发明名称 |
Optical network loss-of-signal detection |
摘要 |
Loss of optical signal is detected in a synchronous communications system by detecting features of a monitor signal occurring at a detection frequency corresponding to the frame rate. Since the frame rate is substantially less than the bit rate, monitoring and detection can be performed at a lower bandwidth than the bit rate. An auto-correlation circuit utilises delays which are an integral multiple of the frame rate and produces a detection value which is compared with a threshold value. Alternatively, detection may be based on a power measurement of a band pass filtered monitor signal by setting the lower bandwidth limit above zero frequency and normalizing the measurement of power relative to an average power measurement. A loss of signal may then be detected by a change in power measurement relative to a threshold and can be used for asynchronous systems as well as synchronous systems. Loss of signal detection may be utilised to control an optical switch to re-route optical signals and generate alarm signals. The use of such detection in all optical networks avoids the requirement for electronic processing at the bit rate as a means of detection of loss of signal.
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申请公布号 |
US6178025(B1) |
申请公布日期 |
2001.01.23 |
申请号 |
US19970984394 |
申请日期 |
1997.12.03 |
申请人 |
NORTEL NETWORKS LIMITED |
发明人 |
HARDCASTLE IAN;ROBERTS KIM BRYON |
分类号 |
H04B10/08;(IPC1-7):H04B10/02;H04B10/00;G01R31/08 |
主分类号 |
H04B10/08 |
代理机构 |
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主权项 |
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地址 |
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