An echo canceller, which includes, receives and sends paths connected to standard
telecommunication interfaces, a non adaptive filter with filter reflection coefficients
which generate an estimated echo signal, which when subtracted from the send path
input produces a nearly echo free send path output, an adaptive filter generating
a second estimated echo signal, which when subtracted from the send signal, provides
a possible alternative nearly echo free send path signal, a fast non iterative
least squares method of estimating a reflection, a controller means which, in response
to an observed non echo free send path output, causes the fast non iterative least
squares method to search for possible new reflections, and a controller means for
expurgating unnecessary reflection coefficients in the non adaptive filter.