| 摘要 |
Disclosed is an adaptive filter that prevents adaptation error from increasing in a state of double talk, without providing a double-talk detection circuit. In this adaptive filter, using input signal x[n] and error signal e[n], a tap coefficient setting section (202) calculates a numerator term of update coefficientΔwn[i] in a delay circuit (301) and a multiplier (302), and calculates a normalized denominator term of update coefficientΔwn[i] in a multiplier (303), a multiplier (304), an adder (305), an averaging circuit (306), and an adder (307). The tap coefficient setting section (202) divides the numerator term by the normalized denominator term in a reciprocal computation circuit (308) and a multiplier (309) and calculates update coefficientΔwn[i]. The tap coefficient setting section (202), in a multiplier (310), an adder (311), and a delay circuit (312), adds update coefficientΔwn[i] multiplied by step size 2μto tap coefficient wn[i] and generates updated tap coefficient wn+1[i].
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