| 摘要 |
PROBLEM TO BE SOLVED: To provide an xDSL transmission speed measurement system that measures the transmission rate of a signal transmitted by an xDSL modem, under an environment where a noise amount changes periodically. SOLUTION: The measurement device 3 obtains the length of a communication line 6 and its frequency characteristics. Furthermore, the measurement device 3 periodically measures a noise which changes periodically in synchronism with a clock received from a clock supply device 5 and obtains the frequency characteristics of the noise respectively. The measurement device 3 gives the measured frequency characteristics of the noise to an analysis device 4. The analysis device 4 analyzes the transmission speed of the uplink direction of the xDSL modem, on the basis of the frequency characteristic and the noise characteristic of the communication line 6 obtained by the measurement device 3 and the system of the selected xDSL modem or the like. Furthermore, the analysis device 4 identifies a cause of the noise according to the matching processing with a noise model from a database for storing various noise models. When the analysis device 4 discriminates that the noise is caused by crosstalks from an adjacent line, the analysis device 4 estimates the noise amount caused in a downlink direction of the xDSL modem from the line on the basis of the type of the line and number of the lines, that is, the amount of noise received by a subscriber when installing the modem therein. The measurement system analyzes the transmission rate of the downlink direction of the xDSL modem on the basis of the estimated noise amount, the frequency characteristic and the length of the communication line 6 and the system of the selected xDSL modem or the like. |
