Distortion-compensated amplifier using predistortion technique

• US 20050068102A1
• Filed: 09/23/2004
• Published: 03/31/2005
• Est. Priority Date: 09/25/2003
• Status: Active Grant

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Akaiwa, Yoshihiko, Hongo, Naoki, Miyatani, Tetsuhiko
• Granted Patent: US 7,098,734 B2
• Time in Patent Office: Days
• US Class Current: 330/149
• CPC Class Codes: H03F 1/3258 based on polynomial terms
• CPC Class Codes: H03F 2201/3224 Predistortion being done for compensating memory effects

Abstract

A memory effect distortion component compensating unit compensates for a distortion component caused by the memory effect of the amplifier by using a time difference of results from raising an input signal to even power. For example, the amplifier may include a memory effect distortion component compensating unit having an even power raising means for raising an input signal to even power, an even power raising result delaying unit for delaying a signal of a result of even power raising, an even power raising result time difference detecting unit for detecting a difference between a signal of an even power raising result and a delayed signal, an input signal multiplying unit for multiplying a signal of a detection result by an input signal, a distortion compensation coefficient multiplying unit for multiplying a signal of a multiplication result by a distortion compensation coefficient, and a distortion compensation coefficient multiplication result adding unit for adding an input signal and a signal of a multiplication result.

Claims

1. A distortion-compensated amplifier using predistortion technique for compensating for distortion occurring in an amplifier for amplifying input signals by a predistortion technique, the amplifier comprising:

memory effect distortion component compensating means for compensating for a distortion component caused by the memory effect of the amplifier by using a time difference of results from raising an input signal to even power.

2. A distortion-compensated amplifier using predistortion technique according to claim 1, the memory effect distortion component compensating means having:

even power raising means for raising an input signal to even power;

even power raising result delaying means for delaying a signal of a result of even power raising by the even power raising means;

even power raising result time difference detecting means for detecting a difference between a signal of an even power raising result by the even power raising means and a delayed signal by the even power raising result delaying means;

input signal multiplying means for multiplying a signal of a detection result by the even power raising result time difference detecting means by an input signal;

distortion compensation coefficient multiplying means for multiplying a signal of a multiplication result by the input signal multiplying means by a distortion compensation coefficient; and

distortion compensation coefficient multiplication result adding means for adding an input signal and a signal of a multiplication result by the distortion compensation coefficient multiplying means.

3. A distortion-compensated amplifier using predistortion technique according to claim 1, the amplifier further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinear characteristic of an AM-AM characteristic and AM-PM characteristic of the amplifier,

the nonlinear distortion component compensating means having;

even power raising means for raising an input signal to even power;

even power raising result multiplying means for multiplying a signal of a result of even power raising by the even power raising means by an input signal;

distortion compensation coefficient multiplying means for multiplying a signal of a multiplication result by the even power raising result multiplying means by a distortion compensation coefficient; and

distortion compensation coefficient multiplication result adding means for adding an input signal and a signal of a multiplication result by the distortion compensation coefficient multiplying means.

4. A distortion-compensated amplifier using predistortion technique according to claim 1, the amplifier further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinearity of an AM-AM characteristic and AM-PM characteristic of the amplifier,

the nonlinear distortion component compensating means having;

envelop detecting means for detecting envelop voltage or envelope power of an input signal;

envelop-to-distortion-compensation-coefficient correspondence storage means for storing a correspondence between envelop voltage or envelop power and a distortion compensation coefficient; and

input signal distortion compensation coefficient multiplying means for multiplying a distortion compensation coefficient corresponding to a value detected by the envelope detecting means based on data stored in the envelope-to-distortion-compensation-coefficient corresponding storage means by an input signal.

5. A distortion-compensated amplifier using predistortion technique according to claim 1, the amplifier further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinearity of an AM-AM characteristic and AM-PM characteristic of the amplifier,

the nonlinear distortion component compensating means having;

envelop detecting means for detecting envelop voltage or envelope power of an input signal;

envelop-to-control-value correspondence storage means for storing a correspondence between envelop voltage or envelop power and a control value; and

input signal changing means for changing an input signal in accordance with a control value corresponding to a value detected by the envelope detecting means based on data stored in the envelope-to-control-value correspondence storage means.

6. A distortion-compensated amplifier using predistortion technique according to claim 1, the memory effect distortion component compensating means having:

even power raising means for raising an input signal to even power;

even power raising result delaying means for delaying a signal of a result of even power raising by the even power raising means;

even power raising result time difference detecting means for detecting a difference between a signal of an even power raising result by the even power raising means and a delayed signal by the even power raising result delaying means;

even-power-raising-result-time-difference-to-control-value correspondence storage means for storing a correspondence between a value detected by the even power raising result time difference detecting means and a control value; and

input signal changing means for changing an input signal in accordance with a control value corresponding to a value detected by the even power result time difference detecting means based on data stored in the even-power-raising-result-time-difference-to-control-value correspondence storage means.

7. A distortion-compensated amplifier using predistortion technique according to claim 6,

wherein the input signal changing means is multiplying means for multiplying a control signal by an input signal.

8. A distortion-compensated amplifier using predistortion technique according to claim 6,

wherein the input signal changing means is input signal amplitude/phase changing means for changing one or both of an amplitude and phase of an input signal based on a control value.

