Infrared signal communication system and method including transmission means having automatic gain control

• US 7,123,840 B2
• Filed: 01/22/2003
• Issued: 10/17/2006
• Est. Priority Date: 08/10/1998
• Status: Expired due to Fees

• Current Assignee: IXYS Intl Limited (Littelfuse Incorporated)
• Original Assignee: ZiLOG Incorporated (Littelfuse Incorporated)
• Inventors: Hamilton, T. Allan
• Primary Examiner(s): Phan, Hanh
• Application Number:
  US10/349,735
• Publication Number:
  US 20030128988A1
• Time in Patent Office: 1,364 Days
• Field of Search: 398/118, 398/120, 398/137, 398/162, 398/197, 398/135, 398/128, 398/136, 455/69, 455/88, 455/522
• US Class Current: 398/137
• CPC Class Codes: H04B 10/1143 Bidirectional transmission

Abstract

An Improved Infrared Signal Communication System and Method Including Transmission Means Having Automatic Gain Control is disclosed. Also disclosed is system and method that adjusts signal transmission power in response to incident signal power amplitude. The preferred system includes a control signal loop within the signal receiving system, and the system further includes a signal transmitting system that is responsive to the control signal loop. The preferred system includes manual, semi-automatic and automatic modes of operation. Still further, the preferred method includes at least two Ir-enabled appliances “stepping” each other “down” in transmit power in response to directives issued by the other Ir-enabled appliance.

Claims

1. A device, comprising:

a transmitter circuit that includes a transmitter driver;

an infrared transmitter that receives an amplified signal from the transmitter driver, wherein the amplified signal contains transmit data, wherein the infrared transmitter transmits a transmitted infrared signal that contains the transmit data, and wherein the transmitted infrared signal has a transmit power level;

an infrared receiver that receives an incident infrared signal, wherein the incident infrared signal contains receive data and exhibits an incident power level; and

a receiver circuit coupled to the infrared receiver, wherein the receiver circuit outputs both the receive data and a control signal, wherein the control signal has an amplitude that depends on the incident power level, and wherein the transmit power level varies in proportion to the amplitude of the control signal.

2. The device of claim 1, wherein the transmitter driver operates to reduce the transmit power level when the control signal indicates that the incident power level is above a preset level.

3. The device of claim 1, wherein the receiver circuit includes an automatic gain control circuit, and wherein the automatic gain control circuit generates the control signal.

4. The device of claim 1, wherein the transmitter driver adjusts the transmit power level proportionately to the amplitude of the control signal when the incident power level is above a preset level.

5. The device of claim 1, wherein the transmitter circuit receives the control signal.

6. A method, comprising:

determining an incident power level of an incident infrared signal received by an infrared receiver;

generating a control signal having an amplitude, wherein the amplitude of the control signal depends on the incident power level; and

adjusting a transmit power level of a transmitted infrared signal transmitted by an infrared transmitter, wherein the transmit power level varies in proportion to the amplitude of the control signal when the incident power level is above a preset value.

7. The method of claim 6, wherein the adjusting the transmit power level is accomplished automatically by electronic circuitry.

8. The method of claim 6, wherein the control signal is generated by an automatic gain control circuit.

9. The method of claim 6, wherein the control signal is generated by a receiver circuit, wherein the transmit power level is adjusted by a transmitter circuit, further comprising:

sending the control signal from the receiver circuit to the transmitter circuit.

10. A device, comprising:

an infrared receiver that receives an incident infrared signal, wherein the incident infrared signal exhibits an incident power level;

a receiver circuit coupled to the infrared receiver, wherein the receiver circuit outputs a control signal, and wherein the control signal has an amplitude that depends on the incident power level;

a transmitter circuit that includes a transmitter driver, wherein the transmitter circuit receives the control signal; and

an infrared transmitter that receives an amplified signal from the transmitter driver, wherein the infrared transmitter transmits a transmitted infrared signal having a transmit power level, and wherein the transmitter driver controls the transmit power level based on the amplitude of the control signal.

11. The device of claim 10, further comprising:

a control signal cross-connect line, wherein the control signal cross-connect line connects the receiver circuit to the transmitter circuit.

12. The device of claim 10, wherein the incident infrared signal contains receive data, wherein the receiver circuit outputs the receive data, wherein the amplified signal contains transmit data, and wherein the transmitted infrared signal contains the transmit data.

13. The device of claim 10, wherein the transmitter driver receives the control signal.

14. The device of claim 10, wherein the receiver circuit includes an automatic gain control circuit, and wherein the automatic gain control circuit generates the control signal.

15. The device of claim 10, wherein the device is part of a portable electronic device.

16. A device, comprising:

an infrared receiver that receives an incident infrared signal, wherein the incident infrared signal exhibits an incident power level;

an infrared transmitter that transmits a transmitted infrared signal having a transmit power level; and

means for adjusting the transmit power level in proportion to the incident power level when the incident power level is above a preset value.

17. The device of claim 16, wherein the means includes an automatic gain control circuit.

18. The device of claim 16, wherein the means employs a control signal having an amplitude, and wherein the amplitude of the control signal depends on the incident power level.

19. The device of claim 16, wherein the device is part of a portable electronic device.

20. The device of claim 16, wherein there is a minimum transmit power level required for reliable communications via the transmitted infrared signal, and wherein the means adjusts the transmit power level to the minimum transmit power level for reliable communications.