Dynamic clock control to reduce radio interference in digital equipment

• US 20030198307A1
• Filed: 04/19/2002
• Published: 10/23/2003
• Est. Priority Date: 04/19/2002
• Status: Abandoned Application

• Current Assignee: Compaq Computer Corporation (HP Inc.)
• Original Assignee: Compal Information Kunshan Company Limited (Compal Electronics Incorporated)
• Inventors: Panditharathne, Chrismal R., Neill, Timothy
• Application Number:
  US10/126,901
• Publication Number:
  US 20030198307A1
• Time in Patent Office: Days
• US Class Current: 375/346
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04B 2215/065 by changing the frequency of clock or reference frequency

Abstract

A system and method of using dynamic clock control to reduce RF interference in digital equipment is disclosed. In one embodiment, the digital equipment comprises a clock module, a wireless module, and a control module. The wireless module is designed to receive RF signals, but may also receive RF interference from the digital equipment. The control module responsively adjusts the clock module to reduce the RF interference, preferably by shifting clock signal harmonics outside selected frequency regions of interest (e.g., a receive channel). The selected frequency regions may change, e.g., due to channel hopping. The control module preferably continues to shift the clock signal harmonics as needed to reduce RF interference. The control module may also adjust display scan rates, hardware states, and computational load assignments. The control module may be further configured to adaptively minimize the RF interference.

Claims

1. A digital apparatus that comprises:

a clock module configured to provide a clock signal;

a wireless module configured to receive radio-frequency (RF) signals, wherein the wireless module also receives RF interference from the digital apparatus; and

a control module configured to adjust the clock module to reduce RF interference in one or more selected frequency regions of interest.

2. The apparatus of claim 1, wherein the control module adjusts the clock module in response to information received from the wireless module.

3. The apparatus of claim 1, wherein the control module adjusts the clock module to shift harmonics of the clock signal outside the one or more selected frequency regions of interest.

4. The apparatus of claim 1, wherein the one or more selected frequency regions of interest include a receive channel for the RF signals.

5. The apparatus of claim 1, wherein the one or more selected frequency regions of interest vary from time to time.

6. The apparatus of claim 1, wherein the wireless module makes a measurement indicative of the RF interference in the one or more selected frequency regions of interest.

7. The apparatus of claim 6, wherein the control module adjusts the clock module to reduce the measurement.

8. A digital apparatus that comprises:

a clock module configured to provide a clock signal;

a wireless module that receives RF interference from the digital apparatus; and

a control module configured to adjust the clock module to determine which of multiple clock signal frequencies minimizes RF interference in one or more selected frequency regions of interest.

9. A device that comprises:

a clock source that provides a clock signal at a programmable frequency;

a wireless module that receives RF interference directly or indirectly caused by the clock signal; and

a control module that sets the programmable frequency of the clock signal so as to move at least some of the RF interference outside a frequency region of interest without stopping the clock signal altogether.

10. A method of reducing RF interference in digital equipment, the method comprising:

providing a clock signal at an initial clock rate;

identifying a frequency region in which to reduce RF interference; and

adjusting the clock signal to a different, nonzero clock rate that reduces RF interference in the identified frequency region.

11. The method of claim 10, wherein the frequency region is identified for receiving wireless communications to the digital equipment.

12. The method of claim 11, wherein the identified frequency region is not identified until a wireless communications transaction is initiated.

13. The method of claim 10, further comprising:

making measurements indicative of RF interference, wherein the adjusting includes trying a plurality of clock rates to determine which of the plurality of clock rates minimizes the RF interference.

14. A digital system that comprises:

a wireless communications device that receives RF interference from the digital system; and

a processor configured to execute a spectrum control procedure that configures the digital system so as to reduce said RF interference in one or more frequency regions during operation of the wireless communications device.

15. The system of claim 14, wherein the spectrum control procedure adjusts a clock signal frequency to shift at least some of the RF interference outside the one or more frequency regions.

16. The system of claim 14, wherein the spectrum control procedure alters a display scan rate to shift at least some of the of the RF interference outside the one or more frequency regions.

17. The system of claim 14, wherein the spectrum control procedure suspends operation of one or more peripherals during operation of the wireless communications device to reduce said RF interference.

18. The system of claim 14, wherein the spectrum control procedure shifts computational tasks to parallel hardware components more distantly spaced from the wireless communications device to reduce said RF interference.

19. The system of claim 14, wherein the processor receives information from the wireless communications device indicative of RF interference in the one or more frequency regions, and wherein the spectrum control procedure determines the effect of multiple configurations on said RF interference.

20. The system of claim 19, wherein the spectrum control procedure creates or maintains a table of preferred digital system configurations as a function of selected frequency regions.

21. A method of reducing RF interference in a digital system, the method comprising:

configuring the digital system to operate in an initial configuration;

identifying a frequency region in which to reduce RF interference; and

automatically reconfiguring the digital system in a manner that reduces RF interference in the identified frequency region.

22. The method of claim 21, wherein the reconfiguration includes altering a display scan rate to shift at least some of the RF interference outside the identified frequency region.

23. The method of claim 21, wherein the reconfiguration includes suspending operation of one or more system components.

24. The method of claim 21, wherein the reconfiguration includes shifting computational tasks from one hardware component to a second, substantially similar hardware component that is located further away from an RF interference sensitive component.

25. The method of claim 21, further comprising:

generating a table of system configurations to minimize RF interference in predetermined frequency regions.