Methods of Calibrating a Clock Using Multiple Clock Periods with a Single Counter and Related Devices and Methods

• US 20090296531A1
• Filed: 05/27/2008
• Published: 12/03/2009
• Est. Priority Date: 05/27/2008
• Status: Active Grant

• Current Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Stek, Aalbert, Haartsen, Jacobus Cornelis
• Granted Patent: US 7,881,895 B2
• Time in Patent Office: Days
• US Class Current: 368/47
• CPC Class Codes: H03L 1/00 Stabilisation of generator output against variations of physical values, e.g. power supply
• CPC Class Codes: H03L 7/00 Automatic control of frequency or phase; Synchronisation
• CPC Class Codes: H04W 52/029 reducing the clock frequency of the controller
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of calibrating a first clock signal using a second clock signal and a plurality of calibration periods may include generating incremented counter values at a counter responsive to edges of the second clock signal. For at least two of the plurality of calibration periods, an initial incremented counter value from the counter may be stored in memory at an initial edge of the first clock signal for the respective calibration period, a final incremented counter value may be stored in memory at a final edge of the clock signal for the respective calibration period, and the at least two of the plurality of calibration periods may be overlapping with different initial and final edges of the first clock signal. For each of the plurality of calibration periods, a number of edges of the second clock signal occurring during the respective calibration period may be determined using the initial and final incremented counter values stored in memory. A relationship between the first and second clock signals may be determined using a sum of a number of edges of the second clock signal occurring during each of the plurality of calibration periods and using a sum of a number of first clock signal cycles occurring during each of the plurality of calibration periods.

Claims

1. A method of calibrating a first clock signal using a second clock signal and a plurality of calibration periods, the method comprising:

generating incremented counter values at a counter responsive to edges of the second clock signal;

for at least two of the plurality of calibration periods, storing in memory an initial incremented counter value from the counter at an initial edge of the first clock signal for the respective calibration period and storing in memory a final incremented counter value at a final edge of the first clock signal for the respective calibration period wherein the at least two of the plurality of calibration periods are overlapping with different initial and final edges of the first clock signal;

for each of the plurality of calibration periods, determining a number of edges of the second clock signal occurring during the respective calibration period using the initial and final incremented counter values stored in memory; and

determining a relationship between the first and second clock signals using a sum of a number of edges of the second clock signal occurring during each of the plurality of calibration periods and using a sum of a number of first clock signal cycles occurring during each of the plurality of calibration periods.

2. A method according to claim 1 wherein determining the relationship comprises determining a ratio using the sum of the number of edges of the second clock signal occurring during each of the plurality of calibration periods and using the sum of the number of first clock signal cycles occurring during each of the plurality of calibration periods.

3. A method according to claim 1 wherein an initial edge of the first clock signal for a first of the plurality of the calibration periods precedes an initial edge of the first clock signal for a second of the plurality of the calibration periods, wherein the initial edge of the first clock signal for the second of the plurality of the calibration periods precedes a final edge of the first clock signal for the first of the plurality of the calibration periods, and wherein the final edge of the first clock signal for the first of the plurality of the calibration periods precedes a final edge of the first clock signal for the second of the plurality of the calibration periods.

4. A method according to claim 1 wherein a same number of first clock cycles occur during each of the plurality of calibration periods.

5. A method according to claim 1 wherein the plurality of calibration periods includes k calibration periods beginning at k consecutive edges of the same transition type of the clock.

6. A method according to claim 1 wherein generating incremented counter values comprises generating incremented counter values at the counter responsive to edges of a same transition type of the second clock signal.

7. A method according to claim 1 wherein a frequency of the first clock signal is not an integer multiple of a frequency of the second clock signal and wherein the frequency of the second clock signal is not an integer multiple of the frequency of the first clock signal.

8. A method according to claim 1 wherein the second clock is coupled to a receiver, the method further comprising:

during a first waking period, operating the receiver using the second clock;

during a sleep period after the first waking period, timing a duration of the sleep period using the first clock with the second clock turned off; and

during a second waking period after the sleep period, operating the receiver using the second clock.

