METHOD AND APPARATUS TO IMPROVE THE LINEARITY OF THE TIME DOMAIN TRACE DERIVED FROM A SINGLE ENDED LINE TEST

摘要

The present invention is related to improvements to SELT testing, and more particularly to methods and apparatuses for reducing the effects of distortions of the reflected signal without sacrificing the integrity of the original signal. In embodiments, a method according to the invention consists of first modifying the transmit sequence to utilize and better “excite” the low frequency tones. In embodiments, the method includes compensating for transformer roll-off at low frequencies. In other embodiments, the method includes filling gaps in the received frequency domain S11 sequence with a predicted, or estimated, version of the S11 signal.

主权项

1. A method of performing a single ended line test (SELT) in a xDSL modem comprising:
constructing a sequence of transmit symbols using available tones in a bandplan for the xDSL modem; modifying the sequence of constructed transmit symbols to utilize and better excite low frequency tones in the constructed transmit symbols; and transmitting the sequence of modified constructed transmit symbols through a hybrid of the xDSL modem while simultaneously sensing received symbols corresponding to the modified constructed transmit symbols through the hybrid.