SYSTEMS AND METHODS FOR FREQUENCY COMPENSATION OF REAL-TIME-CLOCK SYSTEMS

• US 20190013778A1
• Filed: 07/31/2017
• Published: 01/10/2019
• Est. Priority Date: 07/05/2017
• Status: Active Grant

• Current Assignee: Guangzhou On-Bright Electronics Co., Ltd
• Original Assignee: Guangzhou On-Bright Electronics Co., Ltd
• Inventors: ZHOU, RUSHENG, ZHANG, JIAPENG
• Granted Patent: US 10,734,947 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/2824 testing of oscillators or resonators
• CPC Class Codes: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/32 being a piezoelectric resonator selection of piezoelectric material H10N30/00
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/028 of generators comprising piezoelectric resonators H03L1/021, H03L1/022 take precedence; oscillation generators with a piezoelectric resonator H03B5/32

Abstract

Method and system for temperature-dependent frequency compensation. For example, the method for temperature-dependent frequency compensation includes determining a first frequency compensation as a first function of temperature using one or more crystal oscillators, processing information associated with the first frequency compensation as the first function of temperature, and determining a second frequency compensation for a crystal oscillator as a second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature. The one or more crystal oscillators do not include the crystal oscillator, and the first frequency compensation as the first function of temperature is different from the second frequency compensation as the second function of temperature.

Claims

1. A method for temperature-dependent frequency compensation, the method comprising:

determining a first frequency compensation as a first function of temperature using one or more crystal oscillators;

processing information associated with the first frequency compensation as the first function of temperature; and

determining a second frequency compensation for a crystal oscillator as a second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature;

wherein;

the one or more crystal oscillators do not include the crystal oscillator; and

the first frequency compensation as the first function of temperature is different from the second frequency compensation as the second function of temperature.

2. The method of claim 1 wherein the determining a second frequency compensation for a crystal oscillator as a second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature includes:

measuring an actual frequency of the crystal oscillator at a selected temperature;

determining a third frequency compensation for the crystal oscillator at the selected temperature based at least in part on the measured actual frequency;

processing information associated with the third frequency compensation for the crystal oscillator at the selected temperature; and

determining the second frequency compensation for the crystal oscillator as the second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature and the third frequency compensation for the crystal oscillator at the selected temperature.

3. The method of claim 2 wherein the determining a third frequency compensation for the crystal oscillator at the selected temperature based at least in part on the measured actual frequency includes determining the third frequency compensation equal to a desired frequency of the crystal oscillator at the selected temperature minus the actual frequency of the crystal oscillator at the selected temperature.

4. The method of claim 3 wherein:

the selected temperature is a peak temperature for the crystal oscillator; and

the desired frequency of the crystal oscillator at the selected temperature is the desired frequency of the crystal oscillator at the peak temperature.

5. The method of claim 2 wherein the determining the second frequency compensation for the crystal oscillator as the second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature and the third frequency compensation for the crystal oscillator at the selected temperature includes:

determining a frequency compensation value at the selected temperature based at least in part on the first frequency compensation as the first function of temperature;

calculating an frequency offset equal to the frequency compensation value minus the third frequency compensation for the crystal oscillator at the selected temperature; and

determining the second frequency compensation for the crystal oscillator as the second function of temperature equal to the first frequency compensation as the first function of temperature minus the frequency offset.

6. The method of claim 1 wherein the determining a first frequency compensation as a first function of temperature using one or more crystal oscillators includes determining a plurality of coefficients for the first frequency compensation as the first function of temperature.

7. The method of claim 6 wherein the plurality of coefficients is related to the first function of temperature.

8. The method of claim 6 wherein the determining a first frequency compensation as a first function of temperature using one or more crystal oscillators includes:

selecting the one or more crystal oscillators from a batch of crystal oscillators; and

measuring a plurality of actual frequencies of the one or more crystal oscillators at a plurality of temperatures;

wherein the determining a plurality of coefficients for the first frequency compensation as the first function of temperature includes determining the plurality of coefficients based on at least information associated with the plurality of measured actual frequencies of the one or more crystal oscillators at the plurality of temperatures.

9. The method of claim 8 wherein the measuring a plurality of actual frequencies of the one or more crystal oscillators at a plurality of temperatures includes, for each crystal oscillator of the one or more crystal oscillators, measuring multiple actual frequencies at the plurality of temperatures.

10. The method of claim 6 wherein the determining a first frequency compensation as a first function of temperature using one or more crystal oscillators further includes storing the plurality of coefficients.

11. The method of claim 1, and further comprising performing a frequency calibration at a specific temperature for a real-time-clock system, the real-time-clock system including the crystal oscillator.

12. The method of claim 11 wherein the performing a frequency calibration at a specific temperature for a real-time-clock system includes:

measuring an ambient temperature of the crystal oscillator that is included in the real-time-clock system;

determining a frequency compensation value at the ambient temperature using the second frequency compensation for the crystal oscillator as the second function of temperature; and

determining an adjustment value to a counter threshold at the ambient temperature for the real-time-clock system.

13. The method of claim 1 wherein the one or more crystal oscillators include a plurality of crystal oscillators.

14. A method for temperature-dependent frequency compensation, the method comprising:

determining a first frequency compensation as a first function of temperature using one or more crystal oscillators;

processing information associated with the first frequency compensation as the first function of temperature; and

determining a second frequency compensation for a crystal oscillator as a second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature;

wherein;

the first function of temperature is configured to provide multiple first compensation values for the first frequency compensation in response to multiple first temperatures respectively; and

the second function of temperature is configured to provide multiple second compensation values for the second frequency compensation in response to multiple second temperatures respectively.

15. The method of claim 14 wherein:

the one or more crystal oscillators do not include the crystal oscillator; and

the first frequency compensation as the first function of temperature is different from the second frequency compensation as the second function of temperature.

16. The method of claim 14 wherein the determining a second frequency compensation for a crystal oscillator as a second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature includes:

measuring an actual frequency of the crystal oscillator at a selected temperature;

determining a third frequency compensation for the crystal oscillator at the selected temperature based at least in part on the measured actual frequency;

processing information associated with the third frequency compensation for the crystal oscillator at the selected temperature; and

determining the second frequency compensation for the crystal oscillator as the second function of temperature based on at least information associated with the first frequency compensation as the first function of temperature and the third frequency compensation for the crystal oscillator at the selected temperature.

17. The method of claim 14 wherein the determining a first frequency compensation as a first function of temperature using one or more crystal oscillators includes determining a plurality of coefficients for the first frequency compensation as the first function of temperature.

18. The method of claim 17 wherein the plurality of coefficients is related to the first function of temperature.

19. The method of claim 14, and further comprising performing a frequency calibration at a specific temperature for a real-time-clock system, the real-time-clock system including the crystal oscillator.

20. The method of claim 14 wherein the one or more crystal oscillators include a plurality of crystal oscillators.