Clock generating method and apparatus for an asynchronous transmission
First Claim
Patent Images
1. A clock generating method for an asynchronous transmission, comprising:
- determining a plurality of actual signal arrival times for a number of samples;
averaging the plurality of actual signal arrival times over the number of samples;
correcting a timing of a receiving clock on a basis of an average of the plurality of actual signal arrival times and an expected signal arrival time;
deriving an expected signal arrival time from the receiving clock; and
determining a frequency difference between a frequency corresponding to an average of the plurality of actual signal arrival times and a frequency of said receiving clock, and changing the frequency of the receiving clock according to said frequency difference;
wherein the number of samples is set such that a time-dependent cell delay variation of actual signals being asynchronously transmitted has a mean value of zero.
7 Assignments
0 Petitions
Accused Products
Abstract
Clock generating method and apparatus for an asynchronous transmission, wherein a plurality of actual receiving signal arrival times are detected and averaged, to thereby avoid influences of randomly distributed delay variations upon signal transmission. Clock synchronization between a transmitting clock and a receiving clock is recovered by correcting the receiving clock on the basis of the obtained average of the actual arrival times and an expected arrival time. Thereby, overflow and underflow of a receiver buffer can be prevented.
32 Citations
11 Claims
-
1. A clock generating method for an asynchronous transmission, comprising:
-
determining a plurality of actual signal arrival times for a number of samples;
averaging the plurality of actual signal arrival times over the number of samples;
correcting a timing of a receiving clock on a basis of an average of the plurality of actual signal arrival times and an expected signal arrival time;
deriving an expected signal arrival time from the receiving clock; and
determining a frequency difference between a frequency corresponding to an average of the plurality of actual signal arrival times and a frequency of said receiving clock, and changing the frequency of the receiving clock according to said frequency difference;
wherein the number of samples is set such that a time-dependent cell delay variation of actual signals being asynchronously transmitted has a mean value of zero. - View Dependent Claims (2, 3, 4)
-
-
5. A clock generating apparatus for asynchronous transmission comprising:
-
means for determining an average of actual signal arrival times over a number of samples and for generating a control signal on a basis of a determined average of the actual signal arrival times and an expected signal arrival time; and
means for correcting a timing of a receiving clock on a basis of the control signal;
wherein the number of samples is set such that a time-dependent cell delay variation of actual signals being asynchronously transmitted has a mean value of zero. - View Dependent Claims (6, 7, 8, 9, 10, 11)
-
Specification