Patent ID: 6744787
Filing Date: 2004-06-01
Classification: H04J

Abstract:
A method of attenuating pointer justification event induced low frequency jitter during desynchronization of a synchronous data stream into a plesiosynchronous data stream characterized by a clock rate T and by a tb byte multi-frame containing an nominal number rdb of data bits, said method comprising:(a) providing an integer number pc of phase adjustment commands; (b) maintaining, within a range from 1 to tb, a count pjT of a total number of positive ones of said pointer justification events previously encountered in said data stream; (c) maintaining, within a range from 1 to tdb*pc, a count pcT of a total number of previously issued ones of said phase adjustment commands; (d) upon detection of a positive one of said pointer justification events in said data stream, incrementing pjT by 1; (e) upon detection of a negative one of said pointer justification events in said data stream, decrementing pjT by 1; (f) upon detection of a null one of said pointer justification events in said data stream, maintaining pjT without change; (g) if tdb/tb*pjT*pc>pcT, issuing positive ones of said phase adjustment commands while incrementing pcT by 1 for each one of said issued positive phase adjustment commands until tdb/tb*pjT*pc=pcT; (h) if tdb/tb*pjT*pc(i) varying said clock rate T by adding said issued positive phase adjustment commands to said clock rate T and subtracting said issued negative phase adjustment commands from said clock rate T as said positive and said negative phase adjustment commands respectively are issued.