| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission line correction device which can prevent a distortion of a voice signal during a call and an occurrence of a noise at the time of power-on. SOLUTION: A transmission line correction device which has a subtraction means subtracting a noise component from a signal inputted from a transmission line to be outputted, an adaptive filter means performing an adaptive filter operation of a signal outputted to the transmission line and a signal outtptted by the subtraction means to extract a noise component, and which removes the noise component occurring on the transmission line has a nonvolatile memory holding a filter coefficient of the adaptive filter means, and a control means repeatedly executing the adaptive filter operation by gradually decreasing a weighting coefficient to the signal outputted by the subtraction means in the adaptive filter means, transferring the filter coefficient of the adaptive filter means to the nonvolatile memory in a state where the weighting coefficient becomes 0 and the adaptive filter operation is finished, and setting the filter coefficient held in the nonvolatile memory in a state where the adaptive filter operation is finished at the time of power-on to the adaptive filter means. COPYRIGHT: (C)2009,JPO&INPIT
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