发明授权
US5220295A Method and apparatus for detecting and correcting loss of frequency lock
in a phase locked dual clock system
失效
用于检测和纠正锁相双时钟系统中的频率锁定丢失的方法和装置
- 专利标题： Method and apparatus for detecting and correcting loss of frequency lock in a phase locked dual clock system
- 专利标题（中）： 用于检测和纠正锁相双时钟系统中的频率锁定丢失的方法和装置
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申请号： US867978申请日： 1992-04-13
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公开(公告)号： US5220295A公开(公告)日： 1993-06-15
- 发明人: Neal Glover , Peter Murray
- 申请人： Neal Glover , Peter Murray
- 申请人地址： CA Fremont
- 专利权人： Cirrus Logic, Inc.
- 当前专利权人： Cirrus Logic, Inc.
- 当前专利权人地址： CA Fremont
- 主分类号： H03L7/095
- IPC分类号： H03L7/095 ; H03L7/10
摘要：
A Loss of Lock Detector and Re-lock Control function using digital techniques to detect a programmable difference in frequencies over a programmable range. Once Loss of Lock is detected, the Re-lock sequence is initiated and PLLIS, PLLMS & PLLGS are stepped through a programmable sequence. The invention detects the frequency difference by counting down two counters and evaluating the value left in one when the other reaches terminal count using a programmable tolerance of frequency differences before Loss of Lock is declared. The complexity and cost of implementation of the invention is reduced by multiple use of a single down counter. Other features of the invention are disclosed.
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