INITIAL ACQUISITION USING CRYSTAL OSCILLATOR

• US 20120245883A1
• Filed: 03/18/2012
• Published: 09/27/2012
• Est. Priority Date: 03/24/2011
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Ben-Eli, David, Zaslavsky, Alexander
• Granted Patent: US 9,289,422 B2
• Time in Patent Office: Days
• US Class Current: 702/130
• CPC Class Codes: A61K 31/4745 condensed with ring systems having nitrogen as a ring hetero atom, e.g. phenantrolines yohimbine derivatives, vinblastine A61K31/475; ergoline derivatives A61K31/48
• CPC Class Codes: A61K 45/06 Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H04B 1/16 Circuits

Abstract

A method includes holding in a memory of a receiver, for each temperature in a range of temperatures, a respective first parameter indicative of a frequency error of a crystal oscillator in the receiver at the temperature, and a respective second parameter indicative of an uncertainty of the first parameter. An operating temperature of the crystal oscillator is measured. One or more frequencies, for initial acquisition of signals from a transmitter, are selected based on the first and second parameters corresponding to the measured operating temperature. The receiver is tuned to receive the signals from the transmitter on at least one of the selected frequencies.

Claims

1. A method, comprising:

holding in a memory of a receiver, for each temperature in a range of temperatures, a respective first parameter indicative of a frequency error of a crystal oscillator in the receiver at the temperature, and a respective second parameter indicative of an uncertainty of the first parameter;

measuring an operating temperature of the crystal oscillator;

selecting, based on the first and second parameters corresponding to the measured operating temperature, one or more frequencies for initial acquisition of signals from a transmitter; and

tuning the receiver to receive the signals from the transmitter on at least one of the selected frequencies.

2. The method according to claim 1, wherein holding the respective second parameter for each temperature comprises holding a respective indication of a time that elapsed since updating of the corresponding first parameter.

3. The method according to claim 1, wherein selecting the frequencies comprises calculating, based on the second parameter, a number of the frequencies to be selected, and selecting the calculated number of the frequencies.

4. The method according to claim 1, wherein selecting the frequencies comprises selecting a baseline frequency based on the first parameter, and selecting one or more additional frequencies at fixed frequency shifts from the baseline frequency.

5. The method according to claim 1, wherein tuning the receiver comprises attempting to receive the signals on a given frequency among the selected frequencies, and progressing to receive the signals on another frequency among the selected frequencies upon a failure to receive the signals on the given frequency.

6. The method according to claim 1, comprising defining, based on the second parameter, a respective time-out for receiving the signals on each of the selected frequencies, wherein tuning the receiver comprises attempting to receive the signals on any of the selected frequencies for no more than the respective time-out.

7. The method according to claim 1, wherein selecting the frequencies comprises reducing the second parameter of the operating temperature based on the second parameter of another operating temperature, and choosing the frequencies for the operating temperature based on the reduced second parameter.

8. The method according to claim 1, wherein holding the first and second parameters comprises initializing the first and second parameters for each temperature based on characterization data measured for a type of the crystal oscillator.

9. The method according to claim 1, wherein holding the first and second parameters comprises initializing the first and second parameters for each temperature by measuring two or more frequency errors of the crystal oscillator at two or more respective operating temperatures, and fitting a dependence of the frequency error on the operating temperature to the measured frequency errors.

10. The method according to claim 1, comprising updating the first and second parameters corresponding to the measured operating temperature upon successfully communicating on one of the selected frequencies.

11. The method according to claim 10, wherein successfully communicating on the one of the selected frequencies comprises at least one of:

successfully performing the initial acquisition on the one of the selected frequencies; and

receiving the signals from the transmitter on the one of the selected frequencies above a predefined quality level.

12. The method according to claim 10, wherein updating the first and second parameters comprises filtering a current setting and one or more past settings of the first and second parameters.

13. Apparatus, comprising:

a receiver, which is configured to receive signals;

a memory, which is configured to hold for each temperature in a range of temperatures a respective first parameter indicative of a frequency error of a crystal oscillator in the receiver at the temperature, and a respective second parameter indicative of an uncertainty of the first parameter; and

control circuitry, which is configured to obtain a measured operating temperature of the crystal oscillator, to select, based on the first and second parameters corresponding to the measured operating temperature, one or more frequencies for initial acquisition of the signals from a transmitter, and to tune the receiver to receive the signals from the transmitter on at least one of the selected frequencies.

14. The apparatus according to claim 13, wherein the memory is configured to hold, for each temperature, a respective indication of a time that elapsed since updating of the corresponding first parameter.

15. The apparatus according to claim 13, wherein the control circuitry is configured to calculate, based on the second parameter, a number of the frequencies to be selected, and to select the calculated number of the frequencies.

16. The apparatus according to claim 13, wherein the control circuitry is configured to select a baseline frequency based on the first parameter, and to select one or more additional frequencies at fixed frequency shifts from the baseline frequency.

17. The apparatus according to claim 13, wherein the control circuitry is configured to define, based on the second parameter, a respective time-out for receiving the signals on each of the selected frequencies, and to tune the receiver to receive the signals on any of the selected frequencies for no more than the respective time-out.

18. The apparatus according to claim 13, wherein the control circuitry is configured to reduce the second parameter of the operating temperature based on the second parameter of another operating temperature, and to choose the frequencies for the operating temperature based on the reduced second parameter.

19. The apparatus according to claim 13, wherein the control circuitry is configured to initialize the first and second parameters by performing one of:

initializing the first and second parameters for each temperature based on characterization data measured for a type of the crystal oscillator; and

initializing the first and second parameters for each temperature by measuring two or more frequency errors of the crystal oscillator at two or more respective operating temperatures, and fitting a dependence of the frequency error on the operating temperature to the measured frequency errors.

20. The apparatus according to claim 13, wherein the control circuitry is configured to update the first and second parameters corresponding to the measured operating temperature upon successfully communicating on one of the selected frequencies.

21. The apparatus according to claim 20, wherein the control circuitry is configured to update the first and second parameters upon carrying out at least one of:

successfully performing the initial acquisition on the one of the selected frequencies; and

receiving the signals from the transmitter on the one of the selected frequencies above a predefined quality level.

22. The apparatus according to claim 20, wherein the control circuitry is configured to filter a current setting and one or more past settings of the first and second parameters before updating the first and second parameters.

23. A mobile communication terminal comprising the apparatus of claim 13.

24. A chipset for processing signals in a mobile communication terminal, comprising the apparatus of claim 13.