Claims
- 1. A method for calibrating an on-chip clock device to compensate for individual deviation, comprising the steps of:
- taking a first clock reading from a reference clock;
- storing data related to the first clock reading;
- taking a second clock reading from the reference clock;
- storing data related to the second clock reading;
- determining the number of on-chip clock device oscillations between the reference clock readings;
- determining a calculated oscillation frequency using data related to the second and first reference clock readings to compute oscillations per unit time;
- storing data related to the calculated oscillation frequency; and
- adjusting the output of the on-chip clock device in accordance with said calculated oscillation frequency.
- 2. A method according to 1, further comprising the steps of:
- determining the number of oscillations since a known clock reading; and
- computing the current time using said number of oscillations, said calculated oscillation frequency and said known clock reading.
- 3. A method according to claim 2, wherein said step of computing includes the steps of dividing the number of oscillations by the calculated oscillation frequency to obtain an adjustment value; and adding said adjustment value to said known clock reading.
- 4. A method according to claim 1, wherein said on-chip clock device is embodied within a time notary device having at least one memory and wherein the step of storing the calculated oscillation frequency includes the step of storing in said at least one memory a calibration value computed for said on-chip clock device of said time notary device.
- 5. A method according to claim 1, wherein the step determining a calculated oscillation frequency includes the step of using the difference between the second and first reference clock readings to compute oscillations per unit time.
Parent Case Info
This is a divisional of application Ser. No. 08/056,547, filed May 5, 1993, now U.S. Pat. No. 5,422,953.
US Referenced Citations (7)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0 422 757 |
May 1990 |
EPX |
0 427 515 |
May 1991 |
EPX |
WO 9212485 |
Jul 1992 |
WOX |
Non-Patent Literature Citations (1)
Entry |
Jahrbuch Der Deutschen Gesellschaft Fur Chronometrie, vol. 25, No. 2, Feb. 1974, Stuttgart De, pp. C12-1 C12-9, Burth `Die Rationelle Ermittlung Des Optimalen Abgleiches Bei Quarzuhren Mit Der Integrierten Schaltung Saj 310`, p. C6, line 1-p. C7, line 9; Figure 3. |
Divisions (1)
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Number |
Date |
Country |
Parent |
056547 |
May 1993 |
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