| 摘要 |
In a DMT based system, training signals can be chosen based on stored prior connection information to reduce using extra tones in transmitted training signals to improve receiver performance. By choosing training signals based on the stored prior connection information, training signals may be made to indirectly represent a function of the loop impairments. Certain training signal tones in the training signals may be omitted, based on previous connection information, on a loop-by-loop basis. Local echoes are effectively reduced and local receiver training is improved without affecting eventual data transmission performance. Higher AGC gain and higher signal-to-quantization-noise ratios can be achieved, especially in the case of long loops. These benefits can allow (1) improvements in the loop performance in the receiving direction and/or (2) reductions in the requirements on the receiving ADC. Crosstalks into other wire pairs of a bundle, are reduced, improving the transmission environment on those pairs.
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