Variable-loss transmitter and method of operation

• US 7,248,845 B2
• Filed: 07/09/2004
• Issued: 07/24/2007
• Est. Priority Date: 07/09/2004
• Status: Expired due to Fees

• Current Assignee: GE Technology Development Incorporated (General Electric Company)
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Dunn, Doug
• Primary Examiner(s): Nguyen; Duc M.
• Application Number:
  US10/887,772
• Publication Number:
  US 20060009174A1
• Time in Patent Office: 1,110 Days
• Field of Search: 455/126, 4551271-1275, 4551141-1143, 455/120, 455/123, 455/125, 330/127, 330/129, 330/133, 330/167, 330/285, 330/303
• US Class Current: 455/127.1
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

An exemplary transceiver comprises a power amplifier configured to receive a source signal and generate an amplified output signal, an antenna coupled to the power amplifier, the antenna being configured to radiate the amplified output signal, and a controller coupled to the power amplifier. The controller is configured to control an effective gain of the power amplifier based on a power level of operation of the transmitter. A source amplifier configured to operate on the source signal prior to power amplification is also controlled by the controller. The controller configures the gain level of the source amplifier based on the power level of operation of the transmitter and the effective gain of the power amplifier to improve signal-to-noise ratio.

Claims

1. A transmitter for communicating information, the transmitter comprising:

a power amplifier configured to receive a source signal and generate an amplified output signal;

an antenna coupled to the power amplifier, the antenna configured to radiate the amplified output signal;

a variable-loss filter coupled between the power amplifier and the antenna; and

a controller coupled to the power amplifier and the variable loss filter, the controller configured to control a gain of the power amplifier responsive to a power level of operation of the transmitter to a establish first gain of the power amplifier during a low power operation of the transmitter and a second gain during a high power operation of the transmitter, the first gain being less than the second gain, the controller further configured to control an attenuation of the variable-loss filter to establish a first signal attenuation level during the low power operation of the transmitter and a second signal attenuation level during the high power operation of the transmitter, the first signal attenuation level being greater than the second signal attenuation level.

2. The transmitter of claim 1 wherein the power amplifier has a variable gain controlled by the controller.

3. The transmitter of claim 2 wherein the variable-loss filter comprises a ferro-electric filter configured to attenuate the amplified output signal in response to a control command from the controller.

4. The transmitter of claim 3 further comprising a duplexer coupled between the power amplifier and the antenna, the variable-loss filter integrated in the duplexer.

5. The transmitter of claim 2 wherein the variable-loss filter comprises a matching circuit coupled to an output of the power amplifier.

6. The transmitter of claim 2 wherein the controller is further coupled to a source amplifier, the source amplifier configured to operate on the source signal, the controller configured to set a gain level of the source amplifier based on the power level of operation of the transmitter and the effective gain of the power amplifier.

7. The transmitter of claim 6 further comprising a mixer coupled between an output of the source amplifier and an input of the power amplifier, the mixer configured to:

receive signals from the output of the source amplifier, upconvert the received signals over a radio frequency signal to generate upconverted signals, and transmit the upconverted signals to the input of the power amplifier.

8. A method for transmitting a source signal for wireless communication by a transmitter, the transmitter including a power amplifier coupled to an antenna, the method comprising:

receiving the source signal;

determining a power level of operation of the transmitter;

configuring the power amplifier to have a first gain during a low power operation of the transmitter;

configuring the power amplifier to have a second gain during a high power operation of the transmitter, the first gain being less than the second gain;

amplifying, by the power amplifier, the source signal into an amplified output signal;

configuring a variable-loss filter connected between the power amplifier and the antenna to have a first signal attenuation level during the low power operation of the transmitter; and

configuring the variable-loss filter to have a second signal attenuation level during the high power operation of the transmitter, the first signal attenuation level being greater than the second signal attenuation level; and

transmitting the amplified output signal via the antenna.

9. The method of claim 8 wherein the controller is further configured to set a variable gain of the power amplifier to a high gain during the high power operation of the transmitter and to a low gain during the low power operation of the transmitter.

10. The method of claim 9 wherein configuring the variable-loss filter comprises configuring a matching circuit coupled to an output of the power amplifier.

11. The method of claim 9 further comprising configuring a gain level of a source amplifier based on the power level of operation of the transmitter and the gain of the power amplifier.

12. The method of claim 11 further comprising:

receiving signals from an output of the source amplifier;

modulating the received signals over a radio frequency signal to generate upconverted signals; and

transmitting the upconverted signals to the input of the power amplifier.

13. The method of claim 9 wherein configuring the variable-loss filter comprises configuring a ferro-electric filter configured to attenuate the amplified output signal in response to a control command.

14. The method of claim 13 wherein the transmitting comprises transmitting the amplified output signal through a duplexer coupled between the power amplifier and the antenna, the variable-loss filter integrated in the duplexer.

15. A wireless communication device comprising:

a housing;

a transceiver situated in the housing, the transceiver coupled to an antenna for transmitting and receiving radio frequency signals in a plurality of frequency bands;

a mobile power source supplying power to the transceiver, the transceiver comprising;

a power amplifier configured to receive a source signal and generate an amplified output signal, the power amplifier being coupled to the antenna, the antenna configured to radiate the amplified output signal;

a variable-loss filter coupled between the power amplifier and the antenna; and

a controller coupled to the power amplifier and the variable-loss filter, the controller configured to control a gain of the power amplifier responsive to a power level of operation of the transceiver to establish a first gain during a low power operation of the transceiver and a second gain during a high power operation of the transceiver, the first gain being less than the second gain, controller configured to control an attenuation of the variable-loss filter to establish a first signal attenuation level during the low power operation of the transceiver and a second signal attenuation level during the high power operation of the transceiver, the first signal attenuation level being greater than the second signal attenuation level.

16. The wireless communication device of claim 15 wherein the power amplifier has a variable gain controlled by the controller.

17. The wireless communication device of claim 16 wherein the variable-loss filter comprises a ferro-electric filter configured to attenuate the amplified output signal in response to a control command from the controller.

18. The wireless communication device of claim 17 further comprising a duplexer coupled between the power amplifier and the antenna, the variable-loss filter integrated in the duplexer.

19. The wireless communication device of claim 16 wherein the variable-loss filter comprises a matching circuit coupled to an output of the power amplifier.

20. The wireless communication device of claim 16 further comprising a source amplifier configured to operate on the source signal, the controller configured to set a gain level of the source amplifier based on the power level of operation of the transmitter and the effective gain of the power amplifier.