Oscillators – Frequency stabilization – Temperature or current responsive means in circuit
Reexamination Certificate
2005-05-26
2008-12-02
Pascal, Robert J. (Department: 2817)
Oscillators
Frequency stabilization
Temperature or current responsive means in circuit
C331S158000, C331S066000, C342S357490, C342S352000, C342S357490
Reexamination Certificate
active
07459984
ABSTRACT:
The invention provides a method and apparatus to optimally estimate and adaptively compensate the temperature-induced frequency drift of a crystal oscillator in a navigational signal receiver. A Read-Write memory encodes two tables, one for looking up frequency drift values versus temperature readings and another one for valid data confirmation on the first table. The initially empty look-up table is gradually populated with frequency drift values while the receiver computes the frequency drift along with its position. During initial start of the receiver or re-acquisition of satellite signals, the stored frequency drift value corresponding to the current temperature is used. If no valid frequency drift value is available, the frequency drift value is computed based on the existing frequency drift values in the table. This invention reduces the Time-To-First-Fix (TTFF) of the receiver and enables the receiver to self-calibrate, thus no additional factory calibration would be necessary.
REFERENCES:
patent: 4712078 (1987-12-01), Slobodnik, Jr. et al.
patent: 5594453 (1997-01-01), Rodal et al.
patent: 5629708 (1997-05-01), Rodal et al.
patent: 5644271 (1997-07-01), Mollov et al.
patent: 5654718 (1997-08-01), Beason et al.
patent: 5742908 (1998-04-01), Dent
patent: 5765101 (1998-06-01), Prockup
patent: 5768353 (1998-06-01), Browne
patent: 5781073 (1998-07-01), Mii
patent: 5854605 (1998-12-01), Gildea
patent: 5864315 (1999-01-01), Welles, II et al.
patent: 5893044 (1999-04-01), King et al.
patent: 5940027 (1999-08-01), Forseth et al.
patent: 5949372 (1999-09-01), Lennen
patent: 6067503 (2000-05-01), Yakos
patent: 6078224 (2000-06-01), Ujiie
patent: 6321295 (2001-11-01), Vincent
patent: 6384774 (2002-05-01), Mutoh et al.
patent: 6448925 (2002-09-01), Shridhara
patent: 6483457 (2002-11-01), Hirata et al.
patent: 6509870 (2003-01-01), Matsushita et al.
patent: 6522212 (2003-02-01), Kodim
patent: 6662107 (2003-12-01), Gronemeyer
patent: 6674402 (2004-01-01), Hirata et al.
patent: 6683564 (2004-01-01), McBurney
patent: 6691031 (2004-02-01), Lokshin et al.
patent: 6697016 (2004-02-01), Voor et al.
patent: 6778136 (2004-08-01), Gronemeyer
patent: 6864800 (2005-03-01), Leichtfried et al.
patent: 6985811 (2006-01-01), Gronemeyer
patent: 7190307 (2007-03-01), Gronemeyer
patent: 2002/0093452 (2002-07-01), Hirata et al.
patent: 2002/0126039 (2002-09-01), Dalton et al.
patent: 2002/0167441 (2002-11-01), McBurney et al.
patent: 2003/0030584 (2003-02-01), Hirata et al.
patent: 2003/0068977 (2003-04-01), King
patent: 2003/0083814 (2003-05-01), Gronemeyer
patent: 2003/0112179 (2003-06-01), Gronemeyer
patent: 2003/0128157 (2003-07-01), Salkhi
patent: 2003/0154025 (2003-08-01), Fuchs et al.
patent: 2003/0164795 (2003-09-01), McBurney
patent: 2003/0176204 (2003-09-01), Abraham
patent: 2003/0184399 (2003-10-01), Lanoue et al.
patent: 2003/0225514 (2003-12-01), Lokshin et al.
patent: 2004/0220734 (2004-11-01), Gronemeyer
patent: 2004/0225439 (2004-11-01), Gronemeyer
patent: 2005/0162306 (2005-07-01), Babitch et al.
patent: 2006/0047459 (2006-03-01), Underbrink et al.
patent: 2006/0195260 (2006-08-01), Gronemeyer
N. Scott Deno et al., “A Low Cost High Stability Microcontroller Compensated Crystal Oscillator,” Proceedings, IEEE Frequency Control Symposium, May 1998, pp. 358-360.
Raymond L. Filler, “Frequency-Temperature Considerations for Digital Temperature Compensation,” 45thAnnual Symposium on Frequency Control, 1991, pp. 398-404.
Raymond L. Filler, “Measurement and Analysis of Thermal Hysteresis in Resonators and TCXO's,” 42ndAnnual Frequency Control Symposium, 1988, pp. 380-387.
Dejan Habic, “The Design of a Microcontroller Temperature Compensated Crystal Oscillator and Automatic Compensation Line,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 42, No. 4, Jul. 1995, pp. 509-516.
T. Miyayama et al., “A New Digitally Temperature Compensated Crystal Oscillator for a Mobile Telephone System,” 42ndAnnual Frequency Control Symposium, 1988, pp. 327-333.
James A. Barnes et al., “Characterization of Frequency Stability,” IEEE Transactions on Instrumentation and Measurement, vol. IM-20, No. 2, May 1971, pp. 105-120.
Han Shaowei
Mo Jun
Shridhara Kudrethaya A.
Wang Chi-Shin
Wang Hansheng
Johnson Ryan J.
Orrick Herrington & Sutcliffe LLP
Pascal Robert J.
Sirf Technology Holdings, Inc.
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