PURPOSE: To attain initial pull-in and adaptive control at a high speed with high accuracy by updating with a constant step size sufficiently smaller than the unity by means of the direct calculation from an error when the error between an input signal and a pseudo signal is large and by means of the error polarity when smaller.
CONSTITUTION: When a residual error K is large, an echo replica ERMK (f0) stored already is read from an address f0 of a main table memory 101, the residual error K is added to the replica and the result is used as an echo replica revision ERMK+1 (f0), which is again stored in the main table memory 101. Then the echo replica in sub table memories 201, 202 are updated depending on the polarity of the residual error K. When the residual error K is sufficiently small, the echo replica of the main table memory 101 is updated depending on the increase/decrease in the step size SM. The processing above is repeated till the echo canceller is sufficiently converged.
FUKUDA SETSU
TOKIWA KOJI
MARUYAMA KAZUYOSHI
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