PREDISTORTION AND POST-DISTORTION CORRECTION OF BOTH A RECEIVER AND TRANSMITTER DURING CALIBRATION

• US 20090316826A1
• Filed: 06/21/2008
• Published: 12/24/2009
• Est. Priority Date: 06/21/2008
• Status: Active Grant

• Current Assignee: Vyycore Corporation
• Original Assignee: Vyycore Corporation
• Inventors: Toujikov, Sergey, Koren, Doron
• Granted Patent: US 8,126,036 B2
• Time in Patent Office: Days
• US Class Current: 375/296
• CPC Class Codes: H04L 27/366 Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator
• CPC Class Codes: H04L 27/367 using predistortion
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

A post-distorter compensates for receiver nonlinearity in calibration mode. Linearized receiver-side output from the post-distorter is used to correctly compensate for transmitter-side nonlinearities in calibration mode. The post-distorter also compensates for receiver-side nonlinearities during normal receive mode. Thus, the post-distorter features dual modes of use, a calibration mode, wherein calibration signals received from the adjacent transmitter are linearized by the post-distorter and a normal receive mode, wherein communication signals from a remote transmitter are linearized by the post-distorter.

Claims

1. A system for distortion compensation embodied in a transceiver, said system comprising

a predistorter operably disposed between a digital transmitter and a power amplifier;

a post-distorter operably disposed between a receiver amplifier and a digital receiver;

said system being configurable to operate in a configuration mode with said transmitter and receiver active; and

said post-distorter adapted to compensate for nonlinearities in the receiver amplifier and, in configuration mode, produce post-distorted in-phase and quadrature-phase output signals and communicate such signals to the predistorter, and said predistorter adapted to compensate for nonlinearities in the power amplifier.

2. A system for distortion compensation embodied in a transceiver according to claim 1, said system further being configurable to operate in a receive mode, and

said post-distorter, in receive mode, producing post-distorted in-phase and quadrature-phase output signals and communicating such signals to the digital receiver.

3. A system for distortion compensation embodied in a transceiver according to claim 1, said system further being configurable to operate in configuration mode and in a receive mode, and

said post-distorter, in receive mode, producing post-distorted in-phase and quadrature-phase output signals and communicating such signals to the digital receiver.

4. A system for distortion compensation embodied in a transceiver according to claim 1, said system post-distorter being configured to operate only in configuration mode.

5. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising a low noise amplifier operably coupled to said receiver amplifier.

6. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising a low noise amplifier operably coupled to said receiver amplifier and an IQ mixer operably coupled to said receiver amplifier, said receiver amplifier being disposed between said low noise amplifier and said IQ mixer.

7. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising a low noise amplifier operably coupled to said receiver amplifier and an IQ mixer operably coupled to said receiver amplifier, said receiver amplifier being disposed between said low noise amplifier and said IQ mixer and, in calibration mode, cross talk radiation leaking into the low noise amplifier, receiver amplifier and IQ mixer.

8. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising an IQ mixer operably coupled to said receiver amplifier, said IQ mixer being disposed between said receiver amplifier and said post-distorter and, in calibration mode, cross talk radiation leaking into the low noise receiver amplifier and IQ mixer.

9. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising an IQ mixer operably coupled to said receiver amplifier, said IQ mixer being disposed between said receiver amplifier and said post-distorter and, in calibration mode, cross talk radiation leaking into the low noise receiver amplifier and IQ mixer, and a gain control unit operably coupled to said power amplifier.

10. A system for distortion compensation embodied in a transceiver according to claim 1, said system further comprising an IQ mixer operably coupled to said receiver amplifier, said IQ mixer being disposed between said receiver amplifier and said post-distorter and, in calibration mode, cross talk radiation leaking into the low noise receiver amplifier and IQ mixer, and a gain control unit operably coupled to said power amplifier, and a frequency up converter operably coupled to said gain control unit.

13. A system for distortion compensation embodied in a transceiver according to claim 1, said system further being configurable to operate in configuration mode and in a receive mode, and

said post-distorter means, in receive mode, producing post-distorted in-phase and quadrature-phase output signals and communicating such signals to the digital receiver.

14. A system for distortion compensation embodied in a transceiver according to claim 1, said system post-distorter means being configured to operate only in configuration mode.

11. A system for distortion compensation embodied in a transceiver, said system comprising

a predistorter means operably disposed between a digital transmitter and a power amplifier;

a post-distorter means operably disposed between a receiver amplifier and a digital receiver;

said system being configurable to operate in a configuration mode with said transmitter; and

said post-distorter means adapted to compensate for nonlinearities in the receiver amplifier and, in configuration mode, produce post-distorted in-phase and quadrature-phase output signals and communicate such signals to the predistorter means, and said predistorter means adapted to compensate for nonlinearities in the power amplifier.

12. A system for distortion compensation embodied in a transceiver according to claim 11, said system further being configurable to operate in a receive mode, and

said post-distorter means, in receive mode, producing post-distorted in-phase and quadrature-phase output signals and communicating such signals to the digital receiver.

15. A method for linearizing output signals from an inherently non-linear transceiver device during calibration, said method comprising steps of amplifying signals received through an antenna from a transmitter of the transceiver, filtering the amplified signals using a low pass filter, converting the filtered signals to digital signals using an analog to digital converter, producing post-distorted in-phase and quadrature-phase output signals based upon the digital signals, communicating the post-distorted in-phase and quadrature-phase output signals to a predistorter, linearizing output from the transmitter using the predistorter.

16. A method for linearizing output signals from an inherently non-linear transceiver device during calibration according to claim 15, further comprising steps of decreasing gain control of a power amplifier to 0 and then increasing gain control slowly until it reaches a determined back-off point.

17. A method for linearizing output signals from an inherently non-linear transceiver device during calibration according to claim 16, further comprising, after reaching the back-off point, activating a receiver of the transciever and, thereby, causing the receiver to be compressed due to cross talk and intermodulation distortion.

18. A method for linearizing output signals from an inherently non-linear transceiver device during calibration according to claim 17, further comprising a step of calculating post-distorter system identification coefficients for the receiver.

19. A method for linearizing output signals from an inherently non-linear transceiver device during calibration according to claim 18, wherein the step of linearizing output from the transmitter using the predistorter includes applying the post-distorter system identification coefficients to the predistorter, and said method further comprising a step of increasing gain control until the increase causes an increase in error vector magnitude or a decrease in signal to noise ratio, and then decreasing gain control by a determined amount causing a decrease in the error vector magnitude or increase in signal to noise ratio.

20. A method for linearizing output signals from an inherently non-linear transceiver device during calibration according to claim 19, further comprising a step of saving the system identification coefficients in a memory.