Multiplex communications – Duplex – Transmit/receive interaction control
Reexamination Certificate
2006-03-07
2006-03-07
Ngo, Ricky (Department: 2663)
Multiplex communications
Duplex
Transmit/receive interaction control
C379S406010
Reexamination Certificate
active
07009945
ABSTRACT:
An echo cancellation (EC) system for use in a full-duplex communication system having asymmetric signal sampling rates, in particular an ADSL system, is described. The system performs the cancellation of local echo signal in digital or analog domain depending on the loop condition using a switching logic. The EC system further includes an EC unit that generates a digital echo estimate signal at the lower sampling rate of the transmitted signal and then interpolates the digital signal to higher sampling rate to cancel echo signal thereby reducing computation complexity. The digital interpolated echo estimate signal is converted to analog form for use in analog echo cancellation. The subtracted signal resulting from the analog echo cancellation is converted into digital domain and used as feedback for the EC unit to adaptively improve the accuracy of the echo estimate.
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Fazlollahi Amir H.
Long Guozhu
Tang Xiangguo
Centillium Communications Inc.
Haile Feben
Ngo Ricky
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