9. A method of calibrating a first clock signal using a second clock signal, the method comprising:

generating incremented counter values at a counter responsive to edges of the second clock signal;

for at least two different edges of the first clock signal, performing calculations based on respective incremented counter values; and

determining a relationship between the first and second clock signals using linear regression using the calculations based on the respective incremented counter values for the at least two different edges of the first clock signal.

10. A method according to claim 9 wherein performing calculations based on the respective incremented counter values comprises performing the calculations based on the respective incremented counter values taken at edges of the same transition type of respective cycles of the first clock signal.

11. A method according to claim 10 wherein determining the relationship between the first and second clock signals using linear regression comprises calculating a regression coefficient using the incremented counter values from the at least two different edges of the first clock signal.

12. A method according to claim 9 wherein performing calculations based on the respective incremented counter values comprises integrating incremented counter values taken at edges of the same transition type of different cycles of the first clock signal.

13. A method according to claim 9 wherein generating incremented counter values comprises generating incremented counter values at the counter responsive to edges of the second clock signal of the same transition type.

14. A method according to claim 9,

wherein at a first edge of the first clock signal the counter and first and second adders are set to initial values,

wherein at a second edge of the first clock signal after the first edge, an incremented counter value generated by the counter is added to the initial value of the first adder to generate a second value of the first adder, and the initial value of the first adder is added to the initial value of the second adder to generate a second value of the second adder, and

wherein at a third edge of the first clock signal after the second edge, an incremented counter value generated by the counter is added to the second value of the first adder to generate a third value of the first adder, and the second value of the first adder is added to the first value of the second adder to generate a third value of the second adder.

15. A method according to claim 9 wherein the second clock is coupled to a receiver, the method further comprising:

during a first waking period, operating the receiver using the second clock;

during a sleep period after the first waking period, timing a duration of the sleep period using the first clock with the second clock turned off; and

during a second waking period after the sleep period, operating the receiver using the second clock.

16. A method of calibrating a first clock signal using a second clock signal coupled to a receiver, the method comprising:

during a first waking period, operating the receiver using the second clock signal;

for a first calibration period during the first waking period, determining a number of edges of the second clock signal occurring during the first calibration period;

during a sleep period after the first waking period, timing a duration of the sleep period using the first clock signal with the second clock signal turned off;

during a second waking period after the sleep period, operating the receiver using the second clock signal;

for a second calibration period during the second waking period, determining a number of edges of the second clock signal occurring during the second calibration period; and

determining a relationship between the first and second clock signals using the number of edges of the second clock signal occurring during the first interval and the number of edges of the second clock signal occurring during the second interval.

17. A method according to claim 16 wherein determining the relationship between the first and second clock signals comprises calculating an average based on the number of edges of the second clock signal occurring during the first calibration period and the number of edges of the second clock signal occurring during the second calibration period.

18. A method according to claim 17 further comprising:

for a third calibration period during the first waking period, determining a number of edges of the second clock signal occurring during the third calibration period; and

for a fourth calibration period during the second waking period, determining a number of edges of the second clock signal occurring during the fourth calibration period.

19. A method according to claim 18 wherein determining the relationship between the first and second clock signals comprises,

determining a first representation of the relationship between the first and second clock signals for the first waking period using the numbers of edge of the second clock signal occurring during the first calibration period and during the third calibration period,

determining a second representation of the relationship between the first and second clock signals for the second waking period using the number of edges of the second clock signal occurring during the second calibration period and during the fourth calibration period, and

after determining the first and second representations of the relationship between the first and second clock signals, determining an aggregate representation of the relationship between the first and second clock signals using the first and second representations.

20. A method according to claim 18 wherein determining the relationship between the first and second clock signals comprises,

determining a first representation of the relationship between the first and second clock signals using the number of edges of the second clock signal occurring during the first calibration period and the number of edges of the second clock signal occurring during the second calibration period,

determining a second representation of the relationship between the first and second clock signals using the number of edges of the second clock signal occurring during the third calibration period and the number of edges of the second clock signal occurring during the fourth calibration period,

after determining the first and second representations of the relationship between the first and second clock signals, determining an aggregate representation of the relationship between the first and second clock signals using the first and second representations.