9. A distortion-compensated amplifier using predistortion technique according to claim 3, the amplifier further comprising:

a control portion for performing feedback processing and processing based on a level of an input signal in relation to distortion compensating processing by the nonlinear distortion component compensating means and distortion compensating processing by the memory effect distortion component compensating means.

10. A distortion-compensated amplifier using predistortion technique according to claim 4, the amplifier further comprising:

a control portion for performing feedback processing and processing based on a level of an input signal in relation to distortion compensating processing by the nonlinear distortion component compensating means and distortion compensating processing by the memory effect distortion component compensating means.

11. A distortion-compensated amplifier using predistortion technique according to claim 5, the amplifier further comprising:

a control portion for performing feedback processing and processing based on a level of an input signal in relation to distortion compensating processing by the nonlinear distortion component compensating means and distortion compensating processing by the memory effect distortion component compensating means.

12. A distortion-compensated amplifier using predistortion technique according to claim 3, the amplifier further comprising:

a control portion for performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means, and alternately and repeatedly performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means.

13. A distortion-compensated amplifier using predistortion technique according to claim 4, the amplifier further comprising:

a control portion for performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means, and alternately and repeatedly performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means.

14. A distortion-compensated amplifier using predistortion technique according to claim 5, the amplifier further comprising:

a control portion for performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means, and alternately and repeatedly performing processing of updating and converging parameters of distortion compensating processing by the nonlinear distortion component compensating means and updating and converging parameters of distortion compensating processing by the memory effect distortion component compensating means.

15. A base station apparatus including a distortion-compensated amplifier using predistortion technique for compensating for distortion occurring in an amplifier for amplifying input signals by a predistortion technique, the distortion-compensated amplifier using predistortion technique comprising:

memory effect distortion component compensating means for compensating for a distortion component caused by the memory effect of the amplifier by using a time difference of results from raising an input signal to even power.

16. A base station apparatus according to claim 15, wherein the distortion-compensated amplifier using predistortion technique comprises the memory effect distortion component compensating means having:

even power raising means for raising an input signal to even power;

even power raising result delaying means for delaying a signal of a result of even power raising by the even power raising means;

even power raising result time difference detecting means for detecting a difference between a signal of an even power raising result by the even power raising means and a delayed signal by the even power raising result delaying means;

input signal multiplying means for multiplying a signal of a detection result by the even power raising result time difference detecting means by an input signal;

distortion compensation coefficient multiplying means for multiplying a signal of a multiplication result by the input signal multiplying means by a distortion compensation coefficient; and

distortion compensation coefficient multiplication result adding means for adding an input signal and a signal of a multiplication result by the distortion compensation coefficient multiplying means.

17. A base station apparatus according to claim 15, the distortion-compensated amplifier using predistortion technique further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinearity of an AM-AM characteristic and AM-PM characteristic of the amplifier,

wherein the nonlinear distortion component compensating means in the distortion-compensated amplifier using predistortion technique has

even power raising means for raising an input signal to even power;

even power raising result multiplying means for multiplying a signal of a result of even power raising by the even power raising means by an input signal;

distortion compensation coefficient multiplying means for multiplying a signal of a multiplication result by the even power raising result multiplying means by a distortion compensation coefficient; and

distortion compensation coefficient multiplication result adding means for adding an input signal and a signal of a multiplication result by the distortion compensation coefficient multiplying means.

18. A base station apparatus according to claim 15, the distortion-compensated amplifier using predistortion technique further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinearity of an AM-AM characteristic and AM-PM characteristic of the amplifier,

wherein the nonlinear distortion component compensating means in the distortion-compensated amplifier using predistortion technique has;

envelop detecting means for detecting envelop voltage or envelope power of an input signal;

envelop-to-distortion-compensation-coefficient correspondence storage means for storing a correspondence between envelop voltage or envelop power and a distortion compensation coefficient; and

input signal distortion compensation coefficient multiplying means for multiplying a distortion compensation coefficient corresponding to a value detected by the envelope detecting means based on data stored in the envelope-to-distortion-compensation-coefficient correspondence storage means by an input signal.

19. A base station apparatus according to claim 15, the distortion-compensated amplifier using predistortion technique further comprising:

nonlinear distortion component compensating means for compensating for a distortion component caused by the nonlinearity of an AM-AM characteristic and AM-PM characteristic of the amplifier;

wherein the nonlinear distortion component compensating means in the distortion-compensated amplifier using predistortion technique has;

envelop detecting means for detecting envelop voltage or envelope power of an input signal;

envelop-to-control-value correspondence storage means for storing a correspondence between envelop voltage or envelop power and a control value; and

input signal changing means for changing an input signal in accordance with a control value corresponding to a value detected by the envelope detecting means based on data stored in the envelope-to-control-value correspondence storage means.

20. A transmitter including a distortion-compensated amplifier using predistortion technique for compensating for distortion occurring in an amplifier for amplifying input signals by a predistortion technique, the distortion-compensated amplifier using predistortion technique comprising:

memory effect distortion component compensating means for compensating for a distortion component caused by the memory effect of the amplifier by using a time difference of results from raising an input signal to even power.