| US 7,593,494 B1 | ||
| System and method for canceling impulse noise | ||
| Ayman Ghobrial, Huntsville, Ala. (US); Michael D. Turner, Huntsville, Ala. (US); and Daniel M. Joffe, Owens Crossroads, Ala. (US) | ||
| Assigned to ADTRAN, Inc., Huntsville, Ala. (US) | ||
| Filed on Sep. 23, 2004, as Appl. No. 10/948,492. | ||
| Int. Cl. H04B 1/10 (2006.01) | ||
| U.S. Cl. 375—350 [375/347] | 15 Claims |
| 1. A communication apparatus, comprising:
an adaptive impulse canceler configured to receive a common mode component of a signal received from a telecommunication line
and to detect a noise impulse in said common mode component, said impulse canceler configured to store sets of filter coefficients
and data defining a plurality of impulse shapes, each of said impulse shapes associated with a respective one of said sets
of filter coefficients that provides a transfer function for converting an impulse of the associated shape from common mode
to differential mode, said impulse canceler configured to identify a shape of said noise impulse in said common mode component
based on comparisons of said noise impulse in said common mode component to said data, said impulse canceler configured to
select the set of filter coefficients associated with the identified shape for use in filtering said noise impulse in said
common mode component, said impulse canceler having a filter configured to receive and filter said noise impulse in said common
mode component based on the selected set of filter coefficients thereby providing an impulse noise estimation for a differential
mode component of said received signal, wherein said selected set of filter coefficients controls a passband of said filter
while said noise impulse in said common mode component is being filtered by said filter, wherein the filter, by filtering
said noise impulse in said common mode component based on the selected set of filter coefficients, applies to said noise impulse
in said common mode component a transfer function for converting an impulse of the identified shape from common mode to differential
mode;
a combiner configured to receive said differential mode component and said impulse noise estimation and to combine said impulse
noise estimation with said differential mode component thereby canceling impulse noise from said differential mode component;
a plurality of correlators storing said data, each of said correlators configured to provide a correlation value indicative
of an amount of correlation between said detected noise impulse and a respective one of said impulse shapes; and
a compare element configured to compare correlation values provided by said correlators and to identify said shape of said
noise impulse in said common mode component based on said correlation values.
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