System and method for reducing radio frequency interference from digital circuits

• US 8,064,838 B2
• Filed: 06/18/2008
• Issued: 11/22/2011
• Est. Priority Date: 06/18/2008
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Lentschke, Ernest W. III, Hailey, Jeffrey C.
• Primary Examiner(s): Tran; Tuan A
• Application Number:
  US12/141,243
• Publication Number:
  US 20090316844A1
• Time in Patent Office: 1,252 Days
• Field of Search: 455/63.1, 455/114.2, 455/296, 455/300, 455/306, 375/148, 375/219, 375/254, 361/816, 361/818
• US Class Current: 455/63.1
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus

Abstract

An information handling system includes a digital circuit having a first terminal connected to a first voltage reference, and a second terminal connected to a second voltage reference. The digital circuit is configured to be coupled to a radio device. The system also includes a band pass filter having a first terminal connected to the first voltage reference, and a second terminal connected to the second voltage reference. The bandpass filter is configured to produce a low impedance response, to reduce a radio frequency noise generated at a specific frequency band of the band pass filter, and to reduce a radio frequency interference produced by the digital circuit and received at the radio device.

Claims

1. An information handling system comprising:

a digital circuit having a first terminal connected to a first voltage reference, and a second terminal connected to a second voltage reference, the digital circuit configured to be coupled to a radio device; and

a band pass filter having a first terminal connected to the first voltage reference, and a second terminal connected to the second voltage reference, the band pass filter configured to produce a low impedance response and to reduce a radio frequency noise generated at a specific frequency band of the band pass filter, and further configured to reduce a radio frequency interference produced by the digital circuit and received at the radio device.

2. The information handling system of claim 1 wherein the radio device is selected from the group consisting of a Bluetooth device, a radio frequency device, a wireless fidelity device, a worldwide interoperability for microwave access device, and a cellular device.

3. The information handling system of claim 1 wherein the digital circuit is selected from the group consisting of a display device, a memory, and a processor.

4. The information handling system of claim 1 wherein the band pass filter further comprises a third terminal connected to the second voltage reference.

5. The information handling system of claim 1 further comprising:

a resistor having a first terminal connected to a third terminal of the band pass filter, and a second terminal connected to the second voltage reference.

6. The information handling system of claim 1 further comprising:

a resistor having a first terminal connected to a third terminal of the band pass filter, and a second terminal connected to the first voltage reference.

7. The information handling system of claim 1 further comprising:

a first resistor having a first terminal connected the third terminal of the band pass filter, and a second terminal connected to the first voltage reference; and

a second resistor having a first terminal connected to the third terminal of the band pass filter, and a second terminal connected to the to the second voltage reference.

8. A method comprising:

applying a band pass filter to a digital circuit;

providing a low impedance response at a frequency band of the band pass filter;

reducing a radio frequency noise produced by the digital circuit at the frequency band of the band pass filter; and

reducing an amount of radio frequency interference produced by the digital circuit.

9. The method of claim 8 further comprising:

increasing an ability of a radio device, coupled to the digital circuit, to receive a desired radio frequency signal.

10. The method of claim 9 wherein the radio device is selected from the group consisting of a Bluetooth device, a radio frequency device, a wireless fidelity device, a worldwide interoperability for microwave access device, and a cellular device.

11. The method of claim 9 wherein the desired radio frequency signal is within the frequency band of the band pass filter.

12. The method of claim 8 wherein the digital circuit is selected from the group consisting of a display device, a memory, and a processor.

13. The method of claim 8 further comprising:

reducing an amount of voltage produced by the digital circuit, wherein the voltage produces the radio frequency interference.

14. An information handling system comprising:

a radio device configured to receive a radio frequency signal;

a digital circuit coupled to the radio device, the digital circuit having a first terminal connected to a first voltage reference, and a second terminal connected to a second voltage reference, the digital circuit configured to be coupled to the radio device; and

a band pass filter having a first terminal connected to the first voltage reference, and a second terminal connected to the second voltage reference, the band pass filter configured to produce a low impedance response and to reduce a radio frequency noise generated at a specific frequency band of the band pass filter, and further configured to reduce a radio frequency interference produced by the digital circuit and received at the radio device.

15. The information handling system of claim 14 wherein the radio device is selected from the group consisting of a Bluetooth device, a radio frequency device, a wireless fidelity device, a worldwide interoperability for microwave access device, and a cellular device.

16. The information handling system of claim 14 wherein the digital circuit is selected from the group consisting of a display device, a memory, and a processor.

17. The information handling system of claim 14 wherein the band pass filter further comprises a third terminal connected to the second voltage reference.

18. The information handling system of claim 14 further comprising:

a resistor having a first terminal connected to a third terminal of the band pass filter, and a second terminal connected to the second voltage reference.

19. The information handling system of claim 14 further comprising:

a resistor having a first terminal connected to a third terminal of the band pass filter, and a second terminal connected to the first voltage reference.

20. The information handling system of claim 14 further comprising:

a first resistor having a first terminal connected the third terminal of the band pass filter, and a second terminal connected to the first voltage reference; and

a second resistor having a first terminal connected to the third terminal of the band pass filter, and a second terminal connected to the to the second voltage reference.