Communications Transmitter Having High-Efficiency Combination Modulator

• US 20140247907A1
• Filed: 05/08/2014
• Published: 09/04/2014
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: Earl W. Mccune Jr
• Original Assignee: Earl W. Mccune Jr
• Inventors: McCune, Earl W. Jr.
• Granted Patent: US 9,178,734 B2
• Time in Patent Office: Days
• US Class Current: 375/302
• CPC Class Codes: H04L 27/20 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation
• CPC Class Codes: H04L 27/362 Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated H04L27/366 takes precedence

Abstract

A communications transmitter includes a combination modulator and a baseband processor configured to generate amplitude, angle, in-phase and quadrature signals. The combination modulator is configured to modulate in the quadrature domain or the polar domain, depending on an output power level of the transmitter and/or the type of modulation scheme being used. When configured to modulate in the quadrature domain, the baseband processor is configured to generate time-varying in-phase and quadrature modulating signals and time-invariant amplitude and angle signals for the combination modulator. When configured to modulate in the polar domain, the baseband processor is configured to generate time-varying amplitude and angle modulating signals and time-invariant in-phase and quadrature signals for the combination modulator. In another embodiment of the invention, the communications transmitter is configurable to operate in three different operational modes: linear, envelope tracking and switch modes. Which operational mode the communications transmitter is configured to transmit depends on the type of modulation scheme being used and/or the transmitter output power level.

Claims

1. A combination modulator for a communications transmitter, comprising:

a quadrature modulator configurable to modulate a carrier signal by in-phase and quadrature components representing a message to be transmitted; and

an angle modulator, separate and distinct from said quadrature modulator, coupled to said quadrature modulator and configurable to modulate a carrier signal by an angle component representing a message to be transmitted and also configurable to generate an unmodulated carrier signal for said quadrature modulator when said quadrature modulator is configured to modulate according to in-phase and quadrature components representing a message to be transmitted.

2. The combination modulator of claim 1, wherein when said angle modulator is configured to modulate a carrier signal by an angle component representing a message to be transmitted, the in-phase and quadrature inputs of said quadrature modulator are held constant

3. The combination modulator of claim 1, further comprising an amplifier configured to receive a carrier signal that has been angle modulated by said quadrature modulator or angle modulated by said angle modulator.

4. The combination modulator of claim 3, wherein said amplifier includes an output stage that is configurable to operate as a linear amplifier and alternatively as a switch-mode amplifier.

5. The combination modulator of claim 4, further comprising an amplitude modulator configurable to amplitude modulate a power supply for the output stage of said amplifier when said angle modulator is configured to modulate and the output stage of said amplifier is configured to operate as a switch-mode amplifier.

6. The combination modulator of claim 1, further comprising a multiplier coupled between an output of said angle modulator and an input of said quadrature modulator, said multiplier configured to amplitude modulate a carrier signal produced by said angle modulator.

7. The combination modulator of claim 1, further comprising an amplifier that is configurable to operate in a linear mode, an envelope-tracking (ET) mode, and a switch-mode.

8. The combination modulator of claim 7, wherein whether said amplifier is configured to operate in said linear mode, said ET mode, or said switch-mode is determined based on a type of modulation scheme or type of signal being employed or produced.

9. The combination modulator of claim 7, wherein whether said amplifier is configured to operate in said linear mode, said ET mode, or said switch-mode is determined based on a power level the communications transmitter is set or directed to transmit.

10. A multi-mode communications method for a communications transmitter, comprising:

generating in-phase, quadrature, amplitude and angle signal components representing a message to be transmitted;

modulating a carrier signal in the quadrature domain using said in-phase and/or quadrature signal components while holding the amplitude and angle signal components constant or in the polar domain using said amplitude and/or angle signal components while holding said in-phase and quadrature components constant; and

configuring an amplifier to amplify the modulated carrier signal in a linear mode, envelope tracking (ET) mode, or switch mode,

wherein which one of said linear, ET and switch modes said amplifier is configured to operate is dependent on an output power level the communications transmitter is set or directed to transmit.

11. A multi-mode communications method for a communications transmitter, comprising:

generating in-phase, quadrature, amplitude and angle signal components representing a message to be transmitted;

modulating a carrier signal in the quadrature domain using said in-phase and/or quadrature signal components while holding the amplitude and angle signal components constant or in the polar domain using said amplitude and/or angle signal components while holding said in-phase and quadrature components constant; and

configuring an amplifier to amplify the modulated carrier signal in a linear mode, envelope tracking (ET) mode, or switch mode,

wherein which one of said linear, ET and switch modes said amplifier is configured to operate is dependent on the type of modulation scheme being employed or a characteristic or property of the modulated carrier signal.

12. A multi-mode communications method for a communications transmitter, comprising:

generating in-phase, quadrature, amplitude and angle baseband components representing a message to be transmitted;

applying said in-phase, quadrature, amplitude, and angle baseband components to in-phase, quadrature, amplitude, and angle inputs a combination modulator that is configurable to modulate in the quadrature domain and alternatively in the polar domain; and

using said combination modulator, modulating a carrier signal by said in-phase and quadrature baseband components while maintaining the amplitude and angle inputs of the combination modulator constant or, alternatively, modulating the carrier signal by said amplitude and angle baseband components while maintaining the in-phase and quadrature inputs of the combination modulator constant.

13. The multi-mode communications transmitter of claim 12, wherein whether the carrier signal is modulated by said in-phase and quadrature baseband components while maintaining the amplitude and angle inputs of the combination modulator constant or is modulated by said amplitude and angle baseband components while maintaining the in-phase and quadrature inputs of the combination modulator constant depends on an output power level the communications transmitter is set or directed to transmit.

14. The multi-mode communications transmitter of claim 12, wherein whether the carrier signal is modulated by said in-phase and quadrature baseband components while maintaining the amplitude and angle inputs of the combination modulator constant or is modulated by said amplitude and angle baseband components while maintaining the in-phase and quadrature inputs of the combination modulator constant depends on a type of modulation scheme or type of signal being employed or produced by the combination modulator or transmitter.