CLOCK FREQUENCY SELECTION SCHEME

• US 20120042193A1
• Filed: 08/13/2010
• Published: 02/16/2012
• Est. Priority Date: 08/13/2010
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Gupta, Saurabh, Curtis, Robert, Sharma, Anup, Wang, Tow
• Application Number:
  US12/856,104
• Publication Number:
  US 20120042193A1
• Time in Patent Office: Days
• US Class Current: 713/501
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency

Abstract

Systems and methods for selecting and setting clock frequencies for an electronic device are disclosed. Specifically, clock frequencies may be adjusted to avoid interference with input electromagnetic energy, often in radio frequency bands. Clock frequencies may be chosen to minimize signal interference and improve device performance. In some embodiments, clock frequency information is stored in one or more lookup tables in device memory. In certain embodiments, a system processor can access the information stored in the lookup table and instruct system circuitry to adjust clock frequency as needed based on lookup table entries.

Claims

1. An electronic device comprising:

a canless radio frequency (RF) module operative to tune to a plurality of RF frequencies;

a first clock operative to provide a first clock signal having either a first clock frequency or a second clock frequency to the canless RF module;

a second clock operative to provide a second clock signal having either a third clock frequency or a fourth clock frequency;

a processor in operative communication with the canless RF module, the first clock, and the second clock, the processor operative to;

determine the RF frequency that the canless RF module is tuned to;

access a clock frequency data structure to determine whether the first clock should provide the first clock signal having the first clock frequency or the second clock frequency and whether the second clock should provide the second clock signal having the third clock frequency or the fourth clock frequency based on the tuned to RF frequency;

instruct the first clock to operate at the first or second clock frequency based on the determination made in accessing the clock frequency data structure; and

instruct the second clock to operate at the third or fourth clock frequency based on the determination made when accessing the clock frequency data structure, wherein the first and second clocks operate at clock frequencies that substantially minimize interference with the tuned to RF frequency.

2. The electronic device of claim 1, wherein the canless RF module is operative to tune to frequencies selected from the group comprising FM frequencies, AM frequencies, cellular frequencies, and Wi-Fi frequencies.

3. The electronic device of claim 1, wherein the clock frequency data structure stores clock frequency data based on measurement results of an electronic device.

4. The electronic device of claim 1, wherein the clock frequency data structure stores clock frequency data based on electromagnetic simulation results of an electronic device.

5. The electronic device of claim 1, wherein the clock frequency data structure stores clock frequency data associated with more than two clocks.

6. The electronic device of claim 1, wherein the clock frequency data structure stores data associated with input signal bandwidth.

7. The electronic device of claim 1, wherein the clock frequency data structure stores data associated with input signal strength.

8. The electronic device of claim 1, wherein the clock frequency data structure stores data associated with input signal carrier frequency.

9. A method of adjusting clock frequency on an electronic device comprising:

receiving radio frequency (RF) signal data;

determining a RF frequency of a plurality of RF frequencies to tune a canless RF module based on the received RF signal data;

accessing a data structure storing clock frequency operating data for a first clock providing a first clock signal to the canless RF module and a second clock providing a second clock signal,

accessing data in the data structure associated with the determined RF frequency, the first clock, and the second clock;

determining whether the first clock should provide the first clock signal at a first clock frequency or a second clock frequency and whether the second clock should provide the second clock signal at a third clock frequency or a fourth clock frequency based on the accessed data using data accessed from the data structure;

instructing the first clock to operate at the first clock frequency or the second clock frequency; and

instructing the second clock to operate at the third clock frequency or the fourth clock frequency.

10. The method of claim 9, wherein determining whether the first clock should provide the first clock signal at the first clock frequency or the second clock frequency and whether the second clock should provide the second clock signal at the third clock frequency or the fourth clock frequency comprises comparing clock frequency operating data for the first clock with clock frequency operating data for the second clock.

11. The method of claim 10, wherein comparing clock frequency operating data for the first clock with clock frequency operating data for the second clock comprises comparing noise level data associated with different operating frequencies for each clock.

12. The method of claim 10, wherein comparing clock frequency operating data for the first clock with clock frequency operating data for the second clock comprises comparing power consumption data associated with different operating frequencies for each clock.

13. The method of claim 9, wherein the RF signal data is selected from the group comprising FM radio data, AM radio data, left channel spectrum data, and right channel spectrum data.

14. The method of claim 9, further comprising determining whether a third clock should provide a third clock signal at a fifth clock frequency or a sixth clock frequency.

15. The method of claim 9, wherein accessing data in the data structure associated with the determined RF frequency, the first clock, and the second clock comprises accessing multiple data entries associated with the first clock.

16. The method of claim 9, wherein accessing data in the data structure associated with the determined RF frequency, the first clock, and the second clock comprises accessing multiple data entries associated with the second clock.

17. The method of claim 9, wherein instructing the first clock to operate at the first clock frequency or the second clock frequency comprises instructing the first clock to operate at a frequency higher than the determined RF frequency of a plurality of RF frequencies to tune a canless RF module.

18. The method of claim 9, wherein instructing the first clock to operate at the first clock frequency or the second clock frequency comprises instructing the first clock to operate at a frequency lower than the determined RF frequency of a plurality of RF frequencies to tune a canless RF module