发明授权
- 专利标题: Echo canceller
- 专利标题(中): 回音消除器
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申请号: US201336申请日: 1994-02-24
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公开(公告)号: US5528687A公开(公告)日: 1996-06-18
- 发明人: Yoshinori Tanaka , Shigeyuki Unagami , Masayoshi Inoue
- 申请人: Yoshinori Tanaka , Shigeyuki Unagami , Masayoshi Inoue
- 申请人地址: JPX Kawasaki
- 专利权人: Fujitsu Limited
- 当前专利权人: Fujitsu Limited
- 当前专利权人地址: JPX Kawasaki
- 优先权: JPX63-64269 19880317; JPX63-105731 19880428; JPX63-189773 19880729
- 主分类号: H04B3/23
- IPC分类号: H04B3/23 ; H04B3/20
摘要:
An echo canceller provided with an expected echo generating unit which generates an expected echo of a transmission signal and a frequency offset correction unit which detects a phase error between an echo in a received signal and an expected echo from the expected echo generating unit and corrects the frequency offset for the expected echo by an offset frequency estimated based on the phase error, wherein use is made of the expected echo after offset correction by the frequency offset correction unit so as to suppress the echo in the received signal, the frequency offset correction unit using the phase error obtained after normalizing the phase error by the magnitude of the echo in the received signal. By this, it is possible to perform frequency offset correction adaptive to the far-end echo characteristics. Further, it is desirable to perform the frequency offset correction after it is confirmed that the rate of change of the output from a subtractor for cancellation of the near-end echo has become almost zero.
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