| 摘要 |
PURPOSE:To simply apply switching control to an equalizing characteristic in matching with the line in operation by applying switching control to a transmission signal equalizer or a reception signal equalizer so as to minimize the frequency of the retransmission or the reception frequency of an erroneous data by means of an error control section, thereby eliminating the need for another line for the adjustment of an equalizer and complicated control. CONSTITUTION:An error control section 3 checks a reception data and requests the retransmission of a data to an opposite station when an error is detected and retransmits a transmission data in response to a request from the opposite station conversely. A transmission signal equalizer 4 corrects the characteristic of a signal sent from a modulation section 1 to a line 5 and controlled by the error control section 3. A reception signal equalizer 6 corrects the characteristic of the signal sent from the line 5 to the demodulation section 2 and is controlled by the error control section 3. When the gain varies as 1-3 with the frequency as the transmission signal equalizer 4 and the reception signal equalizer 6, the error control section 3 selects one of the characteristics 1-3 at every prescribed time, checks the frequency of retransmission and the reception frequency of an erroneous data and sets the equalizer to the characteristic with the least frequency of occurrence.
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