Precisely adjusting a local clock
View Patent ↗Accurate correction of a local clock that avoids excessive drift in the local clock while avoiding an accumulation of quantization errors. A local clock according to the present techniques generates a local time by accumulating a sequence of rate coefficients selected from a plurality of rate coefficients using a series of progressively longer replacement periods.
1. A circuit that adjusts a local time by accumulating a sequence of rate coefficients selected from a plurality of rate coefficients using a series of progressively longer replacement periods.
2. The circuit of claim 1 , wherein the replacement periods and the rate coefficients are selected to avoid an accumulation of quantization errors in the local time.
3. The circuit of claim 1 , wherein the replacement periods and the rate coefficients are selected to avoid large errors in the local time.
4. The circuit of claim 1 , wherein the replacement periods are multiples of one another.
5. The circuit of claim 4 , wherein the replacement periods increase geometrically by two to an integer power.
6. The circuit of claim 1 , wherein the rate coefficients are derived from a time offset associated with time synchronization.
7. A method for adjusting a local time, comprising:
selecting a sequence of rate coefficients from among a plurality of rate coefficients;
accumulating the sequence of rate coefficients each during a progressively longer replacement period.
8. The method of claim 7 , wherein the replacement periods and the rate coefficients are selected to avoid an accumulation of quantization errors in the local time.
9. The method of claim 7 , wherein selecting a sequence of rate coefficients comprises selecting a sequence of rate coefficients and the replacement periods to avoid large errors in the local time.
10. The method of claim 7 , wherein accumulating the sequence of rate coefficients comprises accumulating the sequence of rate coefficients during a set of replacement periods that are multiples of one another.
11. The method of claim 10 , wherein accumulating the sequence of rate coefficients during a set of replacement periods that are multiples of one another comprises accumulating the sequence of rate coefficients during a set of replacement periods that increase geometrically by two to an integer power.
12. The method of claim 7 , further comprising deriving the rate coefficients from a time sheet associated with time synchronization.
13. A local clock, comprising:
counter that generates a time count;
rate correction circuit that selects a sequence of rate coefficients from among a plurality of rate coefficients using a series of progressively longer replacement periods;
accumulator that generates a local time by accumulating the sequence of rate coefficients.
14. The local clock of claim 13 , wherein the rate correction circuit comprises:
multiplexor that selects from among the rate coefficients in response to a set of enable signals;
enable logic that generates the enable signals in response to the time count using the series of progressively longer replacement periods.
15. The local clock of claim 13 , wherein the replacement periods and the rate coefficients are selected to avoid an accumulation of quantization errors in the local time.
16. The local clock of claim 13 , wherein the replacement periods and the rate coefficients are selected to avoid large errors in the local time.
17. The local clock of claim 13 , wherein the replacement periods are multiples of one another.
18. The local clock of claim 17 , wherein the replacement periods increase geometrically by two to an integer power.
19. The local clock of claim 13 , wherein the rate coefficients are derived from a time offset associated with time synchronization.