HIGH INTER-SYMBOL INTERFERENCE RESISTANCE PHASE COMPARATOR

摘要

PROBLEM TO BE SOLVED: To provide a digital system phase comparator realizable by a small scale circuit and to provide a PLL including the phase comparator.

SOLUTION: The phase is detected by determining an edge only when respective absolute values exceed a threshold in addition to coding of a signal sequence of an edge object. The phase comparator includes a means for detecting an edge by comparing each value of the signal sequence with a designated threshold. Further, the phase comparator includes a means for automatically updating the threshold used for edge determination by using a result of a signal level determination of a Viterbi decoder. Moreover, the phase comparator calculates the threshold value used for edge determination from an average of input signals determined to have a designated target level.

COPYRIGHT: (C)2006,JPO&NCIPI