Clock slaving methods and arrangements
AssigneeMicrosoft Corporation
InventorsMatthijs A. Gates, Alok Chakrabarti, William C. Powell
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Abstract
In accordance with certain aspects of the present invention, an algorithm is provided that can be used to detect and track the difference between an on-host clock (i.e., “host clock”) and a remote clock (i.e., “reference clock”). As part of the algorithm, a scaling value is computed and tracked over time. The scaling value, when applied to the host clock, results in clock values that increase at substantially the same rate as the reference clock itself increases. Hence, the host clock will have been slaved to the reference clock.
Claims24
A method for slaving a clock to a data stream having reference clock value timestamps, the method comprising:
- sampling a local timer to get a current time;
- determining a difference between the current time and a previously sampled current time;
- and
- deriving a new time based on a last new derived time, a scaling value, and the difference between the current time and a previous current time.
A computer-readable medium having computer-executable instructions for slaving a clock to a data stream having reference clock value timestamps, the computer-executable instructions for performing steps comprising:
- sampling a local timer to get a current time;
- determining a difference between the current time and a previously sampled current time;
- and
- deriving a new time based on a last new derived time, a scaling value, and the difference between the current time and a previous current time.
An apparatus for slaving a clock signal to a data stream having reference clock value timestamps, the apparatus comprising:
- a local timer;
- and
- logic configured to:
- sample the local timer to get a current time,
- determine a difference between the current time and a previously sampled current time, and
- derive a new time based on a last new derived time, a scaling value, and the difference between the current time and a previous current time.
Dependencies are inferred from the claim text.