Echo canceller

Details Echo canceller Echo canceller

1994-05-26

1995-10-31

Olms, Douglas W.

Multiplex communications

Wide area network

Packet switching

379410, H04B 323

Patent

active

054636183

ABSTRACT:
In an echo canceller, a first adaptive filter (1) estimates an impulse response of an echo path between reception and transmission side by an NLMS algorithm to synthesize a pseud echo, while a second adaptive filter (3) determines whether there is an echo path change or a double talk. A voice detector (8) detects a short time power of the received input signal (x) to determine whether far-end speech is present or absent. The voice detector controls the second adaptive filter (3) to execute adaptation of the second adaptive filter for renewal of an impulse response of an echo path when far-end speech is present and otherwise to suspend the adaptation of the second adaptive filter when far-end speech is absent, while a double talk detector (9) controls the first adaptive filter to execute or suspend adaptation of the first adaptive filter according to the determination results of the voice detector.

REFERENCES:
patent: 4894820 (1990-01-01), Miyamoto et al.
patent: 4918727 (1990-04-01), Rohrs et al.
patent: 5018134 (1991-05-01), Kakubo et al.
S. Minami et al., "A Double Talk Detection Method for an Echo Canceller", IEEE 1985 International Communications Conference, vol. 3, pp. 1492-1497.
H. Yasukawa, et al., "Acoustic Echo Canceller with High Speech Quality", IEEE ICASSP'87, pp. 2125-2128 (1987).

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