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.