Telephonic communications – Echo cancellation or suppression – Using digital signal processing
Reexamination Certificate
2006-02-07
2006-02-07
Swerdlow, Daniel (Department: 2646)
Telephonic communications
Echo cancellation or suppression
Using digital signal processing
C370S286000
Reexamination Certificate
active
06996230
ABSTRACT:
An echo canceler for a fractionally spaced telecommunication receiver employs a signal estimator, which generates a fractionally spaced representation of a received information signal that has been subjected to Tomlinson preceding. The output of the signal estimator is differentially combined with fractionally spaced outputs of the echo canceller, so as to effectively remove the contribution of the received information signal from the echo cancellation update operation. As a result, the echo update signal will consist primarily of the residual echo and the noise from the wireline/loop. The error signal can be used at the fractional spacing rate to update all of the echo canceler coefficients, largely without interference from the much larger received information signal. This allows a higher echo canceler gain than that currently incorporated into HDSL2 echo canceler updates.
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Chu Fred T.
Ghobrial Ayman K.
Turner Michael D.
Adtran Inc.
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Swerdlow Daniel
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