| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a modem which can realize accurate data transmission, even when a digital PAD is provided in a digital line network in a communication system, according to the V.90 Recommendations by the ITU-T. <P>SOLUTION: A modem includes a DPAD detector 11 for deciding attenuation of the digital PAD 4 in a communication network, on the basis of a inspection signal received from a digital modem 2 on a sender side via the communication network, a table creator 13 for downwardly correcting a corresponding level value of a constellation table for use in the demodulating operation of a demodulator 12 to obtain a corrected constellation table, a constellation selector 14 for selecting a constellation point for use in communication on the basis of the corrected constellation table, and a constellation notifier 15 for generating a signal, to inform the communication device on the sender side of information about the constellation point. <P>COPYRIGHT: (C)2004,JPO |
