Systems and methods of RF power transmission, modulation, and amplification, including embodiments for compensating for waveform distortion

• US 8,050,353 B2
• Filed: 02/28/2007
• Issued: 11/01/2011
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: ParkerVision, Inc.
• Original Assignee: ParkerVision, Inc.
• Inventors: Rawlins, Gregory S., Sorrells, David F., Rawlins, Michael W.
• Primary Examiner(s): Ha; Dac
• Assistant Examiner(s): Stevens; Brian J
• Application Number:
  US11/711,812
• Publication Number:
  US 20070248156A1
• Time in Patent Office: 1,707 Days
• Field of Search: 375/229, 375/297
• US Class Current: 375/297
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 1/0294 using vector summing of two or more constant amplitude phase-modulated signals
• CPC Class Codes: H03F 1/30 Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in differential amplifiers H03F3/45479
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 1/3241 using predistortion circuits H03F1/3211, H03F1/3217 take precedence
• CPC Class Codes: H03F 2200/336 A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit
• CPC Class Codes: H03F 2203/21142 Output signals of a plurality of power amplifiers are parallel combined to a common output
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03H 17/08 Networks for phase shifting
• CPC Class Codes: H03H 7/21 providing two or more phase shifted output signals, e.g. n-phase output
• 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 27/366 Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator

Abstract

Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Claims

1. A method for phase and amplitude error correction in a power amplifier, comprising:

pre-compensating phase and amplitude of first and second constant envelope signals of the power amplifier;

wherein said first and second constant envelope signals are generated in first and second branches of the power amplifier;

measuring phase and amplitude error differential signals from the first and second constant envelope signals, wherein said phase and amplitude error differential signals include differences in phase and amplitude between the first and second constant envelope signals; and

adjusting phase and amplitude of the first and second constant envelope signals of the power amplifier according to said phase and amplitude error differential signals.

2. The method of claim 1, wherein said pre-compensating comprises pre-compensating in-phase (I) and quadrature-phase (Q) inputs of the power amplifier.

3. The method of claim 2, wherein said pre-compensating in-phase (I) and quadrature-phase (Q) inputs of the power amplifier comprises:

determining I and Q error values from an error lookup table according to said I and Q inputs; and

correcting said I and Q inputs according to said I and Q error values.

4. The method of claim 3, wherein said correcting said I and Q inputs is performed by a digital module of the power amplifier.

5. The method of claim 1, wherein each of the first and second branches of the power amplifier includes respective vector modulation circuitry and power amplifier (PA) stage, wherein said measuring phase and amplitude error differential signals comprises measuring said phase and amplitude error differential signals at an output of said vector modulation circuitry.

6. The method of claim 1, wherein each of the first and second branches of the power amplifier includes respective vector modulation circuitry and power amplifier (PA) stage, wherein said measuring phase and amplitude error differential signals comprises measuring said phase and amplitude error differential signals within said PA stage.

7. The method of claim 1, wherein said adjusting comprises adjusting phase and amplitude control signals within a digital module of the power amplifier.

8. The method of claim 1, wherein said adjusting comprises adjusting control signals provided to vector modulation circuitry of the power amplifier, said vector modulation circuitry generating said first and second constant envelope signals.

9. The method of claim 1, wherein said adjusting comprises comparing the measured phase and amplitude error differential signals to respective desired phase and amplitude difference values of the first and second constant envelope signals.

10. The method of claim 1, wherein said differences in phase and amplitude between the first and second constant envelope signals are caused by one or more of process variations in the power amplifier, temperature variations, and phase and amplitude errors in vector modulation circuitry of the power amplifier.

11. A power amplifier, comprising:

a digital module that receives in-phase (I) and quadrature-phase (Q) inputs and that generates a plurality of control signals from said I and Q inputs;

vector modulation circuitry that receives a frequency reference signal and said plurality of control signals and that generates a first and second constant envelope signals;

an output stage that combines said first and second constant envelope signals to generate an output signal; and

differential branch measurement circuitry that measure phase and amplitude error differential signals from said first and second constant envelope signals, wherein said phase and amplitude error differential signals include differences in phase and amplitude between said first and second constant envelope signals,

wherein said digital module pre-compensates said phase and amplitude of said first and second constant envelope signals.

12. The power amplifier of claim 11, wherein said digital module adjusts phase and amplitude of said first and second constant envelope signals according to said phase and amplitude error differential signals.

13. The power amplifier of claim 11, wherein said digital module pre-compensates said I and Q inputs of the power amplifier in order to pre-compensate said phase and amplitude of said first and second constant envelope signals.

14. The power amplifier of claim 13, wherein said digital module determines I and Q error values from an error lookup table according to said I and Q inputs;

and corrects said I and Q inputs according to said I and Q error values.

15. The power amplifier of claim 11, wherein said differential branch measurement circuitry measure said phase and amplitude error differential signals at an output of said vector modulation circuitry.

16. The power amplifier of claim 11, wherein said differential branch measurement circuitry measure said phase and amplitude error differential signals within said output stage.

17. The power amplifier of claim 11, wherein said digital module adjusts said plurality of control signals provided to said vector modulation circuitry to adjust said phase and amplitude of said first and second constant envelope signals.

18. The power amplifier of claim 11, wherein said digital module compares the measured phase and amplitude error differential signals to respective desired phase and amplitude difference values of the first and second constant envelope signals.

19. The power amplifier of claim 11, wherein said differences in phase and amplitude between the first and second constant envelope signals are caused by one or more of process variations in the power amplifier, temperature variations, and phase and amplitude errors in said vector modulation circuitry of the power amplifier.