Method for estimating crystal coefficient values for a signal generator

• US 6,636,121 B2
• Filed: 05/31/2001
• Issued: 10/21/2003
• Est. Priority Date: 05/31/2001
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Barak, Ilan, Petrov, Dimitry
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Glenn, Kimberly E
• Application Number:
  US09/867,571
• Publication Number:
  US 20020180535A1
• Time in Patent Office: 873 Days
• Field of Search: 331/25, 331/66, 331/176, 331/158, 331/116.R
• US Class Current: 331/25
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/027 by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit H03L1/023, H03L1/026 take precedence

Abstract

Based on an initial crystal coefficient value, a processor generates a control signal for a frequency synthesizer. The processor estimates a new crystal coefficient value based on a comparison of the frequency of the output of the frequency synthesizer against a target output frequency in relation to a crystal temperature value.

Claims

1. A method comprising estimating a temperature coefficient value of a crystal functionally associated with a frequency synthesizer in relation to an error signal based on at least partial comparison between an output of the frequency synthesizer and a reference frequency signal of a processor associated with the frequency synthesizer.

2. The method according to claim 1, comprising generating a frequency synthesizer control signal correlated to the reference frequency signal.

3. The method according to claim 2, comprising adjusting the frequency synthesizer control signal in relation to the temperature coefficient value.

4. The method according to claim 1, wherein estimating a temperature coefficient value comprises factoring a crystal temperature value into the temperature coefficient value.

5. The method according to claim 4, comprising estimating a plurality of temperature coefficient values relating to said crystal based on said error signal and said crystal temperature value.

6. The method according to claim 1, comprising repeatedly updating the temperature coefficient value until the error signal falls below a predefined threshold value.

7. The method according to claim 6, comprising adjusting the synthesizer control signal each time the temperature coefficient value is updated.

8. A signal generator comprising:

a frequency synthesizer comprising a crystal oscillator to generate an output frequency;

a frequency error detector operatively connected to said crystal oscillator to provide an error signal responsive to an error of said output frequency relative to an independent reference frequency of the signal generator; and

a processing unit operatively associated with said crystal oscillator and said frequency error detector, said processing unit adapted to store a first value of a temperature coefficient and adapted to estimate a second value of said temperature coefficient in response to said error signal.

9. The signal generator according to claim 8, wherein said processing unit generates a frequency synthesizer control signal correlated to said independent reference target frequency value.

10. The signal generator according to claim 9, further comprising a temperature measurement unit operatively coupled to said crystal oscillator.

11. The signal generator according to claim 10, wherein said processing unit estimates the second value of said temperature coefficient at least partially based on an output from said temperature measurement unit.

12. The signal generator according to claim 11, wherein said processing unit regenerates a new frequency synthesizer control signal correlated to said independent reference target frequency value after estimating the second value of said temperature coefficient.

13. The signal generator according to claim 12, wherein said processing unit is adapted to store first values of a plurality of temperature coefficients and to estimate second values of said plurality of temperature coefficients in response to said error signal.

14. The signal generator according to claim 12, wherein said processing unit is adapted to repeatedly estimate new temperature coefficient values and to regenerate new frequency synthesizer control signals until said error signal indicates a frequency error below a predefined threshold.

15. An article comprising a storage medium having stored thereon instructions, that, when executed by a computing platform, cause the computing platform to estimate a temperature coefficient value relating to a crystal oscillator of a frequency synthesizer, said temperature coefficient value being estimated at least partially based on an error signal responsive to a frequency error between an output frequency of said frequency synthesizer and a reference frequency signal of a processor associated with the frequency synthesizer.

16. The article of claim 15, comprising instructions that, when executed, cause the platform to factor a crystal temperature value into the temperature coefficient value.

17. The article of claim 16, further comprising instructions that, when executed, cause the platform to generate a control signal to said frequency synthesizer.

18. The article of claim 17, further comprising instructions that, when executed, cause said control signal to be calculated to cause said frequency synthesizer to produce a signal at the independent reference target frequency value.

19. The article of claim 18, further comprising instructions that, when executed, cause the platform to repeat estimating a temperature coefficient value and generating a control signal until the error signal is below a predetermined level.

20. A method comprising:

generating a frequency synthesizer control signal correlated to a target frequency; and

estimating a temperature coefficient value of a crystal functionally associated with a frequency synthesizer in relation to an error signal based on at least partial comparison between an output of the frequency synthesizer and the target frequency,

wherein estimating a temperature coefficient value comprises factoring a crystal temperature value into an estimation of the temperature coefficient value and into the synthesizer control signal.

21. The method according to claim 20, further comprising adjusting the frequency synthesizer control signal in relation to the estimated temperature coefficient value.

22. The method according to claim 20, further comprising repeatedly updating the estimated temperature coefficient value until the error signal falls below a predefined threshold value.

23. The method according to claim 22, further comprising adjusting the synthesizer control signal each time the estimated temperature coefficient value is updated.

24. The method according to claim 23, comprising estimating a plurality of temperature coefficient values relating to said crystal based on said error signal and said crystal temperature value.

25. A signal generator comprising:

a frequency synthesizer comprising a crystal oscillator;

a frequency error detector operatively connected to said crystal oscillator;

a processing unit operatively associated with said crystal oscillator and said frequency error detector, said processing unit adapted to store a first value of a temperature coefficient and adapted to estimate a second value of said temperature coefficient in relation to output from said frequency error detector,

wherein said processing unit generates a frequency synthesizer control signal correlated to a target frequency; and

a temperature measurement unit operatively coupled to said crystal oscillator.

26. The signal generator according to claim 25, wherein said processing unit estimates the second value of said temperature coefficient at least partially based on an output from said temperature measurement unit.

27. The signal generator according to claim 26, wherein said processing unit regenerates a new frequency synthesizer control signal correlated to said target frequency after estimating the second value of said temperature coefficient.

28. The signal generator according to claim 27, wherein said processing unit is adapted to store first values of a plurality of temperature coefficients and to estimate second values of said plurality of temperature coefficients in relation to the output from said frequency error detector.

29. The signal generator according to claim 27, wherein said processing unit is adapted to repeatedly estimate new temperature coefficient values and to regenerate new frequency synthesizer control signals until the output from said frequency error detector indicates a frequency error below a predefined threshold.

30. An article comprising a storage medium having stored thereon instructions, that, when executed by a computing platform, cause the computing platform to:

estimate a temperature coefficient value relating to a crystal oscillator of a frequency synthesizer, said temperature coefficient value being estimated at least partially based on input from a frequency error detector;

factor in a crystal temperature;

generate a control signal to said frequency synthesizer;

cause said control signal to be calculated to cause said frequency synthesizer to produce a signal at a target frequency; and

repeat estimating a temperature coefficient value and generating a control signal until the input from said frequency detector indicates a signal error below a predetermined level.