the sampling rate for the channel is reduced to the lowest sample rate consistent with maintaining signal integrity on the highest frequency component of the channel. The sampling rate reduction may accomplished in the analog portion of the receive path, e.g. the analog-to-digital converter (ADC) or in a digital decimator coupled thereto. Concurrently the demodulator complexity is also scaled back. Where the XDSL protocol is digital multi-tone (DMT) the input sample size to the discrete Fourier transform (DFT) engine is reduced accordingly. With these adjustments in place TEQ resources may be scaled inversely. Thus as line length increases and the available bandwidth on the subscriber line is reduced more TEQ resources are made available to deal with the increased delay interval over which intersymbol interference is evidenced. Scaling of TEQ resources may be accomplished using a TEQ architecture which allows either the length or the tap line or the delay between taps to be varied.
REFERENCES:
patent: 5051981 (1991-09-01), Kline
patent: 5274512 (1993-12-01), Tanaka et al.
patent: 5285474 (1994-02-01), Chow et al.
patent: 5388123 (1995-02-01), Uesugi et al.
patent: 5444739 (1995-08-01), Uesugi et al.
patent: 5479447 (1995-12-01), Chow et al.
patent: 5563911 (1996-10-01), Uesugi et al.
patent: 5818740 (1998-10-01), Agazzi
patent: 6002722 (1999-12-01), Wu
patent: 6055268 (2000-04-01), Timm et al.
patent: 6072782 (2000-06-01), Wu
patent: 6233276 (2001-05-01), Simeon
patent: 6285399 (2001-09-01), Tao
patent: 6353629 (2002-03-01), Pal
patent: 6631175 (2003-10-01), Harikumar et al.
patent: 6674795 (2004-01-01), Liu et al.
patent: 6754261 (2004-06-01), Liu et al.
Bajwa Raminder S.
Heidari Sam
Ramaswamy Prem
Rezvani Behrooz
Smith Dale
Cary Charles C
Ikanos Communication Inc.
IP Creators
Tran Khanh
LandOfFree
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