| 摘要 |
The preferred method comprises measuring the signal/noise ratio and intermodulation distortion (IMD) relating to signals being transmitted over a channel (25) and adjusting the transmitting power of the transmitting modem (209) below a maximum permissable power in response to the measurements in order to reduce the error rate of the data transmission, the error rate being a function of both the signal/noise ratio and the IMD. Theoretically, the power can be adjusted to an optimal level, as the decrease in power increases the error rate due to signal/noise ratio according to a first function, but decreases the error rate due to IMD according to a second function. A first preferred manner of determining the final power level to be utilized is to calibrate a modem according to the techniques (e.g., Treillis precoding, etc.) it utilizes, and to utilize a look-up table for that modem to identify the desired power level based on the measured signal/noise ratio and the measured IMD. A second preferred manner is to decrease the signal power according to a formula which is a function of the third harmonic IMD. |
