xDSL transceiver
View Patent ↗An xDSL transceiver comprising a transmission unit for transmitting a DMT-modulated signal through a subscriber line as a transmission path and a receiving unit for receiving the DMT-modulated signal from the subscriber line. The xDSL transceiver further comprises an echo signal suppression unit for suppressing the echo signal from the transmission unit to the receiving unit by matching the phase between the frame of the transmission signal and the frame of the receiving signal.
1. An xDSL transceiver comprising a transmission unit for transmitting a DMT-modulated signal through a subscriber line as a transmission path and a receiving unit for receiving the DMT-modulated signal from said subscriber line, comprising an echo signal suppression unit for suppressing an echo signal from said transmission unit to said receiving unit by matching the phase of the frame of the transmission signal with that of the frame of the receiving signal, wherein phases of transmission signal frames and receiving signal frames are matched to prevent discontinuities between transmission signal frames and receiving signal frames from occurring during a demodulation period for receiving signal frames, thereby preventing out-of-band components of the transmission signal from being generated in the band of the receiving signal.
2. An xDSL transceiver as described in claim 1 , wherein said transmission unit includes said echo signal suppression unit, and said echo signal suppression unit includes a phase compensator for making the same frame boundary of the carrier of said echo signal from said transmission unit to said receiving unit for all the frequencies.
3. An xDSL transceiver as described in claim 2 , wherein said receiving unit includes phase compensation degree determining unit for determining the degree of phase compensation of said phase compensator in said transmission unit by analyzing said receiving signal.
4. An xDSL transceiver as described in claim 1 , wherein said receiving unit includes said echo signal suppression unit, and said echo signal suppression unit includes a phase compensator for making the same frame boundary of the carrier of said echo signal from said transmission unit to said receiving unit for all the frequencies.
5. An xDSL transceiver as described in claim 4 , wherein said phase compensator is configured with a cascade connection of a delay equalizer for correcting the group delay distortion of the echo signal from said transmission unit and a time domain equalizer for relaxing the inter-block interference in the output of said delay equalizer.
6. An xDSL transceiver as described in claim 4 , wherein said phase compensator is configured with a single FIR-type equalizer having the same function as a cascade connection of a delay equalizer for correcting the group delay distortion of the echo signal from said transmission unit and a time domain equalizer for reducing the inter-block interference in the output of said delay equalizer.
7. An xDSL transceiver as described in claim 1 , wherein said transmission unit includes a portion of said echo signal suppression unit and said receiving means includes the other portion of said echo signal suppression unit.