Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1996-02-23
1997-07-08
Zele, Krista M.
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379406, 379390, 370 321, 395 228, 395 242, H04B 320
Patent
active
056469918
ABSTRACT:
A noise replacement system and method for providing a synthesized noise replacement signal to an output speech channel in an echo cancellation system. A far-end speech signal transmitted through a communications channel may be passed through an echo channel to produce an echo signal. The echo signal is summed with near-end speech and transmitted back to the far-end in the output speech channel. An echo canceller rejects the echo signal by forming an estimate of the echo signal and subtracting the estimate from the sum of the near-end speech and the echo signal to produce an echo residual signal. When only the far-end speaker is talking, the echo is completely rejected by replacing the echo residual signal with a synthesized noise signal. The noise is synthesized to match the power and spectral characteristics of the actual background noise at the near-end to prevent the far-end speaker from detecting any change in signal characteristics.
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English Sean
Miller Russell B.
Qualcomm Incorporated
Wolinsky Scott
Zele Krista M.
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