| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrict a change of a modulation method according to the property of a receiving unit. <P>SOLUTION: A modulation/demodulation unit 34 modulates information to be transmitted and demodulates received information. An FER measuring unit 38 measures FER of an up line, and the EVM measuring unit 56 measures EVM of the up line. A transmission rate changing unit 36 determines a modulation method of the up line in accordance with the measured quality from the quality of each signal measured by the FER measuring unit 38 and the EVM measuring unit 56. A memory unit 58 stores the EVM, and a threshold changing unit 60 directs the transmission rate changing unit 36 to make the second threshold value still smaller on the basis of the compared result of the EVM and a third threshold value. An alarming unit 62 alarms, for example, by blinking an LED when the second threshold value, to which a change is directed by the threshold value changing unit 60, in the transmission rate changing unit 36 reaches a previously set limit value. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
