发明授权
US07616553B2 Apparatus and method for clock synchronization in a multi-point OFDM/DMT digital communications system
有权
多点OFDM / DMT数字通信系统中时钟同步的装置和方法
- 专利标题: Apparatus and method for clock synchronization in a multi-point OFDM/DMT digital communications system
- 专利标题(中): 多点OFDM / DMT数字通信系统中时钟同步的装置和方法
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申请号: US10813695申请日: 2004-03-29
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公开(公告)号: US07616553B2公开(公告)日: 2009-11-10
- 发明人: Daniel J. Marchok , Samir Kapoor , Ravi Chandran
- 申请人: Daniel J. Marchok , Samir Kapoor , Ravi Chandran
- 申请人地址: US IL Naperville
- 专利权人: Tellabs Operations, Inc.
- 当前专利权人: Tellabs Operations, Inc.
- 当前专利权人地址: US IL Naperville
- 代理机构: Hamilton, Brook, Smith & Reynolds, P.C.
- 主分类号: H04J11/00
- IPC分类号: H04J11/00
摘要:
A multi-point communications system is set forth herein. The communications system comprises a transmitter for transmitting OFDM/DMT symbols over a predetermined number of bins across a transmission medium. The OFDM/DMT symbols are generated using at least one timing signal. At least one of the predetermined number of bins includes a pilot tone sub-symbol having a frequency corresponding to the clock signal. The communications system also includes a receiver for receiving the OFDM/DMT symbols from the transmission medium. The receiver demodulates the received symbols using at least one timing signal. The receiver has a first pilot tone search mode of operation in which the receiver adjusts its timing signal to scan the frequency range of the predetermined number of bins looking for the pilot tone sub-symbol and identifies the bin including the pilot tone sub-symbol. The receiver further has a subsequent second pilot tone acquisition mode in which the receiver adjusts the timing signal to receive the identified bin containing the pilot tone sub-symbol and measures phase differences between successive pilot tone sub-symbols to thereby perform a further adjustment of the timing signal so that the pilot tone sub-symbol is received within a frequency range sufficient for subsequent phase locked loop processing thereof.
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