| 摘要 |
PROBLEM TO BE SOLVED: To provide a controller or a modem controller by which a state of a control signal is precisely discriminated to control the operation of an external device even in the case that a noise repetitively generated over a comparatively long time on a transmission line and whose statistic property cannot be predicted is applied to the control signal. SOLUTION: An A/D converter 20 samples a modem control signal MC outputted from a terminal 101-10N for a sampling period sufficiently shorter than a period of a line clock generated based on line speed information and quantizes the signal. Then an adaptive filter section 21 executes adaptive signal processing for the quantized modem control signal MC to eliminate a noise N from the modem control signal MC. Thus, an edge of a change point of the modem control signal MC is effectively extracted and a state of the modem control signal MC is precisely discriminated.
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