| 摘要 |
PROBLEM TO BE SOLVED: To prevent decrease-line efficiency by reducing transmission of unwanted modem crosstalk signals caused by the crosstalk of a transformer for two-wire/four-wire conversion by setting a threshold value suitable for an input signal power level when an input signal is a modem signal. SOLUTION: The power value of the input signal is measured by a power value measuring part 1, it is identified by a voice/modem signal identifying part 3 whether this input signal is a voice signal or modem signal, and the measured value is delayed for prescribed time by a delay part 2. When the input signal is a voice signal, the threshold value for voice signal of a fixed value or value corresponding to a background noise is set by a threshold value setting part 4 and when the input signal is a modem signal, the threshold value for modem signal increased adaptively to the measured power value is variably set. Then, it is discriminated by a discrimination part 5 whether the input signal is sounded or soundless. |
